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Voicu Popescu

Associate Professor of Computer Science

Computer Graphics and Visualization Lab

 

305 North University Street

West Lafayette, IN 47907-2107

popescu@cs.purdue.edu

Office: LWSN 3179

Tel:  (765) 494-6010  

Fax : (765) 494-0739

Teaching

-       Fall 2016: CS

Projects

Superimages: Image Generalization through Camera Model Design

Images are used in computer graphics and visualization to convey information. Images are computed by sampling data with rays defined by a camera model. Most images used in computer graphics and visualization are computed using the planar pinhole camera model, which suffers from important limitations such as uniform sampling rate, and single viewpoint. We propose to overcome these limitations through camera model design, an infrastructure-level innovation with broad applicability, including in 3-D scene exploration, remote visualization, acceleration of high-cost rendering effects, and video surveillance.

Augmented Reality Surgical Telementoring:

Prior-art telestrator-based surgical telementoring systems require a trainee surgeon to shift focus frequently between the operating field and a nearby monitor to acquire and apply instructions from a remote mentor. We present a novel approach to surgical telementoring where annotations are superimposed directly onto the surgical field using an augmented reality (AR) simulated transparent display. Annotations are anchored to the surgical field as the trainee tablet moves and as the surgical field deforms or becomes occluded.

Computer Animation Instructor Avatars for Research on Non-Verbal Communication in Education:

Almost a century ago, Edward Sapir noted that we “respond to gestures with an extreme alertness” according to “an elaborate and secret code that is written nowhere, known to none, and understood by all”. We are a team of computer science and psychology researchers who have partnered with the long term goal of breaking the code of effective instructor gestures in education. We are developing a system of computer animation instructor avatars and we are using it to research instructor gesture effectiveness in the context of mathematics learning. We examine both gestures that might convey an appealing and engaging instructor personality and gestures that elucidate the mathematical concepts directly.

Publications

 

Journals (some also presented at conferences as noted)

Multiperspective Focus+Context Visualization. Meng-Lin Wu and Voicu Popescu. IEEE Transactions on Visualization and Computer Graphics, Volume 22, Issue 5, May 2016, pp.1555-1567.

Medical Telementoring Using an Augmented Reality Transparent Display. Daniel Andersen, Voicu Popescu, Maria Eugenia Cabrera, Aditya Shanghavi, Gerardo Gomez, Sherri Marley, Brian Mullis, Juan P. Wachs. Surgery, Volume 159, Issue 6, pp. 1646-1653.

Hand Gesture and Mathematics Learning: Lessons from an Avatar. Susan Wagner Cook, Howard S. Friedman, Katherine A. Duggan, Jian Cui, and Voicu Popescu. Cognitive Science, 2016, pp. 1-18.

Virtual Annotations of the Surgical Field through an Augmented Reality Transparent Display. Daniel Andersen, Voicu Popescu, Maria Eugenia Cabrera, Aditya Shanghavi, Gerardo Gomez, Sherri Marley, Brian Mullis, Juan Wachs. The Visual Computer. Published online on May 27 2015, pp. 1-18, awaiting issue assignment.

Animated Depth Images for Interactive Remote Visualization of Time-Varying Datasets. Jian Cui, Zhiqiang Ma, and Voicu Popescu. IEEE Transactions on Visualization and Computer Graphics, Volume 20, Issue 11, November 2014, pp. 1474-1489.

GEARS: A General and Efficient Algorithm for Rendering Shadows. Lili Wang, Shiheng Zhou, Wei ke, and Voicu Popescu. Computer Graphics Forum, Volume 33, Issue 6, September 2014, pp. 264-275. Also presented at Eurographics Symposium on Rendering 2015.

A Flexible Pinhole Camera Model for Coherent Non-Uniform Sampling. Voicu Popescu, Bedrich Benes, Paul Rosen, Jian Cui, and Lili Wang. IEEE Computer Graphics and Applications, Volume 34, Issue 4, 2014, pp. 30-41.

Second-Order Feed-Forward Rendering for Specular and Glossy Reflections. Lili Wang, Naiwen Xie, Wei Ke, and Voicu Popescu. IEEE Transactions on Visualization and Computer Graphics, Volume 20, Issue 9, 2014, pp. 1316-1329.

Just-in-Time Texture Synthesis. Lili Wang, Yulong Shi, Yi Chen, and Voicu Popescu. Computer Graphics Forum, Volume 32, Issue 1, February 2013, pp. 126-138. Also presented at Pacific Graphics 2014.

A non-expert user interface for posing signing avatars: design and initial evaluation. Nicoletta Adamo-Villani, Voicu Popescu, Jason Lestina. Journal of Disability and Rehabilitation: Assistive Technology, May 2013, 8(3):238-48.

Simplification of Node Position Data for Interactive Visualization of Dynamic Datasets. Paul Rosen, Voicu Popescu. IEEE Transactions on Visualization and Computer Graphics, vol. 18, no. 9, 2012, pp. 1537-1548. Also presented at IEEE Visualization 2012.

Non-Pinhole Approximations for Interactive Rendering. Paul Rosen, Voicu Popescu, Kyle Hayward, and Chris Wyman. IEEE Computer Graphics and Applications, Volume 31, Issue 6, November-December 2011, pp. 68-83.

An Evaluation of 3-D Scene Exploration Using a Multiperspective Image Framework. Paul Rosen and Voicu Popescu. The Visual Computer Volume 27, Numbers 6-8, pp. 623-632. Also presented at Computer Graphics International 2011.

A Curved Ray Camera for Handling Occlusions through Continuous Multiperspective Visualization. Jian Cui, Paul Rosen, Voicu Popescu, and Christoph Hoffmann. IEEE Transactions on Visualization and Computer Graphics, vol. 16, no. 6, November/December 2010, pp. 1235-1242. Also presented at IEEE Visualization 2010.

The General Pinhole Camera. Voicu Popescu, Paul Rosen, Laura Arns, Chris Wyman, Xavier Tricoche, Tion Thomas, Christoph Hoffmann. IEEE Transactions on Visualization and Computer Graphics, vol. 16, no. 5, September/October 2010, pp. 777-790.

The Graph Camera. Voicu Popescu, Paul Rosen, and Nicoletta Adamo-Villani. ACM Transactions on Computer Graphics, article number 158, 2009. Also presented at SIGGRAPH Asia 2009.

Compact Real-Time Modeling of Seated Humans by Video Sprite Sequence Quantization. Chun Jia and Voicu Popescu. The Visual Computer, Volume 25, Numbers 5-7, April 2009. Also presented at Computer Graphics International 2009.

A High-Quality High-Fidelity Visualization of the September 11 Attack on the World Trade Center. Paul Rosen, Voicu Popescu, Christoph Hoffmann, and Ayhan Irfanoglu. IEEE Transactions on Visualization and Computer Graphics, Vol. 14, Issue 4, August 2008.

1001 Acquisition Viewpoints—Efficient and Versatile View-Dependent Modeling of Real-World Scenes. Mihai Mudure and Voicu Popescu. The Visual Computer, Volume 24, Numbers 7-9, July 2008. Also presented at Computer Graphics International 2008.

Virtual Classroom Extension for Distance Education. Radu Dondera, Chun Jia, Voicu Popescu, Cristina Nita-Rotaru, Melissa Dark, Cynthia York. IEEE Computer Graphics and Applications, Volume 28, Issue 1, January-February 2008.

CAD Visualization by Outsourcing. Voicu Popescu and Christoph Hoffmann. Journal of Computer-Aided Design and Applications, vol. 4, nos 1-4, 2007.

Occlusion-Resistant Camera Design for Acquiring Active Environments. Daniel Aliaga, Yi Xu, and Voicu Popescu, vol. 277, no. 5, September-October 2007.

Perception of Surfaces from Line Drawings. Christoph Hoffmann, Zygmunt Pizlo, Voicu Popescu, and Steve Price. Elsevier Journal Displays, Volume 28, Issue 1, February 2007.

Reflected-Scene Impostors for Realistic Reflections at Interactive Rates. Voicu Popescu, Chunhui Mei, Jordan Dauble, and Elisha Sacks. Computer Graphics Forum, Vol. 25., issue 3, 2006. Also presented at Eurographics 2006.

Efficient Large-Scale Acquisition of Building Interiors. Gleb Bahmutov, Voicu Popescu, and Mihai Mudure. Computer Graphics Forum, Vol. 25., issue 3, 2006. Also presented at Eurographics 2006.

Three-Dimensional Display Rendering Acceleration Using Occlusion Camera Reference Images. Voicu Popescu, Paul Rosen, and Daniel Aliaga. IEEE/OSA Journal of Display Technology, 2006.

Forward Rasterization. Voicu Popescu and Paul Rosen. ACM Transactions on Computer Graphics, 25(2), April 2006.

The ModelCamera. Voicu Popescu, Gleb Bahmutov, Elisha Sacks, and Mihai Mudure. Elsevier Journal of Graphical Models, Volume 68, Issues 5-6, September-November 2006, pp 385-401.

Sample-Based Cameras for Feed Forward Reflection Rendering. Voicu Popescu, Elisha Sacks, and Chunhui Mei. In IEEE Transactions on Visualization and Computer Graphics, Nov-Dec, 2006, pp 1590-1600.

Study of the Perception of 3D Spatial Relations for a Volumetric Display. Christoph Hoffmann, Zygmunt Pizlo, Voicu Popescu, and Paul Rosen. SPIE Journal of Electronic Imaging, Vol. 15, No. 3, July-September 2006, pp 033002-1-033002-8.

The Occlusion Camera. Chunhui Mei, Voicu Popescu, and Elisha Sacks. Computer Graphics Forum, Vol. 24, issue 3, 2005. Also presented at Eurographics 2005.

Fidelity in Visualizing Large-Scale Simulations. Voicu Popescu and Christoph Hoffmann. Journal of Computer Aided Design, Elsevier, 37 (2005), pp 99-107.

The Pentagon on September 11th. Christoph Hoffmann, Voicu Popescu, Sami Kilic and Mete Sozen. IEEE Computing in Science and Engineering, January/February 2004, pp 52-60.

The WarpEngine: An Architecture for the Post-Polygonal Age. V. Popescu, J. Eyles, A. Lastra, J. Steinhurst, N. England, and L. Nyland. Proceedings of SIGGRAPH 2000 pages 433-442, July 23-29, 2000.

Images for Accelerating Architectural Walkthroughs. Matthew Rafferty, Daniel Aliaga, Voicu Popescu, Anselmo Lastra. IEEE Computer Graphics and Applications, Nov-Dec 1998 Issue, pages 38-45, 1998.

 

Conferences

Avoiding Focus Shifts in Surgical Telementoring Using an Augmented Reality Transparent Display. Daniel Andersen, Voicu Popescu, Maria Eugenia Cabrera, Aditya Shanghavi, Gerardo Gomez, Sherri Marley, Brian Mullis, Juan Wachs. In Proceedings of Medicine Meets Virtual Reality 22. Published in Studies in Health Technology and Informatics, Volume 220, 2016, pp. 9-14.

Scripted Animation towards Scalable Content Creation for eLearning—a Quality Analysis. Nicoletta Adamo-Villani, Jian Cui, and Voicu Popescu. In Proceedings of eLeot 2014, the 1st International Conference on e-Learning e-Education and Online Training. September 18-20, Bethesda, Maryland, United States, 2014, 9 pages.

Animation Killed the Video Star. Voicu Popescu, Nicoletta Adamo-Villani, Meng-Lin Wu, Suren D. Rajasekaran, Martha W. Alibali, Mitchell Nathan, and Susan Wagner-Cook. Gesture-based Interaction Design: Communication and Cognition. ACM CHI 2014 workshop, April 2014.

A Novel User Interface for Posing Signing Avatars. Adamo-Villani and Voicu Popescu. In proceedings of CSUN 2012 - The 27th Annual International Technology & Persons with Disabilities Conference, February-March 2012, San Diego, CA .

Experiences in Disseminating Educational Visualizations. Nathan Andrysco, Paul Rosen, Voicu Popescu, and B. Bedrich. Proceedings of International Symposium on Visual Computing, ISVC 2011.

Interactive Photorealistic Inside-Looking-Out Automated 3-D Modeling. Voicu Popescu and Mihai Mudure. In Proceedings of Interservice/Industry Training, Simulation, and Education Conference (I/ITSEC), 2008.

General-Purpose Visualization of Large-Scale Finite Element Analysis Simulations. Voicu Popescu and Christoph Hoffmann. In Proceedings of Interservice/Industry Training, Simulation, and Education Conference (I/ITSEC), 2008.

The Epipolar Occlusion Camera. Paul Rosen and Voicu Popescu. In Proceedings of ACM Symposium on Interactive 3D Graphics and Games, 2008.

The Soft Shadow Occlusion Camera. Qi Mo, Voicu Popescu, and Chris Wyman. In Proceedings of Pacific Graphics 2007.

Evaluating interactivity and presence in an online distance learning system. Melissa Dark, Cynthia York, Voicu Popescu, Cristina Nita-Rotaru. In ASEE/IEEE Proceedings of Frontiers in Education, Milwaukee, WI, 2007.

A Hybrid Forward-Backward Method for Rendering Reflections. Chunhui Mei, Voicu Popescu, and Elisha Sacks. In Proceedings of International Conference on Computer Graphics, Theory, and Applications, March 2007.

A Multi-Expertise Application-Driven Class. Cristina Nita-Rotaru, Melissa Dark, and Voicu Popescu. In Proceedings of Technical Symposium on Computer Science Education, SIGCSE 2007.

An Efficient Error-Bounded General Camera Model. Voicu Popescu, Jordan Dauble, Chunhui Mei, and Elisha Sacks. In Proceedings of Third International Symposium on 3D Data Processing Visualization and Transmission,  2006.

The Depth Discontinuity Occlusion Camera. Voicu Popescu and Dan Aliaga. Proc. of ACM Symposium on Interactive 3D Graphics and Games, 2006.

The Lag Camera. Yi Xu, Daniel Aliaga, and Voicu Popescu. In Proceedings of International Conference on Computer Graphics, Theory, and Applications, February 2006.

Depth Enhanced Panoramas. Gleb Bahmutov, Voicu Popescu, Mihai Mudure, and Elisha Sacks. In Proc. of Video Vision and Graphics (VVG) 2005.

Interactive Modeling from Dense Color and Sparse Depth. Voicu Popescu, Elisha Sacks, and Gleb Bahmutov. Symposium on 3D Data Processing, Visualization, and Transmission (3DPVT) 2004.

Perception of 3D spatial relations in 3D images. Paul Rosen, Christoph Hoffmann, Voicu Popescu, Zygmunt Pizlo. IS&T/SPIE 16th International Symposium Electronic Imaging: Science and Technology 2004.

Interactive Point-Based Modeling from Dense Color and Sparse Depth. Voicu Popescu, Elisha Sacks, and Gleb Bahmutov. In Proc. of International Symposium on Point-Based Graphics (PBG) 2004.

Challenges and Advances in Interactive 3D Modeling. Voicu Popescu, Elisha Sacks, and Aliasgar Ganiji. IS&T/SPIE 16th International Symposium Electronic Imaging: Science and Technology 2004.

Producing High-Quality Visualizations of Large-Scale Simulations. Voicu Popescu et al. In Proc. of IEEE Vis 2003.

The ModelCamera: A Hand-Held Device for Interactive Modeling. Voicu Popescu, Elisha Sacks, and Gleb Bahmutov. In Proc. of International Conference on 3D Imaging and Modeling (3DIM) 2003.

The Vacuum Buffer. Voicu Popescu, Anselmo Lastra. Proceedings of 2001 Symposium on Interactive 3D Graphics, Chapel Hill, 2001.

Capturing, Processing and Rendering Real-World Scenes. L. Nyland, A. Lastra, D. McAllister, V. Popescu, C. McCue. Proc. of Videometrics and Optical Methods for 3D Shape Measurement, Electronic Imaging 2001, Photonics West, San Jose, 2001.

Sort-first parallelism for Image-Based Rendering. Voicu Popescu, Anselmo Lastra, John Eyles. Proc. of the 3 rd Eurographics Workshop on Parallel Graphics and Vis. (Girona, Spain), pp. 93-101, Sept. 28-29, 2000.

Interactive exploration of acquired 3D data. L. Nyland, D. McAllister, V. Popescu, C. McCue, and A. Lastra. Proceedings of the SPIE Applied Image and Pattern Recognition Conference, October 13-15, 1999.

The Impact of Dense Range Data on Computer Graphics. L. Nyland, D. McAllister, V. Popescu, C. McCue, A. Lastra et al. Proceedings of Multi-View Modeling and Analysis Workshop, June 23-26, 1999.

Real-Time Rendering of Real-World Environments. D. McAllister, L. Nyland, V. Popescu, A. Lastra, C. McCue. Proceedings of the Eurographics Workshop on Rendering, June 21-23, 1999.

Efficient Warping for Architectural Walkthroughs using Layered Depth Images. V. Popescu, A. Lastra, D. Aliaga, M. Oliveira. In Proceedings of IEEE Visualization '98, pages 211 - 215, Oct18-23, 1998.