Improving residual coding of WASP light field CODEC

Abstract

We study the residual coding by JPEG 2000 in a recently proposed light field compression method, WaSP, with the goal of optimizing the performance with respect to a weighted PSNR criterion, which is the objective performance criterion utilized in the JPEG Pleno Light Field standardization. In WaSP the residual view is encoded by using JPEG 2000. In here we show that instead of encoding by JPEG 2000 the RGB residual view (using the rate-distortion optimization performed by JPEG 2000 for the RGB image), one can obtain better results by performing first an RGB to YCbCr color transformation and reallocating the given bitrate to each color component optimally with respect to the weighted PSNR criterion. Then JPEG 2000 is called separately for each YCbCr component with the selected bitrates. We experiment with the proposed scheme inside the WaSP codec, and show that the weighted PSNR results are improved by nearly as much as 1 dB when compared to the default RGB encoding by JPEG 2000.