Object recognition speed improvement using BITMAP-HoG

Abstract

Commonly, HoG/SVM classifier uses rectangular images for HoG feature descriptor extraction and training. This means significant additional work has to be done to process irrelevant pixels belonging to the background surrounding the object of interest. While some objects may indeed be square or rectangular, most of objects are not easily representable by simple geometric shapes. In Bitmap-HoG approach we propose in this paper, the irregular shape of object is represented by a bitmap to avoid processing of extra background pixels. Bitmap, derived from the training dataset, encodes those portions of an image to be used to train a classifier. Experimental results show that not only the proposed algorithm decreases the workload associated with HoG/SVM classifiers by 75% compared to the state-of-the-art, but also it shows an average increase about 5% in recall and a decrease about 2% in precision in comparison with standard HoG.