Vision system and proximity detector

• US 5,726,443 A
• Filed: 01/18/1996
• Issued: 03/10/1998
• Est. Priority Date: 01/18/1996
• Status: Expired due to Fees

• Current Assignee: Canadian Space Agency (Government of Canada)
• Original Assignee: Canadian Space Agency (Government of Canada)
• Inventors: Chapman, Glenn H., Immega, Guy B.
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): PYO, KEVIN K
• Application Number:
  US08/588,319
• Time in Patent Office: 782 Days
• Field of Search: 250/221, 250/208.1, 250/237 R, 250/559.31, 250/559.29, 250/227.2, 382/124, 382/125, 382/126, 382/127
• US Class Current: 250/227.2
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G06V 40/1312 direct reading, e.g. contactless acquisition
• CPC Class Codes: H03K 17/941 using an optical detector H03K17/968 takes precedence

Abstract

A vision system and proximity detector is provided in the form of an occluding mask with multiple high aspect light pathways positioned over a light detecting surface. Pixel-based images can be generated to provide a vision system utilizing a variety of illumination modes. Proximity can be measured with a triangulating beam.

Claims

1. An electromagnetic ray sensing system for viewing a viewed object that has its surface illuminated with electromagnetic radiation below the X-ray range of the spectrum down to and including the far infrared region comprising:

(a) an electromagnetic ray or light detector having a series of individual light sensor regions positioned across the surface of the detector for receiving and sensing illumination by electromagnetic radiation within the far infra-red to, but not including, the X-ray range, said sensor regions being connected through a sensor output to provide output signals corresponding to the intensity and location of the electromagnetic radiation received by each of the individual light sensor regions in the series of light sensor regions of the detector; and

(b) an occluding mask positioned to cover said light sensor regions, such mask having a specific depth and multiple light pathways extending through the depth of the mask, each pathway having entrance and exit openings and each pathway having an aspect ratio of at least 3 to 1, in terms of the depth to width for each pathway, each of said light pathways being positioned to provide access for rays of electromagnetic illumination to arrive at and illuminate respectively associated light sensor regions on the detector surface

wherein each light pathway provides for the direct, straight line transmission of illumination through the depth of the mask, from said entrance to said exit openings, to provide each of such light sensor regions with a limited conical field of view that is bounded by the straight-line extensions of points on the edges of said entrance and exit openings, and wherein the mask is provided with non-reflecting, absorbing, radiation blocking surfaces for blocking received electromagnetic rays entering a specific light pathway from cross-illuminating other sensor regions on the detector surface than the specific light sensor region being illuminated through said specific associated light pathway.

2. A system as in claim 1 further comprising a source of illumination for the viewed object.

3. A system as in claim 2 wherein the source of illumination is a light emitting panel surmounted on the occluding mask, such panel having light transmitting regions that are in alignment with the light pathways of the mask.

4. A system as in claim 2 wherein the occluding mask is surmounted by a transparent cover having an upper surface wherein the source of illumination provides light laterally to enter within said cover and illuminate a viewed object positioned on or above the upper surface.

5. A system as in claim 2 in combination with a translucent object wherein the source of illumination is located on the side of the object remote from the occluding mask.

6. A system as in claim 2 comprising illuminating light passageways passing through the occluding mask and positioned to receive light from the source of illumination located on the side of the mask remote from the viewed object whereby light to illuminate areas on the viewed object passes through the mask.

7. A system as in claim 2 wherein the source of illumination cyclically changes through differing colors to provide signals through the sensor output that correspond to consecutive monochrome illuminations of the viewed object in each of the differing colors.

8. A system as in claim 1 wherein multiple classes of light pathways are present, each class of light pathway being provided with color filter means for a specific color whereby a representation of the viewed object in color can be provided through the sensor output.

9. A system as in claim 1 wherein a portion of such pathways are non-parallel to other pathways.

10. A system as in claim 9 comprising multiple classes of light pathways wherein one primary class of the classes of light pathways receives light from directly above the detector and one or more other classes of light pathways receive light from regions peripheral to that received by the primary class of light pathways.

11. A system as in claim 9 wherein the light pathways allowing illumination of the central portion of the detector surface are in substantially parallel alignment, and the light pathways at the periphery of the detector surface are angled outwardly, away from the central portion of the detector surface.

12. A system as in claim 9 wherein substantially all light pathways are angled outwardly, away from the central portion of the detector surface.

13. A system as in claim 9 wherein said pathways comprise first and second classes of light pathways classes which have overlapping fields of view and are connected through the sensor output to stereo image processing means whereby a viewed scene lying within the overlapping fields of view is analyzed stereoscopically to provide an output that is an indication of the proximity of the viewed object.

14. A system as in claim 9 wherein said pathways comprise first and second classes of light pathways which classes have overlapping fields of view and are connected through the sensor output to stereo image processing means whereby a viewed scene lying within the overlapping fields of view is analyzed stereoscopically to provide an output that is indication of the three dimensional shape of the surface of the viewed object.

15. A system as in claim 13 wherein the members of the first class of light pathways are separated laterally from the members of the second class of light pathways.

16. A system as in claim 13 wherein the members of the first class of light pathways are interleaved with the members of the second class of light pathways.

17. A system as in claim 2 wherein the source of illumination provides a beam of light directed towards a viewed object at a predetermined angle with respect to the detector surface and further comprising a triangulation proximity detection means coupled to the sensor output that provides an indication of the proximity of a point of illumination of the beam of light on the viewed object based upon triangulation ranging.

18. A system as in claim 17 having multiple beams of light, each beam being oriented spatially to illuminate exclusively, by reflection off of a viewed object, an associated series of sensor regions within the detector.

19. A system as in claim 18 wherein said multiple beams are oriented at differing angles of elevation above the mask.

20. A system as in claim 18 having multiple overlapping beams wherein more than one beam is positioned to illuminate a specific sensor region, and further comprising time multiplexing means for releasing light consecutively from the overlapping beams whereby the illumination from said overlapping beams can be distinguished from each other.

21. A system as in claim 18 having multiple overlapping beams, said overlapping beams differing in their color and further comprising color filter means mounted over the sensors whereby the illumination from said overlapping beams can be distinguished from each other.

22. A system as in claim 1 wherein the mask is of multi-layer structure, having at least two top and second occluding mask layers positioned in a spaced relationship above the surface of the detector, each of said layers having light-passing holes formed therein that are in alignment to define the light pathways, the top layer having a thickness, the thickness of the top layer and the spacing intervals between the top and second layers, and between the surface of the detector and the next upper layer, being dimensioned to prevent, when exposed to illumination from any direction, any cross-illumination by incoming light of light sensor regions through more than one light pathway.

23. A system as in claim 22 wherein layers below the top layer of the mask are thinner than the top layer.

24. A system as in claim 22 wherein the spacing interval S between layers is given by the formula

25. A system as in claim 23 wherein the spacing interval S between layers is given by the formula

26. A sensing system as in claim 1 wherein the detector comprises charge coupled device.

27. A sensing system as in claim 1 wherein the detector comprises a position sensing device.

28. A system as in claim 1, further comprising:

(a) an image presentation means for providing a representation of a viewed object; and

(b) an image processing means coupled between the sensor output and the image presentation means for activating the image presentation means in response to signals originated by the array of sensors to provide a vision system.

29. A system as in claim 1 wherein the mask comprises solid transparent regions that correspond with the light pathways and the regions within the mask between such light pathways that are solid and opaque.

30. A system as in claim 1 wherein the mask comprises in a plurality of crossed louvres which provide the radiation blocking surfaces.

31. A system as in claim 1 wherein the series of light sensor regions are distributed in a linear array.