Method of determining optimal detection beam locations using reflective feature mapping

• US 5,675,326 A
• Filed: 06/07/1995
• Issued: 10/07/1997
• Est. Priority Date: 04/11/1990
• Status: Expired due to Fees

• Current Assignee: Autosense LLC
• Original Assignee: Auto-Sense. Limited
• Inventors: Mathews, Paul, Juds, Scott
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US08/485,099
• Time in Patent Office: 853 Days
• Field of Search: 340/904, 340/903, 340/435, 340/556, 340/961, 340/555, 340/436, 180/167, 180/271, 367/93, 367/94, 367/909, 343/27-29, 343/41, 356/2, 356/3, 364/461
• US Class Current: 340/904
• CPC Class Codes: G01S 17/931 of land vehicles

Abstract

A method of defining a sensing system for detecting the presence of an object in a volume of space under surveillance by determining the optimal placement of a plurality of energy beams which are projected into the volume which comprises the steps of (A) placing the object at a preselected position within the space; (B) directing a plurality of sample beams of energy, which have a predetermined orientation, from a source onto the object; (C) detecting the reflections of the sample beam energy from points on the object by energy detectors; (D) recording the preselected position of the object, the predetermined orientation of sample beams, and the detection status of the energy detectors; (E) changing the equatorial and azimuthal angles of each of the beams and repeating steps (B), (C) and (D); (F) moving the source of the sample beams relative to the object; (G) repeating steps (B) through (F) to produce spatial maps of the locations at which the object is positioned when each of the energy detectors detect reflected sample beam energy; and (H) using the spatial maps so produced to select the optimal orientation of a set of energy beams which will maximize the detection probability of an object located in the volume of space under surveillance. This method is repeated for a plurality of different vehicles.

Claims

1. A method of determining the optimal positions for a plurality of energy beams directed into a volume of space under surveillance to detect the presence of an object within that space, comprising the steps of:

(A) placing the object at a preselected position within the space;

(B) directing a plurality of sample beams of energy, which have a predetermined orientation, from a source onto the object;

(C) detecting the sample beam energy reflected from points on the object by energy detectors;

(D) recording the preselected position of the object, the predetermined orientation of sample beams, and the detection status of the energy detectors;

(E) moving the source of the sample beams relative to the object;

(F) repeating steps (B) through (E) to produce spatial maps of the locations at which the object is positioned when each of the energy detectors detect reflected sample beam energy; and

(G) using the spatial maps so produced to select the optimal orientation of a set of energy beams which will maximize the detection probability of an object located in the volume of space under surveillance.

2. The method of claim 1, wherein step (B) is performed by:

simultaneously training a group of said sample beams onto said object, and

angularly displacing said group of said sample beams about a reference axis to each of a plurality of angular positions, and repeating steps (C) and (D) at each of said angular positions.

3. The method of claim 1, wherein step (E) is performed by linearly displacing said source of said sample beams relative to said object to each of a plurality of sampling positions, there being a set of said sampling positions corresponding to each of said angular positions of said object.

4. The method of claim 1, wherein step (E) is performed by linearly displacing said source of said sample beams relative to said object along a first reference path.

5. The method of claim 4, wherein step (E) includes displacing said source of said sample beams relative to said object in a direction transverse to said first reference path to each of a plurality of transversely spaced apart locations, and linearly displacing one of said source relative to said object along each of a plurality of reference paths extending parallel to said first path, wherein said plurality of reference paths respectively extend through said plurality of transversely spaced apart locations.

6. The method of claim 1, wherein step (E) is performed by angularly displacing said source of said sample beams to each of a plurality of angular positions.

7. The method of claim 6, wherein said source is angularly displaced about a substantially horizontal reference axis such that said sample beams are directed onto said object at a plurality of different elevations respectively associated with and angular positions.

8. The method of claim 7, wherein step (E) further includes linearly displacing said source relative to said object along a preselected path for each of said angular positions.

9. The method of claim 1, wherein steps (A) through (F) are repeated for a plurality of objects.

16. The method of claim 1, wherein steps (A) through (F) are repeated for each of a plurality of objects, method includes the step of selecting the number and optimal positions of said surveillance beams required to detect the presence of any of said plurality of vehicles within said adjacent space.

10. A map of the locations in a volume of space under surveillance, where an object is detected by detecting reflections of at least one sample beam of energy directed into the volume of space by a sensor system located at a reference area, produced by

(A) placing the object at a predetermined location within the volume of space;

(B) locating the sensor system at a selected reference area;

(C) directing at least one sample beam of energy waves from a reference area onto the object within the space;

(D) detecting the energy reflected back to the reference area from the object;

(E) recording the reference area and the detection of energy on a map of the space under surveillance;

(F) relatively moving the sensor system and the object to locate the sensor system at a different selected reference area; and

(G) repeating steps (C), (D), (E) and (F) a predetermined number of times to create said map.

11. The map of claim 10, wherein step (F) is performed by linearly displacing aid beam source relative to said object along a reference path.

12. The map of claim 11, wherein step (F) includes displacing said beam source relative to said object in a direction transverse to said reference path to each of a plurality of transverse locations.

13. The map of claim 10, wherein step (F) is performed by linearly displacing said beam source relative to said object successively along each of a plurality of parallel spaced apart paths.

14. The map of claim 10, wherein step (D) is performed by rotating said beam source about a substantially vertical axis to each of a plurality of first angular positions.

15. The map of claim 14, wherein step (D) includes rotating said beam source about a substantially horizontal axis to each of a plurality of second angular positions.

17. A method for automating the selection of a subset of possible energy beam orientations from a larger set of possible beam orientations for which data has been acquired, comprising the steps of

(A) compiling a list of sample energy beams in relative order according to the total number of detections of beams reflected from an object within the volume of space under surveillance;

(B) selecting the beam having the highest number of detections;

(C) compiling another list of the remaining sample energy beams in relative order according to the total number of detections of beams reflected from an object within the volume of space under surveillance that are non-duplicative of the detections of any selected beam;

(D) selecting the remaining beam having the highest number of detections that are non-duplicative of the detections of any selected beam; and

(E) repeating steps (B), (C) and (D) a predetermined number of times to produce a combined detectivity map of all detections of all selected beams.

18. A method of quantifying the performance of a sensor system used to detect the presence of an object in a volume under surveillance, where the object is detected by detecting reflections of at least one sample beam of energy directed into the volume of space by a sensor system, comprising the steps of

(A) placing the object at a plurality of uniformly spaced locations within the volume;

(B) directing said at least one of sample beams of energy from the sensor system into the volume;

(C) recording the detection status of the reflections of the beams on a map of the volume for each of the locations within the volume to determine the number of detections; and

(D) evaluating the number of detections to quantify the performance of a sensor system.

19. A method of defining a sensing system for detecting the presence of an object vehicle in blind spot of a host vehicle, by determining the optimal placement of a plurality of energy beams which are projected into the blind spot, the reflections of which are detected to detect the presence of the object vehicle, comprising the steps of

(A) placing the object vehicle at a preselected position within the blind spot;

(B) directing a plurality of sample beams of energy, which have a predetermined orientation, from a source onto the object vehicle;

(C) detecting the sample beam energy reflected from points on the object vehicle by energy detectors;

(D) recording the preselected position of the object vehicle, the predetermined orientation of sample beams, and the detection status of the energy detectors;

(E) changing the equatorial and azimuthal angles of each of the beams and repeating steps (A) through (D);

(F) moving the source of the sample beams relative to the object vehicle;

(G) repeating steps (B) through (F) to produce spatial maps of the locations at which the object vehicle is positioned when each of the energy detectors detect reflected sample beam energy; and

(H) using the spatial maps so produced to select the optimal orientation of a set of energy beams which will maximize the detection probability of an object vehicle located in the blind spot.

20. The method of claim 19 further including the step of repeating steps (A) through (G) for a plurality of different vehicles.