Road pavement deterioration inspection system

• US 6,615,648 B1
• Filed: 09/25/2000
• Issued: 09/09/2003
• Est. Priority Date: 12/22/1997
• Status: Expired due to Term

• Current Assignee: Connonwealth Scientific and Industrial Research Organisation, Roads and Maritime Services
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education), Roads & Traffic Authority of New South Wales
• Inventors: Jones, Ronald, Moore, Daniel Peter, Macintyre, Ian Barry, Turtle, Paul Richard, Ferguson, Ronald Allan, Gardner, James Laurie, Kearney, Patrick Dale, Best, Michael John, Breen, Joseph Edmond, Pratt, David Norman, Buckley, Michael James, Berman, Mark
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): ALLEN, ANDRE J
• Application Number:
  US09/582,306
• Time in Patent Office: 1,079 Days
• Field of Search: 751/46--468, 364/550, 364/557
• US Class Current: 73/146
• CPC Class Codes: G01C 7/04 involving a vehicle which moves along the profile to be traced
• CPC Class Codes: G01N 21/88 Investigating the presence of flaws or contamination

Abstract

A system for acquiring, processing, storing, analyzing and reporting data relating to the condition of a road or other pavement surface (102) in real time. The system includes a digital camera (104) mounted on a vehicle and positioned relative to a pavement surface (102) so as to capture images of the pavement surface (102) while the camera (104) is moving relative to the surface (102). The system also includes an illumination assembly (100) to illuminate the region from which an image is taken and an interface between the digital camera (104) and at least one computer. The system also includes a processor in the computer for processing the images to detect and classify cracks and other pavement surface (102) features.

Claims

1. A system for acquiring, processing, storing, analyzing, and reporting data relating to the condition of a road or other pavement surface in real time;

the system including;

at least one digital image acquirer positioned relative to a pavement surface so as to capture images of the pavement surface while the digital image acquirer is moving relative to the pavement surface; and

illumination assembly to illuminate the region on the pavement surface from which an image is taken;

an interface between the image acquirer and at least one computer;

a processor in said at least one computer for real time processing of said images to detect and classify cracks and other pavement surface features.

2. The system as claimed in claim 1 wherein said interface manages the manner in which the digital image acquirer acquires images.

3. The system as claimed in claim 2 wherein said interface adjusts the acquisition timing of the digital image acquirer in relation to the speed at which said digital image acquirer is moving relative to the pavement surface.

4. The system as claimed in claim 3 wherein said interface also adjusts the acquisition timing of the digital image acquirer relative to the reflectivity of the pavement surface.

5. The system as claimed in claim 4 wherein said digital image acquirer is capable of receiving at least one line of image data for every 1 millimeter of movement of said digital image acquirer relative to said pavement surface.

6. The system as claimed in any one of claims 2 to 5 wherein said interface includes a synchronizer for synchronizing the acquisition and processing of images from more than one digital image acquirer.

7. The system as claimed in claim 1 wherein said interface also manages the flow of data to said processor to enable real time processing of said data.

8. The system as claimed in claim 7 wherein said real time processing of said data includes real time continuous processing, real time continuous processing by subsampling, and storage of said data to allow real time post-processing at some later time.

9. The system as claimed in claim 8 wherein said interface manages the flow of data to said processor by a number of steps including:

(a) formatting each acquired image to a size suitable for processing;

(b) marking each image with a unique identification code; and

(c) distributing the images to the processor.

10. The system as claimed in claim 9 including the additional step of selecting a subsample of acquired images for processing.

11. The system as claimed in claim 10 wherein said subsample is selected by means of a sampling table.

12. The system as claimed in claim 9 wherein said unique identification code contains information relating to the location at which the image was acquired.

13. The system as claimed in claim 12 wherein said information on the location at which the image was acquired is at least partly provided to said interface by means of a Global Positioning System (GPS) and/or a road location reference system.

14. The system as claimed in claim 1, wherein said processor is capable of analyzing images of at least one type of road surface in real time.

15. The system as claimed in claim 14 wherein said processor is capable of analyzing images of more than one type of pavement surface in real time.

16. The system as claimed in claim 15 wherein said types of pavement surface include:

i) sprayed seal;

ii) asphalt; and

iii) concrete.

17. The system as claimed in claim 14 wherein said processor processes said images to detect and classify cracks and other pavement surface features by performing a number of steps including:

i) image filtering;

ii) crack isolation; and

/or

iii) crack measurement.

18. The system as claimed in claim 14 wherein said processor utilizes a number of algorithms to detect and classify cracks and other pavement surface features including:

i) a rank filter algorithm;

ii) a shortest path algorithm;

iii) a cracking score algorithm;

iv) a texture adjustment algorithm; and

/or

v) a cracking density algorithm.

19. The system as claimed in claim 14 wherein said processor includes means for separating out artifacts and textures on the pavement surface.

20. The system as claimed in claim 19 wherein said means for separating out artifacts and textures on the pavement surface includes means for the removal of or compensation for tyning and blooming from the images.

21. The system as claimed in claim 14 wherein said processor classifies said cracks as:

i) transverse cracks;

ii) longitudinal cracks;

iii) crocodile cracks; and

/or

iv) straight/non-cracked features.

22. The system as claimed in claim 14 wherein said processor includes either a pipeline processor or a parallel processor.

23. The system as claimed in claim 22 wherein said pipeline processor includes a series of circuit boards capable of analyzing said acquired image data continuously in real time.

24. The system as claimed in claim 22 wherein said parallel processor includes a plurality of image processing CPUs arranged in parallel, each processing a subsample of the acquired data in real time.

25. The system as claimed in claim 1 wherein said illumination assembly includes;

a light source; and

apparatus for controlling the intensity and direction of light according to the level of exposure required by said digital image acquirer.

26. The system as claimed in claim 25 wherein said apparatus for controlling the intensity and direction of light includes at least one reflector which concentrates the light emitted from the light source on an area of the pavement surface from which the digital image is taken.

27. The system as claimed in claim 26 wherein said reflector is a cylindrical reflector and said light source is a linear quartz iodine lamp.

28. The system as claimed in claim 1 wherein the digital image acquirer is a digital camera and includes a sensor;

a time controlled automatic external electronic exposure which captures images of the pavement surface at a speed which is proportionate to the speed at which the digital image acquirer is moving relative to the pavement surface, and which takes the reflectivity of the pavement surface into account.

29. The system as claimed in claim 28 wherein said sensor includes any one of:

a) a photodiode;

b) a charged coupled device (CCD);

or

c) a time delay integration (TDI) of photosensitive elements.

30. The system as claimed in claim 1 wherein the system is mounted on a vehicle, allowing the digital image acquirer to capture images of the pavement surface as the vehicle moves along the pavement.

31. The system as claimed in claim 30 wherein said vehicle is capable of travelling at highway speeds.

32. The system as claimed in claim 31 wherein said highway speeds includes speeds between 5 kilometers per hour and 120 kilometers per hour.

33. The system as claimed in claim 30 wherein said information on the location at which the image was acquired is at least partly provided to said interface from information obtained from a distance transducer attached to a moving part of the vehicle.

41. The system as claimed in claim 1 wherein data is stored in any one of the following ways:

i) no images are saved and only detection and classification results are saved;

ii) only images are saved;

iii) both images and detection and classification results are saved;

or

iv) a sample of images and their corresponding detection and classification results are saved.

34. A system for real time capture and processing of pavement crack data comprising;

a vehicle capable of travelling at highway speeds, a digital image capturer mounted in or on said vehicle for capturing digital images of the pavement surface; and

a processor in communication with said digital image capturer, the processor for processing at least part of said captured data in real time, wherein the processor in communication with said digital image capturer includes a digital camera and the processor means includes computer hardware and software for processing said digital images.

35. The system as claimed in claim 34 wherein said highway speeds includes speeds between 5 kilometers per hour and 120 kilometers per hour.

36. A system for enabling real time capture and processing of data relating to the condition of a pavement, the assembly including;

a vehicle capable of travelling at highway speeds;

a pavement crack data capturer mounted in or on said vehicle for capturing pavement crack data; and

a processor for processing captured data in real time.

37. The system as claimed in claim 36 wherein the pavement is a sprayed seal, asphalt or concrete surface and said means for processing and storage of captured data includes means for removal of unwanted data.

38. The system as claimed in either of claims 36 or 37 wherein said highway speeds include speeds between 5 kilometers per hour and 120 kilometers per hour.

39. A system for real time capture of and processing of pavement crack data relating to the condition of a road pavement, said system comprising;

a vehicle capable of traveling at highway speeds;

a digital camera mounted in or on said vehicle for capturing images of said pavement while said vehicle is in motion;

a processor mounted in or on said vehicle, and linked to said camera, for receiving data captured by said camera, and for removal of any unwanted captured data in real time.

40. The system as claimed in claim 39 wherein said highway speeds include speeds between 5 kilometers per hour and 120 kilometers per hour.

42. A method for real time capture and processing of pavement crack data comprising the steps of:

(a) using digital image acquirer having an electronic exposure control and positioned relative to a pavement surface to capture images of the surface while the digital image acquirer is moving relative to the surface, in conjunction with an illumination assembly which illuminates the region from which an image is taken;

(b) using an interface between the digital image acquirer and at least one computer to manage the manner in which the digital image acquirer acquires images and to manage the way in which the acquired data is passed on to an image processing CPU;

(c) using software and/or hardware in an image processing CPU to process said images(s) of the pavement loaded into the computer by a number of steps which include;

i) image filtering;

ii) crack isolation; and

/or

iii) crack measurement; and

(d) processing the images in real time and providing real time reporting of pavement crack data.