Estimating Motion of Object Contours from Distance Transforms




Soeder, Kyle

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This thesis develops a method for estimating motion for object contours in depth video sequences. First the depth image is thresholded to nd the foreground object. Con- tours are then extracted from the thresholded image. Given the contours in two frames my method estimates the motion that transforms the contour in frame 1 to the contour in frame 2. First the Euclidean Distance Tansform (DT) is computed for the contour in frame 2. The DT and its gradient at each of the points along the contour in frame 1 are used to estimate the motion between the contours in the frames. I consider the obtained motion an estimate of the normal ow between the frames. Finally the normal ow is used to estimate a ne motion between the contours. I demonstrate the method on several synthetic images corresponding to contours of various shapes. Finally I demonstrate the e ectiveness of my method on several image sequences including household objects, a person raising their leg and a long sequence of a human walking.



Computer vision, Distance transform, Gradients, Contour motion, Normal flow