Shearlet Transform Based Prediction Scheme for Light Field Compression

Abstract

Four LF images (Truck, Bunny from Stanford dataset, Set2 and Set9 from High Density Camera Array dataset) are used in the experiments. Input LF views are converted into a pseudo video sequence and compressed with HEVC to serve as anchor. Rate distortion analysis shows the average PSNR gain of 0.98 dB over the anchor scheme. Moreover, in low bit-rates, the compression efficiency of the proposed scheme is higher compared to the anchor and on the other hand the performance of the anchor is better in high bit-rates. Different compression response of the proposed and anchor scheme is a consequence of their utilization of input information. In the high bit-rate scenario, high quality residual information enables the anchor to achieve efficient compression. On the contrary, the shearlet transform relies on key views to predict the decimated views without incorporating residual information. Hence, it has inherit reconstruction error. In the low bit-rate scenario, the bit budget of the proposed compression scheme allows the encoder to achieve high quality for the key views. The HEVC anchor scheme distributes the same bit budget among all the input LF views that results in degradation of the overall visual quality. The sensitivity of human vision system toward compression artifacts in low-bit-rate cases favours the proposed compression scheme over the anchor scheme.