Patent ID: 8325982

Claim:
A method for detecting and tracking shopping carts, utilizing a position-dependent cart shape and motion model based on video images, comprising the following steps of: a) detecting and tracking motion blobs from the video images, wherein pixels within the same motion blob go through the same motion, b) detecting presence of carts within the detected motion blobs by collecting evidence from motions of pixels within the detected motion blobs, c) constructing a motion model of carts that characterizes the motion of passive objects pushed by humans, d) extracting motion features that characterize the motion of passive object by constructing a histogram of relative motions among points within the motion blobs, e) verifying presence of carts in the detected motion blobs based on the motion model of carts, and f) tracking the verified carts so that their individual identities can be maintained across the video images, wherein the histogram captures characteristic rigid motion of a cart and passive motion of the cart relative to a person pushing the cart.