Hongyu Li Rongjie Shi Wenbin Chen I-Fan Shen Image Tangent Space for Image Retrieval. 1126-1130 2006 conf/icpr/2006 ICPR (2) http://doi.ieeecomputersociety.org/10.1109/ICPR.2006.690 db/conf/icpr/icpr2006-2.html#LiSCS06