Method of controlling a traffic surveillance system

• US 10,699,567 B2
• Filed: 11/27/2015
• Issued: 06/30/2020
• Est. Priority Date: 11/27/2014
• Status: Active Grant

• Current Assignee: Kapsch TrafficCom AB (Datax Handelsgmbh), Kapsch TrafficCom AG (Datax Handelsgmbh)
• Original Assignee: Kapsch TrafficCom AB (Datax Handelsgmbh)
• Inventors: Backvall, Johan, Arlig, Ulf, Crona, Bjorn, Karlstrom, Christian
• Primary Examiner(s): Patel, Pinalben
• Application Number:
  US15/529,942
• Publication Number:
  US 20170330454A1
• Time in Patent Office: 1,677 Days
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/30232 Surveillance
• CPC Class Codes: G06T 2207/30236 Traffic on road, railway or crossing
• CPC Class Codes: G06T 7/285 using a sequence of stereo image pairs
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69
• CPC Class Codes: G06V 2201/08 Detecting or categorising vehicles
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

The present disclosure relates to a method of controlling a traffic surveillance system. The method comprises the steps of: capturing first images and second images over time by a plurality of the stereoscopic sensors; processing, by the processing unit, a first image and a second image from a first stereoscopic sensor of the plurality of the stereoscopic sensors to produce a first height image; analyzing said first height image to detect a moving object such as a vehicle located within the primary view; and analysing a part of a primary view of at least a first image, a second image or a combination of the first image and the second image captured by a second stereoscopic sensor based on the detected moving object in said first height image to determine a characteristic of the moving object.

Claims

1. A method of controlling a traffic surveillance system, the system having a plurality of stereoscopic sensors connected to a processing unit, wherein each of the plurality of stereoscopic sensors comprises a first camera and a second camera, wherein each first camera of the plurality of stereoscopic sensors is configured to capture a first image and each second camera of the plurality of stereoscopic sensors is configured to capture a second image, the first image and the second image being capable of being processed into a height image by the processing unit, and each stereoscopic sensor of the plurality of stereoscopic sensors being further configured to define and monitor a main surveillance zone defining a primary coverage in a surveillance plane at a predetermined distance from the stereoscopic sensor, such that any one of the captured first image, the captured second image and the processed height image includes a primary view corresponding to the primary coverage of the stereoscopic sensor, the method comprising:

capturing first images and second images over time by the plurality of stereoscopic sensors;

processing, by the processing unit, a first image from a first camera of a first stereoscopic sensor of the plurality of stereoscopic sensors and a second image from a second camera of the first stereoscopic sensor of the plurality of stereoscopic sensors to produce a first height image;

analysing said first height image to detect a moving object located within the primary view of the first stereoscopic sensor;

determining a position of the moving object with respect to the surveillance plane;

determining a second stereoscopic sensor of the plurality of stereoscopic sensors having a side view of the moving object based on the determined position, wherein the side view overlaps the primary view; and

analysing a part of the primary view of at least a first image captured by a first camera of the second stereoscopic sensor based on the detected moving object in said first height image to determine a characteristic of the moving object.

2. The method according to claim 1, wherein the characteristic is a number of axles of the vehicle, a presence of windows, a ground clearance, an angle of the front window or an indication of objects attached on top of or behind the vehicle.

3. The method according to claim 1, wherein a primary coverage in a surveillance plane of at least the first stereoscopic sensor overlaps a primary coverage in a surveillance plane of the second stereoscopic sensor.

4. The method according to claim 1, further comprising:

determining the characteristic of the moving object based on pattern matching with one or several statistical models of the moving object.

5. The method according to claim 4, wherein any one of the statistical models is based on at least one of standard height levels, standard length levels, standard width levels, cabin size, fingerprinting information, license plate information, or weather condition information.

6. The method according to claim 1, wherein the characteristic of the moving object is determined by determining several height disparity values of the moving object where clusters of disparity values lower than a first threshold indicate the presence of an axle.

7. The method according to claim 6, further comprising:

indicating the wheel of the moving object is in contact with the ground in response to the cluster including values lower than a second threshold.

8. The method according to claim 6, wherein the several height disparity values of the moving object are determined from the first image captured by the first camera of the second stereoscopic sensor, a second image captured by the second stereoscopic sensor, or a combination of the first image and the second image captured by the second stereoscopic sensor prior to producing a second height image.

9. The method according to claim 1, wherein each stereoscopic sensor of the plurality of stereoscopic sensors is arranged to monitor a traffic lane so that the system is configured to monitor a plurality of traffic lanes.

10. The method according to claim 1, wherein at least part of the primary coverage of each stereoscopic sensor of the plurality of stereoscopic sensors is directed towards a predictable vehicle axle region of the vehicle.

11. The method according to claim 1, further comprising:

pre-determining whether a vehicle exceeds a predetermined activation value.

12. The method according to claim 11 wherein analysing a part of the primary view of at least the first image captured by the second stereoscopic sensor of the plurality of stereoscopic sensors is activated when a vehicle exceeds the predetermined activation value.

13. The method according to claim 1, wherein the plurality of stereoscopic sensors is mounted upon a gantry and configured to define the surveillance plane upon a road surface below the gantry.

14. The method according to claim 1, further comprising:

determining a number of axles of a vehicle.

15. A processing unit for a traffic surveillance system configured for implementing the method according to claim 1.

16. The method according to claim 1, wherein the moving object is a vehicle.

17. The method according to claim 11, wherein the predetermined activation value is a minimum height value, a minimum length value, or a minimum number of vehicle axles.

18. A method of controlling a traffic surveillance system, the system having a plurality of stereoscopic sensors connected to a processing unit, wherein each of the plurality of stereoscopic sensors comprises a first camera and a second camera, wherein each first camera of the plurality of stereoscopic sensors is configured to capture a first image and each second camera of the plurality of stereoscopic sensors is configured to capture a second image, the first image and the second image being capable of being processed into a height image by the processing unit, and each stereoscopic sensor of the plurality of stereoscopic sensors being further configured to define and monitor a main surveillance zone defining a primary coverage in a surveillance plane at a predetermined distance from the stereoscopic sensor, such that any one of the captured first image, the captured second image and the processed height image includes a primary view corresponding to the primary coverage of the stereoscopic sensor, the method comprising:

capturing first images and second images over time by the plurality of stereoscopic sensors;

processing, by the processing unit, a first image from a first camera of a first stereoscopic sensor of the plurality of the stereoscopic sensors and a second image from a second camera of the first stereoscopic sensor of the plurality of stereoscopic sensors to produce a first height image;

analysing said first height image to detect a moving object located within the primary view of the first stereoscopic sensor;

determining a position of the moving object with respect to the surveillance plane;

determining a second stereoscopic sensor of the plurality of stereoscopic sensors having a side view of the moving object based on the determined position, wherein the side view overlaps the primary view; and

analysing a part of the primary view of at least a combination of a first image captured by a first camera of the second stereoscopic sensor and a second image captured by a second camera of the second stereoscopic sensor based on the detected moving object in said first height image to determine a characteristic of the moving object.

19. The method according to claim 18, further comprising:

pre-determining whether a vehicle exceeds a predetermined activation value, wherein said analysing the part of the primary view of at least the combination of the first image captured by the first camera of the second stereoscopic sensor and the second image captured by the second camera of the second stereoscopic sensor is activated when a vehicle exceeds the predetermined activation value.

20. A method of controlling a traffic surveillance system, the system having a plurality of stereoscopic sensors connected to a processing unit, wherein each of the plurality of stereoscopic sensors comprises a first camera and a second camera, wherein each first camera of the plurality of stereoscopic sensors is configured to capture a first image and each second camera of the plurality of stereoscopic sensors is configured to capture a second image, the first image and the second image being capable of being processed into a height image by the processing unit, and each stereoscopic sensor of the plurality of stereoscopic sensors being further configured to define and monitor a main surveillance zone defining a primary coverage in a surveillance plane at a predetermined distance from the stereoscopic sensor, such that any one of the captured first image, the captured second image and the processed height image includes a primary view corresponding to the primary coverage of the stereoscopic sensor, the method comprising:

capturing first images and second images over time by the plurality of stereoscopic sensors;

processing, by the processing unit, a first image from a first camera of a first stereoscopic sensor of the plurality of stereoscopic sensors and a second image from a second camera of the first stereoscopic sensor of the plurality of stereoscopic sensors to produce a first height image;

analysing said first height image to detect a moving object located within the primary view of the first stereoscopic sensor;

determining a position of the moving object with respect to the surveillance plane;

determining a second stereoscopic sensor of the plurality of stereoscopic sensors having a side view of the moving object based on the determined position, wherein the side view overlaps the primary view; and

analysing a part of the primary view of at least an image captured by the second stereoscopic sensor based on the detected moving object in said first height image to determine a characteristic of the moving object.