基于KL散度的DCT系数分布模型研究

Research on DCT coefficient distribution model based on KL divergence

利用分布拟合优度检验方法,对DCT系数分布模型进行了研究。通过理论分析和实验,验证了KL散度更适合作为DCT系数分布拟合优度度量;针对单个位置和不同范围的DCT系数,系统地比较了当前应用最广泛的4种DCT系数分布模型。实验结果表明,图像中低频交流系数服从对称α稳态分布而高频交流系数服从广义高斯分布。

Research on DCT coefficient distribution models is proposed utilizing distribution goodness-of-fit（GOF） test.Theoretic analysis and experiment proof that KL（kullback-leibler） divergence is more suitable to be the GOF measure of the comparison of the four distribution models that most commonly used to model the individual and different frequency band of DCT coefficients.The experimental result shows that the low and mid frequency band of AC coefficients satisfy the symmetric α-stable（SαS） distribution while the high frequency band satisfies the generalized Gaussian distribution（GGD）.