LASER BEAM IMAGE CONTRAST ENHANCEMENT

• US 20100265505A1
• Filed: 04/20/2009
• Published: 10/21/2010
• Est. Priority Date: 04/20/2009
• Status: Active Grant

• Current Assignee: Javad GNSS, Inc.
• Original Assignee: Javad GNSS, Inc.
• Inventors: GRIBKOV, Mikhail
• Granted Patent: US 8,629,988 B2
• Time in Patent Office: Days
• US Class Current: 356/369
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 7/499 using polarisation effects

Abstract

An apparatus and method for providing image contrast enhancement is disclosed. A mobile object is equipped with a laser source, polarization filter, and imaging apparatus. The reflection of the laser source output passes through the filter and is received by the imaging apparatus. If the output of the laser source impinges a metallic marker plate located at a pre-determined location, the filter decreases the intensity level of image components not associated with the reflection of the laser source output. The imaging apparatus uses such filtered image components to determine the position and/or orientation of the mobile object.

Claims

1. A mobile object equipped for position or orientation determination, comprising:

a laser source outputting a laser beam;

a polarization filter operable to receive a reflection of the laser beam as an input; and

an imaging apparatus operable to receive an output of the polarization filter.

2. The mobile object of claim 1, further comprising a processor in communication with the imaging apparatus to perform image scanning.

3. The mobile object of claim 1, wherein the reflection of the laser beam is caused by a metallic marker located at a predetermined location, and the reflection comprises diffuse reflection.

4. The mobile object of claim 1, wherein the polarization filter comprises a circular polarization filter.

5. The mobile object of claim 1, wherein the polarization filter comprises a linear polarization filter.

6. The mobile object of claim 1, wherein the polarization filter comprises a linear polarization filter and a second polarization filter.

7. The mobile object of claim 1, wherein a main plane of transmission of the polarization filter is substantially parallel to a plane of polarization of the laser beam.

8. The mobile object of claim 1, wherein the imaging apparatus comprises a digital camera.

9. The mobile object of claim 1, wherein the imaging apparatus is operable to identify contiguous pixels of a captured image at or above a threshold intensity level.

10. The mobile object of claim 1, wherein pixels associated with the reflection of the laser beam in a captured image have an intensity level equal or greater than intensity levels associated with rest of the captured image.

11. A method for determining position or orientation of a mobile unit, comprising:

providing a laser beam from a laser included in the mobile unit;

receiving an image at an imaging apparatus;

providing a filter in front of the imaging apparatus; and

identifying pixels comprising the image that are at or above a threshold intensity level, wherein the pixels that are at or above a threshold intensity level are representative of a reflection of the laser beam.

12. The method of claim 11, further comprising providing a metallic target at a predetermined location.

13. The method of claim 12, further comprising generating the reflection of the laser beam from the laser beam impinging the metallic target.

14. The method of claim 11, wherein the filter comprises one or more polarization filters.

15. The method of claim 11, wherein providing the filter includes orientating a main plane of transmission of the filter substantially parallel to a plane of polarization of the laser beam.

16. The method of claim 11, further comprising determining contiguity of the pixels that is at or above a threshold intensity level.

17. A system for laser contrast enhancement, comprising:

a target positioned at a predetermined location; and

a mobile unit including;

a laser outputting a beam,

an imaging apparatus operable to capture images, and

a polarization filter located in front of the imaging apparatus and operable to decrease intensity of incoming image components not having a plane of polarization substantially parallel to a main plane of transmission of the polarization filter.

18. The system of claim 17, wherein the beam impinges the target to generate a diffuse reflection and the diffused reflection is included in an image captured by the imaging apparatus.

19. The system of claim 18, wherein the mobile unit is in a line of sight to the target and oriented for the beam to impinge on the target.

20. The system of claim 17, further comprising a processor configured to determine pixels comprising the captured images having intensity values equal to or greater than a threshold value.

21. The system of claim 17, further comprising a processor configured to determine a region of pixels comprising the captured images having intensity values equal to or greater than a threshold value.

22. The system of claim 17, further comprising a global positioning system (GPS) included in the mobile unit to determine an orientation of the mobile unit.