Deli Zhao Zhouchen Lin Xiaoou Tang Contextual Distance for Data Perception. 1-8 2007 ICCV https://doi.org/10.1109/ICCV.2007.4408854 https://doi.ieeecomputersociety.org/10.1109/ICCV.2007.4408854 conf/iccv/2007 db/conf/iccv/iccv2007.html#ZhaoLT07