Adaptive skin-color filter

In this paper, we propose a new method, called an adaptive skin color xlter, for detecting skin color regions in a color image. The use of skin color provides an e$cient way to "nd candidate regions for faces or hands in color images. However, it is not easy to "nd skin color regions because the color of skin regions varies from image to image due to a variety of reasons. Since most of the previous methods adopt a "xed threshold scheme, they are useful only in the restricted (i.e., controlled) environment. However, our method is applicable to images in more general situations since it is capable of adaptively adjusting its threshold values and e!ectively separating skin color regions from similar background color regions. Our method consists of basically two stages. In the "rst stage, a thresholding box in HSV color space is updated adaptively using a color histogram under the assumption that the area of skin color regions is comparable to that of similar background color ones. In the second stage, color vectors inside the thresholding box are classi"ed into two groups: skin color vectors and background color vectors. Our method and other conventional methods were tested with 379 images obtained from the Internet. Experimental results show that our method is robust to the variations of skin regions' color compared to the conventional methods. ( 2001 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.