Compression of Bayer-Pattern Video Sequences Using Adjusted Chroma Subsampling

Most consumer digital color cameras are equipped with a single chip. Such cameras capture only one color component per pixel (e.g., Bayer pattern) instead of an RGB triple. Conventionally, missing color components at each pixel are interpolated from its neighboring pixels, so that full color images are constructed. This process is typically referred to as demosaicing. After demosaicing, the full resolution RGB video frames are converted into YUV color space. U and V are then typically subsampled by a factor of four and the resulting video data in the 4:2:0 format become the input for the video encoder. In this letter, we look into the weakness of the conventional scheme and propose a novel solution for compressing Bayer-pattern video data. The novelty of our work lies largely in the chroma subsampling. We properly choose the locations to calculate the chroma pixels U and V according to the positions of B and R pixels in the Bayer pattern and this leads to higher quality of the reconstructed images. In our experiments, we have observed an improvement in composite peak-signal-to-noise ratio performance of up to 1.5 dB at the same encoding rate. Based on this highly efficient approach, we propose also a low-complexity method which saves almost half of the computation at the expense of a small loss in coding efficiency.