Unsupervised Feature Selection and Category Classification for a Vision-Based Mobile Robot

Abstract

This paper presents an unsupervised learning-based method for selection of feature points and object category classification without previous setting of the number of categories. Our method consists of the following procedures: 1) detection of feature points and description of features using a Scale-Invariant Feature Transform (SIFT), 2) selection of target feature points using One Class-Support Vector Machines (OC-SVMs), 3) generation of visual words of all SIFT descriptors and histograms in each image of selected feature points using Self-Organizing Maps (SOMs), 4) formation of labels using Adaptive Resonance Theory-2 (ART-2), and 5) creation and classification of categories on a category map of Counter Propagation Networks (CPNs) for visualizing spatial relations between categories. Classification results of static images using a Caltech-256 object category dataset and dynamic images using time-series images obtained using a robot according to movements respectively demonstrate that our method can visualize spatial relations of categories while maintaining time-series characteristics. Moreover, we emphasize the effectiveness of our method for category classification of appearance changes of objects.