Patent US 6,160,901

An image processing device includes a difference image generating unit for selecting two images at different times from among a plurality of images stored in an image storage unit. The image generating unit computes a difference between the selected two images and generates and stores a difference image. A direction estimating unit estimates a direction or bearing of motion of the moving object along each of several axes for each of the pixels based on the difference image held by the difference image generating unit. The direction estimating unit generates one or more vectors representing the directions of motion of the moving object along the axes for each of the pixels. An initially-estimated motion vector unit computes the sum of the vectors estimated by the direction estimating unit and generates an initially-estimated motion vector for each of the pixels. A vector averaging unit averages initially-estimated motion vectors in the vicinity of each of the plurality of pixels, including the initially-estimated motion vector of each of the pixels, and generates a motion vector for each of the pixels.