Normal Mesh based Geometrical Image Compression

Recently the performance of nonlinear transforms have been given a lot of attention to overcome the suboptimal n-terms approximation power of tensor product wavelet methods on higher dimensions. The suboptimal performance prevails when the lat-ter are used for a sparse representation of functions consisting of smoothly varying areas separated by smooth contours. This paper introduces a method creating nor-mal meshes with nonsubdivision connectivity to approximate the nonsmoothness of such images efficiently. From a domain decomposition viewpoint, the method is a triangulation refinement method preserving contours. The method is nonlin-ear as it depends on the actual image. This paper proposes a normal offset based compression algorithm for digital images. The discretisation causes the transform to become redundant. We further develop a model to encode the obtained coeffi-cients. We show promising rate distortion curves and compare the results with the JPEG2000 encoder. Key words: normal multiresolution mesh, image compression, piecewise smooth, wavelets