1. A moving object recognizer, comprising: an image processing circuit to receive stereo image signals from a stereo camera consecutively, and generate a stereo image including two images; and consecutively store frames of at least one of the two images of the generated stereo image, and generate a brightness image frame; and processing circuitry configured to calculate a disparity between the two images of the stereo image, and generate a disparity image frame, to recognize an object at least from the brightness image frame; track an object recognized at a certain time in an image frame through brightness image frames obtained subsequent to the image frame in which the object was recognized at the certain time, and detect a change in a state of the tracked object from the disparity image frame and the corresponding brightness image frame at two different times, the detecting including, at each time, determining, in the brightness image frame, an area of the tracked object, and calculating, using the disparity image frame, a distance to the tracked object based on a mean disparity of the area of the tracked object.