一种新的JPEG图像无参考客观质量评价方法

New method of no-reference objectively assessing JPEG image quality

Parsval's原理指出,图像压缩前、后像素值的均方误差值等同与图像压缩前、后DCT系数的均方误差值,根据这一思想计了JPEG图像无参考客观质量评价算法。假设图像的DCT系数是Laplacian分布,首先根据JPEG图像的DCT系数估计出图压缩前的DCT系数分布参数,并由此估算出图像压缩前、后DCT系数的均方误差值。实验结果表明,该方法所用指标能准确地述JPEG图像的质量且与空间域均方误差指标相符。

According to Parseval＇s theorem,the MSE in the pixel domain is equivalent to the mean square quantization error in the DCT domain because DCT is a normalized orthogonal transformation.Based on this idea,a new method of no-refrence objectively assessing image quality is presented.The DCT coefficients of the ac eolnponent can be approximated as a Laplacian distribution.Firstly,estimating the Laplacian parameter from the observed dequantized DCT coefficients,amplitude distributions of DCT coefficients of the source are given,the mean square quantization error in the DCT domain is obtained.Experimental results have shown,it is in good accordance with the image quality,and in accordance with the MSE in the pixel domain.