Characterization of a physical object based on its surface roughness

• US 10,341,555 B2
• Filed: 10/10/2012
• Issued: 07/02/2019
• Est. Priority Date: 12/02/2011
• Status: Active Grant

• Current Assignee: ChromoLogic
• Original Assignee: ChromoLogic
• Inventors: Menon, Naresh, Bearman, Gregory Howard, Nelson, Leonard
• Primary Examiner(s): Hess, Michael J
• Application Number:
  US13/573,868
• Publication Number:
  US 20150264254A1
• Time in Patent Office: 2,456 Days
• Field of Search: None
• CPC Class Codes: G01N 21/4738 Diffuse reflection precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration, e.g. also for testing fluids, fibrous materials
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/64 Computer-aided capture of images, e.g. transfer from script file into camera, check of taken image quality, advice or proposal for image composition or decision on when to take image

Abstract

The present invention is directed to a method and apparatus that involves improved characterization of an object based on its surface roughness and other unique features without having to necessarily define a fixed and predetermined region of interest. In accordance with one aspect, the present invention provides a method for characterizing an object based on a pattern of the object'"'"'s surface roughness. The method comprises the steps of obtaining a unique image of a feature on the surface of the object, converting the image obtained into certain electrical signals and processing the electrical signals so they are associated with the object and thereby provide a characterization of the object that is used to generate a unique identifying signature for the object.

Claims

1. A method for characterizing an object, said method comprising:

striking a surface of the object with light from at least two incoherent light sources, each incoherent light source oriented to simultaneously generate incoherent raking light onto a feature on a surface of the object at grazing angles of twenty degrees or less relative to the surface of the object, wherein the at least two incoherent light sources face the surface of the object such that the incoherent light travels directly to the surface of the object, wherein the at least two incoherent light sources are spaced apart such that the at least two incoherent light sources shine light onto the object from different directions;

obtaining a digital image of micro features on the surface of the object;

converting said image into electrical signals comprising micro surface features based on spatial relationships of multiple surface features; and

processing said signals into unique identifying reference information for characterizing the object; and

comparing the unique identifying reference information to corresponding features of a reference.

2. The method as claimed in claim 1, wherein converting said image further comprises converting said image into electrical signals by at least one 2D imaging sensor.

3. The method as claimed in claim 1, wherein processing said signals further comprises performing a Fourier Transform on said signals to link the object with said signals for characterizing the object.

4. The method as claimed in claim 1, wherein the method further comprises storing said signals on at least one of a local repository and a remote repository.

5. An apparatus for characterizing an object, said apparatus comprising:

at least two incoherent light sources, each incoherent light source oriented to simultaneously generate incoherent raking light onto a feature on a surface of the object at grazing angles of twenty degrees or less relative to the surface of the object, wherein the at least two incoherent light sources face the surface of the object such that the incoherent light travels directly to the surface of the object, wherein the at least two incoherent light sources are spaced apart such that the at least two incoherent light sources shine light onto the object from different directions;

at least one imaging device located above the object at a predetermined focal distance, said imaging device adapted to intercept at least one portion of the light reflected and scattered by said surface;

said imaging device further adapted to capture an optical image comprising a pattern representing at least one feature of the object;

said imaging device further adapted to convert said image into electrical signals; and

at least one processing device adapted to process said electrical signals to link the object with said signals for characterizing the object by comparison to stored reference data.

6. The apparatus as claimed in claim 5, wherein said at least two light sources are a point light source or an extended light source.

7. The apparatus of claim 5, wherein the apparatus comprises only light sources oriented at grazing angles of twenty degrees or less relative to the surface of the object.

8. The apparatus as claimed in claim 5, wherein said at least two light sources are an LED, an X-ray, an incandescent lamp, or an electroluminescent lamp.

9. The apparatus as claimed in claim 5, wherein said imaging device further comprises at least one 2D image sensor, said at least one 2D image sensor comprising at least one of a color sensor and a panchromatic sensor.

10. The apparatus as claimed in claim 5, wherein said apparatus further comprises at least one of a local repository and a remote repository.

11. The apparatus as claimed in claim 5, wherein said apparatus further comprises a rectangular viewing platform for placing the object, said platform having a gradually elevated shape with a first end slightly higher than an opposite second end.

12. An apparatus for characterizing an object based on intrinsic properties of the object, the apparatus comprising:

a first incoherent raking light source and a second incoherent raking light source, wherein the first and second raking light sources are each configured to simultaneously direct incoherent light at a grazing angle towards a surface of an object, wherein the grazing angle is an angle of twenty degrees or less relative to the surface, and wherein the incoherent light sources face the surface of the object such that the light is configured to travel directly from the incoherent light sources to the surface of the object, wherein the first and second incoherent light sources are spaced apart such that the first and second incoherent light sources shine light onto the object from different directions, and wherein the apparatus comprises only light sources oriented at grazing angles of twenty degrees or less relative to the surface of the object; and

an imaging device located aligned with the surface of the object at a predetermined focal distance, wherein the imaging device obtains a digital image of the surface of the object, and wherein the digital image comprises microscopic level details of the surface of the object made visible by the light from the raking light source having been reflected and scattered by the surface of the object due to physical properties of the surface of the object.

13. The apparatus of claim 12, wherein the first and second raking light sources are oriented at a same angle with respect to the surface of the object.

14. The apparatus of claim 12, wherein the digital image is stored in a memory associated with the imaging device.

15. The apparatus of claim 12, wherein the imaging device is configured to obtain a digital image of a surface roughness of the object.

16. The apparatus of claim 14, further comprising an electronic storage remote from the imaging device.

17. The apparatus of claim 12, wherein at least one digital image of a sample object is configured to be compared with at least one digital image of a reference object.

18. The apparatus of claim 17, wherein the digital image of the reference object is configured to be stored at a remote location and the digital image of the sample object is configured to be stored at a location local to the imaging device.

19. The apparatus of claim 17, further comprising a user interface configured to inform a user of conformance or traceability after comparison of the at least one digital image of the sample object with the digital image of the reference object.