Boundary crossing object detection system

• US 7,492,306 B2
• Filed: 03/24/2006
• Issued: 02/17/2009
• Est. Priority Date: 03/24/2006
• Status: Expired due to Fees

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Humphrey, Denver, Clarke, Bryan
• Primary Examiner(s): Gregory; Bernarr E
• Application Number:
  US11/387,884
• Publication Number:
  US 20070222663A1
• Time in Patent Office: 1,061 Days
• Field of Search: 342/27, 342/28, 342/59, 342 82-103, 342/175, 342/195, 342 70- 81, 342/118, 342134-147, 342149-158, 342192-194, 342196-197, 340/540, 340541-567, 340901-904, 340/500, 701/300, 701/301
• US Class Current: 342/28
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G08B 13/1609 using active vibration detection systems

Abstract

An boundary monitoring apparatus comprising an object detection device arranged to transmit a signal into a detection region and to detect an object in said detection region upon receipt of a reflected signal from said object; means for defining a boundary in said detection region; means for determining a path of said object in the detection region; means for performing an evaluation of the determined path of the object with respect to the boundary; and means for causing an alarm event depending on the evaluation.

Claims

1. A boundary monitoring apparatus comprising:

a radar device arranged to transmit a signal into a detection region and to detect an object in said detection region upon receipt of a reflected signal from said object;

means for defining a boundary in said detection region;

means for determining a path of said object in the detection region;

means for performing an evaluation to determine if said path intersects with said boundary; and

means for raising an alarm depending on the evaluation,

wherein said means for performing an evaluation is arranged to determine a minimum distance within said boundary of said path of said object from said radar device or other reference location, and wherein said means for raising an alarm raises an alarm if said path of the object is determined to intersect said boundary and if said minimum distance of said path is less than a threshold value, and does not raise said alarm if said path of the object is determined to intersect said boundary and if said minimum distance of the path is greater than said threshold value.

2. An apparatus as claimed in claim 1, wherein said reflected signal is received during use by said object detection device at an incident angle, the apparatus including means for determining said incident angle.

3. An apparatus as claimed in claim 2, wherein said apparatus includes means for determining a distance of said object from said radar device, and wherein determination of said path by said means for determining a path is based on respective incident angles and respective distances determined by said means for determining a distance determined for said object over time.

4. An apparatus as claimed in claim 1, wherein said radar device comprises first and second receiving antennas each receiving, in use, a respective reflected signal from a detected object;

and a summation and subtraction unit for summing and subtracting the respective reflected signals to produce, respectively, a sum reflected signal and a difference reflected signal.

5. An apparatus as claimed in claim 4, wherein an incident angle for the detected object is determined from a ratio of said sum reflected signal and said difference reflected signal.

6. An apparatus as claimed in claim 1, wherein said means for determining a path is arranged to determine a linear path for said detected object.

7. An apparatus as claimed in claim 1, wherein said means for determining a path is arranged to determine a linear path for said detected object, and said means for performing an evaluation is arranged to determine an angle of inclination of the determined path of said object from a reference axis, and wherein said means for raising an alarm raises the alarm if the path of the object is determined to intersect said boundary and if said determined angle meets an angle threshold requirement, and does not raise said alarm if the path of the object is determined to intersect said boundary and if said determined angle does not satisfy said angle threshold requirement.

8. An apparatus as claimed in claim 1, further including means for defining a post-boundary region beyond said boundary with respect to said radar device, the apparatus being arranged to monitor the movement of objects detected in the post-boundary region.

9. An apparatus as claimed in claim 1, further including means for defining a pre-boundary region between said boundary and said radar device, the apparatus being arranged to monitor the movement of objects detected in the pre-boundary region.

10. An apparatus as claimed in claim 1, wherein, in respect of an object first detected outside of said boundary, said means for performing an evaluation is arranged to determine if said determined path indicates that said object is travelling towards the apparatus.

11. An apparatus as claimed in claim 1, wherein, in respect of an object first detected inside of said boundary, said means for performing an evaluation is arranged to determine if said determined path indicates that said object is travelling away from the apparatus.

12. An apparatus as claimed in claim 1, further including means for adjusting a size threshold for detectable objects.

13. An apparatus as claimed in claim 1, wherein said means for determining a path is arranged to monitor movement of said object and to predict said path based on said monitored movement.

14. A boundary monitoring apparatus as claimed in claim 1, wherein said means for raising an alarm is arranged not to raise said alarm until said radar device determines that said object has intersected said boundary.

15. A method of monitoring a boundary in an apparatus comprising a radar device arranged to transmit a signal into a detection region and to detect an object in said detection region upon receipt of a reflected signal from said object, the method comprising defining a boundary in said detection region;

determining a path of said object in the detection region;

performing an evaluation to determine if said path intersects with said boundary;

determining a minimum distance within said boundary of said path of said object from said radar device or other reference location; and

raising an alarm if said path of the object is determined to intersect said boundary and if said minimum distance of the path is less than a threshold value, and not raising said alarm if said path of the object is determined to intersect said boundary and if said minimum distance of the path is greater than said threshold value.

16. A boundary monitoring apparatus comprising:

a radar device arranged to transmit a signal into a detection region and to detect an object in said detection region upon receipt of a reflected signal from said object;

means for defining a boundary in said detection region;

means for determining a linear path of said object in the detection region;

means for performing an evaluation of the determined path to determine if the path intersects with said boundary of the object; and

means for raising an alarm depending on the evaluation,

wherein said means for performing an evaluation is arranged to determine an angle of inclination of said linear path of said object from a reference axis, and wherein said means for raising an alarm raises an alarm if said path of the object is determined to intersect said boundary and if said determined angle meets an angle threshold requirement, and does not raise said alarm if the path of the object is determined to intersect said boundary and if said determined angle does not satisfy said angle threshold requirement.

17. A boundary monitoring apparatus as claimed in claim 16, wherein said means for performing an evaluation is arranged to determine a minimum distance within said boundary of the determined path of said object from said radar device or other reference location, and said means for raising an alarm raises said alarm if the path of the object is determined to intersect said boundary and if said minimum distance of the path is less than a threshold value and does not raise said alarm if the path of the object is determined to intersect said boundary and if said minimum distance of the path is greater than said threshold value.

18. A boundary monitoring apparatus as claimed in claim 17, wherein said reference axis is substantially parallel with a line of sight of said radar device, said means for raising an alarm is arranged not to raise said alarm if said determined path is substantially perpendicular to said reference axis and if said minimum distance is greater than said threshold value.

19. A boundary monitoring apparatus as claimed in claim 18, wherein said means for raising an alarm is arranged not to raise said alarm until said radar device determines that said object has intersected said boundary.

20. A method of monitoring a boundary in an apparatus comprising:

a radar device arranged to transmit a signal into a detection region and to detect an object in said detection region upon receipt of a reflected signal from said object, the method comprising defining a boundary in said detection region;

determining a linear path of said object in the detection region;

performing an evaluation to determine if said path intersects with said boundary;

determining an angle of inclination of the determined linear path of said object from a reference axis;

raising an alarm if said path of the object is determined to intersect said boundary and if said determined angle meets an angle threshold requirement; and

not raising said alarm if the path of the object is determined to intersect said boundary and if said determined angle does not satisfy said angle threshold requirement.