Queue analysis

1. A computer-implemented method of analysing a queue comprising the steps of:

(a) obtaining, by a computer processor, a first image acquired at a first time of a first position within a queue;

(b) obtaining, by the computer processor, a second image acquired at a second time of a second position within the queue;

(c) detecting, by the computer processor, a queue member within the first image;

(d) detecting, by the computer processor, a queue member within the second image;

(e) determining, by the computer processor, that the queue member detected within the second image is the same as the queue member detected within the first image; and

(f) determining, by the computer processor, a trajectory of the queue member within the queue based on a difference between the first time and the second time.

2. The method of claim 1 further comprising obtaining further images of further positions within the queue and detecting the queue member within these further images.

3. The method of claim 1 , wherein the images overlap.

4. The method according to claim 1 , wherein the positions within the queue are selected from the front of the queue, back of the queue, and the middle of the queue.

5. The method according to claim 1 , wherein further pairs of images are obtained, used to detect the queue member, and determine their trajectory, wherein each pair of images includes at least one common point in the queue.

6. The method according to claim 1 , wherein determining the trajectory further includes the step of forming the trajectory from two or more other trajectories.

7. The method according to claim 6 , wherein determining that the queue member detected within the second image is the same as the queue member detected within the first image is based on similarities of visual appearances of the queue member within each image.

8. The method of claim 7 , wherein determining a trajectory of the queue member within the queue further comprises the step of applying a Munkres assignment algorithm to the two or more other trajectories and the similarities of the visual appearances of the queue member within each image.

9. The method according to claim 1 , wherein detecting the queue member within an image further comprises selecting a group of pixels containing the queue member.

10. The method according to claim 1 , wherein determining a trajectory of the queue member within the queue is further based on the queuing distance between the first position and the second position.

11. The method according to claim 1 , further comprising the step of determining from the trajectory a total queuing time for the queue member.

12. The method according to claim 1 , further comprising iterating steps (a) to (f) to determine a plurality of trajectories.

13. The method of claim 12 further comprising determining an average trajectory from the plurality of trajectories.

14. The method of claim 13 , further comprising the step of determining an average queue time from the average trajectory.

15. A system for analysing a queue comprising:

a processor configured to:

(a) receive a first image acquired at a first time of a first position within a queue;

(b) receive a second image acquired at a second time of a second position within the queue;

(c) detect a queue member within the first image;

(d) detect a queue member within the second image;

(e) determine that the queue member detected within the second image is the same as the queue member detected within the first image; and

(f) determine a trajectory of the queue member within the queue based on a difference between the first time and the second time.

16. The system of claim 15 further comprising a first and a second camera arranged to capture the first and second images, respectively.

17. The system of claim 16 , wherein the first and second cameras are arranged to have partially overlapping views of the queue.

18. The system according to claim 15 further comprising a user interface configured to receive a signal indicating the first and the second positions of the queue on the first and second images.

19. The system of claim 18 , wherein the first or second positions of the queue are selected from: the start of the queue, an intermediate position in the queue, and the end of the queue.

20. One or more non-transitory computer readable media storing computer readable instructions that, when executed, cause a system to perform a method of analyzing a queue by:

obtaining a first image acquired at a first time of a first position within a queue;

obtaining a second image acquired at a second time of a second position within the queue;

detecting a queue member within the first image;

detecting a queue member within the second image;

determining that the queue member detected within the second image is the same as the queue member detected within the first image; and

determining a trajectory of the queue member within the queue based on a difference between the first time and the second time.