An error evaluation apparatus for object contour

Arbitrarily shaped video objects are an important concept in modern video coding methods. The techniques presently used are not based on image elements but rather video objects having an arbitrary shape. The contour of this shape has to be transmitted and therefore compressed as well. The example is standard MPEG-4. In mobile video communication, transmission errors and loss of data can occur. In the paper, different approaches to object contour error evaluation are discussed. The contour error occurs as a result of approximation during encoding and transmission errors. As a compare criterion of the evaluation, Hausdorff distance between convex polygons is used. New evaluation is constructed on the technique of transforming the Cartesian x and y contour coordinate functions to the domain of polar coordinates yielding an r and a phi function. New evaluation respects specific local artifacts or errors better if compared to systems based on distance of point sets.