Sensor for determining the angular position of a radiating point source in two dimensions

• US 20050105081A1
• Filed: 11/13/2003
• Published: 05/19/2005
• Est. Priority Date: 11/13/2003
• Status: Active Grant

• Current Assignee: Ascension Technology Corporation (Roper Technologies, Inc.)
• Original Assignee: Ascension Technology Corporation (Roper Technologies, Inc.)
• Inventors: Odell, Don
• Granted Patent: US 7,106,431 B2
• Time in Patent Office: Days
• US Class Current: 356/141.500
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01C 1/00 Measuring angles
• CPC Class Codes: G01D 5/26 characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
• CPC Class Codes: G01D 5/32 with attenuation or whole or partial obturation of beams of light G01D5/40 takes precedence ; mechanical adjustment G01D5/264

Abstract

Embodiments of a device and a technique are disclosed for locating the angular position of a radiating point source with respect to a detector comprising a point source of radiation, a variable transmissivity mask with pseudo-random variations, a multi-element detector and computing means for interpreting the detected image. The mask pattern, when illuminated by a point source of radiation, casts an image on the detector array. Computing means determine the pattern shift to allow determination of point source angular location in two dimensions. The mask transmissivity pattern and corresponding image vary in two dimensions, in such a manner as to yield two correlation peaks that indicate the incident angle in two dimensions. The differential shift and common mode shift in correlation peaks indicate the respective angles of incidence, allowing determination of the angular position of the light source.

Claims

1. A sensor for determining the angular position of a radiating point source in two dimensions, comprising:

a) a point source of light located in a prescribed space;

b) a light detector adjacent said space;

c) a two dimensional mask interposed between said detector and said space, said mask having a two dimensional pseudo-random surface pattern defining a prescribed degree of transmissivity;

d) whereby light from said source travels through said mask and onto said detector, said surface pattern causing said detector to sense two correlation signal peaks usable to indicate incident angle between said source and detector in two dimensions.

2. The sensor of claim 1, wherein said surface pattern comprises an analog or continuously varying pseudo-random sequence of V-shapes.

3. The sensor of claim 1, wherein said surface pattern comprises analog or continuously varying pseudo-random transmissivity components.

4. The sensor of claim 1, wherein said surface pattern comprises digital or discretely varying pseudo-random transmissivity components.

5. The sensor of claim 1, wherein said surface pattern comprises a plurality of V-shapes.

6. The sensor of claim 5, wherein at least some of said V-shapes overlap one another.

7. The sensor of claim 6, wherein non-overlapping portions of said pattern have a first degree of transmissivity and overlapping portions of said pattern have a second degree of transmissivity.

8. The sensor of claim 7, wherein said second degree is greater than said first degree.

9. The sensor of claim 8, wherein said first degree comprises 50% transmissivity.

10. The sensor of claim 8, wherein said second degree comprises 100% transmissivity.

11. The sensor of claim 9, wherein said second degree comprises 100% transmissivity.

12. The sensor of claim 1, wherein said mask is rectangular.

13. The sensor of claim 1, wherein said detector comprises a charge coupled device (CCD).

14. The sensor of claim 12, wherein said detector comprises a charge coupled device (CCD).

15. The sensor of claim 12, wherein said mask extends laterally of said detector.

16. A sensor for determining the angular position of a radiating point source in two dimensions, comprising:

a) a point source of light located in a prescribed space;

b) a light detector adjacent said space;

c) a two dimensional rectangular mask interposed between said detector and said space, said mask having a two dimensional pseudo-random surface pattern defining a prescribed degree of transmissivity, said surface pattern comprising a plurality of V shapes at least some of which partially overlap one another;

d) whereby light from said source travels through said mask and onto said detector, said surface pattern causing said detector to sense two correlation signal peaks usable to indicate incident angle between said source and detector in two dimensions.

17. The sensor of claim 16, wherein non-overlapping portions of said pattern have a first degree of transmissivity and overlapping portions of said pattern have a second degree of transmissivity.

18. The sensor of claim 17, wherein said first degree comprises 50% transmissivity.

19. The sensor of claim 17, wherein said second degree comprises 100% transmissivity.

20. The sensor of claim 18, wherein said second degree comprises 0% transmissivity.

21. The sensor of claim 16, wherein said detector comprises a charge coupled device (CCD).

22. The sensor of claim 16, wherein said mask extends laterally of said detector.