1. An image processing apparatus comprising: an image acquiring unit that acquires an image; a domain extracting unit that extracts a domain characterizing an object of gesture recognition from the image acquired by the image acquiring unit; a mapping unit that maps domains extracted by the domain extracting unit between frames of the image; a direction extracting unit that extracts a moving direction of the domains mapped by the mapping unit; a direction output unit that outputs the moving direction extracted by the direction extracting unit when a moving distance of the domains mapped by the mapping unit is greater than a predetermined threshold; and a threshold updating unit that updates the threshold using a moving distance exceeding the threshold.