I want to detect 4 basic hand gestures of user in front of camera. When the user moves his hand in front of camera from left to right, right to left, top to down and down to top. How can I achieve this using BoofCV for android? What are the starting steps?
This question is a bit high level and is really a generic computer vision question. BoofCV contains the tools so that you could do that using several different techniques. It doesn't contain gesture recognition built in.
If the background is static relative to the camera I would just take a picture with no hand, then subtract that the current image. Look at the centroid of the pixels with the biggest change. Use that (x,y) coordinate to determine how it's moving. This will be good enough for a proof of concept.