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eugene-miles
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Motivations
•To create a common plane for immersive demonstration and perception
•Allow users to focus on the tabletop instead of shifting their vision and attention back and forth between the computer screen and the physical objects
Advantages
•Cheaper than VR
•Works better than head mounting
•One focus (unlike video-conferencing)
•Can use computer-unfriendly objects
DirectShow
•Insert source-filter to grab the image from the camera and do camera calibration
•Insert transform-filter for projector calibration
Camera Correction
• Camera is not perfectly aligned with deskop, has spherical distortion, etc.
• Create Tsai model for calibrated camera
• Sample Tsai model to warp the camera image into canonical space
Projector Calibration
• Projector is misaligned, projection area doesn’t perfectly overlap with camera field of view
• Project sequential pattern onto table, scan output via camera to detect projector “usable area”
• Can then warp images to projector such that they appear squared and aligned
One more problem!
• Problem: Camera <-> projector feedback loop will saturate image
• Solution: Synchronize camera and projector
Synchronization!
• Immediately before the camera grabs an image, stop projecting onto the table
• Result: Camera sees only real objects, nothing from projector
• Accomplished through hardware synchronization pins on camera, software
Applications
• We provide image processing, networking code – you provide the app.
• Application #0: Digital Paper
Applications
• Focus: collaborative teaching
–young children: origami, other art
–school-age: chemistry, physics experiments