Region-based subband/wavelet image coding
Since we need to handle arbitrary shapes, the sample lattices in the region-based discrete wavelet transform (RBDWT) will be more complicated than in the conventional discrete wavelet transform (DWT). But they can not be arbitrary for certain filters, so we first analyze the influence of sample lattices on filter design. Then we discuss how to use them on the RBDWT. We find the sample lattices of odd length biorthogonal filters are very flexible and suitable for the RBDWT. Furthermore, they can simplify odd length filtering, and perfect reconstruction can be realized without the need to add any new sample. When compared to previously reported results there is a significant improvement.