基于人眼感知特性的亮度系数压缩方法

A Perceptual Coding Method Based on the Compression of Luma Coefficients

在传统视频编码系统中，尽管失真大多由均方误差（MSE）度量，但是基于MSE的失真往往难以衡量不同视频流的主观差异，因此，人眼视觉系统对视频流的感知特性有必要被编码器利用。为了进一步提高编码效率，针对人眼对不同亮度的信号敏感程度不同的特性，提出了一种基于人眼感知特性的亮度系数压缩算法，该算法通过前向量化将人眼不能察觉的冗余信息丢掉来提高编码器压缩效率，并保证了人眼对损失的信息不可见。实验结果表明，采用该算法的AVS参考编码器，其输出码率的下降幅度达到8％～40％，而解码图像的主观观测质量却同未采用该算法的编码器相当。

In the conventional video coding system, the distortion is always measured by Mean-square-error （MSE）. However, the MSE-based distortion fails to measure the subjective difference of videos. As a result, the property and interest of human visual system （HVS） should be considered by video coder. This paper proposes a new perceptual coding method aiming at compressing the luma coefficients in terms of the eye＇s sensitivity. By using the pre-quantization strategy, it discards the imperceptible information and improves the compression performance of video eodec without contaminating the video subjective quality. The experiment result proves that this perceptual coding method can efficiently reduce the output bit rate of AVS reference software by 8% -40% while guaranteeing the quality of decoded video.