Binocular Perceptual Model for Symmetric and Asymmetric 3D Stereoscopic Image Compression

The objective approaches of 3D image quality assessment play a key role in the development of compression standards and various 3D multimedia applications. The quality assessment of 3D images faces many new challenges, e.g. asymmetric stereo compression, depth perception, and virtual view synthesis, as compared with its 2D counterparts. Moreover, the widely used 2D image quality metric (e.g. PSNR) cannot be directly applied to deal with these newly introduced challenges. This statement can be verified by the low correlation between the computed objective measures and the subjectively measured mean opinion scores (MOS), when 3D images are the tested targets. In order to meet these challenges, in this work, besides traditional 2D image metrics, two binocular behaviors - the binocular combination and the Binocular Frequency Integration (BFI), are utilized as the bases for measuring the quality of stereoscopic 3D images. The effectiveness of BFI-based metrics is verified by conducting subjective evaluations on a publicly available stereo image dataset. Experimental results show that significant consistency could be reached between the measured MOS and the BFI-based metrics, in which the correlation coefficient between them can go up to 0.89 even if the stereo images have been asymmetrically HEVC compressed. Based on the proposed quality metric, we find that asymmetric-stereo compression schemes outperform the corresponding symmetric ones in high bit rate scenarios, which opens up a new research direction for 3D stereo image/video compression studies.