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Our parallel manipulation algorithm requires that parts' positions be known at all times. This is addressed by having a camera overlook the plate and feed an NTSC signal back to the host PC. The camera setup is shown below:

dan_shaker2.jpg (98757 bytes)dan_shaker3.jpg (89415 bytes)

A typical input frame is shown below. We use black-painted "pennies" for parts. 

A sequence of filtering, edge detection, and Hough transform operations is performed which yields the location of the table's edges. Then the image is convolved with a disk-like mask to locate the coins' centers. This operation is done once-and for all prior to an experiment, resulting in a reliable map of the experiment's features, as shown below:

During the experiment per se, coins will move very little from frame to frame, so recalculating the coins' new locations can be done efficiently by local convolution-based search, as shown below:

 
© 2000 Dan S. Reznik, <dreznik@cs.berkeley.edu>