Border line approximate conversion manner and border line coding equipment

摘要

A method for approximating a contour of an object expressed in a digital video signal divides the contour into a multiplicity of primary contour segments and approximates each primary contour segment by a primary line segment, to thereby calculate a set of errors between the primary contour segment and the primary line segment for each primary contour segment. And the method codes and decodes the set of errors, to thereby generate of a set of reconstructed errors and a reconstructed contour segment which are used to determine a reconstruction error. Thereafter, the method generates one or more secondary contour segment on the primary contour segment with each secondary contour segments approximated by a secondary line segment. Subsequently, the method finds an approximation error and approximates said each primary contour segment by using either the reconstructed contour segment or the secondary line segments based on the reconstruction error and the approximation error.