说明：  空间特征提取： * canny.m Canny edge detector incorporating modifications suggested by Fleck. * harris.m Harris corner detector. * fastradial.m An implementation of Loy and Zelinski s fast radial feature detector.
(Spatial Feature Extraction:* canny.m Canny edge detector incorporating modifications suggested by Fleck .* harris.m Harris corner detector .* fastradial.m An implementation of Loy and Zelinski s fast radial feature detector.)