Kentaro Miyamoto Tetsuo Kamina Tetsuo Sugiyama Keisuke Kameyama Kazuo Toraichi An Image Segmentation Method for Function Approximation of Gradation Images. 238-243 2006 conf/sspra/2006 SPPRA db/conf/sspra/sspra2006.html#MiyamotoKSKT06