Region of interest access with three-dimensional SBHP algorithm

One interesting feature of image compression is support of region of interest (ROI) access, in which an image sequence can be encoded only once and then the decoder can directly extract a subset of the bitstream to reconstruct a chosen ROI of required quality. In this paper, we apply Three-dimensional Subband Block Hierarchical Partitioning (3-D SBHP), a highly scalable wavelet transform based algorithm, for volumetric medical image compression to support ROI access. The codeblock selection method by which random access decoding can be achieved is outlined and the performance empirically investigated. The experimental results show that there are a number of parameters that affect the effectiveness of ROI access, the most important being the size of the ROI size, code-block size, wavelet composition level, number of filter taps and target bit rate. Finally, one possible way to optimize ROI access performance is addressed.