针对虚拟视点合成系统中虚拟视点的绘制质量不高,主观效果不理想的问题,同时为了提高自由视点电视系统中的深度图压缩性能,对基于下/上采样的深度图编码方法中的深度图滤波及上采样方法进行了研究。首先,根据深度图的特性使用H.264/MVC对深度图进行下采样压缩。其次,提出使用À-Trous小波滤波器对解码后的低分辨率深度图进行滤波,减少由编码器引入的块效应,继而提出多相似度自适应权重上采样方法恢复原始分辨率深度图。最后,使用上采样后的深度图与未压缩的彩色视频序列进行虚拟视点合成,通过虚拟视点的峰值信噪比(PSNR)来衡量客观绘制质量。实验结果显示,使用提出的中值滤波和多相似度上采样方法与À-Trous小波滤波和多相似度上采样方法生成的虚拟视点的PSNR分别比自适应权值上采样方法提高至少0.04 dB和0.22 dB,而且后者极大程度上改善了虚拟视点的主观绘制质量。

In order to deal with the problem of lower render quality and unsatisfactory subjective effect of virtual view in the virtual views synthesis system, and to improve the compression performance of the depth map,the filtering for decoded low resolution depth maps and a depth upsampling method are investigated in the depth map encoding method based on the down/up sampling in this paper. First, H.264/MVC is used to compress the low-resolution depth map according to the character of the depth map. Then, the À-Trous wavelet filter is used to filter the decoded low-resolution depth map to decrease the artificial effect, and a depth upsampling method based on multi-similarity adaptive support weight is used to reconstruct the original resolution depth map. Finally, up-sampling depth map and an uncompressed color sequence is used to render the virtual view and to evaluate the render quality by PSNR of the virtual view. The experimental result shows that the PSNR of two proposed methods are 0.04 dB and 0.22 dB higher than ASW(adaptive support-weight) respectively, and subjective quality of the virtual view is improved a lot, especially the later one.