IEEE Trans Image Process. 2014 Nov;23(11):4879-92. doi: 10.1109/TIP.2014.2355715. Epub 2014 Sep 8.
Depth video is used as the geometrical information of 3D world scenes in 3D view synthesis. Due to the mismatch between the number of depth levels and disparity levels in the view synthesis, the relationship between depth distortion and rendering position error can be modeled as a many-to-one mapping function, in which different depth distortion values might be projected to the same geometrical distortion in the synthesized virtual view image. Based on this property, we present an allowable depth distortion (ADD) model for 3D depth map coding. Then, an ADD-based rate-distortion model is proposed for mode decision and motion/disparity estimation modules aiming at minimizing view synthesis distortion at a given bit rate constraint. In addition, an ADD-based depth bit reduction algorithm is proposed to further reduce the depth bit rate while maintaining the qualities of the synthesized images. Experimental results in intra depth coding show that the proposed overall algorithm achieves Bjontegaard delta peak signal-to-noise ratio gains of 1.58 and 2.68 dB on average for half and integer-pixel rendering precisions, respectively. In addition, the proposed algorithms are also highly efficient for inter depth coding when evaluated with different metrics.
深度视频被用作 3D 视图合成中的 3D 世界场景的几何信息。由于视图合成中深度级别和视差级别之间的不匹配，深度失真和渲染位置误差之间的关系可以建模为多对一映射函数，其中不同的深度失真值可能会被投影到合成虚拟视图图像中的相同几何失真。基于此特性，我们提出了一种用于 3D 深度图编码的可允许深度失真 (ADD) 模型。然后，针对模式决策和运动/视差估计模块，提出了一种基于 ADD 的率失真模型，旨在在给定的比特率约束下最小化视图合成失真。此外，还提出了一种基于 ADD 的深度位减少算法，在保持合成图像质量的同时，进一步降低深度位率。在内部深度编码中的实验结果表明，对于半像素和整像素渲染精度，所提出的整体算法平均分别获得了 1.58 和 2.68dB 的 Bjontegaard 峰信噪比增益。此外，所提出的算法在使用不同的度量标准进行评估时，对于内部深度编码也非常有效。
