Concavity trees have been known for quite some time as structural descriptors of 2-D shape; however, they haven’t been explored further until recently. This paper shows how 2-D shapes can be concisely, but reversibly, represented during concavity tree extraction. The representation can be exact, or approximate to a pre-set degree. This is equivalent to a lossless, or lossy compression of the image containing the shape. This paper details the proposed technique and reports nearlossless compression ratios that are 150% better than the JBIG standard on a test set of binary silhouette images.
Ossama El Badawy, Mohamed S. Kamel