Truth in Motion: The Unprecedented Risks and Opportunities of Extended Reality Motion Data
Vivek Nair, Louis Rosenberg, James F. O'Brien, Dawn Song
IEEE S&P
Motion tracking “telemetry” data lies at the core of nearly all modern extended reality (XR) and metaverse experiences. While generally presumed innocuous, recent studies ... [more]
Berkeley Open Extended Reality Recordings 2023 (BOXRR-23): 4.7 Million Motion Capture Recordings from 105,000 XR Users
Vivek Nair, Wenbo Guo, Rui Wang, James F. O'Brien, Louis Rosenberg, Dawn Song
IEEE VR 2024
Extended reality (XR) devices such as the Meta Quest and Apple Vision Pro have seen a recent surge in attention, with motion tracking "telemetry" data lying at the core of nearly ... [more]
Unique Identification of 50,000+ Virtual Reality Users from Head and Hand Motion Data
Vivek Nair, Wenbo Guo, Justus Mattern, Rui Wang, James F. O'Brien, Louis Rosenberg, Dawn Song
USENIX Security 23
With the recent explosive growth of interest and investment in virtual reality (VR) and the “metaverse,” public attention has rightly shifted toward the unique security and ... [more]
Exploring the Unprecedented Privacy Risks of the Metaverse
Vivek Nair, Gonzalo Munilla Garrido, Dawn Song, James F. O'Brien
PoPETS 2023
Thirty study participants playtested an innocent-looking "escape room" game in virtual reality (VR). Behind the scenes, an adversarial program had accurately inferred over ... [more]
KBody: Balanced monocular whole-body estimation
Nikolaos Zioulis, James F. O'Brien
CVFAD 2023
KBody is a method for fitting a low-dimensional body model to an image. It follows a predict-and-optimize approach, relying on data-driven model estimates for the constraints ... [more]
KBody: Towards general, robust, and aligned monocular whole-body estimation
Nikolaos Zioulis, James F. O'Brien
RHOBIN 2023
KBody is a method for fitting a low-dimensional body model to an image. It follows a predict-and-optimize approach, relying on data-driven model estimates for the constraints ... [more]
Monocular Facial Performance Capture Via Deep Expression Matching
Stephen Bailey, Jérémy Riviere, Morten Mikkelsen, James F. O'Brien
SCA 2022
Facial performance capture is the process of automatically animating a digital face according to a captured performance of an actor. Recent developments in this area have ... [more]
This photograph has been altered: Testing the effectiveness of image forensic labeling on news image credibility
Cuihua Shen, Mona Kasra, James F. O'Brien
Misinformation Review
Despite the ubiquity of images and videos in online news environments, much of the existing research on misinformation and its correction is solely focused on textual misinformation ... [more]
Fast and Deep Facial Deformations
Stephen Bailey, Dalton Omens, Paul Dilorenzo, James F. O'Brien
SIGGRAPH 2020
Film-quality characters typically display highly complex and expressive facial deformation. The underlying rigs used to animate the deformations of a character’s face ... [more]
Fake images: The effects of source, intermediary, and digital media literacy on contextual assessment of imag credibility online
Cuihua Shen, Mona Kasra, Wenjing Pan, Grace A. Bassett, Yining Malloch, James F. O'Brien
New Media and Society
Fake or manipulated images propagated through the Web and social media have the capacity to deceive, emotionally distress, and influence public opinions and actions. Yet ... [more]
Fast and Deep Deformation Approximations
Stephen Bailey, Dave Otte, Paul Dilorenzo, James F. O'Brien
SIGGRAPH 2018
Character rigs are procedural systems that compute the shape of an animated character for a given pose. They can be highly complex and must account for bulges, wrinkles, and ... [more]
Approximate svBRDF Estimation From Mobile Phone Video
Rachel A. Albert, Dorian Yao Chan, Dan B Goldman, James F. O'Brien
EGSR 2018
We describe a new technique for obtaining a spatially varying BRDF (svBRDF) of a flat object using printed fiducial markers and a cell phone capable of continuous flash video ... [more]
Seeing Is Believing: How People Fail to Identify Fake Images on the Web
Mona Kasra, Cuihua Shen, James F. O'Brien
CHI 2018
The growing ease with which digital images can be convincingly manipulated and widely distributed on the Internet makes viewers increasingly susceptible to visual misinformation ... [more]
Simulation of Subseismic Joint and Fault Networks Using a Heuristic Mechanical Model
Paul Gillespie, Giulio Casini, Hayley Iben, James F. O'Brien
SSRD 2017
Flow simulations of fractured and faulted reservoirs require representation of subseismic structures about which subsurface data are limited. We describe a method for ... [more]
Seeing Is Believing: Do People Fail to Identify Fake Images on the Web?
Mona Kasra, Cuihua Shen, James F. O'Brien
AoIR 2016
Images have historically been perceived as photographic proof of the depicted events. However, the growing ease with which digital images can be convincingly manipulated ... [more]
Repurposing Hand Animation for Interactive Applications
Stephen Bailey, Martin Watt, James F. O'Brien
SCA 2016
In this paper we describe a method for automatically animating interactive characters based on an existing corpus of key-framed hand-animation. The method learns separate ... [more]
Interactive Detailed Cutting of Thin Sheets
Pierre-Luc Manteaux, Wei-Lun Sun, Francois Faure, Marie-Paule Cani, James F. O'Brien
MIG 2015
In this paper we propose a method for the interactive detailed cutting of deformable thin sheets. Our method builds on the ability of frame-based simulation to solve for ... [more]
View-Dependent Adaptive Cloth Simulation with Buckling Compensation
Woojong Koh, Rahul Narain, James F. O'Brien
TVCG 2015
This paper describes a method for view-dependent cloth simulation using dynamically adaptive mesh refinement and coarsening. Given a prescribed camera motion, the method ... [more]
Optimal Presentation of Imagery with Focus Cues on Multi-Plane Displays
Rahul Narain, Rachel A. Albert, Abdullah Bulbul, Gregory J. Ward, Marty Banks, James F. O'Brien
SIGGRAPH 2015
We present a technique for displaying three-dimensional imagery of general scenes with nearly correct focus cues on multi-plane displays. These displays present an additive ... [more]
Resampling Adaptive Cloth Simulations onto Fixed-Topology Meshes
George Brown, Armin Samii, James F. O'Brien, Rahul Narain
SCA 2015 Poster
We describe a method for converting an adaptively remeshed simulation of cloth into an animated mesh with fixed topology. The topology of the mesh may be specified by the ... [more]
Mirror Mirror: Crowdsourcing Better Portraits
Jun-Yan Zhu, Aseem Agarwala, Alexei A. Efros, Eli Shechtman, Jue Wang
SIGGRAPH Asia 2014
We describe a method for providing feedback on portrait expressions, and for selecting the most attractive expressions from large video/photo collections. We capture a ... [more]
Exposing Photo Manipulation from Shading and Shadows
Eric Kee, James F. O'Brien, Hany Farid
TOG 2014
We describe a method for detecting physical inconsistencies in lighting from the shading and shadows in an image. This method imposes a multitude of shading- and shadow-based ... [more]
Eyeglasses-free Display: Towards Correcting Visual Aberrations with Computational Light Field Displays
Fu-Chung Huang, Gordon Wetzstein, Brian A. Barsky, Ramesh Raskar
ACM SIGGRAPH 2014
Millions of people worldwide need glasses or contact lenses to see or read properly. We introduce a computational display technology that predistorts the presented content ... [more]
Adaptive Tearing and Cracking of Thin Sheets
Tobias Pfaff, Rahul Narain, Juan Miguel de Joya, James F. O'Brien
SIGGRAPH 2014
This paper presents a method for adaptive fracture propagation in thin sheets. A high-quality triangle mesh is dynamically restructured to adaptively maintain detail ... [more]
Self-Refining Games using Player Analytics
Matt Stanton, Ben Humberston, Brandon Kase, James F. O'Brien, Kayvon Fatahalian, Adrien Treuille
SIGGRAPH 2014
Data-driven simulation demands good training data drawn from a vast space of possible simulations. While fully sampling these large spaces is infeasible, we observe that ... [more]
View-Dependent Adaptive Cloth Simulation
Woojong Koh, Rahul Narain, James F. O'Brien
SCA 2014
This paper describes a method for view-dependent cloth simulation using dynamically adaptive mesh refinement and coarsening. Given a prescribed camera motion, the method ... [more]
AverageExplorer: Interactive Exploration and Alignment of Visual Data Collections
Jun-Yan Zhu, Yong Jae Lee, Alexei A. Efros
SIGGRAPH 2014
This paper proposes an interactive framework that allows a user to rapidly explore and visualize a large image collection using the medium of average images. Average images ... [more]
User-Assisted Video Stabilization
Jiamin Bai, Aseem Agarwala, Maneesh Agrawala, Ravi Ramamoorthi
EGSR 2014
We present a user-assisted video stabilization algorithm that is able to stabilize challenging videos when state-of-the-art automatic algorithms fail to generate ... [more]
Can 3D Shape be Estimated from Focus Cues Alone?
Rachel A. Albert, Abdullah Bulbul, Rahul Narain, James F. O'Brien, Martin S. Banks
VSS 2014
Focus cues—blur and accommodation—have generally been regarded as very coarse, ordinal cues to depth. This assessment has been largely determined by the inability to display ... [more]
Correct blur and accommodation information is a reliable cue to depth ordering.
Marina Zannoli, Rachel A. Albert, Abdullah Bulbul, Rahul Narain, James F. O'Brien, Martin Banks
VSS 2014
Marshall et al. (1996) showed that blur could in principle also be used to determine depth ordering of two surfaces across an occlusion boundary from the correlation between ... [more]
The Perception of Surface Material from Disparity and Focus Cues
Martin Banks, Abdullah Bulbul, Rachel Albert, Rahul Narain, James F. O'Brien, Gregory Ward
VSS 2014
The visual properties of surfaces reveal many things including a floor's cleanliness and a car's age. These judgments of material are based on the spread of light reflected ... [more]
External mask based depth and light field camera
Dikpal Reddy, Jiamin Bai, Ravi Ramamoorthi
ICCV 2013 Workshop
We present a method to convert a digital single-lensreflex (DSLR) camera into a high resolution consumer depth and light field camera by affixing an external aperture mask ... [more]
Depth from Combining Defocus and Correspondence Using light-Field Cameras
Michael W. Tao, Sunil Hadap, Jitendra Malik, Ravi Ramamoorthi
ICCV 2013
Light-field cameras have recently become available to the consumer market. An array of micro-lenses captures enough information that one can refocus images after acquisition ... [more]
Fast Simulation of Mass-Spring Systems
Tiantian Liu, Adam Bargteil, James F. O'Brien, Ladislav Kavan
SIGGRAPH Asia 2013
We describe a scheme for time integration of mass-spring systems that makes use of a solver based on block coordinate descent. This scheme provides a fast solution for classical ... [more]
Exposing Photo Manipulation with Inconsistent Shadows
Eric Kee, James F. O'Brien, Hany Farid
TOG 2013
We describe a geometric technique to detect physically inconsistent arrangements of shadows in an image. This technique combines multiple constraints from cast and attached ... [more]
Folding and Crumpling Adaptive Sheets
Rahul Narain, Tobias Pfaff, James F. O'Brien
SIGGRAPH 2013
We present a technique for simulating plastic deformation in sheets of thin materials, such as crumpled paper, dented metal, and wrinkled cloth. Our simulation uses a framework ... [more]
Near-exhaustive Precomputation of Secondary Cloth Effects
Doyub Kim, Woojong Koh, Rahul Narain, Kayvon Fatahalian, Adrien Treuille, James F. O'Brien
SIGGRAPH 2013
The central argument against data-driven methods in computer graphics rests on the curse of dimensionality: it is intractable to precompute "everything" about a complex ... [more]
Axis-Aligned Filtering for Interactive Physically-Based Diffuse Indirect Lighting
Soham Uday Mehta, Brandon Wang, Ravi Ramamoorthi, Fredo Durand
SIGGRAPH 2013
We introduce an algorithm for interactive rendering of physically-based global illumination, based on a novel frequency analysis of indirect lighting. Our method combines ... [more]
Type-Constrained Direct Fitting of Quadric Surfaces
James Andrews, Carlo H. Séquin
CAD 2013
We present a catalog of type-specific, direct quadric fitting methods: Given a selection of a point cloud or triangle mesh, and a desired quadric type (e.g. cone, ellipsoid, paraboloid ... [more]
Automatic Cinemagraph Portraits
Jiamin Bai, Aseem Agarwala, Maneesh Agrawala, Ravi Ramamoorthi
EGSR 2013
Cinemagraphs are a popular new type of visual media that lie in-between photos and video; some parts of the frame are animated and loop seamlessly, while other parts of the ... [more]
Sharpening Out of Focus Images using High-Frequency Transfer
Michael Tao, Jitendra Malik, Ravi Ramamoorthi
EG 2013
Focus misses are common in image capture, such as when the camera or the subject moves rapidly in sports and macro photography. One option to sharpen focus-missed photographs ... [more]
Simulating Liquids and Solid-Liquid Interactions with Lagrangian Meshes
Pascal Clausen, Martin Wicke, Jonathan Shewchuk, James F. O'Brien
TOG 2013
This paper describes a Lagrangian finite element method that simulates the behavior of liquids and solids in a unified framework. Local mesh improvement operations maintain ... [more]
Generalized, Basis-Independent Kinematic Surface Fitting
James Andrews, Carlo H. Séquin
JCAD 2013
Kinematic surfaces form a general class of surfaces, including surfaces of revolution, helices, spirals, and more. Standard methods for fitting such surfaces are either specialized ... [more]
Interactive Albedo Editing in Path-Traced Volumetric Materials
Miloš Hašan, Ravi Ramamoorthi
TOG 2013
Materials such as clothing or carpets, or complex assemblies of small leaves, flower petals or mosses, do not fit well into either BRDF or BSSRDF models. Their appearance is ... [more]
Gloss Perception in Painterly and Cartoon Rendering
Adrien Boussean, James P. O'Shea, Frédo Durand, Ravi Ramamoorthi, Maneesh Agrawala
TOG 2013
Depictions with traditional media such as painting and drawing represent scene content in a stylized manner. It is unclear however how well stylized images depict scene ... [more]
Axis-Aligned Filtering for Interactive Sampled Soft Shadows
Soham Mehta, Brandon Wang, Ravi Ramamoorthi
Siggraph Asia 2012
We develop a simple and efficient method for soft shadows from planar area light sources, based on explicit occlusion calculation by raytracing, followed by adaptive image-space ... [more]
Adaptive Anisotropic Remeshing for Cloth Simulation
Rahul Narain, Armin Samii, James F. O'Brien
SIGGRAPH Asia 2012
We present a technique for cloth simulation that dynamically refines and coarsens triangle meshes so that they automatically conform to the geometric and dynamic detail ... [more]
Correcting for Optical Aberrations using Multilayer Displays
Fu-Chung Huang, Douglas Lanman, Brian A. Barsky, Ramesh Raskar
SIGGRAPH ASIA 2012
Optical aberrations of the human eye are currently corrected using eyeglasses, contact lenses, or surgery. We describe a fourth option: modifying the composition of displayed ... [more]
Frequency-Space Decomposition and Acquisition of Light Transport under Spatially Varying Illumination
Dikpal Reddy, Ravi Ramamoorthi, Brian Curless
ECCV 2012
We show that, under spatially varying illumination, the light transport of diffuse scenes can be decomposed into direct, near-range (subsurface scattering and local inter-reflections ... [more]
On Differential Photometric Reconstruction for Unknown, Isotropic BRDFs
Manmohan Chandraker, Jiamin Bai, Ravi Ramamoorthi
PAMI 2012
This paper presents a comprehensive theory of photometric surface reconstruction from image derivatives, in the presence of a general, unknown isotropic BRDF. We derive ... [more]
Selectively De-Animating Video
Jiamin Bai, Aseem Agarwala, Maneesh Agrawala, Ravi Ramamoorthi
SIGGRAPH 2012
We present a semi-automated technique for selectively de-animating video to remove the large-scale motions of one or more objects so that other motions are easier to see ... [more]
Updated Sparse Cholesky Factors for Corotational Elastodynamics
Florian Hecht, Yeon Jin Lee, Jonathan Shewchuk, James F. O'Brien
TOG 2012
We present warp-canceling corotation, a nonlinear finite element formulation for elastodynamic simulation that achieves fast performance by making only partial or ... [more]
Compressive Structured Light for Recovering Inhomogeneous Participating Media
Jinwei Gu, Shree K. Nayar, Eitan Grinspun, Peter N. Belhumeur, Ravi Ramamoorthi
PAMI 2012
We propose a new method named compressive structured light for recovering inhomogeneous participating media. Whereas conventional structured light methods emit coded ... [more]
Analytic Tangent Irradiance Environment Maps for Anisotropic Surfaces
Soham Mehta, Ravi Ramamoorthi, Mark Meyer, Christophe Hery
EGSR 2012
We extend spherical harmonic irradiance maps to anisotropic surfaces, replacing Lambertian reflectance with the diffuse term of the popular Kajiya-Kay model. We show ... [more]
Interactive Inverse 3D Modeling
James Andrews, Hailin Jin, Carlo H. Séquin
CAD 2012
“Interactive Inverse 3D Modeling” is a user-guided approach to shape construction and redesign that extracts well-structured, parameterized, procedural descriptions ... [more]
Importance Sampling of Reflection from Hair Fibers
Christophe Hery, Ravi Ramamoorthi
JCCT 2012
Hair and fur are increasingly important visual features in production rendering, and physically-based light scattering models are now commonly used. In this paper, we enable ... [more]
SimpleFlow: A Non-iterative, Sublinear Optical Flow Algorithm
Michael Tao, Jiamin Bai, Pushmeet Kohli, Sylvain Paris
EG 2012
Optical flow is a critical component of video editing applications, e.g. for tasks such as object tracking, segmen- tation, and selection. In this paper, we propose an optical ... [more]
Exposing Digital Forgeries in Ballistic Motion
Valentina Conotter, James F. O'Brien, Hany Farid
TIFS 2012
We describe a geometric technique to detect physically implausible trajectories of objects in video sequences. This technique explicitly models the three-dimensional ... [more]
Real-Time Rendering of Rough Refraction
Charles de Rousiers, Adrien Bousseau, Kartic Subr, Nicolas Holzschuch, Ravi Ramamoorthi
TVCG 2012
We present an algorithm to render objects made of transparent materials with rough surfaces in real-time, under all-frequency distant illumination. Rough surfaces cause ... [more]
A Theory of Monte Carlo Visibility Sampling
Ravi Ramamoorthi, John Anderson, Mark Meyer, Derek Nowrouzezahrai
TOG 2012
Soft shadows from area lights are one of the most crucial effects in high quality and production rendering, but Monte Carlo sampling of visibility is often the main source ... [more]
Exposing Photo Manipulation with Inconsistent Reflections
James F. O'Brien, Hany Farid
TOG 2012
The advent of sophisticated photo editing software has made it increasingly easier to manipulate digital images. Often visual inspection cannot definitively distinguish ... [more]
Practical Filtering for Efficient Ray-Traced Directional Occlusion
Kevin Egan, Fredo Durand, Ravi Ramamoorthi
SIGGRAPH Asia 2011
Ambient occlusion and directional (spherical harmonic) occlusion have become a staple of production rendering because they capture many visually important qualities ... [more]
What An Image Reveals About Material Reflectance
Manmohan Chandraker, Ravi Ramamoorthi
ICCV 2011
We derive precise conditions under which material reflectance properties may be estimated from a single image of a homogeneous curved surface (canonically a sphere), lit ... [more]
A Linear Variational System for Modeling From Curves
James Andrews, Pushkar P. Joshi, Nathan Carr
CGF 2011
We present a linear system for modelling 3D surfaces from curves. Our system offers better performance, stability and precision in control than previous non-linear systems ... [more]
Data-Driven Elastic Models for Cloth: Modeling and Measurement
Huamin Wang, Ravi Ramamoorthi, James F. O'Brien
SIGGRAPH 2011
Cloth often has complicated nonlinear, anisotropic elastic behavior due to its woven pattern and fiber properties. However, most current cloth simulation techniques simply ... [more]
Perceptually Based Tone Mapping for Low-Light Conditions
Adam Kirk, James F. O'Brien
SIGGRAPH 2011
In this paper we present a perceptually based algorithm for modeling the color shift that occurs for human viewers in low-light scenes. Known as the Purkinje effect, this ... [more]
Illumination Decomposition for Material Recoloring with Consistent Interreflections
Robert Carroll, Ravi Ramamoorthi, Maneesh Agrawala
SIGGRAPH 2011
Changing the color of an object is a basic image editing operation, but a high quality result must also preserve natural shading. A common approach is to first compute reflectance ... [more]
Interactive Furniture Layout Using Interior Design Guidelines
Paul Merrell, Eric Schkufza, Zeyang Li, Maneesh Agrawala, Vladlen Koltun
SIGGRAPH 2011
We present an interactive furniture layout system that assists users by suggesting furniture arrangements that are based on interior design guidelines. Our system incorporates ... [more]
Sparse Reconstruction of Visual Appearance for Computer Graphics and Vision
Ravi Ramamoorthi
Wavelets and Sparsity 2011
A broad range of problems in computer graphics rendering, appearance acquisition for graphics and vision, and imaging, involve sampling, reconstruction, and integration ... [more]
Optimizing Environment Maps for Material Depiction
Adrien Bousseau, Emmanuelle Chapoulie, Ravi Ramamoorthi, Maneesh Agrawala
EGSR 2011
We present an automated system for optimizing and synthesizing environment maps that enhance the appearance of materials in a scene. We first identify a set of lighting ... [more]
A Theory of Differential Photometric Stereo for Unknown BRDFs
Manmohan Chandraker, Jiamin Bai, Ravi Ramamoorthi
CVPR 2011
We present a comprehensive theory of photometric surface reconstruction from image derivatives. For unknown isotropic BRDFs, we show that two measurements of spatial ... [more]
On the Duality of Forward and Inverse Light Transport
Manmohan Chandraker, Jiamin Bai, Tian-Tsong Ng, Ravi Ramamoorthi
PAMI 2011
Inverse light transport seeks to undo global illumination effects, such as interreflections, that pervade images of most scenes. This paper presents the theoretical and ... [more]
From the Rendering Equation to Stratified Light Transport Inversion
Tian-Tsong Ng, Ramampreet Singh Pahwa, Jiamin Bai, Kar-Han Tan, Ravi Ramamoorthi
IJCV 2011
Recent advances in fast light transport acquisition have motivated new applications for forward and inverse light transport. While forward light transport enables image ... [more]
Interactive Extraction and Re-Design of Sweep Geometries
James Andrews, Pushkar P. Joshi, Carlo H. Séquin
CGI 2011
We introduce two interactive extraction modules that can fit the parameters of generalized sweeps to large, unstructured meshes for immediate, high-level, detail-preserving ... [more]
Bringing Clothing into Desired Configurations with Limited Perception
Marco Cusumano-Towner, Arjun Singh, Stephen Miller, James F. O'Brien, Pieter Abbeel
ICRA 2011
We consider the problem of autonomously bringing an article of clothing into a desired configuration using a general-purpose two-armed robot. We propose a hidden Markov ... [more]
Modeling and Perception of Deformable One-Dimensional Objects
Shervin Javdani, Sameep Tandon, Jie Tang, James F. O'Brien, Pieter Abbeel
ICRA 2011
Recent advances in the modeling of deformable one-dimensional objects (DOOs) such as surgical suture, rope, and hair show significant promise for improving the simulation ... [more]
Frequency Analysis and Sheared Filtering for Shadow Light Fields of Complex Occluders
Kevin Egan, Florian Hecht, Frédo Durand, Ravi Ramamoorthi
TOG 2011
Monte Carlo ray tracing of soft shadows produced by area lighting and intricate geometries, such as the shadows through plant leaves or arrays of blockers, is a critical challenge ... [more]
Design Principles for Visual Communication
Maneesh Agrawala, Wilmot Li, Floraine Berthouzoz
CACM
Design principles connect the visual design of a visualization with the viewer’s perception and cognition of the underlying information the visualization is meant to ... [more]
Real-Time Rough Refraction
Charles De Rousiers, Adrien Bousseau, Kartic Subr, Nicolas Holzschuch, Ravi Ramamoorthi
I3D 2011
We present an algorithm to render objects of transparent materials with rough surfaces in real-time, under distant illumination. Rough surfaces cause wide scattering ... [more]
Eden: A Professional Multitouch Tool for Constructing Virtual Organic Environments
Kenrick Kin, Tom Miller, Björn Bollensdorff, Tony DeRose, Björn Hartmann, Maneesh Agrawala
CHI 2011
Set construction is the process of selecting and positioning virtual geometric objects to create a virtual environment used in a computer-animated film. Set construction ... [more]
FingerGlass: Efficient Multiscale Interaction on Multitouch Screens
Dominik Käser, Maneesh Agrawala, Mark Pauly
Many tasks in graphical user interfaces require users to inter- act with elements at various levels of precision. We present FingerGlass, a bimanual technique designed ... [more]
CommentSpace: Structured Support for Collaborative Visual Analysis
Wesley Willett, Jeffrey Heer, Joseph Hellerstein, Maneesh Agrawala
Collaborative visual analysis tools can enhance sensemaking by facilitating social interpretation and parallelization of effort. These systems enable distributed ... [more]
Computer generation of ribbed sculptures
James Hamlin, Carlo H. Séquin
JMA 2010
Charles Perry's monumental sculpture Solstice is analysed and its generative geometrical logic based on a twisted toroidal sweep is captured in a computer programme with ... [more]
Multi-Resolution Isotropic Strain Limiting
Huamin Wang, James F. O'Brien, Ravi Ramamoorthi
SIGGRAPH Asia 2010
In this paper we describe a fast strain-limiting method that allows stiff, incompliant materials to be simulated efficiently. Unlike prior approaches, which act on springs ... [more]
Automatic Generation of Destination Maps
Johannes Kopf, Maneesh Agrawala, David Bargeron, David Salesin, Michael F. Cohen
SIGGRAPH Asia 2010
Destination maps are navigational aids designed to show anyone within a region how to reach a location (the destination). Hand-designed destination maps include only the ... [more]
Symmetrical Embeddings of Regular Maps R5.13 and R5.6
Carlo H. Séquin
This report is a documentation of my trial-and-error design process to find a symmetrical embedding of the regular map R5.13 on a genus-5 2-manifold. It documents the non-linear ... [more]
Personalized Photograph Ranking and Selection System
Che-Hua Yeh, Yuan-Chen Ho, Brian A. Barsky, Ming Ouhyoung
ACM MM 2010
In this paper, we propose a novel personalized ranking system for amateur photographs. Although some of the features used in our system are similar to previous work, new features ... [more]
A Dual Theory of Inverse and Forward Light Transport
Jiamin Bai, Manmohan Chandraker, Tian-Tsong Ng, Ravi Ramamoorthi
ECCV 2010
We present the theoretical and computational foundations for inverse light transport as a dual of forward rendering. Inverse light transport seeks to undo global illumination ... [more]
Error-tolerant Image Compositing
Michael W. Tao, Micah K. Johnson, Sylvain Paris
ECCV 2010
Gradient-domain compositing is an essential tool in computer vision and its applications, e.g., seamless cloning, panorama stitching, shadow removal, scene completion and ... [more]
Example-Based Wrinkle Synthesis for Clothing Animation
Huamin Wang, Florian Hecht, Ravi Ramamoorthi, James F. O'Brien
SIGGRAPH 2010
This paper describes a method for animating the appearance of clothing, such as pants or a shirt, that fits closely to a figure's body. Compared to flowing cloth, such as loose ... [more]
Dynamic Local Remeshing for Elastoplastic Simulation
Martin Wicke, Daniel Ritchie, Bryan Klingner, Sebastian Burke, Jonathan Shewchuk, James F. O'Brien
SIGGRAPH 2010
We propose a finite element simulation method that addresses the full range of material behavior, from purely elastic to highly plastic, for physical domains that are substantially ... [more]
My Search for Symmetrical Embeddings of Regular Maps
Carlo H. Séquin
Bridges 2010
Various approaches are discussed for obtaining highly symmetrical and aesthetically pleasing space models of regular maps embedded in surfaces of genus 2 to 5. For many ... [more]
Image Warps for Artistic Perspective Manipulation
Robert Carroll, Aseem Agarwala, Maneesh Agrawala
Painters and illustrators commonly sketch vanishing points and lines to guide the construction of perspective images. We present a tool that gives users the ability to ... [more]
Illustrating How Mechanical Assemblies Work
Niloy J. Mitra, Yong-Liang Yang, Dong-Ming Yan, Wilmot Li, Maneesh Agrawala
How things work visualizations use a variety of visual techniques to depict the operation of complex mechanical assemblies. We present an automated approach for generating ... [more]
Sparsely Precomputing The Light Transport Matrix for Real-Time Rendering
Fu-Chung Huang, Ravi Ramamoorthi
EGSR 2010
Precomputation-based methods have enabled real-time rendering with natural illumination, all-frequency shadows, and global illumination. However, a major bottleneck ... [more]
Common Sense Community: Scaffolding Mobile Sensing and Analysis for Novice Users
Wesley Willett, Paul Aoki, Neil Kumar, Sushmita Subramanian, Allison Woodruff
As sensing technologies become increasingly distributed and democratized, citizens and novice users are becoming responsible for the kinds of data collection and analysis ... [more]
Two New Approaches to Depth of Field Post-Processing: Pyramid Spreading and Tensor Filtering
Todd J. Kosloff, Brian A. Barsky
VISIGRAPP 2010
Depth of field refers to the swath that is imaged in sharp focus through an optics system, such as a camera lens. Control over depth of field is an important artistic tool, which ... [more]
Simulation of Needle Insertion and Tissue Deformation for Modeling Prostate Brachytherapy
Nuttapong Chentanez, Ron Alterovitz, Daniel Ritchie, Lita Cho, Kris Hauser, Ken Goldberg, Jonathan Shewchuk, James F. O'Brien
ABS 2010
Realistic modeling of needle insertion during brachytherapy can be used for training and in automated planning to reduce errors between intended and actual placement ... [more]
Using Blur to Affect Perceived Distance and Size
Robert (Robin) Held, Emily Cooper, James F. O'Brien, Marty Banks
TOG 2010
We present a probabilistic model of how viewers may use defocus blur in conjunction with other pictorial cues to estimate the absolute distances to objects in a scene. Our ... [more]
An intuitive explanation of third-order surface behavior
Pushkar P. Joshi, Carlo H. Séquin
CAGD
We present a novel parameterization-independent exposition of the third-order geometric behavior of a surface point. Unlike existing algebraic expositions, our work ... [more]
Perceptual Guidelines for Creating Rectangular Treemaps
Nicholas Kong, Jeffrey Heer, Maneesh Agrawala
Treemaps are space-filling visualizations that make efficient use of limited display space to depict large amounts of hi- erarchical data. Creating perceptually effective ... [more]
Exploded View Diagrams of Mathematical Surfaces
Olga Karpenko, Wilmot Li, Niloy J. Mitra, Maneesh Agrawala
We present a technique for visualizing complicated mathematical surfaces that is inspired by hand-designed topological illustrations. Our approach generates exploded ... [more]
Removing Image Artifacts Due to Dirty Camera Lenses and Thin Occluders
Jinwei Gu, Ravi Ramamoorthi, Peter Belhumeur, Shree Nayar
SIGGRAPH ASIA 09
Dirt on camera lenses, and occlusions from thin objects such as fences, are two important types of artifacts in digital imaging systems. These artifacts are not only an annoyance ... [more]
Adaptive Wavelet Rendering
Ryan Overbeck, Craig Donner, Ravi Ramamoorthi
SIGGRAPH ASIA 09
Effects such as depth of field, area lighting, antialiasing and global illumination require evaluating a complex high-dimensional integral at each pixel of an image. We ... [more]
User-Assisted Intrinsic Images
Adrien Bousseau, Sylvain Paris, Fredo Durand
SIGGRAPH Asia 2009
For many computational photography applications, the lighting and materials in the scene are critical pieces of information. We seek to obtain intrinsic images, which decompose ... [more]
Edge-Based Image Coarsening
Raanan Fattal, Robert Carroll, Maneesh Agrawala
This paper presents a new dimensionally-reduced linear image space that allows a number of recent image manipulation techniques to be performed efficiently and robustly ... [more]
Generating Surface Crack Patterns
Hayley Iben, James F. O'Brien
Graphical Models
We present a method for generating surface crack patterns that appear in materials such as mud, ceramic glaze, and glass. To model these phenomena, we build upon existing physically ... [more]
Simulating Gaseous Fluids with Low and High Speeds
Yue Gao, Chen-Feng Li, Shi-Min Hu, Brian A. Barsky
Pacific Graphics 09
Gaseous fluids may move slowly, as smoke does, or at high speed, such as occurs with explosions. High-speed gas flow is always accompanied by low-speed gas flow, which produces ... [more]
Three Techniques for Rendering Generalized Depth of Field Effects
Todd J. Kosloff, Brian A. Barsky
MI 09
Depth of field refers to the swath that is imaged in sufficient focus through an optics system, such as a camera lens. Control over depth of field is an important artistic tool ... [more]
Radiometric Compensation Using Stratified Inverses
Tian-Tsong Ng, Ramanpreet S. Pahwa, Jiamin Bai, Tony Q. S. Quek, Kar-han Tan
ICCV 2009
Through radiometric compensation, a projector-camera system can project a desired image onto a non-flat and non-white surface. This can be achieved by computing the inverse ... [more]
Interactive Simulation of Surgical Needle Insertion and Steering
Nuttapong Chentanez, Ron Alterovitz, Daniel Ritchie, Lita Cho, Kris Hauser, Ken Goldberg, Jonathan Shewchuk, James F. O'Brien
SIGGRAPH 2009
We present algorithms for simulating and visualizing the insertion and steering of needles through deformable tissues for surgical training and planning. Needle insertion ... [more]
Real-Time Deformation and Fracture in a Game Environment
Eric G. Parker, James F. O'Brien
SCA 2009
This paper describes a simulation system that has been developed to model the deformation and fracture of solid objects in a real-time gaming context. Based around a corotational ... [more]
3D Clothing Fitting Based on the Geometric Feature Matching
Zhong Li, Xiaogang Jin, Brian Barsky, Jun Liu
CAD/Graphics 2009
The 3D clothing fitting on a body model is an important research topic in the garment computer aided design (GCAD). During the fitting process, the match between the clothing ... [more]
Optimizing Content-Preserving Projections for Wide-Angle Images
Robert Carroll, Maneesh Agrawala, Aseem Agarwala
SIGGRAPH 2009
Any projection of a 3D scene into a wide-angle image unavoidably results in distortion. Current projection methods either bend straight lines in the scene, or locally distort ... [more]
Generating Photo Manipulation Tutorials by Demonstration
Floraine Grabler, Maneesh Agrawala, Wilmot Li, Mira Dontcheva, Takeo Igarashi
We present a demonstration-based system for automatically generating succinct step-by-step visual tutorials of photo manipulations. An author first demonstrates ... [more]
An Empirical BSSRDF Model
Craig Donner, Jason Lawrence, Ravi Ramamoorthi, Toshiya Hachisuka, Henrik Wann Jensen, Shree Nayar
SIGGRAPH 09
We present a new model of the homogeneous BSSRDF based on large-scale simulations. Our model captures the appearance of materials that are not accurately represented using ... [more]
Frequency Analysis and Sheared Reconstruction for Rendering Motion Blur
Kevin Egan, Yu-Ting Tseng, Nicolas Holzschuch, Fredo Durand, Ravi Ramamoorthi
SIGGRAPH 09
Motion blur is crucial for high-quality rendering, but is also very expensive. Our first contribution is a frequency analysis of motionblurred scenes, including moving ... [more]
Moving Gradients: A Path-Based Method for Plausible Image Interpolation
Dhruv Mahajan, Fu-Chung Huang, Wojciech Matusik, Ravi Ramamoorthi, Peter Belhumeur
SIGGRAPH 09
We describe a method for plausible interpolation of images, with a wide range of applications like temporal up-sampling for smooth playback of lower frame rate video, smooth ... [more]
Tubular Sculptures
Carlo H. Séquin
Bridges 2009
This paper reviews ways in which many artists have constructed large sculptures from tubular elements, ranging from single cylinders to toroidal or knotted structures ... [more]
Visualizing High-Order Surface Geometry
Pushkar P. Joshi, Carlo H. Séquin
CAD&A 2009
We have derived parameters that describe the higher-order geometric behavior of smooth surfaces. Our parameters are similar in spirit to the principal directions and ... [more]
An Effective Third-order Local Fitting Patch and Its Application
Zhong Li, Brian Barsky, Xiaogang Jin
SMI 2009
In this paper, we extend Razdan and Bae’s second-order local fitting method [11] to construct an effective third-order fitting patch. Compared to other estimation algorithms ... [more]
Ribbed Surfaces for Art, Architecture, and Visualization
James Hamlin, Carlo H. Séquin
CAD&A 2009
Sequences of parameterized Hermite curves following with their endpoints along two guide rails are used to create "transparent" surfaces and tubular sculptures. This parameterized ... [more]
CAD Tools for Creating Space-filling 3D Escher Tiles
Mark Howison, Carlo H. Séquin
CAD&A 2009
We discuss the design and implementation of CAD tools for creating decorative solids that tile 3-space in a regular, isohedral manner. Starting with the simplest case of ... [more]
Interpolating Splines: Which is the fairest of them all?
Raph Levien, Carlo H. Séquin
CAD&A 2009
Interpolating splines are a basic primitive for designing planar curves. There is a wide diversity in the literature but no consensus on a "best" spline, or even criteria for ... [more]
Depth of Field Postprocessing For Layered Scenes Using Constant-Time Rectangle Spreading
Todd Kosloff, Michael W. Tao, Brian Barsky
GI 2009
Control over what is in focus and what is not in focus in an image is an important artistic tool. The range of depth in a 3D scene that is imaged in sufficient focus through an optics ... [more]
Determining the Benefits of Direct-Touch, Bimanual, and Multifinger Input on a Multitouch Workstation
Kenrick Kin, Maneesh Agrawala, Tony DeRose
Multitouch workstations support direct-touch, bimanual, and multifinger interaction. Previous studies have separately examined the benefits of these three interaction ... [more]
Parallax Photography: Creating 3D Cinematic Effects from Stills
Ke Colin Zheng, Alex Colburn, Aseem Agarwala, Maneesh Agrawala, Brian Curless, David Salesin, Michael Cohen
We present an approach to convert a small portion of a light field with extracted depth information into a cinematic effect with simulated, smooth camera motion that exhibits ... [more]
Precomputation-Based Rendering
Ravi Ramamoorthi
Foundations and Trends
High quality image synthesis is a long-standing goal in computer graphics. Complex lighting, reflection, shadow and global illumination effects can be rendered with modern ... [more]
Affine Double and Triple Product Wavelet Integrals for Rendering
Bo Sun, Ravi Ramamoorthi
TOG
Many problems in computer graphics involve integrations of products of functions. Double- and triple-product integrals are commonly used in applications such as all-frequency ... [more]
Refolding Planar Polygons
Hayley Iben, James F. O'Brien, Erik Demaine
DCG
This paper describes an algorithm for generating a guaranteed intersection-free interpolation sequence between any pair of compatible polygons. Our algorithm builds ... [more]
Compressive Light Transport Sensing
Pieter Peers, Dhruv Mahajan, Bruce Lamond, Abhijeet Ghosh, Wojciech Matusik, Ravi Ramamoorthi, Paul Debevec
TOG
In this article we propose a new framework for capturing light transport data of a real scene, based on the recently developed theory of compressive sensing. Compressive ... [more]
Sizing the Horizon: The Effects of Chart Size and Layering on the Graphical Perception of Time Series Visualizations
Jeffrey Heer, Nicholas Kong, Maneesh Agrawala
We investigate techniques for visualizing time series data and evaluate their effect in value comparison tasks. We compare line charts with
Perceptual Interpretation of Ink Annotations on Line Charts
Nicholas Kong, Maneesh Agrawala
Asynchronous collaborators often use freeform ink annotations to point to visually salient perceptual features of line charts such as peaks or humps, valleys, rising slopes ... [more]
A layered, heterogeneous reflectance model for acquiring and rendering human skin
Craig Donner, Tim Weyrich, Eugene d'Eon, Ravi Ramamoorthi, Szymon Rusinkiewicz
SIGGRAPH ASIA 08
We introduce a layered, heterogeneous spectral reflectance model for human skin. The model captures the inter-scattering of light among layers, each of which may have an ... [more]
Interactive 3D Architectural Modeling from Unordered Photo Collections
Sudipta Sinha, Drew Steedly, Rick Szeliski, Maneesh Agrawala, Marc Pollefeys
We present an interactive system for generating photorealistic, textured, piecewise-planar 3D models of architectural structures and urban scenes from unordered sets ... [more]
Video Puppetry: A Performative Interface for Cutout Animation
Connelly Barnes, David E. Jacobs, Jason Sanders, Dan B Goldman, Szymon Rusinkiewicz, Adam Finkelstein, Maneesh Agrawala
We present a video-based interface that allows users of all skill levels to quickly create cutout-style animations by performing the character motions. The puppeteer ... [more]
Searching the World's Herbaria: A System for Visual Identification of Plant Species
Peter N. Belhumeur, Daozheng Chen, Steven Feiner, David W. Jacobs, W. John Kress, Haibin Ling, Ida Lopez, Ravi Ramamoorthi, Sameer Sheorey, Sean White, Ling Zhang
ECCV 2008
We describe a working computer vision system that aids in the identification of plant species. A user photographs an isolated leaf on a blank background, and the system extracts ... [more]
Compressive Structured Light for Recovering Inhomogeneous Participating Media
Jinwei Gu, Shree Nayar, Eitan Grinspun, Peter Belhumeur, Ravi Ramamoorthi
ECCV 2008
We propose a new method named compressive structured light for recovering inhomogeneous participating media. Whereas conventional structured light methods emit coded ... [more]
Large Ray Packets for Real-time Whitted Ray Tracing
Ryan Overbeck, Ravi Ramamoorthi, William R. Mark
IRT 2008
In this paper, we explore large ray packet algorithms for acceleration structure traversal and frustum culling in the context of Whitted ray tracing, and examine how these ... [more]
Light Field Transfer: Global Illumination Between Real and Synthetic Objects
O. Cossairt, S. K. Nayar, Ravi Ramamoorthi
SIGGRAPH 08
We present a novel image-based method for compositing real and synthetic objects in the same scene with a high degree of visual realism. Ours is the first technique to allow ... [more]
Multiscale Texture Synthesis
Charles Han, Eric Risser, Ravi Ramamoorthi, Eitan Grinspun
SIGGRAPH 2008
Example-based texture synthesis algorithms have gained widespread popularity for their ability to take a single input image and create a perceptually similar non-periodic ... [more]
Automatic Generation of Tourist Maps
Floraine Grabler, Maneesh Agrawala, Robert W. Sumner, Mark Pauly
Tourist maps are essential resources for visitors to an unfamiliar city because they visually highlight landmarks and other points of interest. Yet, hand-designed maps ... [more]
The Assumed Light Direction for Perceiving Shape from Shading
James P. O'Shea, Martin S. Banks, Maneesh Agrawala
Recovering 3D shape from shading is an ill-posed problem that the visual system can solve only by making use of additional information such as the position of the light source ... [more]
Automated Generation of Interactive 3D Exploded View Diagrams
Wilmot Li, Maneesh Agrawala, Brian Curless, David Salesin
We present a system for creating and viewing interactive exploded views of complex 3D models. In our approach, a 3D input model is organized into an explosion graph that encodes ... [more]
Intricate Isohedral Tilings of 3D Euclidean Space
Carlo H. Séquin
Bridges 2008
Various methods to create intricate tilings of 3D space are presented. They include modulated extrusions of 2D Escher tilings, free-form deformations of the fundamental ... [more]
An Analysis of the In-Out BRDF Factorization for View-Dependent Relighting
Dhruv Mahajan, Yu-Ting Tseng, Eugene d'Eon, Ravi Ramamoorthi
ESR 08
Interactive rendering with dynamic natural lighting and changing view is a long-standing goal in computer graphics. Recently, precomputation-based methods for all-frequency ... [more]
Making Big Things Look Small: Blur combined with other depth cues affects perceived size and distance
Robert (Robin) Held, Emily Cooper, James F. O'Brien, Marty Banks
VSS 2008
Blur is commonly considered a weak distance cue, but photographic techniques that manipulate blur cause significant and compelling changes in the perceived distance ... [more]
A Precomputed Polynomial Representation for Interactive BRDF Editing with Global Illumination
Aner Ben-Artzi, Kevin Egan, Kevin Egan, Frédo Durand, Ravi Ramamoorthi
TOG
The ability to interactively edit BRDFs in their final placement within a computer graphics scene is vital to making informed choices for material properties. We significantly ... [more]
A Theory of Frequency Domain Invariants: Spherical Harmonic Identities for BRDF/Lighting Transfer and Image Consistency
Dhruv Mahajan, Ravi Ramamoorthi, Brian Curless
PAMI 2008
This work develops a theory of frequency domain invariants in computer vision. We derive novel identities using spherical harmonics, which are the angular frequency domain ... [more]
Geometrically exact dynamic splines
Adrien Theetten, Laurent Grisoni, Claude Andriot, Brian Barsky
Computer-Aided Design 2008
We propose a complete model handling the physical simulation of deformable 1D objects. We formulate continuous expressions for stretching, bending and twisting energies ... [more]
Design Considerations for Collaborative Visual Analytics
Jeffrey Heer, Maneesh Agrawala
Visualizations leverage the human visual system to support the process of sensemaking, in which information is collected, organized, and analyzed to generate knowledge ... [more]
Generalized Selection via Interactive Query Relaxation
Jeffrey Heer, Maneesh Agrawala, Wesley Willett
Selection is a fundamental task in interactive applications, typically performed by clicking or lassoing items of interest. However, users may require more nuanced forms ... [more]
Graphical Histories for Visualization: Supporting Analysis, Communication, and Evaluation
Jeffrey Heer, Jock D. Mackinlay, Chris Stolte, Maneesh Agrawala
Interactive history tools, ranging from basic undo and redo to branching timelines of user actions, facilitate iterative forms of interaction. In this paper, we investigate ... [more]
Effect of Character Animacy and Preparatory Motion on Perceptual Magnitude of Errors in Ballistic Motion
Paul Reitsma, James Andrews, Nancy Pollard
EG 2008
An increasing number of projects have examined the perceptual magnitude of visible artifacts in animated motion. These studies have been performed using a mix of character ... [more]
Agressive Tetrahedral Mesh Improvement
Bryan Klingner, Jonathan Shewchuk
2007 Meshing Roundtable
We present a tetrahedral mesh improvement schedule that usually creates meshes whose worst tetrahedra have a level of quality substantially better than those produced ... [more]
Liquid Simulation on Lattice-Based Tetrahedral Meshes
Nuttapong Chentanez, Bryan Feldman, François Labelle, James F. O'Brien, Jonathan Shewchuk
SCA 2007
This paper describes a simulation method for animating the behavior of incompressible liquids with complex free surfaces. The region occupied by the liquid is discretized ... [more]
A Theory of Locally Low Dimensional Light Transport
Dhruv Mahajan, Ira Kemelmacher Shlizerman, Ravi Ramamoorthi, Peter Belhumeur
SIGGRAPH 2007
Blockwise or Clustered Principal Component Analysis (CPCA) is commonly used to achieve real-time rendering of shadows and glossy reflections with precomputed radiance ... [more]
An Algorithm for Rendering Generalized Depth of Field Effects Based on Simulated Heat Diffusion
Todd Kosloff, Brian Barsky
ICCSA 2007
Depth of field refers to the swath through a 3Dscene that is imaged in acceptable focus through an optics system, such as a camera lens. Control over depth of field is an important ... [more]
Isosurface Stuffing: Fast Tetrahedral Meshes with Good Dihedral Angles
François Labelle, Jonathan Shewchuk
SIGGRAPH 2007
The isosurface stuffing algorithm fills an isosurface with a uniformly sized tetrahedral mesh whose dihedral angles are bounded between 10.7o and 164.8o, or (with a change ... [more]
Frequency Domain Normal Map Filtering
Charles Han, Bo Sun, Ravi Ramamoorthi, Eitan Grinspun
SIGGRAPH 2007
Filtering is critical for representing image-based detail, such as textures or normal maps, across a variety of scales. While mipmapping textures is commonplace, accurate ... [more]
Symmetric Embedding of Locally Regular Hyperbolic Tilings
Carlo H. Séquin
Bridges 2007
Various methods to create intricate tilings of 3D space are presented. They include modulated extrusions of 2D Escher tilings, free-form deformations of the fundamental ... [more]
Energy Minimizers for Curvature-Based Surface Functionals
Pushkar P. Joshi, Carlo H. Séquin
We compare curvature-based surface functionals by comparing the aesthetic properties of their minimizers. We introduce an enhancement to the original inline curvature ... [more]
Computer-Aided Design and Realization of Geometrical Sculptures
Carlo H. Séquin
The use of computer-aided design tools in the conception and realization of large-scale geometrical bronze sculptures is described. An inspirational piece of sculpture ... [more]
Viewpoint-Coded Structured Light
Mark Young, Erik Beeson, James Davis, Szymon Rusinkiewicz, Ravi Ramamoorthi
CVPR 2007
We introduce a theoretical framework and practical algorithms for replacing time-coded structured light patterns with viewpoint codes, in the form of additional camera ... [more]
Dirty Glass: Rendering Contamination on Transparent Surfaces
Jinwei Gu, Ravi Ramamoorthi, Peter N. Belhumeur, Shree Nayar
EGSR 2007
Rendering of clean transparent objects has been well studied in computer graphics. However, real-world transparent objects are seldom clean--their surfaces have a variety ... [more]
A Real-Time Beam Tracer with Application to Exact Soft Shadows
Ryan Overbeck, Ravi Ramamoorthi, William R. Mark
EGSR 2007
Efficiently calculating accurate soft shadows cast by area light sources remains a difficult problem. Ray tracing based approaches are subject to noise or banding, and most ... [more]
A Method for Cartoon-Style Rendering of Liquid Animations
Ashley M. Eden, Adam Bargteil, Tolga Goktekin, Sara Beth Eisinger, James F. O'Brien
GI 2007
In this paper we present a visually compelling and informative cartoon rendering style for liquid animations. Our style is inspired by animations such as Futurama, The Little ... [more]
Hyper-Seeing the Regular Hendeca-choron
Carlo H. Séquin
ISAMA 2007
The hendecachoron is an abstract 4-dimensional polytope composed of eleven cells in the form of hemi-icosahedra. This paper tries to foster an understanding of this intriguing ... [more]
Design and Implementation of Pax Mundi II
Carlo H. Séquin
On January 18, 2007 a ten foot tall bronze sculpture Pax Mundi II was installed in the courtyard of the H&R Block headquarters in Kansas City. This paper describes the computer-aided ... [more]
Time-Varying BRDFs
Bo Sun, Kalyan Sunkavalli, Ravi Ramamoorthi, Peter Belhumeur, Shree Nayar
TVCG 2007
The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However ... [more]
Real-Time Ambient Occlusion for Dynamic Character Skins
Adam Kirk, Okan Arikan
I3D 2007
We present a single-pass hardware accelerated method to reconstruct compressed ambient occlusion values in real-time on dynamic character skins. This method is designed ... [more]
A first-order analysis of lighting, shading, and shadows
Ravi Ramamoorthi, Dhruv Mahajan, Peter Belhumeur
TOG
The shading in a scene depends on a combination of many factors---how the lighting varies spatially across a surface, how it varies along different directions, the geometric ... [more]
4D compression and relighting with high-resolution light transport matrices
Ewen Cheslack-Postava, Nolan Goodnight, Ren Ng, Ravi Ramamoorthi, Greg Humphreys
I3D 2007
This paper presents a method for efficient compression and relighting with high-resolution, precomputed light transport matrices. We accomplish this using a 4D wavelet ... [more]
A semi-Lagrangian contouring method for fluid simulation
Adam Bargteil, Tolga Goktekin, James F. O'Brien, John A. Strain
ACM Trans. Graphics
In this paper we present a semi-Lagrangian surface tracking method for use with fluid simulations. Our method maintains an explicit polygonal mesh that defines the surface ... [more]
Optimization of HDR brachytherapy dose distributions using linear programming with penalty costs
Ron Alterovitz, Etienne Lessard, Jean Pouliot, I-Chow Joe Hsu, James F. O'Brien, Ken Goldberg
J. Medical Physics
Prostate cancer is increasingly treated with high-dose-rate (HDR) brachytherapy, a type of radiotherapy in which a radioactive source is guided through catheters temporarily ... [more]
Efficient Shadows from Sampled Environment Maps
Aner Ben-Artzi, Ravi Ramamoorthi, Maneesh Agrawala
JGT 06
This paper addresses the problem of efficiently calculating shadows from environment maps. Since accurate rendering of shadows from environment maps requires hundreds ... [more]
A Texture Synthesis Method for Liquid Animations
Adam Bargteil, Funshing Sin, Jonathan E. Michaels, Tolga Goktekin, James F. O'Brien
SCA 2006
In this paper we present a method for synthesizing textures on animated liquid surfaces generated by a physically based fluid simulation system. Rather than advecting ... [more]
Generating Surface Crack Patterns
Hayley Iben, James F. O'Brien
SCA 2006
We present a method for generating surface crack patterns that appear in materials such as mud, ceramic glaze, and glass. To model these phenomena, we build upon existing physically ... [more]
Simultaneous Coupling of Fluids and Deformable Bodies
Nuttapong Chentanez, Tolga Goktekin, Bryan Feldman, James F. O'Brien
SCA 2006
This paper presents a method for simulating the two-way interaction between fluids and deformable solids. The fluids are simulated using an incompressible Eulerian formulation ... [more]
Fluid Animation with Dynamic Meshes
Bryan Klingner, Bryan Feldman, Nuttapong Chentanez, James F. O'Brien
SIGGRAPH 2006
This paper presents a method for animating fluid with unstructured tetrahedral meshes that change at each time step. Meshes that conform well to changing boundaries and ... [more]
A Texture Synthesis Method for Liquid Animations
Adam Bargteil, Funshing Sin, Jonathan Michaels, James F. O'Brien
SIGGRAPH 2006 Tech Sketch
In this sketch we present a method for synthesizing textures on animated liquid surfaces generated by a physically based fluid simulation system. Rather than advecting ... [more]
Acquiring Scattering Properties of Participating Media by Dilution
Srinivasa G. Narasimhan, Mohit Gupta, Craig Donner , Ravi Ramamoorthi, Shree Nayar, Henrik Wann Jensen
SIGGRAPH 2006
The visual world around us displays a rich set of volumetric effects due to participating media. The appearance of these media is governed by several physical properties ... [more]
Reflectance Sharing: Predicting Appearance from a Sparse Set of Images of a Known Shape
Todd Zickler, Sebastian Enrique, Ravi Ramamoorthi, Peter Belhumeur
PAMI 2006 Aug
When the shape of an object is known, its appearance is determined by the spatially-varying reflectance function defined on its surface. Image-based rendering methods ... [more]
Time-varying surface appearance: acquisition, modeling and rendering
Jinwei Gu, Chien-I Tu, Ravi Ramamoorthi, Peter Belhumeur, Wojciech Matusik, Shree Nayar
SIGGRAPH 2006
In this project, we take a significant step towards measuring, modeling and rendering time-varying surface appearance. Traditional computer graphics rendering generally ... [more]
A Compact Factored Representation of Heterogeneous Subsurface Scattering
Pieter Peers, Karl vom Berge, Wojciech Matusik, Ravi Ramamoorthi, Jason Lawrence, Szymon Rusinkiewicz, Philip Dutr{\'e}
SIGGRAPH 2006
Heterogeneous subsurface scattering in translucent materials is one of the most beautiful but complex effects. We acquire spatial BSSRDF datasets using a projector, and ... [more]
Simultaneous Coupling of Fluids and Deformable Bodies
Nuttapong Chentanez, Tolga Goktekin, Bryan Feldman, James F. O'Brien
SIGGRAPH 2006 Tech Sketch
We describe a method for simultaneous two-way coupling of fluid and deformable bodies. The interaction between a fluid and deformable body can create complex and interesting ... [more]
Inverse shade trees for non-parametric material representation and editing
Jason Lawrence, Aner Ben-Artzi, Christopher DeCoro, Wojciech Matusik, Hanspeter Pfister, Ravi Ramamoorthi, Szymon Rusinkiewicz
SIGGRAPH 2006
Recent progress in the measurement of surface reflectance has created a demand for non-parametric appearance representations that are accurate, compact, and easy to use ... [more]
Real-Time BRDF Editing in Complex Lighting
Aner Ben-Artzi, Ryan Overbeck, Ravi Ramamoorthi
SIGGRAPH 06
Current systems for editing BRDFs typically allow users to adjust analytic parameters while visualizing the results in a simplified setting (e.g. unshadowed point light ... [more]
Patterns on the Genus-3 Klein Quartic
Carlo H. Séquin
Bridges 2006
Projections of Klein's quartic surface of genus 3 into 3D space are used as canvases on which we present regular tessellations, Escher tilings, knot- and graph-embedding ... [more]
Refolding Planar Polygons
Hayley Iben, James F. O'Brien, Erik Demaine
SoCG 2006
This paper describes an algorithm for generating a guaranteed-intersection-free interpolation sequence between any pair of compatible polygons. Our algorithm builds ... [more]
Extensions for 3D Graphics Rendering Engine used for Direct Tessellation of Spline Surfaces
Adrien Sfarti, Brian Barsky, Todd Kosloff, Egon Pasztor, Alex Kozlowski, Eric Roman, Alex Perelman
ICCS 2006
In current 3D graphics architectures, the bus between the triangle server and the rendering engine GPU is clogged with triangle vertices and their many attributes (normal ... [more]
New 3D Graphics Rendering Engine Architecture for Direct Tessellation of Spline Surfaces
Adrien Sfarti, Brian Barsky, Todd Kosloff, Egon Pasztor, Alex Kozlowski, Eric Roman, Alex Perelman
3IA 2006
In current 3D graphics architectures, the bus between the triangle server and the rendering engine GPU is clogged with triangle vertices and their many attributes (normal ... [more]
Human Vision Based Detection of Non-Uniform Brightness on LCD Panels
Jee Hong Kim, Brian Barsky
MVAII 2004
We propose a method to detect defects due to spatially non-uniform brightness on LCD panels by using a machine vision technique. The detection method is based on human vision ... [more]
Exploiting Temporal Coherence for Incremental All-Frequency Relighting
Ryan Overbeck, Aner Ben-Artzi, Ravi Ramamoorthi, Eitan Grinspun
EGSR 2006
Current PRT methods exploit spatial coherence of the lighting (such as with wavelets) and of light transport (such as with CPCA). We consider a significant, yet unexplored form ... [more]
Modeling Illumination Variation with Spherical Harmonics
Ravi Ramamoorthi
The appearance of objects including human faces can vary dramatically with the lighting. We present results that use spherical harmonic illumination basis functions ... [more]
Computational Studies of Human Motion: Tracking and Motion Synthesis
David Forsyth, Okan Arikan, Leslie Ikemoto, James F. O'Brien, Deva Ramanan
Foundations and Trends
We review methods for kinematic tracking of the human body in video. The review is part of a projected book that is intended to cross-fertilize ideas about motion representation ... [more]
Interactive Procedural Computer-Aided Design
Carlo H. Séquin
CAD/Graphics 2005
The typical engineering design process can be decomposed into several phases: creative exploration of ideas, testing soundness of proposed concepts, refining concepts ... [more]
Semi-Automated Ultrasound Interpretation System Using Anatomical Knowledge Representation
Michael S. Downes, Brian Barsky
VC 2005
Interpreting ultrasound data presents a significant challenge to medical personnel, which limits the clinical applications of the technology. We have addressed this ... [more]
Elimination of Artifacts Due to Occlusion and Discretization Problems in Image Space Blurring Techniques
Brian Barsky, Michael Tobias, Derrick P. Chu, Daniel R. Horn
GM 2005
Traditional computer graphics methods render images that appear sharp at all depths. Adding blur can add realism to a scene, provide a sense of scale, and draw a viewerÕs attention ... [more]
Animating Gases with Hybrid Meshes
Bryan Feldman, James F. O'Brien, Bryan Klingner
SIGGRAPH 2005
This paper presents a method for animating gases on unstructured tetrahedral meshes to efficiently model the interaction of the fluids with irregularly shaped obstacles ... [more]
Efficiently Combining Positions and Normals for Precise 3D Geometry
Diego Nehab, Szymon Rusinkiewicz, James Davis, Ravi Ramamoorthi
SIGGRAPH 2005
Range scanning, manual 3D editing, and other modeling approaches can provide information about the geometry of surfaces in the form of either 3D positions (e.g., triangle meshes ... [more]
A Practical Analytic Single Scattering Model for Real Time Rendering
Bo Sun, Ravi Ramamoorthi, Srinivasa Narasimhan, Shree Nayar
SIGGRAPH 2005
We consider real-time rendering of scenes in participating media, capturing the effects of light scattering in fog, mist and haze. While a number of sophisticated approaches ... [more]
Provably Good Moving Least Squares
Ravi Kolluri
SODA 2005
We analyze a moving least squares algorithm for reconstructing a surface from point cloud data. Our algorithm defines an implicit function I whose zero set U is the reconstructed ... [more]
Fast and Detailed Approximate Global Illumination by Irradiance Decomposition
Okan Arikan, David A. Forsyth, James F. O'Brien
SIGGRAPH 2005
In this paper we present an approximate method for accelerated computation of the final gathering step in a global illumination algorithm. Our method operates by decomposing ... [more]
Fluids in Deforming Meshes
Bryan Feldman, James F. O'Brien, Bryan Klingner, Tolga Goktekin
SCA 2005
This paper describes a simple modification to an Eulerian fluid simulation that permits the underlying mesh to deform independent of the simulated fluid's motion. The modification ... [more]
Pushing People Around
Okan Arikan, David Forsyth, James F. O'Brien
SCA 2005
We present an algorithm for animating characters being pushed by an external source such as a user or a game environment. We start with a collection of motions of a real person ... [more]
A semi-Lagrangian contouring method for fluid simulation
Adam Bargteil, Tolga Goktekin, James F. O'Brien, John A. Strain
SIGGRAPH 2005 Tech Sketch
In this sketch we present a semi-Lagrangian surface tracking method for use with fluid simulations. Our method main- tains an explicit polygonal mesh that defines the surface ... [more]
Symmetrical Hamiltonian Manifolds on Regular 3D and 4d Polytopes
Carlo H. Séquin
Coxeter Day 2005
Hamiltonian cycles on the edge graphs of the regular polytopes in three and four dimensions are investigated with the primary goal of finding complete multi-colored coverages ... [more]
Splitting Tori, Knots, and Moebius Bands
Carlo H. Séquin
Bridges 2005
A study of sculptures and puzzles resulting from splitting lengthwise, tori, Moebius bands, various knots and graphs, illustrated with many models made on rapid prototyping ... [more]
Adaptive Numerical Cumulative Distribution Functions for Efficient Importance Sampling
Jason Lawrence, Szymon Rusinkiewicz, Ravi Ramamoorthi
EGSR 2004
As image-based surface reflectance and illumination gain wider use in physically-based rendering systems, it is becoming more critical to provide representations that ... [more]
Skeletal Parameter Estimation from Optical Motion Capture Data
Adam Kirk, James F. O'Brien, David Forsyth
CVPR 2005
In this paper we present an algorithm for automatically estimating a subject’s skeletal structure from optical mo- tion capture data. Our algorithm consists of a series ... [more]
New 3D Graphics Rendering Engine Architecture for Direct Tessellation of Spline Surfaces
Adrien Sfarti, Brian Barsky, Todd Kosloff, Egon Pasztor, Alex Kozlowski, Eric Roman, Alex Perelman
ICCS 2005
In current 3D graphics architectures, the bus between the triangle server and the rendering engine GPU is clogged with triangle vertices and their many attributes (normal ... [more]
A Fourier Theory for Cast Shadows
Ravi Ramamoorthi, Melissa Koudelka, Peter Belhumeur
PAMI 2005
Cast shadows can be significant in many computer vision applications, such as lighting-insensitive recognition and surface reconstruction. Nevertheless, most algorithms ... [more]
Spacetime Stereo: A Unifying Framework for Depth from Triangulation
James Davis, Diego Nehab, Ravi Ramamoorthi, Szymon Rusinkiewicz
PAMI 2005
Depth from triangulation has traditionally been treated in a number of separate threads in the computer vision literature, with methods like stereo, laser scanning, and ... [more]
Reflectance Sharing: Image-based Rendering from a Sparse Set of Images
Todd Zickler, Sebastian Enrique, Ravi Ramamoorthi, Peter Belhumeur
EGSR 2005
When the shape of an object is known, its appearance is determined by the spatially-varying reflectance function defined on its surface. Image-based rendering methods ... [more]
A Signal-Processing for Reflection
Ravi Ramamoorthi, Pat Hanrahan
TOG 2004
We present a signal-processing framework for analyzing the reflected light field from a homogeneous convex curved surface under distant illumination. This analysis ... [more]
A Method for Animating Viscoelastic Fluids
Tolga Goktekin, Adam Bargteil, James F. O'Brien
SIGGRAPH 2004
This paper describes a technique for animating the behavior of viscoelastic fluids, such as mucus, liquid soap, pudding, toothpaste, or clay, that exhibit a combination of both ... [more]
Skeletal Parameter Estimation from Optical Motion Capture Data
Adam Kirk, James F. O'Brien, David Forsyth
SIGGRAPH 2004 Tech Sketch
In this sketch we present an algorithm for automatically estimating a subject's skeletal structure from optical motion capture data without using any a priori skeletal ... [more]
Refolding Planar Polygons
Hayley Iben, James F. O'Brien, Erik Demaine
SIGGRAPH 2004 Tech Sketch
This sketch describes a guaranteed technique for generating intersection-free interpolation sequences between arbitrary, non-intersecting, planar polygons. The computational ... [more]
Interpolating and Approximating Implicit Surfaces from Polygon Soup
Chen Shen, James F. O'Brien, Jonathan Shewchuk
SIGGRAPH 2004
This paper describes a method for building interpolating or approximating implicit surfaces from polygonal data. The user can choose to generate a surface that exactly ... [more]
Radiance Caching and Local Geometry Correction
Okan Arikan, David A. Forsyth, James F. O'Brien
SIGGRAPH 2004 Tech Sketch
We present a final gather algorithm which splits the irradiance integral into two components. One component captures the incident radiance due to distant surfaces. This ... [more]
An Opponent Process Approach to Modeling the Blue Shift of the Human Color Vision System
Brian Barsky, Todd Kosloff, Steven D. Upstill
APGV 2004
Low light level affects human visual perception in various ways. Visual acuity is reduced and scenes appear bluer, darker, less saturated, and with reduced contrast. We confine ... [more]
Rendering Skewed Plane of Sharp Focus and Associated Depth of Field
Brian Barsky, Egon Pasztor
SIGGRAPH 2004
Depth of field is the region of a scene that is in focus in an image. This is measured relative to a plane-of-sharp focus. When using a physical camera, this plane is perpendicular ... [more]
Vision-Realistic Rendering: Simulation of the Scanned Foveal Image from Wavefront Data of Human Subjects
Brian Barsky
APGV 2004
We introduce the concept of vision-realistic rendering – the com- puter generation of synthetic images that incorporate the charac- teristics of a particular individual ... [more]
Efficient BRDF Importance Sampling Using a Factored Representation
Jason Lawrence, Szymon Rusinkiewicz, Ravi Ramamoorthi
SIGGRAPH 2004
High-quality Monte Carlo image synthesis requires the ability to importance sample realistic BRDF models. However, analytic sampling algorithms exist only for the Phong ... [more]
Triple Product Wavelet Integrals for All-Frequency Relighting
Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
SIGGRAPH 2004
This paper focuses on efficient rendering based on pre-computed light transport, with realistic materials and shadows under all-frequency direct lighting such as environment ... [more]
Spectral Surface Reconstruction from Noisy Point Clouds
Ravi Kolluri, Jonathan Shewchuk, James F. O'Brien
SGP 2004
We introduce a noise-resistant algorithm for reconstructing a watertight surface from point cloud data. It forms a Delaunay tetrahedralization, then uses a variant of ... [more]
Practical Rendering of Multiple Scattering Effects in Participating Media
Simon Premože, Michael Ashikhmin, Ravi Ramamoorthi, Shree K. Nayar
EGSR 2004
Volumetric light transport effects are significant for many materials like skin, smoke, clouds, snow or water. In particular, one must consider the multiple scattering of ... [more]
An Energy-Driven Approach to Linkage Unfolding
Jason Cantarella, Erik Demaine, Hayley Iben, James F. O'Brien
SoCG 2004
We present a new algorithm for unfolding planar polygonal linkages without self-intersection based on following the gradient flow of a "repulsive" energy function. This ... [more]
A Fourier Theory for Cast Shadows
Ravi Ramamoorthi, Melissa Koudelka, Peter Belhumeur
ECCV 2004
Cast shadows can be significant in many computer vision applications such as lighting-insensitive recognition and surface reconstruction. However, most algorithms ... [more]
Motion Synthesis from Anotations
Okan Arikan, David Forsyth, James F. O'Brien
SIGGRAPH 2003
This paper describes a framework that allows a user to synthesize human motion while retaining control of its qualitative properties. The user paints a timeline with annotations ... [more]
Animating Suspended Particle Explosions
Bryan Feldman, James F. O'Brien, Okan Arikan
SIGGRAPH 2003
This paper describes a method for animating suspended particle explosions. Rather than modeling the numerically troublesome, and largely invisible blast wave, the method ... [more]
All-Frequncy Shadows Using Non-linear Wavelet Lighting Approximation
Ren Ng, Ravi Ramamoorthi, Pat Hanrahan
SIGGRAPH 2003
We present a method, based on pre-computed light transport, for real-time rendering of objects under all-frequency, time-varying illumination represented as a high-resolution ... [more]
Spectral Watertight Surface Reconstruction
Ravi Kolluri, Jonathan Shewchuk, James F. O'Brien
SIGGRAPH 2003 Tech Sketch
We use spectral partitioning to reconstruct a watertight surface from point cloud data. This method is particularly effective for noisy and undersampled point sets with ... [more]
Investigating Occlusion and Discretization Problems in Image Space Blurring Techniques
Brian Barsky, Michael J. Tobias, Daniel R. Horn, Derrick P. Chu
VVG 2003
Traditional computer graphics methods render images that appear sharp at all depths. Adding blur can add realism to a scene, provide a sense of scale, and draw a viewer’s attention ... [more]
Interactive Deformation Using Modal Analysis with Constraints
Kris Hauser, Chen Shen, James F. O'Brien
Graphics Interface 2003
Modal analysis provides a powerful tool for efficiently simulating the behavior of deformable objects. This paper shows how manipulation, collision, and other constraints ... [more]
Camera Models and Optical Systems Used in Computer Graphics: Part I, Object Based Techniques
Brian Barsky, Daniel R. Horn, Stanley A. Klein, Jeffrey A. Pang, Meng Yu
ICCSA 03
Images rendered with traditional computer graphics techniques, such as scanline rendering and ray tracing, appear focused at all depths. However, there are advantages to ... [more]
Camera Models and Optical Systems Used in Computer Graphics: Part II, Image Based Techniques
Brian Barsky, Daniel R. Horn, Stanley A. Klein, Jeffrey A. Pang, Meng Yu
ICCSA 03
In our companion paper [5], we described the optics underlying camera models that have been used in computer graphics, and presented object space techniques for rendering ... [more]
Structured Importance Sampling of Environment Maps
Sameer Agarwal, Ravi Ramamoorthi, Serge J. Belongie, Henrik Wann Jensen
SIGGRAPH 2003
We introduce structured importance sampling, a new technique for efficiently rendering scenes illuminated by distant natural illumination given in an environment map ... [more]
Spacetime Stereo: A Unifying Framework for Depth from Triangulation
James Davis, Ravi Ramamoorthi, Szymon Rusinkiewicz
CVPR 2003
Depth from triangulation has traditionally been treated in a number of separate threads in the computer vision literature, with methods like stereo, laser scanning, and ... [more]
Using Specularities for Recognition
Margarita Osadchy, David Jacobs, Ravi Ramamoorthi
ICCV 2003
Recognition systems have generally treated specular highlights as noise. We show how to use these highlights as a positive source of information that improves recognition ... [more]
An Energy-Driven Approach to Linkage Unfolding
Jason Cantarella, Erik Demaine, Hayley Iben, James F. O'Brien
DIMACS 2002
In this paper, we introduce a new energy-driven approach for straightening polygonal arcs and convexifying polygonal cycles without self-intersection based on following ... [more]
Modelling with Implicit Surfaces that Interpolate
Greg Turk, James F. O'Brien
TOG
We introduce new techniques for modelling with interpolating implicit surfaces. This form of implicit surface was first used for problems of surface reconstruction and ... [more]
Graphical Modeling and Animation of Ductile Fracture
James F. O'Brien, Adam Bargteil, Jessica Hodgins
SIGGRAPH 2002
In this paper, we describe a method for realistically animating ductile fracture in common solid materials such as plastics and metals. The effects that characterize ductile ... [more]
Synthesizing sounds from rigid-body simulations
James F. O'Brien, Chen Shen, Christine Gatchalian
SCA 2002
This paper describes a real-time technique for generating realistic and compelling sounds that correspond to the motions of rigid objects. By numerically precomputing ... [more]
Modal Analysis for Real-Time Viscoelastic Deformation
Chen Shen, Kris Hauser, Christine Gatchalian, James F. O'Brien
SIGGRAPH 2002 Tech Sketch
This technical sketch describes how a standard analysis technique known as modal decomposition can be used for real-time model- ing of viscoelastic deformation. While ... [more]
Modeling the Accumulation of Wind-Driven Snow
Bryan Feldman, James F. O'Brien
SIGGRAPH 2002 Tech Sketch
This technical sketch presents a method for modeling the appearance of snow drifts formed by the accumulation of wind-blown snow near buildings and other obstacles. Our ... [more]
Frequency Space Environment Map Rendering
Ravi Ramamoorthi, Pat Hanrahan
SIGGRAPH 2002
We present a new method for real-time rendering of objects with complex isotropic BRDFs under distant natural illumination, as specified by an environment map. Our approach ... [more]
Analytic PCA construction for theoretical analysis of lighting variability in images of a Lambertian object
Ravi Ramamoorthi
PAMI 2001
We analyze theoretically the subspace best approximating images of a convex Lambertian object taken from the same viewpoint, but under different distant illumination ... [more]
Synthesizing Sounds from Physically Based Motion
James F. O'Brien, Perry R. Cook, Georg Essl
SIGGRAPH 2001
The goal of this work is to develop techniques for approximating sounds that are generated by the motions of solid objects. Our methods builds on previous work in the field ... [more]
Image Based Rendering and Illumination Using Spherical Mosaics
Chen Shen, Heung-Yeung Shum, James F. O'Brien
SIGGRAPH 2001 Tech Sketch
The work described here extends the concentric mosaic representation developed by Shum and He to spherical mosaics that allow the viewer greater freedom of movement. Additionally ... [more]
Implicit Surfaces that Interpolate
Greg Turk, GHuong Quynh Dinh, James F. O'Brien, Gary Yngve
Shape Modeling International 2001
Implicit surfaces are often created by summing a collection of radial basis functions. Recently, researchers have begun to create implicit surfaces that exactly interpolate ... [more]
Analysis of Planar Light Fields From Homogeneous Convex Curved Surfaces Under Distant Illumination
Ravi Ramamoorthi, Pat Hanrahan
We consider the flatland or 2D properties of the light field generated when a homogeneous convex curved surface reflects a distant illumination field. Besides being of ... [more]
An Efficient Representation for Irradiance Environment Maps
Ravi Ramamoorthi, Pat Hanrahan
SIGGRAPH 2001
We consider the rendering of diffuse objects under distant illumination, as specified by an environment map. Using an analytic expression for the irradiance in terms of ... [more]
A Signal-Processing Framework for Inverse Rendering
Ravi Ramamoorthi, Pat Hanrahan
SIGGRAPH 2001
Realism in computer-generated images requires accurate input models for lighting, textures and BRDFs. One of the best ways of obtaining high-quality data is through measurements ... [more]
On the relationship between Radiance and Irradiance: Determining the illumination from images of a convex Lambertian object
Ravi Ramamoorthi, Pat Hanrahan
JOSA 2001
We present a theoretical analysis of the relationship between incoming radiance and irradiance. Specifically, we address the question of whether it is possible to compute ... [more]
Animating Fracture
James F. O'Brien, Jessica Hodgins
CACM
We have developed a simulation technique that uses non-linear finite element analysis and elastic fracture mechanics to compute physically plausible motion for three-dimensional ... [more]
Combining Active and Passive Simulations for Secondary Motion
James F. O'Brien, Victor Zordan, Jessica Hodgins
CG&A
Objects that move in response to the actions of a main character often make an important contribution to the visual richness of an animated scene. We use the term "secondary ... [more]
Animating Explosions
Gary D. Yngve, James F. O'Brien, Jessica K. Hodgins
SIGGRAPH 2000
In this paper, we introduce techniques for animating explosions and their effects. The primary effect of an explosion is a disturbance that causes a shock wave to propagate ... [more]
Automatic Joint Parameter Estimation from Magnetic Motion Capture Data
James F. O'Brien, Robert Bodenheimer, Gabriel Brostow, Jessica Hodgins
GI 2000
This paper describes a technique for using magnetic motion capture data to determine the joint parameters of an articulated hierarchy. This technique makes it possible ... [more]
Efficient Image-Based Methods for Rendering Soft Shadows
Maneesh Agrawala, Ravi Ramamoorthi, Alan Heirich, Laurent Moll
SIGGRAPH 2000
We present two efficient image-based approaches for computation and display of high-quality soft shadows from area light sources. Our methods are related to shadow maps ... [more]
Graphical Modeling and Animation of Brittle Fracture
James F. O'Brien, Jessica Hodgins
SIGRAPH 1999
In this paper, we augment existing techniques for simulating flexible objects to include models for crack initiation and propagation in three-dimensional volumes. By ... [more]
Shape Transformation Using Variational Implicit Functions
James F. O'Brien, Greg Turk
SIGGRAPH 1999
Traditionally, shape transformation using implicit functions is performed in two distinct steps: 1) creating two implicit functions, and 2) interpolating between these ... [more]
Animating Sand, Mud, and Snow
Robert Sumner, James F. O'Brien, Jessica Hodgins
CGF
Computer animations often lack the subtle environmental changes that should occur due to the actions of the characters. Squealing car tires usually leave no skid marks ... [more]
Creating Generative Models from Range Images
Ravi Ramamoorthi, James Arvo
SIGGRAPH '99
We describe a new approach for creating concise high-level generative models from range images or other methods of obtaining approximate point clouds. Using a variety ... [more]
Perception of Human Motion with Different Geometric Models
Jessica Hodgins, James F. O'Brien, Jack Tumblin
TVCG 1998
Human figures have been animated using a variety of geometric models including stick figures, polygonal models, and NURBS-based models with muscles, flexible skin, or clothing ... [more]
Animating Sand, Mud, and Snow
Robert Sumner, James F. O'Brien, Jessica Hodgins
GI 98
Computer animations often lack the subtle environmental changes that should occur due to the actions of the char- acters. Squealing car tires usually leave no skid marks ... [more]
Combining Active and Passive Simulations for Secondary Motion
James F. O'Brien, Victor Zordan, Jessica Hodgins
SIGGRAPH 1997 Tech Sketch
The secondary motion of passive objects in the scene is essential for appealing and natural-looking animated characters, but because of the difficulty of controlling ... [more]
Do Geometric Models Affect Judgments of Human Motion?
Jessica Hodgins, James F. O'Brien, Jack Tumblin
GI 97
Human figures have been animated using a wide variety of geometric models including stick figures, polygonal models, and NURBS-based models with muscles, flexible skin ... [more]
Fast Construction of Accurate Quaternion Splines
Ravi Ramamoorthi, Alan H. Barr
SIGGRAPH '97
In 1992, Barr et al proposed a method for interpolating orientations with unit quaternion curves by minimizing covariant acceleration. This paper presents a simple improved ... [more]
Animating Human Athletics
Jessica Hodgins, Wayne Wooten, David Brogan, James F. O'Brien
SIGGRAPH 1995
This paper describes algorithms for the animation of men and women performing three dynamic athletic behaviors: running, bicycling, and vaulting. We animate these behaviors ... [more]
Dynamic Simulation of Splashing Fluids
James F. O'Brien, Jessica Hodgins
Computer Animation 95
In this paper we describe a method for modeling the dynamic behavior of splashing fluids. The model simulates the behavior of a fluid when objects impact or float on its surface ... [more]