基于离散四元数傅里叶变换的彩色图像质量评价

Quality Evaluation of Color Image Based on Discrete Quaternion Fourier Transform

彩色图像质量的评价在图像数据的采集、压缩、存储、传输等方面具有重要意义。然而传统的评价方法往往因损失部分彩色信息或者忽略彩色图像的整体性,导致其结果不能很好地与主观结果保持一致,因此提出一种彩色图像客观质量评价方法。将彩色图像表示成四元数矩阵,并对其进行离散四元数傅里叶变换;根据人眼视觉系统特性对频域进行非均匀分块,计算失真图像和参考图像之间的幅值相似度和相位相似度;采用熵值法综合考虑两者对图像质量的影响,获得表示整体图像质量的指标。最后,使用图像数据库针对高斯模糊失真进行相关性分析,以验证方法的可行性和有效性。实验结果表明,客观评价能较好地与主观评价保持一致,且对于3个数据库的性能表现稳定,算法性能总体上优于对比方法。

Quality evaluation of color image is of great significance in image acquisition,compression,storage,transmission and so on.However,traditional objective evaluation methods often lose some color information or ignore the integrity of color image,making the results can not be well consistent with the subjective scores.This paper proposed an objective quality evaluation method of color image based on discrete quaternion Fourier transform（DQFT）.A color image is expressed as a quaternion matrix and the discrete quaternion Fourier transform is applied.Then,the spectrum is divided into non-uniform bins and a reduced space representation of the spectrum is obtained by considering the characteristics of Human vision system which is sensitive to the distortion of lower frequency components and insensitive to higher frequency components.Next,the amplitude similarity and phase similarity between the distorted image and the reference image are described.Taking into account the influence on the image quality of the amplitude similarity and phase similarity,both of them are integrated by using entropy method and the index of the distorted image quality is achieved.Finally,image databases were used to analyze the correlation between the objective scores and the subjective scores.The experimental results demonstrate the feasibility and effectiveness of the proposed method.