The visibility threshold is the maximum contrast where a stimulus remains invisible. This value varies with the spatial frequency and orientation of the stimulus and is often used in determining the quantization step size of a subband for visually lossless coding. When an image is displayed at a different resolution level, the spatial frequency of each subband is also changed. Previous JPEG2000 visually lossless algorithms have a single set of quantization step sizes optimized for the full display resolution. This implies that if the image is rendered at reduced resolution there are significant amounts of extraneous information in the codestream. In this paper we present a new coding method which effectively incorporates multiple quantization step sizes into the JPEG2000 framework. This allows for visually lossless decoding at a variety of resolutions, using only a portion of the full resolution codestream.
['Han Oh', 'Ali Bilgin', 'Michael W. Marcellin']
Multi-resolution visually lossless image coding using JPEG2000