This is main function of using HOG extraing features, the main function, can be applied in two scenarios.
Note: if you are going to use vl_hog in my_rep.m, please uncomment the following lines in HOGfeature.m when you first run the file. You may want to comment it until you restart MATLAB next time because it slows down the code.
run('vlfeat-0.9.20/toolbox/vl_setup')
vl_version verbose
This is the function to extract HOG. Three methods. Usually method 2 is the most stable one.
This is another functinon for HOG(). Pretty useless because of the high error. But sometimes if you have an error of 90%, try this maybe.