1. Freak: Fast retina keypoint;Alahi,2012
2. Visual object recognition;Biederman,1995
3. Learning mid-level features for recognition;Boureau,2010
4. Brief: Binary robust independent elementary features;Calonder,2010
5. C. Chang, C. Lin, Libsvm: a library for support vector machines. (2006). Software available at http://www.csie.ntu.edu.tw/~jlin/libsvm.