======================================================================== Image Classification using Bag of Words and Spatial Pyramid BoW Created by Piji Li Email: pagelee.sd@gmail.com Blog: http://www.zhizhihu.com Weibo: http://www.weibo.com/pagecn 10/24/2011 Some code are from: S. Lazebnik, C. Schmid, and J. Ponce, "Beyond Bags of Features: Spatial Pyramid Matching for Recognizing Natural Scene Categories," CVPR 2006. ======================================================================== Use: 1, follow labes/readme to prepare data 2, go to libsvm/: make 3, modify ini.m: rootpath=your demo path, and then run main.m. The BOW and Dictionary is in the dir:/data/global, size of BOW_sift.mat is (DictionarySize * #images). Size of dictionary.mat is (DictionarySize * dim of features).spatial_pyramid.mat is the Spatial Pyramid BoW. In /data/local is the sift features for each images. ======================================================================== Classification using BOW rbf_svm Accuracy = 76.6667% (92/120) (classification) Classification using histogram intersection kernel svm Accuracy = 81.6667% (98/120) (classification) Classification using Pyramid BOW rbf_svm Accuracy = 82.5% (99/120) (classification) Classification using Pyramid BOW histogram intersection kernel svm Accuracy = 90% (108/120) (classification) ======================================================================== Idea from: S. Lazebnik, C. Schmid, and J. Ponce, "Beyond Bags of Features: Spatial Pyramid Matching for Recognizing Natural Scene Categories," CVPR 2006. Images from: Piji Li, Jun Ma, Shuai Gao. Actions in Still Web Images: Visualization, Detection and Retrieval. The 12th International Conference on Web-Age InformationManagement (WAIM 2011). Springer, 2011. SVM from: Chih-Chung Chang and Chih-Jen Lin, LIBSVM : a library for support vector machines. ACM Transactions on Intelligent Systems and Technology, 2:27:1--27:27, 2011. Software available at http://www.csie.ntu.edu.tw/~cjlin/libsvm