An image processing apparatus, comprising: a sensor which senses occurrences of a predetermined event in each pixel of a plurality of image pixels and which outputs event signals in response to the sensed occurrences; a time stamp unit which generates time stamp information by mapping respective pixels corresponding to the event signals to a time at which the event signals are output from the sensor; and an optical flow generator which generates an optical flow based on the time stamp information in response to the outputting of the event signals by the sensor; wherein the optical flow generator includes a neighborhood pixel obtaining unit which obtains neighborhood pixels of a pixel of the plurality of pixels, a time difference calculating unit which calculates information related to a time difference between the pixel and each of the neighborhood pixels, using the time stamp information, characterized in that the optical flow generator further includes: a distance difference calculating unit which calculates information related to a distance between the pixel and each of the neighborhood pixels, an optical flow calculating unit which calculates a two-dimensional vector A corresponding to the pixel based on the information related to the time differences and the information related to the distances, by multiplying, for each of the neighborhood pixels, the information related to the distance between the pixel and said each of the neighborhood pixels by the information related to the time difference between the pixel and said each of the neighborhood pixels, and using a sum of the results of the multiplication corresponding to each of said neighborhood pixels; wherein the information related to the distance between the pixel and said each of the neighborhood pixels comprises inverse numbers of pixel distances between the pixel and the neighborhood pixels. a sensor which senses occurrences of a predetermined event in each pixel of a plurality of image pixels and which outputs event signals in response to the sensed occurrences; a time stamp unit which generates time stamp information by mapping respective pixels corresponding to the event signals to a time at which the event signals are output from the sensor; and an optical flow generator which generates an optical flow based on the time stamp information in response to the outputting of the event signals by the sensor; wherein the optical flow generator includes a neighborhood pixel obtaining unit which obtains neighborhood pixels of a pixel of the plurality of pixels, a time difference calculating unit which calculates information related to a time difference between the pixel and each of the neighborhood pixels, using the time stamp information, characterized in that the optical flow generator further includes: a distance difference calculating unit which calculates information related to a distance between the pixel and each of the neighborhood pixels, an optical flow calculating unit which calculates a two-dimensional vector A corresponding to the pixel based on the information related to the time differences and the information related to the distances, by multiplying, for each of the neighborhood pixels, the information related to the distance between the pixel and said each of the neighborhood pixels by the information related to the time difference between the pixel and said each of the neighborhood pixels, and using a sum of the results of the multiplication corresponding to each of said neighborhood pixels; wherein the information related to the distance between the pixel and said each of the neighborhood pixels comprises inverse numbers of pixel distances between the pixel and the neighborhood pixels. a distance difference calculating unit which calculates information related to a distance between the pixel and each of the neighborhood pixels, an optical flow calculating unit which calculates a two-dimensional vector A corresponding to the pixel based on the information related to the time differences and the information related to the distances, by multiplying, for each of the neighborhood pixels, the information related to the distance between the pixel and said each of the neighborhood pixels by the information related to the time difference between the pixel and said each of the neighborhood pixels, and using a sum of the results of the multiplication corresponding to each of said neighborhood pixels; wherein the information related to the distance between the pixel and said each of the neighborhood pixels comprises inverse numbers of pixel distances between the pixel and the neighborhood pixels.