Progressive-to-Lossless Compression of Color-Filter-Array Images Using Macropixel Spectral-Spatial Transformation

We present a low-complexity integer-reversible spectral-spatial transform that allows for efficient loss less and lossy compression of color-filter-array images (also referred to as camera-raw images). The main advantage of this new transform is that it maps the pixel array values into a format that can be directly compressed in a loss less, lossy, or progressive-to-loss less manner by an existing typical image coder such as JPEG 2000 or JPEG XR. Thus, no special codec design is needed for compressing the camera-raw data. Another advantage is that the new transform allows for mild compression of camera-raw data in a near-loss less format, allowing for very high quality offline post-processing, but with camera-raw files that can be half the size of those of existing camera-raw formats.