I've around $500$ binary (black and white) images, of which I attach $2$ samples. I'm working on a machine learning problem of classifying images like them. I'd like to know what image features I can use that'd be very distinct for distinct images of this type. I tried HOG features, but the difficulty is they're very high dimensional (even for a $64 \times 64$ image, the HOG feature dimension is $1764$), so the models will overfit. Hence the question. Thanks!