Color Image Quality Assessment with Quaternion Moments

Color information is important to image quality assessment (IQA). However, most image quality assessment methods transform color image into gray scale, which fail to consider color information. In recent years, color image processing by using the algebra of quaternions has been attracting tremendous attention. Extensive moments based on quaternion have been introduced to deal with the red, green and blue channels of color images in a holistic manner, which have been proved more effective in color processing. With these inspirations, this paper presents a full-reference color image quality assessment metric based on Quaternion Tchebichef Moments (QTMs). QTMs are first employed to measure color and structure distortions simultaneously. Considering that moments are insensitive to weak distortions in high-quality images, gradient is incorporated as a complementary feature. Luminance is also considered as an auxiliary feature. Finally, a QTM-feature-based weighting map is proposed to conduct the pooling, producing an overall quality score. The experimental results on five public image quality databases demonstrate that the proposed method outperforms the state-of-the-arts.