Method of adjusting monitor axis

• US 20050219530A1
• Filed: 03/29/2005
• Published: 10/06/2005
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: Omron Corporation
• Original Assignee: Omron Corporation
• Inventors: Matsuura, Yoshio, Horibe, Koji
• Granted Patent: US 7,280,211 B2
• Time in Patent Office: Days
• US Class Current: 356/399
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4026 Antenna boresight
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/4034 in elevation, i.e. in the vertical plane
• CPC Class Codes: G01S 7/4972 Alignment of sensor

Abstract

The invention relates to a method of adjusting a monitor having a radar and a camera and correcting the positions and orientations of their detection areas based on intensity of reflected light from a target object. A single target having a specified pattern of bright and dark areas in placed in front of the monitor in the detection areas of the radar and the camera. The detection area of the radar is adjusted first based on measurements taken of the target by the radar and thereafter axial displacement of the detection area of the camera is determined a coordinate conversion parameter is obtained based on an image of the target taken by the camera.

Claims

1. A method of adjusting a monitoring apparatus, said monitoring apparatus being adapted to carry out a measurement operation by receiving waves from a detection area at each position on a standard direction and outputting data for identifying at least position of a target object of detection in said detection area based at least on intensity of said received waves, said method serving to correct an axial displacement of said detection area in the direction of rolling;

said method comprising the steps of;

providing a target having a detection surface, said detection surface having a specified peripheral shape and having a pattern of bright areas with a larger reflectivity and dark areas with a smaller reflectivity, said peripheral shape and said pattern being such that a waveform of W-form or inverse W-form is obtained due at least to said specified pattern if said measurement operation is carried out with said target placed in front of said monitoring apparatus and with said detecting area facing said detection surface, said waveform being such that a standard position of said detection surface in said standard direction can be calculated therefrom;

placing said target in front of said monitoring apparatus by orienting said detection surface according to said standard direction;

carrying out said measurement operation at least twice by each time changing the position of said monitoring apparatus in the perpendicular direction to said standard direction; and

determining the axial deviation of said detection area in the rolling direction based on change in said standard position calculated from said waveform.

2. The method of claim 1 wherein said detection surface of said target has outer edges which are perpendicular to said standard direction and has a width in said standard direction, said width being smaller than the dimension of said detection area in said standard direction;

wherein said pattern includes an elongated belt-like region traversing a center part of said detection surface and inversion areas on both sides of said belt-like region, either said belt-like region or said inversion areas having higher reflectivity than the other; and

wherein said standard position is determined from position data a and b of points on opposite sides of the center valley or hill of said waveform of W-form or inverse W-form having the same received wave intensity as at said center valley or hill.

3. The method of claim 1 wherein said pattern includes an elongated belt-like region traversing a center part of said detection surface, inversion areas on both sides of said belt-like region and frame areas further outside of said inversion areas, either said belt-like region and said frame areas or said inversion areas having higher reflectivity than the other, boundary lines between said inversion areas and said frame areas being parallel to said perpendicular direction and mutually separated by a distance smaller than the dimension of said detection area in said standard direction;

and

wherein said standard position is determined from position data a and b of points on opposite sides of the center valley or hill of said waveform of W-form or inverse W-form having the same received wave intensity as at said center valley or hill.

4. The method of claim 1 wherein said detection surface of said target has a width in said standard direction which is smaller than the dimension of said detection area in said standard direction;

wherein said pattern includes an elongated belt-like region traversing a center part of said detection surface and inversion areas on both sides of said belt-like region, either said belt-like region or said inversion areas having higher reflectivity than the other, said belt-like region extending parallel to said perpendicular direction; and

wherein said standard position is determined from position data c of the center valley or hill of said waveform of W-form or inverse W-form.

5. The method of claim 1 wherein said pattern includes an elongated belt-like region traversing a center part of said detection surface, inversion areas on both sides of said belt-like region and frame areas further outside of said inversion areas, either said belt-like region and said frame areas or said inversion areas having higher reflectivity than the other, boundary lines between said inversion areas and said frame areas being mutually separated by a distance smaller than the dimension of said detection area in said standard direction, said belt-like region extending parallel to said perpendicular direction;

and

wherein said standard position is determined from position data c of the center valley or hill of said waveform of W-form or inverse W-form.

6. The method of claim 1 further comprising the step of adjusting an environmental condition according to the reflectivity of said pattern after said target was placed in front of said monitoring apparatus.

7. The method of claim 1 further comprising the step of correcting the determined axial deviation by changing angle of attachment of said monitoring apparatus or by changing a parameter for setting said detection area.

8. A method of adjusting a monitoring apparatus, said monitoring apparatus having a radar adapted to carry out a measurement operation by receiving waves, from a first detection area at each position on a standard direction and outputting data for identifying at least position of a target object of detection in said first detection area based at least on intensity of said received waves and a camera for taking an image of a second detection area that overlaps said first detection area, said method serving to adjust positions and orientations of said first detection area and said second detection area and to obtain a coordinate conversion parameter between said radar and said camera;

said method comprising the steps of;

setting a single target at a specified position which is both in said first detection area and said second detection area;

adjusting said first detection area based on measurements taken of said target by said radar; and

thereafter determining axial displacement of said second detection area and obtaining said coordinate conversion parameter based on an image of said target taken by said camera.

9. The method of claim 8 further comprising the steps of:

obtaining axial displacement data on axial displacement of said first detection area or said second detection area based on results of measurement by said radar or said image of said target taken by said camera;

displaying said axial displacement data on a display device; and

adjusting said first detection area or said second detection area while observing said displayed axial displacement data until the axial displacement of said first detection area or said second detection area becomes within an allowable range.

10. A method of adjusting a monitoring apparatus, said monitoring apparatus having a radar adapted to carry out a measurement operation by receiving waves from a first detection area at each position on a standard direction and outputting data for identifying at least position of a target object of detection in said first detection area based at least on intensity of said received waves and a camera for taking an image of a second detection area that overlaps said first detection area, said method serving to adjust position and orientation of said first detection area and said second detection area and to obtain a coordinate conversion parameter between said radar and said camera;

said method comprising the steps of;

setting a single target at a specified position which is both in said first detection area and said second detection area;

determining adjustability of said first detection area based on measurements taken of said target by said radar and adjusting said first detection area only if it is determined to be adjustable; and

thereafter determining adjustability of axial displacement of said second detection area based on an image of said target taken by said camera and obtaining said coordinate conversion parameter based on said image of said target taken by said camera if it is determined to be adjustable.

11. The method of claim 10 further comprising the steps of:

obtaining axial displacement data on axial displacement of said first detection area or said second detection area based on results of measurement by said radar or said image of said target taken by said camera;

displaying said axial displacement data on a display device; and

adjusting said first detection area or said second detection area while observing said displayed axial displacement data until the axial displacement of said first detection area or said second detection area becomes within an allowable range if adjustment is determined to be possible.