1. A method for controlling a device based on computer vision, the method comprising obtaining a sequence of images of a field of view, each of the images comprising at least one hand; applying a shape recognition algorithm on the images to identify the at least one hand; detecting, from the images, movement of the hand; determining a size of the moving hand relative to the image frame which includes the hand; and moving a displayed object according to movement of the hand while normalizing movement of the displayed object according to the determined size of the hand.