Trade-marks' retrieval has obtained more and more attention in recent research on content-based manage-ment and utilization of image database system.To retrieve the images,the key is to get the shape features.In this paper,a new method for extracting shape features of trade-marks is presented.Based on the theory of information,the method uses images' entropy and invariant moments to capture the shape and spatial information of images.The algorithm is easy and the experimental results show its invariabili...