Composite Model-Based DC Dithering for Suppressing Contour Artifacts in Decompressed Video
Composite Model-Based DC Dithering for Suppressing Contour Artifacts in Decompressed Video
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DOI：
10.1109/tip.2011.2114356
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发表时间：
2011-08
影响因子：
10.6
通讯作者：
Xin Jin;S. Goto;K. Ngan
中科院分区：
文献类型：
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作者：
Xin Jin;S. Goto;K. Ngan
由于在提高压缩效率方面的突出贡献，基于块的量化在最新的图像/视频编码标准中被广泛接受。然而，引入了假轮廓伪影，导致解码图像/视频的保真度降低，特别是在主观质量方面。本文提出了一种基于分块去环的方法，根据梯度平滑和分块边缘平滑之间建立的复合模型，通过自动抖动图像/视频的直流（DC）值来减少解码图像/视频中的假轮廓伪影。将模型上的特征点与相应的轮廓伪影抑制准则进行比较，结果表明模型与实际处理效果具有较好的一致性。基于离散余弦变换（DCT）的块级轮廓伪影检测机制保证了纹理区域内的块不受DCT抖动的影响。分析了实现方法和算法复杂度，证明了将该方法集成到现有的嵌入式平台或片上系统（SoC）视频解码器中的可行性。实验结果表明，与现有方法相比，该方法在主观质量和处理复杂度方面都是有效的。
Because of the outstanding contribution in improving compression efficiency, block-based quantization has been widely accepted in state-of-the-art image/video coding standards. However, false contour artifacts are introduced, which result in reducing the fidelity of the decoded image/video especially in terms of subjective quality. In this paper, a block-based decontouring method is proposed to reduce the false contour artifacts in the decoded image/video by automatically dithering its direct current (DC) value according to a composite model established between gradient smoothness and block-edge smoothness. Feature points on the model with the corresponding criteria in suppressing contour artifacts are compared to show a good consistency between the model and the actual processing effects. Discrete cosine transform (DCT)-based block level contour artifacts detection mechanism ensures the blocks within the texture region are not affected by the DC dithering. Both the implementation method and the algorithm complexity are analyzed to present the feasibility in integrating the proposed method into an existing video decoder on an embedded platform or system-on-chip (SoC). Experimental results demonstrate the effectiveness of the proposed method both in terms of subjective quality and processing complexity in comparison with the previous methods.