Cross-view post-filtering for fidelity enhancement on asymmetric coding of 3D video
3D video employing depth-image-based rendering (DIBR) typically contains a stereo pair plus two associated depth maps. The stereo pair may be compressed asymmetrically (e.g., using mixed resolution coding) to effectively reduce the bit rate while maintaining the stereoscopic visual quality at the same level as that from symmetric coding. With depth information, it is straightforward to locate high-fidelity (HF) inter-view correspondences of pixels in the low-fidelity (LF) view. However, we find that LF-view fidelity cannot be consistently improved by simply substituting LF pixels with their HF counterparts, due to inter-view color/geometric differences and depth errors. In this paper, we propose an effective post-filter which first checks the coherence between local LF and HF waveforms to distinguish unreliable correspondences. Then, the LF view is adaptively rectified by the reliable HF pixels to improve its fidelity. Experimental results show that the proposed cross-view fidelity enhancement scheme can promote Peak Signal-to-Noise Ratio (PSNR) of LF views by up to 1.1 dB, and can effectively suppress ringing and blocking artifacts in flat regions of LF views.