Error-free image decomposition/reconstruction for subband coding schemes

摘要

It is shown first that quadrature filters (QFs) and wavelet-generated filters designed for an exact reconstruction of an infinite signal, in a subband coding system, induce a reconstruction error at the picture boundaries. This error is evaluated. Then, a new image coding system is proposed in which sampled images are decomposed into subbands in a one-step procedure. Ideal filters are used and an error-free reconstruction is achieved. Filters are implemented with FFT. A few overhead bits are necessary. The computer load is evaluated and compared with the pyramidal subband coding with FIR QMFs. Illustrative examples allow a comparison of the proposed method with subband coding using QMFs and show clearly the PPSNR gain in the reconstructed images.