We have developed a method to enhance small cloth stains, such as weak coffee stains, that are slight in color and gray level. The proposed method is composed of four steps. First, we obtain two color images observed under two types of light (near-ultraviolet LEDs and white LEDs). Second, we create the RGB components of the color images to be uncorrelated Using principal component analysis. Third, we transform the uncorrelated components into independent components to obtain more enhanced images. Finally, we reduce the texture structure from the independent component image by Using sparse coding in order to recognize the cloth stain more easily. Experimental results demonstrate that the proposed method is effective for enhancing weak cloth stains in texture images.
