关键词: 无参考图像质量评价, 四元数小波变换, 四元小波金字塔, 支持向量回归(SVR)

Abstract: This paper proposes a new general purpose no-reference image quality assessment based on quaternion wavelet transform. It projects a two-dimenisonal image to four-dimenisonal space by using the quaternion wavelet pyramid. Each level of pyramid provides a shift-invariant magnitude and 3-angle (Φ, θ, ψ) phase. Phase ψ includes image texture information and can effectively characterize the structural information of the image. So the method extracts the features which can reflect the degree of image distortion and constitute the feature vector. Finally, the extracted feature is inputted to the support vector regression (SVR) model to predict image quality score. The experimental results show that the proposed algorithm can effectively reflect the visual quality of the image in different distortion types. Spearman correlation coefficient (SROCC) value can reach 0.942.

Key words:  no-reference image quality assessment, quaternion wavelet transform, quaternion wavelet pyramid, support vector regression (SVR)