Research Projects:

Projector-Guided Painting	[ video, 53MB, Quicktime ]
Virtual Rear Projection	[ video 1, 10.8MB, MPEG4, video 2, 26.8MB ]
Multi-Planar Projected Displays	[ video, 6.3MB, DivX ]
Real-Time Projector Calibration	[ video, 13MB, MPEG4 ]

Publications:

Conference Papers
	Projector-Guided Painting Matthew Flagg and James M. Rehg, Appeared in Proceedings of User Interface Software and Technology (UIST). Montreux, Switzerland, October 2006. [ pdf, 2.2MB, project page, PPT slides, 39MB, talk video, featured on the cover! ]
	GVU-PROCAMS: Enabling Novel Projected Interfaces Jay Summet, Matthew Flagg, James M. Rehg and Gregory Abowd Appeared in ACM Multimedia 2006. Santa Barbara, California, October 2006. [ pdf, 3.5MB ]
	A Flexible Projector-Camera System for Multi-Planar Displays Mark Ashdown, Matthew Flagg, Rahul Sukthankar, James M. Rehg, Appeared in IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2004), Jun. 2004. [ pdf, 0.67MB ]
	Projected Light Displays Using Visual Feedback J. M. Rehg, M. Flagg, T.-J. Cham, R. Sukthankar, and G. Sukthankar, Appeared in Intl. Conf. on Control, Automation, Robotics, and Vision, Singapore, Dec. 2-5, 2002. [ pdf, 0.56MB ]
Journal Articles
	Shadow Elimination and Blinding Light Suppression for Interactive Projected Displays Jay Summet, Matthew Flagg, Tat-Jen Cham, James M. Rehg, and Rahul Sukthankar To Appear in IEEE Transactions on Visualization and Computer Graphics, 2006.
Workshop Publications
	Improving the Speed of Virtual Rear Projection: A GPU-Centric Approach Matthew Flagg, Jay Summet, James M. Rehg, Appeared in IEEE International Workshop on Projector-Camera Systems (PROCAMS) held in conjunction with the IEEE International Conference on Computer Vision and Pattern Recognition (CVPR 2005), June, 2005, San Diego, CA, USA. [ pdf, 1.2MB, video, 10.8MB, DiVX ]
	Robust Projected Displays for Ubiquitous Computing Jay Summet, Matthew Flagg, Mark Ashdown, Rahul Sukthankar, James M. Rehg, Gregory Abowd, Tat-Jen Cham Appeared in Proceedings of Ubicomp Workshop on Ubiquitous Display Environments, September 2004. [ pdf, 0.37MB ]
	Increasing the Usability of Virtual Rear Projection Jay Summet, Matthew Flagg, James M. Rehg, Gregory M. Corso, Gregory D. Abowd, Appeared in IEEE International Workshop on Projector-Camera Systems (PROCAMS) held in conjunction with the International Conference on Computer Vision (ICCV 2003), Nice, France, October 2003. [ pdf, 0.70MB ]
Tech Reports
	Shadow Elimination and Blinding Light Suppression for Interactive Projected Displays Jay Summet, Matthew Flagg, Tat-Jen Cham, James M. Rehg, Rahul Sukthankar, Technical Report GIT-GVU-06-02 [ pdf, 1.2MB ]
	Oil Painting Assistance Using Projected Light: Bridging the Gap Between Digital and Physical Art Matthew Flagg and James M. Rehg, Technical Report GIT-GVU-05-35 [ pdf, 1.6MB ]

Virtual Rear Projection

Jay Summet and I are working on a system that leverages two projectors to compensate for shadows and blinding light on users - we call this virtual rear projection because the goal is to emulate a rear projection display using front projection.

Watch this video (6.5MB, DIVX avi) of our demonstration, given at ICCV 2003 in Nice, France. Here is a 1 page demonstration explanation (PDF).

In the following publication, we report the results of a user study and the use of markers to calibrate the system in real-time with the combined effort of increasing the usability of virtual rear projection:

Jay Summet and I gave a GVU brown bag talk on Virtual Rear Projection on March 18, 2004. You may watch our presentation in streaming Quicktime and download slides.

Virtual rear projection requires calibration for geometric alignment of multiple projected displays and photometric compensation for illumination differences caused by reflectance properties of the screen and variations due to physical projector placement. Here are two images that illustrate these needs:

Geometric Alignment - Here you see myself and Jay Summet with two projectors projecting green grids on top of each other.

Photometric Calibration - Here you see myself with one projector projecting a black and white checkerboard and the other projector projecting an inverted checkerboard. This configuration has no photometric calibration applied; it is easy to tell the difference between projectors 1 and 2! With ideal photometric calibration, we should see an evenly illuminated white square.

Projector-Camera System for Multi-Planar Displays

I helped create a system that calibrates a projected display onto multiple planes. This system works by discovering the planar surfaces using a form of structured light and calculating a set of metric-rectified homographies. A metric-rectified homography is a mapping from the projector to the plane that is precise enough to let someone make metric measurements from each plane, such as distances on a map for both a plan view and topographic view. Here is a technical report on this system:

Real-Time Projector Calibration

I work with projectors and cameras to automatically correct keystone distortions. With our system, the user may put four blue poker chips on a wall inside a region of projected light and the sytem will automatically project inside the region defined by the poker chips. Furthermore, the system will account for environmental disturbances such as movements of the projector, camera, or poker chips. To learn more about this system, read the ICARCV publication:

video demonstration 13MB MPEG4 AVI

Courses

Ph.D. program at Georgia Tech (started Fall 2004)

Summer 2008 Design of Experiments Fall 2008 Spring 2007 Fall 2007 Qualifying Exam Summer 2006 internship at Industrial Light + Magic Fall 2006 Spring 2006 (no classes) Fall 2005 Deterministic Optimization Spring 2005 Introduction to Probabilistic Graphical Models Fall 2004 Introduction to Graduate Studies

Masters program at Georgia Tech (graduated December 2003)

Fall 2003 Computability and Algorithms Cognitive Modeling Intelligence, Perception and Robotics Seminar Telecommunications Systems Spring 2003 Advanced Image Synthesis Medical Image Processing Advanced Operating Systems Pattern Recognition (auditing) Fall 2002 Multiple View Geometry in Computer Vision Artificial Intelligence Design and Engineering Databases Computational Perception Seminar GVU Brown Bag Seminar

Pertinent undergraduate program at Georgia Tech (graduated May 2002)

Spring 2002 Digital Video Special FX Computer Animation Computational Perception Computational Perception Seminar Technical Communication Practices Human Development Fall 2001 Computers in Society Video Game Design Computer Vision User Interface Design