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.
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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
