Naonori Ueda Satoshi Suzuki Learning Visual Models from Shape Contours Using Multiscale Convex/Concave Structure Matching. 337-352 1993 15 IEEE Trans. Pattern Anal. Mach. Intell. 4 https://doi.org/10.1109/34.206954 http://doi.ieeecomputersociety.org/10.1109/34.206954 db/journals/pami/pami15.html#UedaS93