Coding of Mosaic Image Based on Wavelet Sub-band Substitute

In this paper, we propose a visual lossless compression scheme of mosaic image based on wavelet sub-band substitute. The proposed compression scheme consists of three coding pipelines: green component lossless coder, red component near-lossless coder and blue component near-lossless coder. Firstly, full resolution green image which is demosaiced from raw mosaic image is produced and green mosaic image is losslessly coded by LOCO-I scheme designed by Weinberger. Then low frequency sub-bands of red and blue mosaic component are also coded by LOCO-I while their high frequency sub-bands are ignored. In the decoder, the high frequency sub-bands of red and blue mosaic component are taken from the high frequency sub-bands of full resolution green image which locate at the same position as raw red or blue mosaic image, so we can reconstruct raw red or blue mosaic image based on decoded low frequency sub-bands of red and blue mosaic component. Consequently, we can encode mosaic images at low complexity level at higher compression ratio. Compared with JPEG2000, the performance of proposed method is apparently better.