1. An image processing apparatus, comprising: a sensor which senses an occurrence of a predetermined event associated with a change in a brightness of one image pixel among a plurality of image pixels, and which outputs an event signal including location information of the one image pixel in response to the sensed occurrence; a time stamp unit which generates time stamp information by mapping a pixel corresponding to the event signal to a time at which the event signal is output from the sensor, wherein the pixel corresponding to the event signal is determined based on the location information; and an optical flow generator which generates an optical flow based on the time stamp information.