Cindy Grimm

Cindy Grimm

Faculty in Robotics

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portfolio

publications

Smooth Iso-Surface Approximation

Published in Implicit Surfaces, 1995

Fitting S-patches to implicit surfaces, We present a method for approximating an isosurface with a smooth parametric representation. From the isosurface we first produce a patch mesh, a description of how many surface patches there are and how they are connected. We then create a smooth surface from the patch mesh. 3D surface modeling and editing,

Authors: Cindy Grimm and John Hughes
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Modeling Surfaces of Arbitrary Topology

Published in Proceedings of the 22nd Annual Conference on Computer Graphics and Interactive Techniques, 1995

The original manifold-style surface modeling paper, We describe an extension of B-splines to surfaces of arbitrary topology, including arbitrary boundaries. The technique inherits many of the properties of B-splines: local control, a compact representation, and guaranteed continuity of arbitrary degree. The surface is specified using a polyhedral control mesh instead of a rectangular one; the resulting surface approximates the polyhedral mesh much as a B-spline approximates its rectangular control mesh. Like a B-spline, the surface is a single, continuous object. This is achieved by modeling the domain of the surface with a manifold whose topology matches that of the polyhedral mesh, then embedding this domain into 3-space using a basis-function/control-point formulation. We provide a constructive approach to building a manifold. 3D surface modeling and editing,

Authors: Cindy Grimm and John Hughes
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Visual Interfaces for Solids Modeling

Published in Proceedings of the 8th Annual ACM Symposium on User Interface and Software Technology , 1995

Widgets for 3D surface editing, This paper explores the use of visual operators for solids modeling. We focus on designing interfaces for free-form operators such as blends, sweeps, and deformations, because these operators have a large number of interacting parameters whose effects are often determined by an underlying parameterization. In this type of interactive modeling good solutions to the design problem have aesthetic as well as engineering components. Traditionally, interaction with the parameters of these operators has been through text editors, curve editors, or trial-and-error with a slider bar. Parametric values have been estimated from data, but not interactively. These parameters are usually one- or two-dimensional, but the operators themselves are intrinsically three-dimensional in that they are used to model surfaces visualized in 3D. The traditional textual style of interaction is tedious and interposes a level of abstraction between the parameters and the resulting surface. A 3D visual interface has the potential to reduce or eliminate these problems by combining parameters and representing them with a higher-level visual tool. The visual tools we present not only speed up the process of determining good parameter values but also provide visual interactions that are either independent of the particular parameterizations or make explicit the effect of the parameterizations. Additionally, these tools can be manipulated in the same 3D space as the surfaces produced by the operators, supporting quick, interactive exploration of the large design space of these free-form operators. This paper discusses the difficulties in creating a coherent user interface for interactive modeling. To this end we present four principles for designing visual operators, using several free-form visual operators as concrete examples. 3D surface editing, computer aided geometric design,

Authors: Cindy Grimm and David Pugmire and John Hughes and Mark Bloomenthal and Elaine Cohen
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A Framework for Synchronized Editing of Multiple Curve Representations

Published in Computer Graphics Forum, 1998

Editing curves and surfaces is difficult in part because their mathematical representations rarely correspond to most people\\s idea of a curve or surface. The implementation (and hence behavior) of most manipulation tools is intertwined with a particular curve or surface representation; this can make reimplementing the tool with a different representation problematic. A system using a single representation must therefore either limit the types of tools available or convert existing tools to work on the system\\s representation. In this paper we present a framework for editing curves or surfaces which supports multiple representations and ensures that they stay synchronized. As a proof of concept, we have created a curve editor which contains several tools each of which manipulate one of three different curve representations: polylines, NURBs, and multi-resolution B-splines.

Authors: Cindy Grimm, Matthew Ayers,
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Implicit Generalized Cylinders using Profile Curves

Published in Implicit Surfaces, 1998

Creating sweep surfaces using sketching, We introduce an implicit generalized cylinder which is constructed from an axis and one or more profile curves. This surface is related to the sweep which is traditionally formed by an axis curve and one or more cross sections. Instead of cross sections, this definition uses profile curves to define how far the surface is from the axis. This facilitates the construction of surfaces which have continually varying cross sections. We extend this definition to a generalized cylinder with two axis curves. This model is useful for surfaces where one side of the surface curves sharply away from the axis while the axis itself is curving. We also present a user interface for editing these sweeps. 3D surface modeling and editing,

Authors: Cindy Grimm and John Hughes
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Making Faces

Published in Proceedings of the 25th Annual Conference on Computer Graphics and Interactive Techniques, 1998

We have created a system for capturing both the three-dimensionalgeometry and color and shading information for human facial expressions. We use this data to reconstruct photorealistic, 3D animations of the captured expressions. The system uses a large setof sampling points on the face to accurately track the three dimensional deformations of the face. Simultaneously with the trackingof the geometric data, we capture multiple high resolution, registered video images of the face. These images are used to create atexture map sequence for a three dimensional polygonal face modelwhich can then be rendered on standard 3D graphics hardware. Theresulting facial animation is surprisingly life-like and looks verymuch like the original live performance. Separating the capture ofthe geometry from the texture images eliminates much of the variance in the image data due to motion, which increases compressionratios. Although the primary emphasis of our work is not compression we have investigated the use of a novel method to compressthe geometric data based on principal components analysis. Thetexture sequence is compressed using an MPEG4 video codec. Animations reconstructed from 512x512 pixel textures look good atdata rates as low as 240 Kbits per second. Facial animation, facial traction,

Authors: Brian Guenter and Cindy Grimm and Daniel Wood and Henrique Malvar and Frederic Pighin
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Post-rendering Composition for 3D Scenes

Published in Eurographics short papers, 2001

Objects have their own cameras and lighting effects, In traditional art a painter displays a 3D scene on a 2D image plane in a manner that is aesthetically pleasing. The arrangement of objects and colors is called composition and is the subject of many art books and classes. While a painter may use perspective to create depth in a scene they may also alter the perspective and color, either subtly or dramatically, to influence the focus of viewer and the effect of the image. To date, traditional 3D graphics packages have largely concentrated on modeling, textures, and lighting to create images and provide few tools for altering the composition post-rendering. In this paper we present several simple techniques for creating images with non-standard perspective and color using standard 3D rendering packages. The scene is modeled in 3D but each object has its own camera, color balance, and image size, allowing the user to alter the composition after the 3D rendering step. The purpose of this paper is not to present a complete composition system but rather to illustrate the potential of composition-based tools. composition, lighting, non-linear projection,

Authors: Cindy Grimm
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Published in , 1900

Simple Manifolds for Surface Modeling and Parameterization

Published in Shape Modeling International (SMI 2002), 2002

Spherical, toroidal, and cylindrical manifolds, We present a surface modeling technique using manifolds. Our approach uses a single, simple parameterization for all surfaces of a given genus. This differs from previous approaches which build a parameterization based on the elements of a mesh. The simple parameterization is more appropriate for applications that do complex operations in parameter space or on the mesh surface. We define a manifold and a corresponding embedding function for three genera (plane, sphere, and torus). The manifold can be used simply as a parameterization tool or as a smooth surface approximating the original mesh. We demonstrate how to build a correspondence between the mesh and the manifold, then how to build an embedding that approximates the mesh. Surface modeling, parameterization,

Authors: Cindy Grimm
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Contact Areas and Ligament Lengths are Abnormal in Patients with Malunited Distal Radius Fracture Despite Normal Radioulnar Kinematics

Published in World Congress Biomechanics, 2002

First draft of the IEEE paper. Altered kinematics of the distal radioulnar joint (DRUJ) and/or bone impingement are considered causes of long-term complications associated with malunited distal radius fractures. However, a CT image-based in vivo study of patients with malunited distal radius fractures found that malunion did not alter forearm kinematics and that limitations of pronosupination were not caused by bony impingement (Moore et al. . In this study, data from the previous study was reanalyzed to explore focal changes in the articulation at the DRUJ (location and area of bone contact) and potential soft tissue constraints (\\length\\ of the dorsal and palmar radioulnar ligaments). ,

Authors: G. Elisabeta Marai and David H. Laidlaw and Cagatay Demiralp and Cindy Grimm and Joseph J. Crisco and Douglas Moore and E. Akelman
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(Not) Interacting with a Robotic Photographer

Published in AAAI Spring Symposium, 2003

Interaction observations with Lewis the robot photographer, We have deployed a robot ``photographer\\\ at several events. The robot, Lewis, navigates through the space, opportunistically taking photographs of people. We summarize the different types of human-robot interactions we have observed at these events, and put forth some possible explanations for the different behaviors. We also discuss potential models for human-robot interactions in this constrained setting. Human-computer interaction, robotics, path planning.

Authors: William Smart and Cindy Grimm
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A Thesis on a 3D Input Device for Sketching Characters

Published in Washington University in St. Louis, 2003

Tracking a piece of paper as a drawing surface., The goal of this project is to develop a 3D input device using a stiff piece ofpaper and a camera. The camera tracks the piece of paper in 3D space. The userorients the paper in 3D space and then draws on the paper using a pen-like device. The camera tracks the movement of the pen on the piece of paper. The location of the pen in 3D space can then be calculated from the orientation of the paper.A drawing application that uses this 3D input device was also developed. Theapplication allows a user to make characters by sketching ellipses. The drawing application creates a virtual rendering of the paper and displays this to the user. As the user positions the real paper, the virtual one mirrors its movements. The user can draw shapes on the paper. These shapes then get rendered in the virtual scene., Tracking, 3D drawing , https://openscholarship.wustl.edu/cse_research/1068/,

Authors: Mark Schroering
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A 3D Pattern for Pose Estimation for Object Capture

Published in Vision Interface, 2003

A 3D camera calibration pattern, We describe a new pose estimation approach for a 3D object capture system. This 3D pose estimation approach offers several advantages: increased visibility, robustness to lighting conditions, and improved reliability with evenly distributed errors. The calibration pattern is built using 3D conic features. We use simplex search to find the camera position and orientations that minimizes the error between the projected 3D cone features and the corresponding 2D image features. We demonstrate that our approach is accurate, efficient and robust. Camera tracking, sketching, 3D input device,

Authors: Lei Wang and Cindy Grimm and Robert Pless
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A New Input Device for 3D Sketching

Published in Vision Interface, 2003

A novel sketch device using a piece of paper and a camera. We present a 3D input device consisting of a stiff piece of paper which is tracked by a digital video camera. The user can also draw on the paper using a pen-like device. The user moves the paper to specify the location of a virtual plane. By drawing on the paper, the user can specify points in 3D space. The primary technical contribution of this paper is a new pose estimation algorithm suitable for a hand-held, moving pattern. To demonstrate the usefulness of the device we developed a sketching application for simple characters. The characters are constructed by sketching and joining together 3D ellipses, much as traditional cartoon characters are created in 2D using 2D ellipses. Camera tracking, sketching, 3D input device,

Authors: Mark Schroering and Cindy Grimm and Robert Pless
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Say Cheese!: Experiences with a Robot Photographer

Published in Proceedings of the Fifteenth Conference on Innovative Applications of Artificial Intelligence, 2003

The basic Lewis system. We have developed an autonomous robot system that takes well-composed photographs of people at social events, such as weddings and conference receptions. The robot, Lewis, navigates through the environment, opportunistically taking photographs of people. In this paper, we outline the overall architecture of the system and describe how the various components inter-relate. We also describe our experiences of deploying the robot photographer at a number of real-world events. Robots, robot photography,

Authors: Zachary Byers and Michael Dixon and Cindy Grimm and William Smart
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Techniques for Non-photorealistic Shading using Real Paint

Published in Washington University in St. Louis, 2003

Non-photorealistic techniques combining shading with texture. Published in Pacific Graphics, 2003, The goal of this research is to explore techniques for shading 3D computer generated models using scanned images of actual paint samples. The techniques presented emphasize artistic control of brush stroke texture and color. We first demonstrate how the texture of a paint sample can be separated from its color transition. Four methods, three real-time and one off-line, for producing rendered images from the paint samples are then presented. Finally, we develop metrics for evaluating how welleach method achieves our goal in terms of texture similarity, shading correctness, and temporal coherence., 3D painting, texture synthesis, shading, https://openscholarship.wustl.edu/cse_research/1108/

Authors: Reynold Bailey
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Parameterizing N-holed Tori

Published in Mathematics of Surfaces, 2003

Using hyperbolic geometry to parameterize n-holed objects. We define a parameterization for an n-holed tori based on the hyperbolic polygon. We model the domain using a manifold with 2n+2 charts, and linear fractional transformations for transition functions. We embed the manifold using standard spline techniques to produce a surface. parameterization, hyperbolic geometry, n-holed tori,

Authors: Cindy Grimm and John Hughes
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An Autonomous Robot Photographer

Published in Proceedings 2003 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2003), 2003

The internals of the robot photographer system, We describe a complete, end-to-end system for taking well-composed photographs using a mobile robot. The general scenario is a reception, or other event, where people are roaming around talking to each other. The robot serves as an ``event photographer\\\, roaming around the same space as the participants, periodically taking photographs. These images are then sent to a workstation where participants can print the photographs out, or email them. Robot systems, navigation, photographer,

Authors: Zachary Byers and Michael Dixon and Kevin Goodier and William Smart and Cindy Grimm
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Using Texture Synthesis for Non-Photorealistic Shading from Paint Samples

Published in 11th Pacific Conference on Computer Graphics and Applications (Pacific Graphics), 2003

Shading using texture, This paper presents several methods for shading meshes from scanned paint samples that represent dark to light transitions. Our techniques emphasize artistic control of brush stroke texture and color. We first demonstrate how the texture of the paint sample can be separated from its color gradient. We demonstrate three methods, two real-time and one off-line for producing rendered, shaded images from the texture samples. All three techniques use texture synthesis to generate additional paint samples. Finally, we develop metrics for evaluating how well each method achieves our goal in terms of texture similarity, shading correctness and temporal coherence. Texture synthesis, non-photorealistic rendering,

Authors: Christopher Kulla and James Tucek and Reynold Bailey and Cindy Grimm
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The IBar: A Perspective-based Camera Widget

Published in Proceedings of the 17th annual ACM symposium on User interface software and technology, 2004

The first draft of the IBar. <a href=\"./IBar\">Source code</a> and more implementation details. We present a new screen space widget, the IBar, for effective camera control in 3D graphics environments. The IBar provides a compelling interface for controlling scene perspective based on the artistic concept of vanishing points. Various handles on the widget manipulate multiple camera parameters simultaneously to create a single perceived projection change. For example, changing just the perspective distortion is accomplished by simultaneously decreasing the camera\\s distance to the scene while increasing focal length. We demonstrate that the IBar is easier to learn for novice users and improves their understanding of camera perspective. Camera control,

Authors: Karan Singh and Cindy Grimm and Nisha Sudarsanam
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Non-Photorealistic Rendering of Algorithmically Generated Trees

Published in Washington University in St. Louis, 2005

Combining abstraction and realisim for rendering trees. Published in <a href=\"http://grapp.visigrapp.org/GRAPP2007/\">GRAPP</a>, 2007, This work presents a novel rendering technique inspired by artistic approaches.Instead of trying to recreate the appearance of a traditional medium, such as charcoal or watercolor, this approach is a mixture of both photo-realism and abstraction.Artists use a process of abstraction to provide structural information about subjects that do not have clearly defined shapes, such as groups of leaves in a tree. For example, an artist will first use a color wash to approximate a group of leaves, then add detail on top of parts of this wash to indicate individual leaves. Similarly, weuse an abstract shape that approximates the image of leaves clustered at the end of a branch. To prevent oversimplification, we add photo-realistic detail using a blendingprocess. Inter-frame coherence is achieved by smoothly interpolating the abstract shapes as well as by the continuity inherent in the photo-realistically rendered detail., Non-photorealistic rendering, abstraction

Authors: Nathan Dudley
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What a Mesh: Dependent Data Types for Correct Mesh Manipulation Algorithms

Published in Washington University in St. Louis, 2005

Programming language approach to representing meshes, The Edinburgh Logical Framework (LF) has been proposed as a system forexpressing inductively defined sets. I will present an inductive definition of the set of manifold meshes in LF. This definition takes into account the topological characterizationof meshes, namely their Euler Characteristic.I will then present a set of dependent data types based on this inductive definition.These data types are defined in a programming language based on LF. Thelanguage’s type checking guarantees that any typeable expression represents a correctmanifold mesh. Furthermore, any mesh can be represented using these data types.Hence, the encoding is sound and complete., Meshes, formal language theory, proofs, https://openscholarship.wustl.edu/cse_research/932/, 52,

Authors: Joel Brandt
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Table-top Computed Lighting for Practical Digital Photography

Published in Eurographics Symposium on Rendering, 2005

Specifying lighting of real-world objects using a sketching approach. We apply simplified image-based lighting methods to reduce the equipment, cost, time, and specialized skills required for high-quality photographic lighting of desktop-sized static objects such as museum artifacts. We place the object and a computer-steered moving-head spotlight inside a simple foam-core enclosure, and use a camera to quickly record low-resolution photos as the light scans the box interior. Optimization guided by interactive user sketching selects a small set of frames whose weighted sum best matches the target image. The system then repeats the lighting used in each of these frames, and constructs a high resolution result from re-photographed basis images. Unlike previous image-based re-lighting efforts, our method requires only one light source, yet can achieve high resolution light positioning to avoid multiple sharp shadows. A reduced version uses only a hand-held light, and may be suitable for battery-powered, field photography equipment that fits into a backpack. lighting,

Authors: Ankit Mohan and Jack Tumblin and Bobby Bodenheimer and Cindy Grimm and Reynold Bailey
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Curvature Maps for Local Shape Comparison

Published in International Conference on Shape Modeling and Applications 2005 (SMI\ 05), 2005

A local shape comparison technique for meshes, The ability to identify similarities between shapes is important for applications such as medical diagnosis, object registration and alignment, and shape retrieval. In this paper we present a method, the Curvature Map, that uses surface curvature properties in a region around a point to create a unique signature for that point. These signatures can then be compared to determine the similarity of one point to another. To gather curvature information around a point we explore two techniques, rings (which use the local topology of the mesh) and Geodesic Fans (which trace geodesics along the mesh from the point). We explore a variety of comparison functions and provide experimental evidence for which ones provide the best discriminatory power. We show that Curvature Maps are both more robust and provide better discrimination than simply comparing the curvature at individual points. Curvature, feature point, differential geometry, curve fitting, curvature map, local shape comparison, surface curvature property, geodesic fans, Histograms,

Authors: Timothy Gatzke and Steve Zelinka and Cindy Grimm and Michael Garland
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Interactive Manipulation of Projections with a Curved Perspective

Published in EG Short Presentations, 2005

A specific type of non-linear projection that takes vanishing lines to sinusoids. The concept of ``curved perspective\\\ has been used by artists such as M.C. Escher in order effectively convey a sense of three dimensional space while being restricted to a two dimensional canvas. We present an interactive system to create and manipulate projections with a curvilinear perspective. Our system presents the user with a set of intuitive screen-space perspective primitives that control the vanishing points of the scene. This allows the user to generate diverse projections having curved perspective. non-linear projection,

Authors: Nisha Sudarsanam and Cindy Grimm and Karan Singh
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Spherical Manifolds for Adaptive Resolution Surface Modeling

Published in Proceedings of the 3rd International Conference on Computer Graphics and Interactive Techniques in Australasia and South East Asia, 2005

Spherical shape modeling using a hierarchical approach. \\"Any patch any where\\". We present a surface modeling technique that supports adaptive resolution and hierarchical editing for surfaces of spherical topology. The resulting surface is analytic, Ck, and has a continuous local parameterization defined at every point. To manipulate these surfaces we describe a user-interface based on multiple, overlapping subdivision-style meshes. arbitrary topology, hierarchical, hypberbolic geometry, parameterization, splines, surface modeling,

Authors: Cindy Grimm
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3D Screen-space Widgets for Non-linear Projection

Published in Proceedings of the 3rd International Conference on Computer Graphics and Interactive Techniques in Australasia and South East Asia , 2005

This paper lets the user specify multiple cameras using screen-space widgets. Linear perspective is a good approximation to the format in which the human visual system conveys 3D scene information to the brain. Artists expressing 3D scenes, however, create nonlinear projections that balance their linear perspective view of a scene with elements of aesthetic style, layout and relative importance of scene objects. Manipulating the many parameters of a linear perspective camera to achieve a desired view is not easy. Controlling and combining multiple such cameras to specify a nonlinear projection is an even more cumbersome task. This paper presents a direct interface, where an artist manipulates in 2D the desired projection of a few features of the 3D scene. The features represent a rich set of constraints which define the overall projection of the 3D scene. Desirable properties of local linear perspective and global scene coherence drive a heuristic algorithm that attempts to interactively satisfy the given constraints as a weight-averaged projection of a minimal set of linear perspective cameras. This paper shows that 2D feature constraints are a direct and effective approach to control both the 2D layout of scene objects and the conceptually complex, high dimensional parameter space of nonlinear scene projection. Non-linear projection, image-space camera control,

Authors: Leon Barrett and Patrick Coleman and Nisha Sudarsanam and Karan Singh and Cindy Grimm
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A View-Based Deformation Tool-kit

Published in Washington Universtiy in St. Louis, 2006

CubeCam for single camera control and a framework for non-linear projection. CubeCam was published in Computational Aesthetics, 2009, the curved perspective in Eurographics short papers 2005, and the non-linear perspective rendering in NPAR 2008., Camera manipulation is a hard problem since a graphics camera is defined by specifying 11 independent parameters. Manipulating such a high-dimensional space to accomplish specific tasks is difficult and requires a certain amount of expertise. We present an intuitive interface that allows novice users to perform camera operations in terms of the change they want see in the image. In addition to developing a naturalmeans for camera interaction, our system also includes a novel interface for viewing and organizing previously saved views. When exploring complex 3D data-sets a single view is not sufficient. Instead, a composite view built from multiple views may be more useful. While changing a single camera is hard enough, manipulating several cameras in a single scene is still harder. In this thesis, we also present a framework for creating composite views and an interface that allows users to manipulate such views in real-time., Camera control and non-linear perspective, https://openscholarship.wustl.edu/cse_research/196/,

Authors: Nisha Sudarsanam

The Real Effect of Warm-Cool Colors on Depth Ordering

Published in Proceedings of the 3rd Symposium on Applied Perception in Graphics and Visualization, 2006

The relationship between color and perceived depth for realistic, colored objects with varying shading was explored. Background: Studies have shown that warm-colored stimuli tend to appear nearer in depth than cool-colored stimuli. The majority of these studies asked human observers to view physically equidistant, colored stimuli and compare them for relative depth. However, in most cases, the stimuli presented were rather simple: straight colored lines, uniform color patches, point light sources, or symmetrical objects with uniform shading. Additionally, the colors were typically highly saturated. Although such stimuli are useful for isolating and studying depth cues in certain contexts, they leave open the question of whether the human visual system operates similarly for realistic objects. Method: Participants were presented with all possible pairs from a set of differently colored objects and were asked to select the object in each pair that appears closest to them. The objects were presented on a standard computer screen, against 4 different uniform backgrounds of varying intensity. Results: Our results show that the relative strength of color as a depth cue increases when the colored stimuli are presented against darker backgrounds and decreases when presented against lighter backgrounds. Conclusion: Color does impact our depth perception even though it is a relatively weak indicator and is not necessarily the overriding depth cue for complex, realistic objects. Application: Our observations can be used to guide the selection of color to enhance the perceived depth of objects presented on traditional display devices and newer immersive virtual environments. Warm cool colors, depth,

Authors: Reynold Bailey and Cindy Grimm and Christopher Davoli
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The Effect of Warm and Cool Object Colors on Depth Ordering

Published in Symposium on Applied Perception in Graphics and Visualization, 2006

A study on the effect of color on depth. A longer version can be found <a href=\"https://openscholarship.wustl.edu/cse_research/166/\">here</a>. Colors that appear closer to the red end of the visible spectrum are said to be warm while the colors that appear closer to the blue end are said to be cool. The phenomenon of warmer colors appearing nearer in depth to viewers than cooler colors has been studied extensively by psychologists and other vision researchers (see [Sundet 1978] for a summary). The vast majority of these studies have asked human observers to view physically equidistant, colored stimuli and compare them for relative depth. However, in most cases, the stimuli presented were rather simple: straight colored lines, uniformcolor patches, point light sources, or symmetrical objects with uniformshading. Additionally, the colors used were typically highly saturated. Although such stimuli are useful in isolating and studying depth cues in certain contexts, they leave open the question of whether the human visual system operates similarly for realistic objects.This paper presents the results of an experiment designed to explore the color-depth relationship for realistic, colored objects with varying shading and contours. Warm cool, depth,

Authors: Reynold Bailey and Cindy Grimm and Christopher Davoli
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Feature Detection Using Curvature Maps and the Min-Cut/Max-Flow Algorithm

Published in Geometric Modeling and processing, 2006

Feature detection. A longer version can be found <a href=\"http://www.cse.seas.wustl.edu/techreportfiles/getreport.asp?510\">here</a>. Automatic detection of features in three-dimensional objects is a criticalpart of shape matching tasks such as object registration and recognition. Previousapproaches often required some type of user interaction to select features.Manual selection of corresponding features and subjective determination of thedifference between objects are time consuming processes requiring a high levelof expertise. The Curvature Map represents shape information for a point and itssurrounding region and is robust with respect to grid resolution and mesh regularity.It can be used as a measure of local surface similarity.We use these curvaturemap properties to extract feature regions of an object. To make the selection of thefeature region less subjective, we employ a min-cut/max-flow graph cut algorithmwith vertex weights derived from the curvature map property. A multi-scale approachis used to minimize the dependence on user defined parameters. We showthat by combining curvature maps and graph cuts in a multi-scale framework, wecan extract meaningful features in a robust way. Feature detection, min-cut max-flow,

Authors: Timothy Gatzke and Cindy Grimm
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Sketching Reaction-Diffusion Texture

Published in Proceedings of the Third Eurographics Conference on Sketch-Based Interfaces and Modeling, 2006

Using machine learning to make reaction-diffusion usable. In this work, we present an interactive interface for sketching synthesized textures. Reaction-Diffusion (RD) is used as the basis for texture synthesis. RD allows an unlimited amount of non-repeating texture and offers great flexibility for mapping textures to arbitrary surfaces. However, it can be difficult to find starting values of parameters that will produce interesting patterns. We use machine learning to resolve the difficulty of determining appropriate initial values of the RD system. The system described here allows a user to sketch a pattern of spots or stripes with arbitrary orientations, and then automatically generates a pattern with the same attributes as the sketch. It also allows the user to interactively create more complex textures by adding another layer of pattern, as well as manipulate the color of the resulting texture. We also show that this procedure can be applied to realistic 3D surfaces. Creating Reaction Diffusion, textures, sketching,

Authors: Ly Phan and Cindy Grimm
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Non-Photorealistic Rendering of Algorithmically Generated Trees

Published in Proceedings of the Second International Conference on Computer Graphics Theory and Applications , 2007

Nathan\s master\s thesis. This paper presents a novel rendering technique inspired by artistic approaches. Instead of trying to recreate a traditional medium, such as charcoal or watercolor, this approach is a mixture of both photo-realism and abstraction. Artists use a process of abstraction to provide structural information about subjects that do not have clearly defined shapes, such as groups of leaves in a tree. For example, an artist will use a color wash to first approximate a group of leaves. They then add detail on top of parts of this wash to indicate the presence of individual leaves. Similarly, we use an abstract shape that approximates the image of leaves clustered at the end of a branch. To prevent oversimplification, we add photo-realistic detail using a blending process. Interframe coherence is achieved both by smoothly interpolating the abstract shapes, and the continuity inherent inthe photo-realistically rendered detail. Non-photorealistic rendering, abstractionism, tree rendering,

Authors: Nathan Dudley and Cindy Grimm
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Painting Lighting and Viewing Effects

Published in 2nd International Conference on Computer Graphics Theory and Applications, 2007

Combines the previous several tech reports and poster presentation at Graphics Interface 2003 into one paper. We present a system for painting how the appearance of an object changes under different lighting and viewingconditions. The user paints what the object should look like under different lighting conditions (dark, partiallydark, fully lit, etc.), or different viewing angles, or both. The system renders the object under new lightingconditions and a new viewing angle by combining these paintings. For surfaces without a pre-defined texturemap the system can construct texture maps directly from the user’s paintings. Texture mapping, view-dependent painting,

Authors: Cindy Grimm and Michael Kowalski
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A Fingerspelling Sign Language Visualization

Published in Washington University in St. Louis, 2007

The goal of the Fingerspell Visualization Project is to research methods to improve learning of reading skills through sign language. The techniques are centered on Fingerspelling as the method to bridge stages of skill development. Visualization of a string of text in images of a hand performing the letters of the alphabet in standardized fingerspell sign language positions provide Full Motion Learning as opposed to learning from single pictures., https://openscholarship.wustl.edu/cse_research/140/,

Authors: Carol Brickman
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Perception Guided Image Manipulation

Published in Washington University in St. Louis, 2007

Published in APGV (study on depth ordering), TAP and TOG (subtle gaze direction), and the Visual Computer (motion and depth ordering of content in images), This dissertation presents a novel approach to image editing and manipulation where the goal is to explicitly trigger certain visual cues. We refer to this as perceptually meaningful image manipulation. Existing image editing approaches typically do not take human visual perception into account, whereas our approach relies heavily on the principles of human visual perception. We present computer-based techniques for simulating artistic control of apparent depth in an image, conveying a sense of motion in an image, and subtly directing a viewer\s gaze about an image. Our techniques combine elements of traditional art with research from various fields of science. Our image-based technique for simulating artistic control of apparent depth works by automatically adjusting color or luminance in specific regions of an image. The color and luminance adjustment is based on several simple rules that artists use to convey and manipulate apparent depth in their work. Our technique for conveying a sense of motion in a visually static image introduces spatial imprecision in the image plane. This is also patterned after work done by traditional artists. It has been suggested that spatially imprecise stimuli are processed differently by our foveal vision and our peripheral vision and that this difference in visual processing causes the image to appear to have a dynamic component. Finally, our subtle gaze directing technique exploits differences in visual acuity and processing speed between our foveal and peripheral vision. We present brief, subtle image-space modulations to the low acuity peripheral regions of the ?eld of view. These stimuli, which are detected quickly, attract the slower, high acuity foveal vision to fixate on the modulated regions.

Authors: Reynold Bailey
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Improving Search Task Performance using Subtle Gaze Direction

Published in Proceedings of the 5th Symposium on Applied Perception in Graphics and Visualization, 2008

A new experiment is presented which demonstrates the usefulness of an image space modulation technique called Subtle Gaze Direction (SGD) for guiding the user in a simple searching task. SGD uses image space modulations in the luminance channel to guide a viewer\s gaze about a scene without interrupting their visual experience. The goal of SGD is to direct a viewer\s gaze to certain regions of a scene without introducing noticeable changes in the image. Using a simple searching task we compared performance using no modulation, using subtle modulation and using obvious modulation. Results from the experiments show improved performance when using subtle gaze direction, without affecting the user\s perception of the image. Results establish the potential of the method for a wide range of applications including gaming, perceptually based rendering, navigation in virtual environments and medical search tasks. eye-tracking, gaze direction, luminance, psychophysics,

Authors: Reynold Bailey and Ann McNamara and Cindy Grimm
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Non-linear Perspective Widgets for Creating Multiple-View Images

Published in Proceedings of the 6th International Symposium on Non-photorealistic Animation and Rendering, 2008

This is the paper version of the tech report. The full details can be found in Nisha\s thesis. Viewing data sampled on complicated geometry, such as a helix or atorus, is hard because a single camera view can only encompass a partof the object. Either multiple views or non-linear projection can beused to expose more of the object in a single view, however, specifying such views is challenging because of the large number ofparameters involved. We show that a small set of versatile widgetscan be used to quickly and simply specify a wide variety of suchviews. These widgets are built on top of a general framework that inturn encapsulates a variety of complicated camera placement issuesinto a more natural set of parameters, making the specification of newwidgets, or combining multiple widgets, simpler. This framework isentirely view-based and leaves intact the underlying geometry of thedataset, making it applicable to a wide range of data types. Non-linear perspective, user interfaces, visualization, camera control, rendering,

Authors: Nisha Sudarsanam and Karan Singh and Cindy Grimm
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CubeCam: A Screen-Space Camera Manipulation Tool

Published in Proceedings of the Fifth Eurographics Conference on Computational Aesthetics in Graphics, Visualization and Imaging, 2009

A full version of the siggraph 2005 poster, Diffuse reflection, specular reflection, lighting paintings,

Authors: Nisha Sudarsanam and Cindy Grimm and Karan Singh
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Adding Lighting and Viewing Effects to Digital Images

Published in Proceedings of the Fifth Eurographics Conference on Computational Aesthetics in Graphics, Visualization and Imaging, 2009

Real paintings are not truly flat but change subtly with variations in viewing direction. The pigments and painting layers also interact with the lighting environment, producing changes that range from subtle to quite dramatic. These effects are lacking in digital images. This paper describes a system that allows an artist to introduce, and control, a variety of lighting and viewing effects, such as specular reflection and refraction, through the use of additional images. Diffuse reflection, specular reflection, lighting paintings,

Authors: Cindy Grimm
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Volume Viewer: an Interactive Tool for Fitting Surfaces to Volume Data

Published in Proceedings of the 6th Eurographics Symposium on Sketch-Based Interfaces and Modeling, 2009

Software available <a href = \"http://volumeviewer.cse.wustl.edu/\">here</a>, Recent advances in surface reconstruction algorithms [BM07, LBD? 08] allow surfaces to be built from contours lying on non-parallel planes. Such algorithms allow users to construct surfaces of similar quality more ef?ciently by using a small set of oblique contours, rather than many parallel contours. However, current medical imaging systems do not provide tools for sketching contours on oblique planes. In this paper, we take the ?rst steps towards bridging the gap between the new surface reconstruction technologies and putting those methods to use in practice. We develop a novel interface for modeling surfaces from volume data by allowing the user to sketch contours on arbitrarily oriented cross-sections of the volume, and we examine the users? ability to contour the same structures using oblique cross-sections with similar consistency as they can using parallel cross-sections. We measure the inter-observer and intra-observer variability of trained physicians contouring on oblique cross-sections of real patient data as compared to the traditional parallel cross-sections, and show that the variation is much higher for oblique contouring. We then show that this variability can be greatly reduced by integrating a collection of training images into the interface. Contouring, user interfaces, user studies, oblique contouring, sketching, segmentation,

Authors: Ross Sowell and Lu Liu and Tao Ju and Cindy Grimm and Christopher Abraham and Garima Gokhroo and Daniel Low
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Editing Level-Set Models with Sketched Curves

Published in Proceedings of the 6th Eurographics Symposium on Sketch-Based Interfaces and Modeling, 2009

Using level sets to evolve surfaces, Level set models are deformable implicit surfaces where the deformation is controlled by a speed function in the level set partial differential equation (PDE). These models are widely used in computer graphics applications due to their implicit de?nition, low-level volumetric representation and the powerful numerical techniques used to produce the PDE-based deformation. We present a set of interactive sketch-based level-set surface editing operators. These operators allow a user to sketch curves above or on a level-set surface in order to edit the surface?s shape. Once the curves are sketched the surface interactively evolves to locally ?t to the curves. A user may then modify the curves in order to re?ne the shape of the model. The mathematics, algorithms and techniques needed to implement numerous sketch-based level set modeling capabilities are described. The speed functions that produce the surface deformations within the context of solving the level-set PDE are detailed. Several examples are presented to demonstrate the ?exibility and usefulness of the editing operators. Sketching, level-sets, surface editing,

Authors: Manolya Eyiyurekli and Cindy Grimm and David Breen
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Polygonizing Extremal Surfaces with Manifold Guarantees

Published in Proceedings of the 14th ACM Symposium on Solid and Physical Modeling, 2010

Moving least squares surfaces for surfaces with boundaries, Extremal surfaces are a class of implicit surfaces that have been found useful in a variety of geometry reconstruction applications. Compared to iso-surfaces, extremal surfaces are particularly challenging to construct in part due to the presence of boundaries and the lack of a consistent orientation. We present a novel, grid-based algorithm for constructing polygonal approximations of extremal surfaces that may be open or unorientable. The algorithm is simple to implement and applicable to both uniform and adaptive grid structures. More importantly, the resulting discrete surface preserves the structural property of the extremal surface in a grid-independent manner. The algorithm is applied to extract ridge surfaces from intensity volumes and reconstruct surfaces from point sets with unoriented normals. Implicit surface, moving least squares, reconstruction from point sets,

Authors: Ruosi Li and Liu Lu and Sasakthi Abeysinghe and Ly Phan and Cindy Grimm and Tao Ju
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Local Shape Descriptors, A Survey and Evaluation

Published in Proceedings of the 4th Eurographics Conference on 3D Object Retrieval, 2011

Sourcecode available at <a ref=\"http://sourceforge.net/projects/meshprocessing/\">Sourceforge</a>, Local shape descriptors can be used for a variety of tasks, from registration to comparison to shape analysis and retrieval. There have been a variety of local shape descriptors developed for these tasks, which have been evaluated in isolation or in pairs, but not against each other. We provide a survey of existing descriptors and a framework for comparing them. We perform a detailed evaluation of the descriptors using real data sets from a variety of sources. We first evaluate how stable these metrics are under changes in mesh resolution, noise, and smoothing. We then analyze the discriminatory ability of the descriptors for the task of shape matching. Our conclusion is that sampling the normal distribution and the mean curvature, using 25 samples, and reducing this data to 5-10 samples via Principal Components Analysis provides robustness to noise and the best shape discrimination results. Local shape descriptors, spin images, heat map, curvature, shape matching, feature matching,

Authors: Paul Heider and Alain Pierre-Pierre and Ruosi Li and Cindy Grimm
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Refining Shape Correspondence for Similar Objects using Strain

Published in Proceedings of the 4th Eurographics Conference on 3D Object Retrieval, 2011

An iterative implicit, matrix solve of Andy\s journal of biomedical engineering paper, We propose the adaptation of mechanical strain to the problem of measuring similarity between non-rigid shapes and constructing shape correspondence. In the mechanics literature, strain is a well-established technique for studying how a body deforms. The traditional de?nition applies to an n-D material embedded in n-D. In this paper, we demonstrate how to de?ne strain for a 2D surface (either analytical or discrete, i.e. a mesh) embedded in 3D. We then demonstrate adjusting the correspondence between two surfaces so that the strain is evenly distributed across the surface. shape matching, correspondence,

Authors: Ly Phan and Andrew Knutsen and Philip Bayly and Sandra Rugonyi and Cindy Grimm
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Results of an observational study on sketching

Published in Sketch-based interfaces and modeling, 2011

This is the poster version of the full technical report. More details <a href=\"drawing.htm\"> here </a>, We present the results of an observational study on sketching. Artists were asked to sketch a small number of objects and comment on how and why they made the marks they did. We summarize these findings, from low-level details on individual marks through the drawing construction order. Based on these observations we provide suggestions for future research directions in 3D sketching. Sketching, stroke, marks,

Authors: Cindy Grimm
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Image-space Constraints for Controlling Camera Interpolation

Published in Symposium on Interactive 3D Graphics and Games, 2011

The full version can be found <a href=\"./content/papers/i3d2011ci/i3d2011ciFull.pdf\">here</a>. This paper presents a novel interface for using image-space con- straints to control camera interpolation in animation sequences. Traditional camera control can be challenging because the user must envision how the camera should be positioned in order to place the objects on the image plane the way they want. While it is fairly simple to place an object in the center of the scene and rotate the camera around it, more complex camera motions that involve both view direction change and motion of the object across the screen can be very difficult to envision and implement with smooth motion. In contrast, we provide a simple interface that allows the user to directly draw out the trajectory, size, and orientation of an object on the screen, while the system automatically solves for a sequence of cameras that satisfies those constraints. Unlike previous image- space constraint approaches, we use a constraint vocabulary which is both easy to use and produces more stable solutions. Camera interpolation, Storytelling Alice,

Authors: Ross Sowell and Tom Erez and Emily Feder and Cindy Grimm and Jianqi Xing and Leon Barrett
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Bioinspiration from Biodiversity in Sensor Design

Published in ASME 2001 International Mechanical Engineering Congress and Exposition, 2011

Biological systems are organized along a hierarchy that ranges from bio-molecules to large-scale ecosystems. In the present work, the level of biodiversity is considered as a source for engineering knowledge. In the process of evolution and adaptive radiation in particular, common functional principles have been adapted to suit a multitude of tasks and constraints. The resulting biodiversity can hence be regarded as a source for inspiration on how a single functional principle can be adapted to suit the requirements of different applications. The biosonar systems of bats are an example for a biological sensing principle that has been adjusted to fit a multitude of sensing tasks. The unique combination of biosonar sensing and flight has allowed bats to settle almost the entire land surface of the earth and exploit a wide range of food sources that range from airborne insect prey to terrestrial vertebrates. The geometries of the mechanical baffles that surround the sides of sound emission and reception are a conspicuous correlate of this diversification in the uses of biosonar. Understand the principles that underlie this diversification, requires an array of customized methods: First, objective and quantitative descriptions are needed for the biological variation in irregular, organic shapes at an inter-specific level. Second, functional features of the sensors must be characterized in a similar fashion. Finally, a link between form and function needs to be established. A description of the biodiversity in shape requires some form of registration between shapes from different species. For the outer ears of bats, this problem has been addressed by virtue of an ad-hoc method that represents the ears in cylindrical coordinates with a reference frame that is fixed through a potential field in analogy to the interactions between molecules. An alternative method that is likely to generalize to more difficult geometries such as the noseleaves of bats can be based on modal analysis. In the process of \"spectral embedding\" the location of pinna surfaces is expressed in a space that is spanned by the amplitudes of different modes at the respective positions. For the acoustic function of diffracting baffles local features such as grooves and ridges can be of prime importance. These are not easily captured by methods that are more likely to provide robust estimates of variability in a sample at low spatial frequencies. Hence, local shape descriptors capable of quantifying these features are needed. sonar, local shape, pca, shape space,

Authors: Rolf Mueller and Jianguo Ma and Zhen Yan and Washington Mio and Cindy Grimm
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Impact of Subtle Gaze Direction on Short-Term Spatial Information Recall

Published in Proceedings of the Symposium on Eye Tracking Research and Applications, 2012

Contents of Visual Short-Term Memory depend highly on viewer attention. It is possible to influence where attention is allocated using a technique called Subtle Gaze Direction (SGD). SGD combines eye tracking with subtle image-space modulations to guide viewer gaze about a scene. Modulations are terminated before the viewer can scrutinize them with high acuity foveal vision. This approach is preferred to overt techniques that require permanent alterations to images to highlight areas of interest. In our study, participants were asked to recall the location of objects or regions in images. We investigated if using SGD to guide attention to these regions would improve recall. Results showed that the influence of SGD significantly improved accuracy of target count and spatial location recall. This has implications for a wide range of applications including spatial learning in virtual environments as well as image search applications, virtual training and perceptually based rendering. subtle gaze, information recall, eye-tracking, gaze direction, short-term memory, https://dl.acm.org/citation.cfm?id=2168567,

Authors: Reynold Bailey and Aaron Costello and Ann McNamara and Srinivas Sridharan and Cindy Grimm
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Subtle Gaze Manipulation for Improved Mammography Training

Published in Proceedings of the Symposium on Eye Tracking Research and Applications, 2012

The ability to direct viewer gaze about an image has important application in medical image training and analysis. We use a novel gaze manipulation technique called Subtle Gaze Direction [Bailey et al. 2009] to guide novice users as they try to identify abnormalities in digital mammogram images. Subtle Gaze Direction is achieved by performing brief image-space modulations on specific regions of the viewer\s peripheral vision in order to attract their attention. The viewer\s gaze is monitored in real-time and the modulations are terminated before the viewer is allowed to scrutinize them with their high-acuity foveal vision. This approach is preferred to more overt techniques which require permanent alterations to the original images in order to highlight specific areas of interest. In our experiment we use Subtle Gaze Direction to guide novices along the scanpath of an expert radiologist. We hypothesized that this approach would increase the likelihood of novices correctly identifying irregularities in the mammograms. gaze manipulation, image-space modulations, mammography, radiological training,

Authors: Srinivas Sridharan and Reynold Bailey and Ann McNamara and Cindy Grimm
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JustDrawIt: A 3D Sketching System

Published in Proceedings of the International Symposium on Sketch-Based Interfaces and Modeling, 2012

Video: <a href=\"http://www.youtube.com/watch?v=S4Gufhi6xHg&feature=youtu.be\">teapot</a>, <a href=\"http://www.youtube.com/watch?v=EdQDQ_kM6ig&f\">Tower</a>, We present \"JustDrawIt\", a sketch-based system for creating 3D curves suitable for surfacing. The user can sketch in a free-form manner from any view at any time, and the system infers how those sketch strokes should be added to the drawing. Specifically, existing curves are projected to 2D and analyzed to see if the stroke edits or extends an existing curve, or if the stroke should make a new curve. In the former case the 2D stroke is promoted to 3D using the position of the existing curve, and then joined to that curve. In the latter case, we use additional spatial information (e.g. temporary 3D surfaces) to create a new curve in 3D. All non-sketching interactions are based on unintrusive context-aware, in-screen pie menus designed for rapid pen-based input. We also provide novel rendering styles and aides for interpreting and working with 3D sketches. Finally, we support snapping together curve networks and specifying normals in order to create surface models. 3D drawing, sketching,

Authors: Cindy Grimm and Pushkar Joshi
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Directing Gaze in Narrative Art

Published in Proceedings of the ACM Symposium on Applied Perception, 2012

Narrative art tells a story, either as a moment in an ongoing story or as a sequence of events unfolding over time. In many works of art separate panels within the same frame are used to depict the sequence of events. Often, there is no clear delineation between these panels, or any indication of the optimal viewing order. To improve visual literacy we propose using Subtle Gaze Direction (SGD) to direct the viewers gaze across an image in a manner which reveals the story. SGD uses small image space modulations in the luminance channel to guide a viewer\s gaze about an image without disrupting their normal visual experience. Using a simple ordering task we compared performance using no modulation and using subtle modulation with the correct order of narrative episodes as intended by the artist. Results from experiments show improved performance when SGD is employed. This experiment establishes the potential of the method as an aid to visual navigation in images where the viewing order is unclear. art history education, eye-tracking, gaze direction,

Authors: Ann McNamara and Stephen Caffey and Thomas Booth and Cindy Grimm and Srinivas Sridharan and Reynold Bailey
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Surface Patches for 3D Sketching

Published in Proceedings of the International Symposium on Sketch-Based Interfaces and Modeling, 2013

3D sketching is an appealing approach for creating concept shapes in the early stages of design. While curve networks alone can convey shape, surfacing the network can dramatically help with visualization and interaction. Unfortunately, surfacing a curve network is an inherently ambiguous problem, and even if the correct surface patches are identified, they can have an arbitrarily complex 3D geometry, making it challenging to produce a reasonable tessellation. In this paper we address the problem of creating light-weight surface tessellations on the fly. Our approach is to identify potential patches in the curve network, and then break complicated patches into simpler ones which can be tessellated using any simple algorithm. Our surfacing approach relies on the observation that breaking a complicated patch into a set of nearly planar ones with small total area seems to create a simple, natural-looking surfaces. We demonstrate our approach on curve networks generated by two different 3D sketching systems. curve-based modeling, sketching 3D curves, surface patches,

Authors: Fatemeh Abbasinejad and Pushkar Joshi and Cindy Grimm and Nina Amenta
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Guiding Attention in Controlled Real-World Environments

Published in Proceedings of the ACM Symposium on Applied Perception, 2013

The ability to direct a viewer\s attention has important applications in computer graphics, data visualization, image analysis, and training. Existing computer-based gaze manipulation techniques, which direct a viewer\s attention about a display, have been shown to be effective for spatial learning, search task completion, and medical training applications. In this work we extend the concept of gaze manipulation beyond digital imagery to include controlled, real-world environments. We address two main challenges in guiding attention to real-world objects: determining what object the viewer is currently paying attention to, and providing (projecting) a visual cue on a different part of the scene in order to draw the viewer\s attention there. Our system consists of a pair of eye-tracking glasses to determine the viewer\s gaze location, and a projector to create the visual cue in the physical environment. The results of a user study show that we can effectively direct the viewer\s gaze in the real-world scene. Our technique has applicability in a wide range of instructional environments, including pilot training and driving simulators. SIFT, eye-tracking, gaze manipulation, training,

Authors: Thomas Booth and Srinivas Sridharan and Reynold Bailey and Ann McNamara and Cindy Grimm
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Using Video Manipulation to Protect Privacy in Remote Presence Systems

Published in International Conference on Social Robotic, 2015

Remote presence systems that allow remote operators to physically move around the world, observe it, and, in some cases, manipulate it, introduce a new set of privacy concerns. Traditional telepresence systems allow remote users to passively observe, forcing them to look at whatever the camera is pointing at. If we want something to remain private, then we simply do not put it in front of the camera. Remote presence systems, on the other hand, allow active observation, and put the control of the camera in the hands of the remote operator. They can drive around, and look at the world from different viewpoints, which complicates privacy protection.In this paper, we look at how we can establish privacy protections for remote presence systems by manipulating the video data sent back to them. We evaluate a number of manipulations of these data, balancing privacy protection against the ability to perform a given task, and report on the results of two studies that attempt to evaluate these techniques. Video Stream

Authors: Alexander Hubers and Emily Andrulis and Levi Scott and Tanner Stirrat and Ruonan Zhang and Ross Sowell and Matthew Rueben and Cindy M. Grimm and William D. Smart

Guided Structure-Aligned Segmentation of Volumetric Data

Published in International Symposium on Visual Computing, 2015

Segmentation of volumetric images is considered a time and resource intensive bottleneck in scientific endeavors. Automatic methods are becoming more reliable, but many data sets still require manual intervention. Key difficulties include navigating the 3D image, determining where to place marks, and maintaining consistency between marks and segmentations. Clinical practice often requires segmenting many different instances of a specific structure. In this research we leverage the similarity of a repeated segmentation task to address these difficulties and reduce the cognitive load for segmenting on non-traditional planes. We propose the idea of guided contouring protocols that provide guidance in the form of an automatic navigation path to arbitrary cross sections, example marks from similar data sets, and text instructions. We present a user study that shows the usability of this system with non-expert users in terms of segmentation accuracy, consistency, and efficiency. ,

Authors: Michelle Holloway and Anahita Sanandaji and Deniece Yates and Amali Krigger and Ross Sowell and Ruth West and Cindy Grimm

Visualization Techniques for the Developing Chicken Heart

Published in International Symposium on Visual Computing, 2015

We present a geometric surface parameterization algorithm and several visualization techniques adapted to the problem of understanding the 4D peristaltic-like motion of the outflow tract (OFT) in an embryonic chick heart. We illustrated the techniques using data from hearts under normal conditions (four embryos), and hearts in which blood flow conditions are altered through OFT banding (four embryos). The overall goal is to create quantitative measures of the temporal heart-shape change both within a single subject and between multiple subjects. These measures will help elucidate how altering hemodynamic conditions changes the shape and motion of the OFT walls, which in turn influence the stresses and strains on the developing heart, causing it to develop differently. We take advantage of the tubular shape and periodic motion of the OFT to produce successively lower dimensional visualizations and quantifications of the cardiac motion. Medial Axis, Cardiac Motion, Heart Tube, Consistent Parameterization, Lumen Surface ,

Authors: Ly Phan and Cindy Grimm and Sandra Rugonyi

Where Do Experts Look While Doing 3D Image Segmentation

Published in Proceedings of the Ninth Biennial ACM Symposium on Eye Tracking Research \\& Applications, 2016

3D image segmentation is a fundamental process in many scientific and medical applications. Automatic algorithms do exist, but there are many use cases where these algorithms fail. The gold standard is still manual segmentation or review. Unfortunately, even for an expert this is laborious, time consuming, and prone to errors. Existing 3D segmentation tools do not currently take into account human mental models and low-level perception tasks. Our goal is to improve the quality and efficiency of manual segmentation and review by analyzing how experts perform segmentation. As a preliminary step we conducted a field study with 8 segmentation experts, recording video and eye tracking data. We developed a novel coding scheme to analyze this data and verified that it successfully covers and quantifies the low-level actions, tasks and behaviors of experts during 3D image segmentation. 3D image segmentation, coding scheme, perception,

Authors: Anahita Sanandaji and Jeremy Deutsch and Max Parola and Meghan Kajihara and Anne Carlew and Ruth West and Cindy Grimm

Visual cues used to evaluate grasps from images

Published in 2016 IEEE International Conference on Robotics and Automation, 2016

We analyze visual cues people used to evaluate a robot grasp. Participants were presented with two (front and side) orthogonal views of a robot hand grasping an object and asked how successful the grasp would be on a scale of 1-5; they were eye-tracked while completing this survey. Ground truth of the success of the grasps is known. Our primary observations were that (1) Most of the failed grasp predictions were false positives, and this was exacerbated for grasps that were ranked as human-like. (2) Two visual cues from human-grasp research (object center-line and top) were used, but not contact points. Instead, participants gazed at robot finger, wrist, and arm locations. (3) There was a difference in the visual patterns between the left and right images, indicating that the second image was primarily used to verify the locations of fingers and wrist while the first was used to establish the object\s location and shape. Finally, we generate transition matrices to model the temporal aspect of the gaze patterns. gaze tracking, grippers, robot vision, visual cues, front-orthogonal views, side-orthogonal views, robot hand grasping evaluation, eye-tracking, ground truth

Authors: Matthew Sundberg and Walter Litwinczyk and Cindy Grimm and Ravi Balasubramanian

Evaluating Human Gaze Patterns During Grasping Tasks: Robot Versus Human Hand

Published in Proceedings of the ACM Symposium on Applied Perception, 2016

Where do people look when grasping an object with their hand versus puppetteering a robot hand to grasp the object?,

Authors: Sai Krishna Allani and Brendan John and Javier Ruiz and Saurabh Dixit and Jackson Carter and Ravi Balasubramanian and Cindy Grimm

Interpreting Survey Items using Exploratory Factor Analysis

Published in Second International Workshop on Evaluation Methods Standardization in Human-Robot Interaction, in conjunction with RO-MAN 2016, 2016

How to take apart a survey to get started understanding what is important. ,

Authors: Matthew Rueben and Frank J. Bernieri and Cindy M. Grimm and William D. Smart

Evaluation of Physical Marker Interfaces for Protecting Visual Privacy from Mobile Robots

Published in 25th IEEE International Symposium on Robot and Human Interactive Communication, 2016

We present a study that examines the efficiency and usability of three different interfaces for specifying which objects should be kept private (i.e. not visible) in an office environment. Our study context is a robot “janitor” system that has the ability to blur out specified objects from its video feed. One interface is a traditional point-and-click GUI on a computer monitor, while the other two operate in the real, physical space: users either place markers on the objects to indicate privacy or use a wand tool to point at them. We compare the interfaces using both self-report (e.g. surveys) and behavioral measures. Our results showed that (1) the graphical interface performed better both in terms of time and usability, and (2) using persistent markers increased the participants\ ability to recall what they tagged. Choosing the right interface appears to depend on the application scenario. We also summarize feedback from the participants for improving interfaces that specify visual privacy preferences. data privacy, graphical user interfaces, human-robot interaction,

Authors: Matthew Rueben and Frank J. Bernieri and Cindy M. Grimm and William D. Smart

Analyzing Human Gaze Patterns During Grasping Tasks To Advance Robotic Grasping

Published in Oregon State University, 2016

Published in Symposium on Applied Perception 2018, There is a strong interest in the robotics community in learning how humans grasp and manipulate objects, partly because robots need to operate in human environments and partly because humans are currently much better in physical interaction tasks than robots. This thesis seeks to identify the human heuristics for grasping by analyzing human gaze patterns when humans perform grasping tasks using their own hand and when they use a robotic hand. This thesis uses a human-subject experiment to analyze the participant\s eye-gaze for finding what features people think are important for grasping objects. The features included where the fingertips settle down on the object relative to the object’s edges, center of mass, etc. It was found that while gaze patterns on the objects are similar whether the human used the robot hand or the human hand, participants spent substantially more time gazing at the robotic hand then their own, particularly the wrist and finger positions. In a subsequent study, it was also shown that choosing camera angles that clearly display the features participants are interested in enables the participants to more effectively determine the effectiveness of a grasp from images. This thesis’s findings are relevant both for robotic grasp planning algorithms (where visual cues are important for analyzing objects for potential grasps) and for designing tele-operation interfaces (how best to present the visual data to the remote operator)., https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/k930c277f,

Authors: Sai Krishna Allani
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Advancing Robotic Grasp Planning using Human Heuristics for Grasp Similarity

Published in Oregon State University, 2016

This thesis explores the use of human kinesthetic input to advance robotic grasp planning. It specifically focuses on identification of human heuristics of grasp similarity by extensive human-subject experiments. This heuristic is then utilized to develop a robust metric for identifying similar robotic grasps. The central hypothesis of this work is to speed up grasp planning and improve the reliability of the planned grasps by using the human heuristic for grasp similarity. Experimental results show that (i) new similar grasps generated from interpolation of human-provided grasps have similar performance (93.75% success rate) compared to original human grasps (97% success rate) and (ii) grasps with similar hand configurations are functionally similar when applied to large regions of everyday objects, but functionally similar grasp does not necessarily dictate similar hand configuration., Published in AAAI Fall Symposium 2016, https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/37720j09c,

Authors: Saurabh Milind Dixit
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Eliciting Tacit Expertise in 3D Volume Segmentation

Published in Proceedings of the 9th International Symposium on Visual Information Communication and Interaction, 2016

The output of 3D volume segmentation is crucial to a wide range of endeavors. Producing accurate segmentations often proves to be both inefficient and challenging, in part due to lack of imaging data quality (contrast and resolution), and because of ambiguity in the data that can only be resolved with higher-level knowledge of the structure and the context wherein it resides. Automatic and semi-automatic approaches are improving, but in many cases still fail or require substantial manual clean-up or intervention. Expert manual segmentation and review is therefore still the gold standard for many applications. Unfortunately, existing tools (both custom-made and commercial) are often designed based on the underlying algorithm, not the best method for expressing higher-level intention. Our goal is to analyze manual (or semi-automatic) segmentation to gain a better understanding of both low-level (perceptual tasks and actions) and high-level decision making. This can be used to produce segmentation tools that are more accurate, efficient, and easier to use. Questioning or observation alone is insufficient to capture this information, so we utilize a hybrid capture protocol that blends observation, surveys, and eye tracking. We then developed, and validated, data coding schemes capable of discerning low-level actions and overall task structures. ,

Authors: Ruth West and Meghan Kajihara and Max Parola and Kathryn Hays and Luke Hillard and Anne Carlew and Jeremey Deutsch and Brandon Lane and Michelle Holloway and Brendan John and Anahita Sanandaji and Cindy Grimm

A Method for Establishing Correspondences Between Hand-Drawn and Sensor-Generated Maps

Published in International Conference on Social Robotics, 2016

Maps, and specifically floor plans, are useful for planning a variety of tasks from arranging furniture to designating conceptual or functional spaces (e.g. kitchen, walkway). However, maps generated directly from robot sensor data can be hard to interpret and use for this purpose, especially for individuals who are not used to them, because of sensor and odometry measurement errors and the probabilistic nature of the mapping algorithms themselves. In this paper, we present an algorithm for quickly laying a floor plan (or other conceptual map) onto a map generated from sensor data, creating a one-to-one mapping between the two This allows humans interacting with the robot to use a more readily-understandable representation of the world, while the robot itself uses the sensor-generated map.We look at two use cases: specifying “no-go” regions within a room, and visually locating objects within a room. Although a user study showed no statistical difference between the two types of maps in terms of performance on this spatial memory task, we argue that floor plans are closer to the mental maps people naturally draw to characterize spaces, and are easier to use for untrained individuals. Map understanding SLAM Map correspondence ,

Authors: Leo Bowen-Biggs and Suzanne Dazo and Yili Zhang and Alexander Hubers and Matthew Rueben and Ross Sowell and William D. Smart and Cindy M. Grimm

Human-Planned Robotic Grasp Ranges: Capture and Validation

Published in AAAI Fall Symposium Series, 2016

Leveraging human grasping skills to teach a robot to perform a manipulation task is appealing, but there are several limitations to this approach: time-inefficient data capture procedures, limited generalization of the data to other grasps and objects, and inability to use that data to learn more about how humans perform and evaluate grasps. This paper presents a data capture protocol that partially addresses these deficiencies by asking participants to specify ranges over which a grasp is valid. The protocol is verified both qualitatively through online survey questions (where within-range grasps are identified correctly with the nearest extreme grasp) and quantitatively by showing that there is small variation in grasps ranges from different participants as measured by joint angles and position. We demonstrate that these grasp ranges are valid through testing on a physical robot (93.75% of grasps interpolated from grasp ranges are successful). grasping, learning from demonstration, grasp range,

Authors: Brendan John and Jackson Carter and Javier Ruiz and Sai Krishna Allani and Saurabh Dixit and Cindy Grimm and Ravi Balasubramanian

A summer research experience in robotics

Published in The Seventh Symposium on Educational Advances in Artificial Intelligence , 2017

A summary of the philosophy we use when running our NSF REU site. We have run this site for over 12 years, so we must be doing something right. Many of our students go on to pursue graduate work and/or become leaders in industrial positions. ,

Authors: Cindy Grimm and Alicia Lyman-Holt and William Smart

Framing Effects on Privacy Concerns about a Home Telepresence Robot

Published in Proceedings of the 2017 ACM/IEEE International Conference on Human-Robot Interaction, 2017

Privacy-sensitive robotics is an emerging area of HRI research. Judgments about privacy would seem to be context-dependent, but none of the promising work on contextual \"frames\" has focused on privacy concerns. This work studies the impact of contextual \"frames\" on local users\ privacy judgments in a home telepresence setting. Our methodology consists of using an online questionnaire to collect responses to animated videos of a telepresence robot after framing people with an introductory paragraph. The results of four studies indicate a large effect of manipulating the robot operator\s identity between a stranger and a close confidante. It also appears that this framing effect persists throughout several videos. These findings serve to caution HRI researchers that a change in frame could cause their results to fail to replicate or generalize. We also recommend that robots be designed to encourage or discourage certain frames. privacy, robotics,

Authors: Matthew Rueben and Frank Bernieri and Cindy Grimm and William Smart

Modeling a Spectrum of 3D Printed Materials for Soft Robots

Published in Oregon State University, 2017

Soft robotics is an emerging field that heavily relies on the ability of 3D printers. The limitations in soft robotics lie in the area of the 3D printers and the predictive models of the printed materials. There are currently no reliable models for optimizing the gradients required to create soft robots. These gradients are necessary to go from soft to hard materials which are used in electronics and soft robotics grips. This is achievable with the soft materials printed by the Stratasys Objet 500 Connex3, which can print a gradient in materials from hard to soft. Here we show the ability to print a homogeneous gradient on the printer, characterize these homogeneous materials, and model the optimized parameters of the nonlinear elastic material model according to techniques based upon Ogden., https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/s4655k29q,

Authors: Samantha Hemleben
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Gender Differences in Robot Teleoperation

Published in Oregon State University, 2017

Published as a paper in Ubiquitous Robots 2018, Gender issues have recently received increased attention in human robot interaction(HRI). Because robots are becoming part of our homes and daily lives, it isimportant to understand how di erent groups of people use them. To the bestof our knowledge, almost no research has been done that investigates gender differencesin users information need, information processing strategy, self-e cacy, tinkering and their impact in human robot interaction. This thesis investigatesthese four aspects by examining object manipulation task from gender perspectiveusing a humanoid robot (PR2). We used both qualitative and quantitative approachesfor cross validation and methodological triangulation. Our experimentalresults show that females asked for more information before using the robot thanmales (p = 0.0002). Females processed information comprehensively and malesprocessed information selectively (p < 0.001) for using the robot. Males showedgreater self-e cacy than females (p = 0.0002). Males tinkered more with the robotthan females (p = 0.0021). We found that tinkering was positively correlated (p= 0.0068) with task success and negatively correlated (p = 0.0032) with taskcompletion time. Tinkering perhaps led to males greater task success and lowertask completion time with the robot. Findings from this research can be useful formaking design decisions for robots and open new research directions., https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/fb494f20n,

Authors: Dilruba Showkat
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Inferring Cross-sections of 3D Objects: A 3D Spatial Ability Test Instrument for 3D Volume Segmentation

Published in Proceedings of the ACM Symposium on Applied Perception, 2017

Understanding 3D shapes through cross-sections is a mental task that appears both in 3D volume segmentation and solid modeling tasks. Similar to other shape understanding tasks — such as paper folding — performance on this task varies across the population, and can be improved through training and practice. We are — long term — interested in creating training tools for 3D volume segmentation. To this end, we have modified (and evaluated) an existing cross-section performance measure in the context of our intended application. Our primary adaptations were 1) to use 3D stimuli (instead of 2D) to more accurately capture the real-world application and 2) evaluate performance on 3D biological shapes relative to the 3D geometric shapes used in the previous study. Our findings are: 1) Participants had the same pattern of errors as the original study, but overall their performance improved when they could see the objects rotating in 3D. 2) Inferring cross-sections of biological shapes is more challenging than pure geometric shapes. 3D volume segmentation, cross-sections, spatial ability test,

Authors: Anahita Sanandaji and Cindy Grimm and Ruth West

Biodiversifying bioinspiration

Published in Bioinspiration and Biomimetics, 2018

Authors: R. M{\"u}ller, N. Abaid, J.B. Boreyko, C. Fowlkes, A.K. Goel, C. Grimm, S. Jung, B. Kennedy, C. Murphy, N.D. Cushing, J.-P. Han,
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An Education Model of Reasonable and Good-Faith Effort for Autonomous Systems

Published in Proceedings of the 2018 AAAI/ACM Conference on AI, Ethics, and Society, 2018

In this paper we propose a framework for conceptualizing and demonstrating a good-faith effort when developing autonomous systems. The framework addresses two fundamental problems facing autonomous systems: (1) the disconnect between human-mental models and machine-based sensors and algorithms; and (2) unpredictability in complex systems. We address these problems using a mix of education - explicitly delineating the mapping between human concepts and their machine equivalents in a structured manner - and data sampling with expected ranges as a testing mechanism. ethics, mental models, product law, unit testing,

Authors: Cindy Grimm and William Smart and Woodrow Hartzog

Grasping Objects Big and Small: Human Heuristics Relating Grasp-Type and Object Size

Published in IEEE International Conference on Robotics and Automation, 2018

<a href=\"https://www.youtube.com/watch?v=zV2D9pDQ6IE\">Video</a>, This paper presents an online data collection method that captures human intuition about what grasp types are preferred for different fundamental object shapes and sizes. Survey questions are based on an adopted taxonomy that combines grasp pre-shape, approach, wrist orientation, object shape, orientation and size which covers a large swathe of common grasps. For example, the survey identifies at what object height or width dimension (normalized by robot hand size) the human prefers to use a two finger precision grasp versus a three-finger power grasp. This information is represented as a confidence-interval based polytope in the object shape space. The result is a database that can be used to quickly find potential pre-grasps that are likely to work, given an estimate of the object shape and size. grasp type, human study,

Authors: Ammar Kothari and John Morrow and Victoria Thrasher and Kadon Engle and Ravi Balasubramanian and Cindy Grimm

A Grasping Metric based on Hand-Object Collision

Published in ICRA Workshop on Multimodal Robot Perception: Perception, Inference, and Learning for Joint Semantic, Geometric, and Physical Understanding, 2018

Look at the space between the hand and the object to determine if the grasp will be successful; how much can the object move without intersecting the hand? ,

Authors: Matthew Sundberg and Ryan Sherman and Ammar Kothari and Ravi Balasubramanian and Ross Hatton and Cindy Grimm

Dataset for Near Contact Grasping Trajectories

Published in Robotics: Science and Systems, New Benchmarks Metrics and Competitions for Robot Learning Workshop, 2018

To date the design of grasping metrics has largelyfocused on finding (and calculating) specific features that are(potentially) relevant to grouping or characterizing grasps, andparticularly on metrics that might predict success (or failure) ofa grasp. These metrics leverage human knowledge of physicalinteraction and are typically relatively quick to compute. Onedrawback to them, however, is that they are heterogeneous (eg, some combination of number of contact points, force vectors, positional or joint data), often specific to the robotic handemployed (eg, joint angles) and rarely take the full object shapeinto account (often reducing the shape geometry via PCA toa simple 3-vector). From a machine-learning perspective thismakes it challenging to combine and learn over mixed datasets. A more subtle challenge is that the metrics (particularlycontact points) are unstable, in that very small movements ofthe geometry can result in big changes in the number andlocation of contacts.In this paper we explore an alternative metric which ishand and object agnostic, and very stable with respect to smallchanges in the geometry of the hand or object. Although computationally more expensive than existing, specialized approaches(and also higher dimensional), we propose that it may be moresuited to machine learning analysis. At heart, this metric simplycaptures the ways in which the object is free to “twist” or moveout of the hand, grasping metric,

Authors: Ammar Kothari and Yi Ong and John Morrow and Ravi Balasubramanian and Cindy Grimm

Using human studies to analyze capabilities of underactuated and compliant hands in manipulation tasks

Published in IEEE/RSJ International Conference on Intelligent Robots and Systems, 2018

We present a human-subjects study approach that supports the analysis of the manipulation performance of robotic hands that have the same morphology but different actuation and compliance. Specifically, we use this approach to analyze three different types of hands (one underactuated, one fully actuated, one fully actuated with compliant distal joints) as they are used to perform two manipulation tasks. The first task uses a power grasp (spraying with a spray bottle), the second a precision grasp (tracing a line on a bowl with a pen). We show that compliance in the distal joints significantly improves performance and task completion. We also show that humans choose significantly different poses for the same task when using a fully-actuated versus underactuated hand, which also results in superior task performance. Our results suggest that humans use a combination of under-actuated and fully-actuated techniques, which when used on robotic systems would also improve their performance on manipulation tasks. underactuated hands, human studies,

Authors: John Morrow and Ammar Kothari and Yi Herng Ong and Nathan Harlan and Ravi Balasubramanian and Cindy Grimm

Using Geometric Features to Represent Near-contact Behavior in Robotic Grasping

Published in International Conference on Robotics and Automation, 2019

What sensors/metrics are the best to use when evaluating whether a grasp will succeed before grasping it. We validated using simple time of flight sensors in a follow-on paper at icra 2023. ,

Authors: Eadom Dessalene and Yi Herng Ong and John Morrow and Ravi Balasubramanian and Cindy Grimm

Hand Design Approach for Planar Fully Actuated Manipulators

Published in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2023

How to pick link lengths for a 2-fingered gripper to maximize in-hand translation

Authors: Keegan Nave, Kyle DuFrene, Nigel Swenson, Ravi Balasubramanian, Cindy Grimm

Semi-autonomous precision pruning of upright fruiting offshoot orchard systems

Published in IEEE Robotics and Automation Magazine, Special Issue on Embracing robotics and intelligent machine systems, 2023

Running the entire automated pruning system (planar tree)

Authors: Alexander You, Nidhi Parayil, Gopala Krishna Josyula, Uddhav Bhattarai, Ranjan Sapkota, Dawood Ahmed, Matthew Whiting, Manoj Karkee, Cindy Grimm, and Joseph Davidson

Branch Diameter Measurement System

Published in IROS 2024 Workshop: AI and Robotics for Future Farming, 2024

A measurement ssystem for getting branch diameter and position in a light-weight way (part of the AI pruning project)

Authors: Ryan Schofield and Cindy Grimm
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talks

teaching

ME203 Comp for Engineers

Undergraduate course, Oregon State University, 2024

This is a second year course in programming designed for Mechanical Engineers. The focus is on learning to use libraries like numpy and scipy for tasks such as data processing and simulation.

ROB 456 Intelligent robotics

Undergraduate course, Oregon State University, 2024

This is an introductory robotics course that builds up all the pieces needed to do SLAM.