3d pose detection used by kinect accurate when the pose closely matches a stored pose inaccurate...
Post on 17-Jan-2016
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3d Pose Detection• Used by Kinect• Accurate when the pose closely matches a stored pose• Inaccurate when novel poses are made• Can often produce shaky movement due to pose snapping
3d Pose Tracking
• Calculate poses based on previous poses and current data• No datasets required• Has issues with local minima
Hybrid
• Store a collection of preprocessed poses• Start session with a detected pose• Track until a failure is hit• Detect that frame, and continue
tracking from there
Pose Tracking in Detail
• Given the current set of pixels, and the calculated poses of the past few frames, calculate the most probable current pose• Repeat the following until error is reduced• Calculate a hypothesized 3d representation (rendered image) using the 3d
camera image (observed data)• Calculate quite a lot about the rendered image:
• Edepth, Eextra, Esilhouette, Eprior
• Adjust the hypothesized pose accordingly• If that fails significantly, “detect” the current pose and try again
Optimizing the Position
• Solve energy minimization problems:• Edepth: Depth data, excluding any rendered foreground pixels that match
background observed pixels• Eextra: The above depth term, but with added calculations where rendered
pixels don’t match with observed pixels• Esilhouette: The difference in silhouettes (pixel is in foreground of one image but
the background of the other)• Eprior: Evaluation of the rendered pose based on the previous rendered poses
More Pose Detecting
• Grab a random subset of pixels and match them to known poses• Throw out uncertain data• 20k poses total
Setup
• User must stand in a specific pose for calibration• Select random subset of pixels to determine widths of limbs
Results
Results
• Roughly 1 in 200 frames reinitialized by the detector• Very fast movement often
causes local minima• On average, 1 failure every
33 seconds• High performance running in
parallel on the GPU
http://www.youtube.com/watch?v=ICFKEOk3SyA&feature=youtu.be
Further Work
• Use skinned mesh models• Increase pose set• Use color data in the
algorithm as well
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