Angle extent estimation method for a motor vehicle object detection system

• US 6,002,983 A
• Filed: 08/27/1997
• Issued: 12/14/1999
• Est. Priority Date: 08/27/1997
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Wherry, Kevin Ray, Alland, Stephen William, Searcy, James Fredrick
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US08/968,737
• Time in Patent Office: 839 Days
• Field of Search: 701/301, 701/208, 701/300, 701/302, 342/69, 342/70, 342/36, 342/456, 342/71, 342/107, 382/291, 382/103, 382/104, 356/376
• US Class Current: 701/301
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/66 Radar-tracking systems; Analogous systems
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/9319 Controlling the accelerator
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence

Abstract

A method of operation for a motor vehicle object detection system is described, in which the extent angle of an identified target is accurately determined by applying a point source scatterer identification technique to data at the periphery of a composite return. Return amplitude data from one or more complete scans of the sensor beam are collected and compared with a target threshold to identify objects in the viewing angle, thereby forming an array of amplitude data associated with successive beam positions for each identified object. In each array, the left-most and right-most pair of amplitude data points associated with successive beam positions are selected and individually used to compute the angle of a point source scatterer which would be responsible for that data pair. The computed scatterer angles are taken as the left and right edges of the target and used to determine the angle extent of the identified object, which in turn, enables reliable determination as to whether the identified object is in or out of the vehicle travel path, and what, if any, vehicle response is appropriate to maintain a given headway or avoid a collision with the object.

Claims

1. In a motor vehicle object detection system having a sensor beam which is scanned back and forth through a viewing angle including a vehicle travel path, the system processing reflected beam energy to detect and respond to objects disposed in the travel path, a method of determining angular extent of an object comprising the steps of:

processing energy return data from one or more complete scans of said sensor beam to identify objects in the viewing angle and to form an array of return amplitude data associated with successive beam positions for each identified object;

selecting a first pair of return amplitude data associated with successive beam positions at a left-most edge of a selected array of return amplitude data, including left-most and next-to-left-most amplitude values;

computing an angle of a point source scatterer which would be responsible for said first pair of return amplitude data by computing an amplitude ratio of said next-to-left-most amplitude value and said left-most amplitude value, and storing such angle as a left extent angle of a respective identified object;

selecting a second pair of return amplitude data associated with successive beam positions at a right-most edge of the selected array;

computing an angle of a point source scatterer which would be responsible for said second pair of return amplitude data, and storing such angle as a right extent angle of a respective identified object; and

determining the overall extent angle of the respective identified object as an angle defined by the stored left and right extent angles.

2. The method of claim 1, wherein step of computing an angle of a point source scatterer which would be responsible for said first pair of return amplitude data further includes the steps of:

computing a scatterer angle as a function of said amplitude ratio; and

offsetting the computed scatterer angle by an angle value midway between sensor beam positions associated with said left-most and next-to-left-most amplitude values.

3. In a motor vehicle object detection system having a sensor beam which is scanned back and forth through a viewing angle including a vehicle travel path, the system processing reflected beam energy to detect and respond to objects disposed in the travel path, a method of determining angular extent of an object comprising the steps of:

processing energy return data from one or more complete scans of said sensor beam to identify objects in the viewing angle and to form an array of return amplitude data associated with successive beam positions for each identified object;

selecting a first pair of return amplitude data associated with successive beam positions at a left-most edge of a selected array of return amplitude data, and storing such angle as a left extent angle of a respective identified object;

selecting a second pair of return amplitude data associated with successive beam positions at a right-most edge of the selected array including right-most and next-to-right-most amplitude values;

computing an angle of a point source scatterer which would be responsible for said second pair of return amplitude data by computing a ratio of said next-to-right-most amplitude value and said right-most amplitude value, and storing such angle as a right extent angle of a respective identified object; and

determining the overall extent angle of the respective identified object as an angle defined by the stored left and right extent angles.

4. The method of claim 3, wherein step of computing an angle of a point source scatterer which would be responsible for said first pair of return amplitude data further includes the steps of:

computing a scatterer angle as a function of said amplitude ratio; and

offsetting the computed scatterer angle by an angle value midway between sensor beam positions associated with said left-most and next-to-left-most amplitude values.

5. A method of operation for a motor vehicle object detection system having a sensor beam which is scanned back and forth through a viewing angle including a vehicle travel path angle, comprising the steps of:

receiving reflected beam energy data from one or more complete scans of said sensor beam;

processing said data to identify objects disposed in the viewing angle;

forming an array of reflected beam energy amplitude data associated with successive beam positions for any identified object; and

for a selected array of amplitude data,

obtaining a first pair of amplitude data points associated with successive beam positions at a left-most edge of the selected array including left-most and next-to-left-most amplitude values;

computing an angle of a point source scatterer which would be responsible for said first pair of amplitude data points by computing an amplitude ratio of said next-to-left-most amplitude value and said left-most amplitude value, and storing such angle as a left extent angle of the respective identified object;

obtaining a second pair of amplitude data points associated with successive beam positions at a right-most edge of the selected array;

computing an angle of a point source scatterer which would be responsible for said second pair of amplitude data points, and storing such angle as a right extent angle of the respective identified object;

determining the overall extent angle of the respective identified object as an angle defined by the stored left and right extent angles;

identifying an in-path object based on a coincidence of the determined overall extent angle and the vehicle travel path angle; and

initiating a vehicle action in response to identification of an in-path object.

6. The method of claim 5, wherein step of computing an angle of a point source scatterer which would be responsible for said first pair of amplitude data points further includes the steps of:

computing a scatterer angle as a function of said amplitude ratio; and

offsetting the computed scatterer angle by an angle value midway between sensor beam positions associated with said left-most and next-to-left-most amplitude values.

7. A method of operation for a motor vehicle object detection system having a sensor beam which is scanned back and forth through a viewing angle including a vehicle travel path angle, comprising the steps of;

receiving reflected beam energy data from one or more complete scans of said sensor beam;

processing said data to identify objects disposed in the viewing angle;

forming an array of reflected beam energy amplitude data associated with successive beam positions for any identified object; and

for a selected array of amplitude data, obtaining a first pair of amplitude data points associated with successive beam positions at a left-most edge of the selected array;

computing an angle of a point source scatterer which would be responsible for said first pair of amplitude data points, and storing such angle as a left extent angle of the respective identified object;

obtaining a second pair of amplitude data points associated with successive beam positions at a right-most edge of the selected array including right-most and next-to-right-most amplitude values;

computing an angle of a point source scatterer which would be responsible for said second pair of amplitude data points by computing a ratio of said next-to-right-most amplitude value and said right-most amplitude value, and storing such angle as a right extent angle of the respective identified object;

determining the overall extent angle of the respective identified object as an angle defined by the stored left and right extent angles;

identifying an in-path object based on a coincidence of the determined overall extent angle and the vehicle travel path angle; and

initiating a vehicle action in response to identification of an in-path object.

8. The method of claim 7, wherein the step of computing an angle of a point source scatterer which would be responsible for said second pair of amplitude data points further includes the steps of:

computing a scatterer angle as a function of said amplitude ratio; and

offsetting the computed scatterer angle by an angle value midway between sensor beam positions associated with said right-most and next-to-right-most amplitude values.