OBJECT TRACKING TECHNIQUE USING POLYLINE CONTOURS

A technique of tracking an object of interest in a sequence of images using active polyline contours. An image processor converts a sequence of images into digital image data related to light intensity at the pixels of each image. A computer stores the digital image data and forms an initial polyline that substantially outlines an edge of the object in a first image. The computer forms input polylines for each of the subsequent images which substantially outline the edge in the corresponding images and are derived from the optimal polyline of each previous such image. The computer processes the digital image data, performing a graph exploration procedure that starts with the initial polyline in the first image and the input polylines in the subsequent images. The graph exploration procedure searches polylines in a predefined search space to find the corresponding optimal polylines. The computer evaluates edge strength of the different polylines with respect to the light intensity of its underlying pixels to obtain corresponding contour costs. The polyline with the smallest contour cost is selected as the optimal contour for each of the images. The set of optimal contours are used to track the object of interest.