一种检测DCT编码图像方块化的客观质量评价方法

在图像和视频编码的过程中，基于块的离散余弦变换DCT被广泛应用于JPEG、MPEG以及H.26x等压缩标准中。当压缩图像的比特率较低时会产生明显的方块化效应，影响人的主观视觉感受。许多文献提出了去除块效应的方法，但是如何评价这些方法的有效性，需要有一定的评价标准来衡量。针对这一情况，提出了一种新的评价去除块效应有效性的方法（BBSR）。该方法通过计算各种编码方法后图像的块效应度和模糊度来计算编码方法对图像的去块效应的改善结果和影响，实验结果表明该方法的评价结果与人的主观感觉一致。

Objective Image Quality Measure for Block-Based DCT Coding

The transformation of block-based DCT has been widely used in many compression standards, such as JPEG, MPEG and H.26x etc. However, for the case that the compression bit-rate is lower, the blockness effect will obviously happen in compressed images. Though many methods have been proposed for removing block effect, the standard to evaluate their effectiveness has to be required. Aiming at the above issue, this paper proposes a new approach to measure the effectiveness of removing black effect, in which both blockness and blurriness strength ratio (BBSR) are computed for measuring the improvement effect of coding method. The experimental results show that the proposed method is identical to the human's subjective assessment.