supported in part by the grants from NNSFC 10905030;Beijing Natural Science Foundation (Research on key techniques of medical conebeam CT reconstruction from little data based on com-pressed sensing theory)~~
国家自然科学基金( the National Natural Science Foundation of China under Grant No60672098) ; 重庆市科技公关计划( the KeyTechnologies R&D Program of Chongqing City; China under Grant NoCSTC2006AB3027)