METHOD AND SYSTEM FOR CALIBRATING LASER PROFILING SYSTEMS

• US 20120274768A1
• Filed: 04/27/2011
• Published: 11/01/2012
• Est. Priority Date: 04/27/2011
• Status: Active Grant

• Current Assignee: Loram Technologies Incorporated (Loram Maintenance of Way, Inc.)
• Original Assignee: Georgetown Rail Equipment Company (Loram Maintenance of Way, Inc.)
• Inventors: Aaron, Charles W., Belcher, Jeb E.
• Granted Patent: US 8,711,222 B2
• Time in Patent Office: Days
• US Class Current: 348/148
• CPC Class Codes: B61K 9/08 Measuring installations for surveying permanent way applications of measuring apparatus or devices for track building purposes E01B35/00; measuring techniques G01
• CPC Class Codes: G01B 11/2504 Calibration devices

Abstract

A laser profiling calibration system includes a light emitting device, a light-reflecting target, and an optical receiver. The light emitting device is configured to project a light and define a light plane. The light-reflecting target is configured to be positioned at multiple positions within the light plane, and has a plurality of non-reflective regions. The optical receiver is oriented to receive light reflected from the target, and further configured to capture a plurality of images, comprising at least one image at each of the target'"'"'s multiple positions. The system is configured to use the plurality of images to calibrate the optical receiver within the light plane.

Claims

1. A laser profiling calibration system comprising:

a light emitting device, configured to project a light, the light defining a light plane;

a light-reflecting target, configured to be positioned at multiple positions within the light plane, the target having a plurality of non-reflective regions;

an optical receiver, oriented to receive light reflected from the target, and further configured to capture a plurality of images, comprising at least one image at each of the target'"'"'s multiple positions; and

the calibration system configured to use the plurality of images to calibrate the optical receiver within the light plane.

2. The system of claim 1, wherein the light emitting device is a laser.

3. The system of claim 2, wherein the laser is a line-generating laser.

4. The system of claim 1, wherein the light-reflecting target comprises a bar having a series of protrusions and gaps, the gaps defined by sides of adjacent, disconnected upstanding protrusions of the target.

5. The system of claim 4, wherein the protrusions and gaps alternate in a regular linear pattern.

6. The system of claim 5, wherein each protrusion has a length of 1 inch.

7. The system of claim 5, wherein each gap has a length of 1 inch.

8. The system of claim 4, wherein the target includes a center-most protrusion, the center-most protrusion comprising a unique marker to facilitate the identification of the center-most protrusion.

9. The system of claim 8, wherein the unique marker is an indentation in the center-most protrusion.

10. The system of claim 1, wherein the target is moveable substantially only within the light plane.

11. An optical railroad track inspection system, comprising:

at least one downwardly oriented laser device, attachable to a rail vehicle, configured to project a laser defining a substantially vertical laser plane;

a target connected to the rail vehicle, wherein the target may be positioned at various vertical positions with respect to the rail vehicle and within the laser plane, the target being reflective and having a plurality of non-reflective regions spaced at known intervals;

an optical receiver, attachable to the rail vehicle and oriented to receive laser light reflected from the target, configured to capture a plurality of images, comprising at least one image at each of the target'"'"'s multiple positions; and

the inspection system configured to use the plurality of images to calibrate the optical receiver within the laser plane.

12. The optical railroad track inspection system of claim 11, wherein the laser is a line-generating laser.

13. The optical railroad track inspection system of claim 11, wherein the plurality of non-reflective regions comprise a series of gaps defined by sides of adjacent, disconnected upstanding protrusions of the target.

14. The optical railroad track inspection system of claim 13, wherein the protrusions and gaps alternate in a regular linear pattern.

15. The optical railroad track inspection system of claim 13, wherein the series of protrusions and gaps includes a center-most protrusion of the target, said center-most protrusion comprising a unique marker to facilitate identification of the target'"'"'s center.

16. A method for calibrating a laser profiling system comprising:

a) projecting a laser toward a target thereby defining a laser plane, the target being positioned within the laser plane, the target having a plurality of non-reflective regions spaced at known intervals;

b) receiving laser light reflected from the target with an optical receiver and recording an image of the target;

c) repeating (a) and (b) with the target at a plurality of positions within the laser plane to record a plurality of images of the target; and

d) providing the plurality of images in a file for calibration purposes.

17. The method of claim 16, wherein the laser and the optical receiver are stationary while the target images are captured.

18. The method of claim 16, further comprising calibrating the optical receiver in a horizontal plane defined by and substantially parallel to the target'"'"'s plurality of non-reflective regions.

19. The method of claim 18, wherein the calibration in the laser and horizontal planes is performed concurrently.

20. A laser profiling calibration system, comprising:

a light generating device configured to emit light in a plurality of predefined orientations;

a target comprising a plurality of reflective and non-reflective regions, the target arranged to be within the plurality of predefined orientations, the target configured to be positioned at a plurality of predefined distances from the light generating device;

an optical receiver configured to capture reflected light from the reflective regions of the target;

the optical receiver configured to capture the reflected light for each of the plurality of predefined orientations and configured to capture the reflected light for each of the predefined distances; and

the system being configured to use data captured by the optical receiver in a calibration process.