1. A method for measuring an attribute of a queue, comprising: acquiring a plurality of images of a queue; extracting features from the images of the queue; analyzing, using at least one computer system, the extracted features; and measuring the attribute based on the analysis of the extracted features, wherein the attribute comprises a fullness of the queue that is determined based on a waiting line length of the queue, a length of the queue, a number of objects in the queue, and a density of the queue, wherein the density of the queue is equal to a ratio of the number of objects in the queue to the waiting line length of the queue; wherein the analyzing further comprises analyzing the extracted features at a plurality of successive time points to determine successive correspondences between the extracted features, wherein the measuring further comprises determining the fullness of the queue based on the successive correspondences, wherein the fullness of the queue is determined by comparing the waiting line length of the queue to the length of the queue, and wherein the queue is determined to be full if the waiting line length of the queue is about equal to the length of the queue and the density of the queue is above a predetermined threshold.