Cargo sensing system

• US 7,421,112 B2
• Filed: 03/12/2004
• Issued: 09/02/2008
• Est. Priority Date: 03/12/2004
• Status: Active Grant

• Current Assignee: Asset Intelligence LLC (PowerFleet, Inc.)
• Original Assignee: General Electric Company
• Inventors: Calver, Andrew J., Cobello, Rick, McKenney, Kurtis G.
• Primary Examiner(s): Bali; Vikkram
• Assistant Examiner(s): ZARKA, DAVID PETER
• Application Number:
  US10/800,342
• Publication Number:
  US 20050199782A1
• Time in Patent Office: 1,635 Days
• Field of Search: 382/154
• US Class Current: 382/154
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/89 for mapping or imaging

Abstract

A cargo sensing system is configured to determine if cargo is present within a container. In one implementation, the cargo sensing system senses lines within an image of a cargo space. The lines may be straight, curved or otherwise configured, and are evaluated for indications of the presence of cargo within the cargo space. In a first implementation of the cargo sensing system, the lines within the cargo space are formed by a laser tracing over a predetermined projection pattern. In a second implementation of the cargo sensing system, the lines sensed are formed by intersection of planes defining the cargo space.

Claims

1. A system for detecting a presence of cargo in a container, comprising:

an ambient light sensor to determine if an ambient light level within the container exceeds a threshold value;

a camera to obtain an image of an interior of the container;

an edge detection module configured to recognize lines formed by intersection of floor and walls of the container, and to compare the recognized lines to a plurality of images of empty cargo containers within an edge image library, and upon failure to match the recognized lines to an image within the edge image library, to within a threshold level of differences, to assume that cargo is present within the container;

a laser unit, controlled by a projection pattern generator and operated only when ambient lighting is below the threshold value, to create a laser projection pattern in the container; and

a laser pattern evaluation module to evaluate the laser projection pattern to determine if cargo is present in the container.

2. The system of claim 1, wherein ambient light below the threshold results in use of an auxiliary light source while the edge detection module is operating.

3. The system of claim 1, wherein ambient light above the threshold results in operation of the edge detection module without an auxiliary light source and prevents operation of the laser unit and laser pattern evaluation module.

4. The system of claim 1, wherein the threshold value associated with the ambient light level is set so that light levels equal to or greater than the threshold value would reasonably allow personnel to work within in the container.

5. The system of claim 1, wherein the edge detection module compares the recognized lines to plural images within the edge image library to determine differences, and where the differences with one image in the library are less than a threshold difference, to assume the container to be empty.

6. The system of claim 1, wherein the edge detection module evaluates the recognized lines for indications of cargo, including gaps, breaks and distortions of lines formed by intersection of floor and walls of the container.

7. The system of claim 1, wherein the laser pattern evaluation module evaluates two points of the laser projection pattern on the image having similar Y-coordinates to see if a distance between X-coordinate values of the points indicate alteration of the projection pattern by cargo within the container.

8. The system of claim 1, wherein the laser pattern evaluation module evaluates the image for distortions and discontinuities not present in an image of the projection pattern in the container obtained when no cargo was present.

9. A method of sensing cargo in a container, comprising:

verifying that personnel are not inside the container by sensing an ambient light level to determine if the ambient light level exceeds a threshold value and assuming that personnel are not in the container if the ambient light level is below a threshold;

operating an auxiliary lighting unit when the ambient light level does not exceed the threshold;

obtaining an image of an inside of the container using a camera;

evaluating lines in the image formed by intersection of floor and walls of the container for indications of cargo, wherein the evaluation compares lines found by edge detection of the walls and floor in the image to an edge image library comprising a plurality of images of empty cargo containers, and upon failure to match the image to an image within the edge image library to within a threshold level of differences, assumes that cargo is present within the container;

projecting a laser projection pattern into the container using a laser unit, only when ambient lighting is below the threshold value and personnel are not inside the container; and

evaluating the laser projection pattern to determine if cargo is present in the container, wherein the evaluating selects at least two lines from the image of the projection pattern, measures a distance between those lines, and compares the measured distance to an expected distance as an indicator that cargo within the container disrupted the laser projection pattern.

10. The method of claim 9, wherein evaluating lines in the image formed by intersection of floor and walls of the container for indications of cargo also evaluates lines formed by double wall construction of the container.

11. The method of claim 9, wherein evaluating lines in the image includes looking for gaps, breaks and distortions of lines formed by intersection of floor, walls and double walls of the container.

12. The method of claim 9, evaluating the laser projection pattern evaluates the image for distortions and discontinuities not present in an image of the projection pattern in the container obtained when no cargo was present.

13. The method of claim 9, wherein the evaluating the laser projection pattern evaluates two points of the laser projection pattern on the image having similar Y-coordinates to see if a distance between X-coordinate values of the points indicate alteration of the projection pattern by cargo within the container.

14. A cargo sensing system, comprising:

an ambient light sensor to determine if an ambient light level within a container exceeds a threshold value;

a camera to obtain an image of an interior of the container;

an edge detection module configured to evaluate the image to recognize lines formed by intersection of a floor and walls of the container and to recognize indications of cargo, wherein ambient light below the threshold results in use of an auxiliary light source while the edge detection module is operating, wherein the edge detection module is additionally configured to compare results of edge detection of the image to each of a plurality of images within an edge image library associated with standard images of empty cargo containers, and upon failure to match the image to an image within the edge image library to within a threshold level of differences, to assume that cargo is present within the container;

a laser unit, controlled by a projection pattern generator and operated only when ambient lighting is below the threshold value, to create a laser projection pattern within the interior of the container; and

a laser pattern evaluation module to evaluate the laser projection pattern to determine if cargo is present in the container, wherein the evaluation module selects at least two lines from the image of the laser projection pattern, measures a distance between those lines, and compares the measured distance to an expected distance as an indicator of whether cargo within the container disrupted the laser projection pattern.

15. The cargo sensing system of claim 14, wherein the threshold value associated with the ambient light level is set so that light levels equal to or greater than the threshold value would reasonably allow personnel to work within in the container.

16. The system of claim 14, wherein edge detection module is also configured to recognize in the image lines formed by double wall construction of the container.

17. The system of claim 14, wherein the edge detection module evaluates lines recognized at intersections of the floor and the walls for indications of cargo, including gaps, breaks and distortions.

18. The system of claim 14, wherein the laser pattern evaluation module evaluates two points of the laser projection pattern having similar Y-coordinates to see if a distance between X-coordinate values of the points indicates alteration of the projection pattern by cargo within the container.

19. The system of claim 14, wherein the laser pattern evaluation module evaluates the image for distortions and discontinuities not present in an image of the projection pattern in the container obtained when no cargo was present.

20. The system of claim 14, wherein the laser pattern evaluation module evaluates the image by comparison to a projection pattern database having images of empty cargo areas, and concludes cargo is present when differences exceed a threshold value.