Generalized Bitplane-by-Bitplane Shift Method for JPEG2000 Region of Interest Image Coding

The current JPEG2000 image coding standard defines two kinds of region of interest (ROI) coding methods: the general scaling based method and the maximum shift (Maxshift) method. The former requires shape coding of the ROIs, which leads to increased complexity of codec implementations and limits the choice of ROI shapes (currently, only rectangle and ellipse shapes are defined). The latter allows for arbitrarily shaped ROI coding without explicitly transmitting any shape information to the decoder, but does not have the flexibility to select an arbitrary scaling value to define the relative importance of the ROI and the background wavelet coefficients.

Can the JPEG2000 ROI coding be improved?

YES! we propose a generalize bitplane-by-bitplane shift (GBbBShift) method, which delivers much more flexibility than both Maxshift and BbBShift for “degree-of-interest” adjustment of the ROI with trivial reduction of coding efficiency and increase of computational complexity. Experiments show that it can provide significantly better visual quality than Maxshift at low bit rates. See paper and demo images below.


JPEG2000 ROI coding results of 24bpp RGB “Barbara” image using the Maxshift method (s = 12) and the GBbBShift method (BP_mask = 111111000000111111000000).


Left: Maxshift; Right: GbbBShift; Top: 0.5bpp; Middle: 1.0bpp; Bottom: 2.0bpp.


See paper

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Last updated Mar. 6, 2002