US Patent 8131010 High density queue estimation and line management

The present invention is directed to the measurement of attributes of a queue. A method for measuring an attribute of a queue in accordance with an embodiment includes: acquiring a plurality of images of a queue; extracting features from the images of the queue; analyzing the extracted features; and measuring the attribute based on the analysis of the extracted features; wherein the analyzing further comprises analyzing the extracted features at a plurality of successive time points to determine successive correspondences between the extracted features, and wherein the measuring further comprises measuring the attribute based on the successive correspondences