SYSTEM AND METHOD FOR INSPECTING SURFACES USING OPTICAL WAVELENGTH FILTERING

• US 20090273788A1
• Filed: 05/13/2009
• Published: 11/05/2009
• Est. Priority Date: 06/30/2004
• 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 Wayne, Nagle, John Anthony II, Orrell, Steven C., Villar, Christopher M.
• Granted Patent: US 8,405,837 B2
• Time in Patent Office: Days
• US Class Current: 356/445
• 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: G01C 3/08 Use of electric radiation detectors

Abstract

A system and method for daylight inspection of a surface, such as a railroad track, is disclosed. The disclosed system includes lasers, cameras, and a processor. The lasers are positioned adjacent the surface. The laser emits a beam of light across the surface at a combined intensity of at least 0.15 watts of intensity per inch of width of the surface, and the camera captures images of the surface having the beam of light emitted thereon. The camera includes a bandpass filter which passes only a band of light corresponding to a dip in solar radiation. The laser is selected to provide an emitted light beam which is more intense than the solar radiation at the dip. The processor formats the images so that they can be analyzed to determine various measurable aspects of the surface. The system and method includes one or more algorithms for determining these measurable aspects of the surface.

Claims

1. A system for inspecting a surface, the system comprising:

at least one light generator positioned adjacent the surface, the light generator adapted to project a beam of light across the surface, the beam of light totaling at least 0.15 watts of intensity per inch of a width of the beam of light;

at least one camera positioned adjacent the surface for receiving at least a portion of the light reflected from the surface and for generating at least one image representative of a profile of at least a portion of the surface, the camera comprising a bandpass filter adapted to pass a band of the beam of light projected by the light generator, the band corresponding to a dip in solar radiation; and

at least one processor adapted to analyze the at least one image and determine one or more physical characteristics of the portion of the surface.

2. A system as defined in claim 1, wherein an angular spread of the beam of light projected by the generator is 45 degrees.

3. A system as defined in claim 1, wherein the light generator comprises:

a center laser; and

two outer lasers located on opposites sides of the center laser, the two outer lasers each being tilted outwardly from the center laser at a 10 degree angle.

4. A system as defined in claim 1, wherein the light generator is a 808 nm laser.

5. A system as defined in claim 1, wherein the camera further comprises:

a lens;

a spacer positioned adjacent the lens; and

a charge coupled device, the bandpass filter being coupled between the charge coupled device and the spacer.

6. A system as defined in claim 1, wherein the bandpass filter is located behind a lens of the camera.

7. A system as defined in claim 1, wherein the surface is a railroad track bed and the processor comprises an algorithm for determining a distance between crossties of the railroad track bed, the algorithm comprising the steps of:

(a) analyzing a first frame, one or more intermediate frames and an end frame of the at least one image, the first and end frames comprising crossties while the one or more intermediate frames lack crossties;

(b) determining a number of the one or more intermediate frames lacking crossties;

(c) determining a known spacing between frames; and

(d) determining the distance between the crossties of the first and end frames based upon the number of the one or more intermediate frames lacking crossties and the known spacing between the frames.

8. A system as defined in claim 1, wherein the surface is a railroad track bed and the processor comprises an algorithm for detecting a misaligned or sunken tie plate of the railroad track bed, the algorithm comprising the steps of:

(a) analyzing a frame of the at least one image, the frame comprising a region of interest;

(b) determining whether the region of interest contains a tie plate;

(c) if a tie plate is present, determining a crosstie contour and a tie plate contour;

(d) comparing an orientation of the crosstie contour and an orientation of the tie plate contour; and

(e) determining whether the tie plate is misaligned or sunken based upon the comparison.

9. A system as defined claim 1, wherein the surface is a railroad track bed and the processor comprises an algorithm for identifying a break in a rail of the railroad track bed, the algorithm comprising the steps of:

(a) analyzing a first frame, one or more intermediate frames and an end frame of the at least one image, the first and end frames comprising rails while the one or more intermediate frames lack rails;

(b) determining a number of the one or more intermediate frames lacking rails;

(c) determining a known spacing between frames; and

(d) identifying the break in the rail based upon the number of the one or more intermediate frames lacking rails and the known spacing between the frames.

10. A system as defined in claim 1, wherein the surface comprises one or more of a road, plant, building foundation, automobile bridge or sidewalk.

11. A method for inspecting a surface, the method comprising the steps of:

(a) illuminating a light across the span of the surface, the light totaling a combined intensity of at least 0.15 watts of intensity per inch of a width of the light;

(b) receiving at least a portion of the light reflected from the surface using one or more cameras, the one or more cameras comprising a bandpass filter adapted to pass only a band of the reflected light, the band corresponding to a dip in solar radiation;

(c) generating at least one image representative of a profile of at least a potion of the surface;

(d) analyzing the at least one image;

(e) determining one or more physical characteristics of the portion of the surface; and

(f) outputting the determined physical characteristics of the portion of the surface.

12. A method as defined in claim 11, wherein step (a) comprises the step of projecting a plurality of beams of light to form the light illuminated across the surface, the plurality of beams of light each having an angular spread of 45 degrees.

13. A method as defined in claim 12, wherein the plurality of beams of light comprise a center beam and two outer beams on opposite sides of the center beam, step (a) further comprising the step of projecting the two outer beams outwardly from the center beam at a 10 degree angle.

14. A method as defined in claim 11, wherein the light illuminated across the span of the surface is created using 808 nm lasers.

15. A method as defined in claim 11, wherein the surface is a railroad track bed, the method further comprising the step of determining a distance between crossties of the railroad track bed, the step of determining the distance comprising the steps of:

(a) analyzing a first frame, one or more intermediate frames and an end frame of the at least one image, the first and end frames comprising crossties while the one or more intermediate frames lack crossties;

(b) determining a number of the one or more intermediate frames lacking crossties;

(c) determining a known spacing between frames; and

(d) determining the distance between the crossties of the first and end frames based upon the number of the one or more intermediate frames lacking crossties and the known spacing between the frames.

16. A method as defined in claim 11, wherein the surface is a railroad track bed, the method further comprising the step of identifying a break in a rail of the railroad track bed, the step of identifying comprising the steps of:

(a) analyzing a first frame, one or more intermediate frames and an end frame of the at least one image, the first and end frames comprising rails while the one or more intermediate frames lack rails;

(b) determining a number of the one or more intermediate frames lacking rails;

(e) determining a known spacing between frames; and

(d) identifying the break in the rail based upon the number of the one or more intermediate frames lacking rails and the known spacing between the frames.

17. A method as defined in claim 11, wherein the surface is a railroad track bed, the method further comprising the step of detecting a misaligned or sunken tie plate of the railroad track bed, the step of detecting comprising the steps of:

(a) analyzing a frame of the at least one image, the frame comprising a region of interest;

(b) determining whether the region of interest contains a tie plate;

(c) if a tie plate is present, determining a crosstie contour and a tie plate contour;

(d) comparing an orientation of the crosstie contour and an orientation of the tie plate contour; and

(e) determining whether the tie plate is misaligned or sunken based upon the comparison.

18. A method for inspecting a surface, the method comprising the steps of:

(a) projecting a light onto the surface, the light having an intensity of at least 0.15 watts of intensity per inch of a width of the light;

(b) receiving at least a portion of the light reflected from the surface into a receiver;

(c) utilizing a bandpass filter of the receiver to pass a band of the reflected light which corresponds to a dip in solar radiation, wherein the reflected light is adapted to be more intense than the solar radiation at the dip;

(d) utilizing the passed band of the reflected light to generate one or more images representative of a profile of at least a portion of the surface;

(e) determining one or more characteristics of the portion of the surface; and

(f) outputting the determined characteristics of the portion of the surface.

19. A method as defined in claim 18, wherein step (a) further comprises the step of projecting a plurality of beams of light to form the light projected onto the surface, the plurality of beams of light each having an angular spread of 45 degrees.

20. A method as defined in claim 19, wherein the plurality of beams of light comprise a center beam and two outer beams on opposite sides of the center beam, step (a) further comprising the step of projecting the two outer beams outwardly from the center beam at a 10 degree angle.

21. A method as defined in claim 18, wherein the surface is a railroad track bed, the method further comprising the step of determining a distance between crossties of the railroad track bed, the step of determining the distance comprising the steps of:

(a) analyzing a first frame, one or more intermediate frames and an end frame of the one or more images, the first and end frames comprising crossties while the one or more intermediate frames lack crossties;

(b) determining a number of the one or more intermediate frames lacking crossties;

(c) determining a known spacing between frames; and

(d) determining the distance between the crossties of the first and end frames based upon the number of the one or more intermediate frames lacking crossties and the known spacing between the frames.

22. A method as defined in claim 18, wherein the surface is a railroad track bed, the method further comprising the step of identifying a break in a rail of the railroad track bed, the step of identifying comprising the steps of:

(a) analyzing a first frame, one or more intermediate frames and an end frame of the one or more images, the first and end frames comprising rails while the one or more intermediate frames lack rails;

(b) determining a number of the one or more intermediate frames lacking rails;

(c) determining a known spacing between frames; and

(d) identifying the break in the rail based upon the number of the one or more intermediate frames lacking rails and the known spacing between the frames.

23. A method as defined in claim 18, wherein the surface is a railroad track bed, the method further comprising the step of detecting a misaligned or sunken tie plate of the railroad track bed, the step of detecting comprising the steps of:

(a) analyzing a frame of one or more images, the frame comprising a region of interest;

(b) determining whether the region of interest contains a tie plate;

(c) if a tie plate is present, determining a crosstie contour and a tie plate contour;

(d) comparing an orientation of the crosstie contour and an orientation of the tie plate contour; and

(e) determining whether the tie plate is misaligned or sunken based upon the comparison.