A New Projection Space for Separation of Specular-Diffuse Reflection Components in Color Images

In this paper, we propose a new reflectance separation model to separate the diffuse and specular reflection components. The model is based on a two-dimensional space called Ch-CV space, which is spanned by maximum chromaticity and the coefficient of variation (CV) of RGB color. The space exhibits a more direct correspondence to diffuse and specular reflection components than the RGB color space, as well as the HSI color space. Under the whitened illumination, the surface points with the same diffuse chromaticity have the same slope in Ch-CV space. Based on these properties, we propose a slope-based region growing method to implement an image segmentation in the specular regions, and to separate the reflection components for each segmented region. The comparison experiments with several state-of-the-art algorithms show its superior capability to separate the specular and diffuse reflection components.