Method for encoding a contour of an object in a video signal by using a contour motion estimation technique

摘要

A method for encoding a contour of an object predicts a current contour by using a current and a reconstructed previous contours and generates the motion vector representing a displacement between the reconstructed previous and the predicted current contours. A matched contour between the predicted current and the current contours is subtracted from the current contour to provide a differential contour. Thereafter, vertex points is determined based on a polygonal approximation for the differential contour. A set of approximation errors calculated at a predetermined number of sample points on each line segment between two vertex points is transformed and quantized to obtain a set of quantized discrete sine transform coefficients. The quantized discrete sine transform coefficients are encoded together with the motion vector, and the vertex points are encoded based on the predicted current contour for transmission thereof. And, the coded vertex information is decoded based on the predicted current contour, and the quantized discrete sine transform coefficients are converted into the reconstructed errors to reconstruct the differential contour. The reconstructed differential contour is added to the matched contour to provide the reconstructed previous contour.