Improved block-based image segmentation

The previous block-based MAP image segmentation is improved in this paper. The first improvement is achieved by adopting a criterion to differentiate various texture blocks using multi-resolution 2×2 DCT coefficients. To do that, we obtain an octave-band multi-resolution representation of each image block by faking a 2×2 DCT-rearrangement process for the DC values recursively. Then, comparing the energy distributions of the coefficients for each frequency band, we can differentiate the neighboring texture image blocks. Secondly, we propose a scheme to avoid the under-segmentation problem of the previous block-based MAP segmentation. So, as the block size reduces, we can also identify small monotone regions without affecting previously segmented large texture regions