1. A method of adaptively determining the exposure time for each frame captured by an image capture system of the type having an image sensor, optics for forming an image of a scene on the image sensor, and an image processor for determining an exposure time for the image sensor, said method comprising the steps of: a) acquiring two time-separated image frames during an initial exposure time set for each of the image frames, wherein each image frame includes one or more moving objects from the scene; b) spatially registering the two image frames; c) measuring spatial displacements between the two image frames for the same moving objects; d) determining a fastest moving object in the scene from the measured spatial displacements; e) calculating a speed of the fastest moving object; f) calculating object smear for the fastest moving object based on the initial exposure time; g) if the object smear exceeds a maximum desired smear, calculating a new exposure time; and h) setting the exposure time for a subsequent image frame to the new exposure time.