一种有效的空间域视频传输差错掩盖算法

An Efficient Spatial Error Concealment for Video Transmission

针对易错信道中传输视频图像容易发生差错而导致图像块丢失的现象,提出一种有效的空间域差错掩盖算法.根据周围正确解码块中的边缘信息把丢失块分成平滑块和边缘块两类.对于不含有边缘的丢失块用简单的线性插值进行恢复;对含有边缘的丢失块先用基于梯度的自适应预测(GAP)法获得丢失块的初始值,然后用最大后验概率方法对初始值进行优化.实验结果表明该算法能够获得优越的图像质量,同时计算复杂度低,适用于视频图像的实时性传输.

The encoded bit streams of video transmitted in error-prone channel are vulnerable to transmission errors, which usually result in missing blocks at the decoder. In this paper, an efficient spatial error concealment method for video transmission is proposed. The missing blocks are classified into uniform blocks and edge blocks by using the edge information extracted from the surrounding correctly received blocks. For the missing blocks, which are uniform blocks, the error can be concealed by simple linear interpolation. For the missing blocks, which are edge blocks, the initial values of the missing blocks can be obtained by prediction based on gradient adaptive prediction （GAP）. The maximum a posteriori （MAP） method is used to implement the optimization with the initial value of the missing block. The experimental results demonstrate that the proposed algorithm not only can obtain excellent image quality, but also can be applied for real-tlme video transmission because of low computational complexity.