In this video, you will see a fast HOG algorithm for object detection, which is more than 10 time faster than that of OpenCV. Tools developed for analysis and sample data sets are also presented. Besides, some of my understanding about training SVM classifier are also given as comments. Wish you like it!
I wrote a short review on the modified HOG descriptor,  you can check out here http://www.sci520.com/ihog
Paper on this algorithm: http://www.sci520.com/?page_id=2483
Website: http://www.sci520.com