A new JPEG2000 region-of-interest coding method: generalized partial bitplanes shift [5637-75]

Region-of-interest (ROI) image coding is an interesting feature in JPEG2000, which allows for encoding the ROIs in an image with better quality than the background (BG). Considering the limitations of two standard ROI coding methods, a new ROI coding method called generalized partial bitplanes shift (GPBShift) is presented in this paper. To control the relative importance between ROI and BG, the method divides the bitplanes of ROI and BG coefficients into two parts by using scaling values S1 and S2, respectively. Instead of shifting the bitplanes all at once by the same scaling value S in the standard methods, GPBShift shifts part of them on the basis of the bitplane shifting scheme. The GPBShift not only can code arbitrarily shaped ROI without explicitly transmitting any shape information to the decoder, but also flexibly select the scaling values to adjust relative compression quality in ROI and BG. Additionally, the method can efficiently code multiple ROI with different priorities in an image. Experimental results show that the GPBShift method can provide significantly better visual quality than the Maxshift method at low bit rates, and higher coding efficiency than the general scaling based method.