Hirokazu Madokoro Masahiro Tsukada Kazuhito Sato Unsupervised feature selection and category formation for mobile robot vision. 320-327 2011 IJCNN https://doi.org/10.1109/IJCNN.2011.6033238 conf/ijcnn/2011 db/conf/ijcnn/ijcnn2011.html#MadokoroTS11