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Next: Hyperbolic Smoothing of Shapes Up: Computer Vision Previous: Face DetectionRecognition and

Fast Image Segmentation Using Stereo Vision

M. Ezzati, M. D. Levine Binocular stereo vision is a biologically motivated approach that uses two slightly different views of a scene to extract information about its three-dimensional properties. The two underlying principles of our approach to stereopsis are parallel computation of binocular disparities and the use of the resulting disparity map for image segmentation. The method divides the two images of the stereo pair into small sections and obtains initial estimations for the disparities of all such sections. The devision of the image pair is motivated by data representation in the ocular dominance columns of the primary visual cortex where information from the left and right eyes are represented in the form of interlacing image ``patches''. The algorithm uses cepstrum, a method traditionally used in echo detection and provides a local estimation of binocular disparity between corresponding patches. We study cepstrum and its properties and use the developed insight in two ways. First the properties of cepstrum are used to offer improvements to the initial disparity estimation stage. Second the knowledge of the performance of cepstrum is used to provide an interpretation of the initial disparity map and motivate a method for its refinement. In the next stage, we refine the initial disparity estimations using neighbouring disparity information. We employ a modified median filtering scheme for the refinement stage. Finally, based on the characteristics of the methods used in the disparity estimation and refinement stages, we illustrate that the overall disparity map is suitable for figure-ground separation. Our approach to stereopsis is different from traditional stereo algorithms, which use simultaneous search and optimization, in the following ways:

We provide evidence for the plausibility of the disparity estimation algorithm and the properties of the overall disparity map in the context of biological stereopsis. The algorithm has been implemented on a network of TMS320C40 processors and has achieved a processing time of 0.7 seconds for a 128 pixel x 128 pixel image.


next up previous contents
Next: Hyperbolic Smoothing of Shapes Up: Computer Vision Previous: Face DetectionRecognition and

Thierry Baron
Mon Apr 7 12:54:24 EDT 1997