I. Introduction
Color image segmentation has been extensively applied in pattern recognition, image analysis and computer vision such as image retrieval [1], face recognition and image compression [6]. In the literature, one image segmentation approach is pixel-based segmentation, in which the conventional means clustering algorithm [3] is commonly used to classify color pixels into different clusters [5], [7]. The -means generally requests to pre-assign an appropriate cluster number . Otherwise, its performance may seriously deteriorate. Unfortunately, such a value selection is an intractable problem from a practical viewpoint.