Note that the image has more levels of variation and convoluted shape. Image segmentation will not produce any meaningful shape. Our experiments show that when the number of layers in an image is not too large and the region of a similar intensity is not too small and scattered, our signature works extremely well. For comparison, we display, in Figure 4b , the result of a query using the same image on Virage search engine. The condition we used in Virage query is equal weighting on colour, structure, texture and composition, the same as the above.
Query results from Virage search engine.
The first one is the query image. The condition we used in Virage search engine is equal weighting on colour, structure, texture and composition. It is the best combination we can get for the same query image. We also test our method over more complicated images. The test result is shown in Figure 6 .