1. A moving object recognizer comprising: an image input to receive stereo image signals from a stereo camera consecutively and output a stereo image; a brightness image generator configured to consecutively store frames of at least one of images of the stereo image output from the image input and generate a brightness image frame; a disparity image generator configured to calculate a disparity between the images of the stereo image output to the brightness image generator from the image input and generate a disparity image frame; an object recognizer configured to recognize an object at least from the brightness image frame; a tracking processor configured to track an object recognized at a certain time from an image frame by the object recognizer through brightness image frames obtained from image frames subsequent to the image frame recognized at the certain time; and a change detector configured to detect a change in a state of the tracked object from the disparity image frame synchronized with the brightness image frame.