Based on the specimen images generated by the SEM, we found that the toe pads surface of the tree frog consists of different kinds of polygons, mainly including pentagons, hexagons and heptagons, depending on the number of edges. According to our assumption, the type of polygon with the largest number in the images may have a major influence on the function of tree frog's toe pads, so that we evaluated the number of different kinds of polygons on its toe pads surface. To get more reliable results, we collected 111 images from different parts of 16 toe pads using SEM. The example of original image is shown in Fig. . To avoid the subjective mistakes and improve the calculation efficiency, we used the image processing method to count the polygons automatically. For an input image, we firstly adopted the Canny operator to extract the edges of polygons. In this step, each polygon in the original image was separated and represented by an irregular shape. Then for each polygon, we employed the Hough transformation to fit the straight lines on the edge of the irregular shape. These straight lines were extended to get the final convex polygons. In this operation, the polygons in the boundary of images were ignored, because they might be incomplete and led to unreliable results. An example of processed images is shown in Fig. . Since the detected lines might have noise, which can influence the final results, we designed a filter to remove the line which is too short to be regarded as a single line, and combine each of two neighbor lines if their formed angle is very large so that they may be actually in the same straight line. After filtering, we calculated the number of remained lines as the number of edges for these polygons. An example of all the detected polygons with different number of edges is shown in Fig. . Red, green and blue represent pentagons, hexagons and heptagons, respectively. In the end, the program counted the number of three different types of polygons in all images and found that the polygons with six edges are the main components on toe pads surface of the tree frog. Based on the image processing results, accordingly, we proposed the novel MFSA whose surface textures are composed of six edge polygons with different size.