Object detection system

• US 5,877,849 A
• Filed: 05/12/1997
• Issued: 03/02/1999
• Est. Priority Date: 05/12/1997
• Status: Expired due to Term

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: Advanced Optical Technologies, LLC
• Inventors: Rains, Jack C. Jr., Ramer, David P.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/854,796
• Time in Patent Office: 659 Days
• Field of Search: 356/3.01, 356/3.03, 356/3.08, 356/3.06, 356/3.13, 356/141.1, 356/141.2, 396/120, 250/206.1
• US Class Current: 356/3.01
• CPC Class Codes: G01C 3/085 with electronic parallax measurement
• CPC Class Codes: G01S 17/26 wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 3/783 using amplitude comparison of signals derived from static detectors or detector systems
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/486 Receivers
• CPC Class Codes: G01S 7/491 Details of non-pulse systems

Abstract

The present invention provides for a detection system for detecting an object, comprising optical elements including a radiation source of an electromagnetic nature and at least one detector detecting radiation reflected off the object from the radiation source. The system is configured so that trigonometric relationships are established between all or selected of the optical elements and the object. Using the angle of radiation from the radiation source and the angle of reflection into the detector, the system determines the range or distance, and/or velocity of the object relative to the system. While the use of one detector is sufficient to provide an angle measurement for the system to determine the object range and/or velocity, an additional detector may be used to increase accuracy and flexibility. The detectors of the system may have be normal-looking, or side-looking detectors, either of which detects intensity variations. Each detector uses a mask and a baffle in accordance with the concept of constructive occlusion, which improves the response characteristics of the detector. The mask occupies a predetermined position within the detector to enable the detector to provide a tailored response profile. The baffle is configured within the detector to partition a diffusely-reflective cavity within the detector. An LED array or a scanning light assembly may be used with the system as the radiation source.

Claims

1. A detection system for detecting an object, comprising:

a plurality of optical elements, including;

a radiation source for emitting radiation toward said object;

at least one detector for detecting reflected radiation, including;

a detection surface;

a mask spaced from said surface;

a baffle positioned between said surface and said mask for defining radiation receiving sections within the detector;

a plurality of photodetectors wherein each photodetector is configured for response to said reflected radiation incident on a distinct radiation receiving section, each photodetector generating a signal representative of said incident reflected radiation; and

an electronic circuit processing said signal for detecting said object.

2. A detection system as defined in claim 1, wherein said system is configured such that said optical elements and said object form vertices of a triangle.

3. A detection system as defined in claim 1, wherein said system is configured such that said radiation source, said detector and said object form vertices of a triangle.

4. A detection system as defined in claim 1, wherein said optical elements further comprise an additional detector.

5. A detection system as defined in claim 4, wherein said system is configured such that said detector, said additional detector and said object form vertices of a triangle.

6. A detection system as defined in claim 5, wherein said radiation source is positioned between said detector and said additional detector.

7. A detection system as defined in claim 1, wherein said signal is representative of an intensity of said reflected radiation incident on said distinct radiation receiving section.

8. A detection system as defined in claim 1, wherein said radiation source emits infra-red electromagnetic radiation.

9. A detection system as defined in claim 1, wherein said detector is a normal-looking detector.

10. A detection system as defined in claim 1, wherein said detector is a side-looking detector.

11. A detection system as defined in claim 1, wherein said electronic circuit processes said signal for generating range data for said object.

12. A detection system as defined in claim 1, wherein said electronic circuit processes said signal for generating velocity data for said object.

13. A detection system as defined in claim 1, further comprising an acoustic device responsive to said electronic circuit for generating an audio signal.

14. A detection system as defined in claim 1, wherein said radiation source generates a radiation angle signal representative of a radiation angle, said radiation angle signal being processed by said electronic circuit.

15. A detection system as defined in claim 1, wherein said detector generates a reflection angle signal representative of a reflection angle, said reflection angle signal being processed by said electronic circuit.

16. A detection system as defined in claim 1, wherein said mask and said baffle have diffusely reflective surfaces.

17. A detection system as defined in claim 1, wherein said detection surface is defined by an aperture of a diffusely reflective cavity configured in said base.

18. A detection system as defined in claim 1, wherein said radiation source comprises an LED array.

19. A detection system as defined in claim 1, wherein said radiation source comprises a radiation scanning assembly.

20. A detection system as defined in claim 1, wherein each of said optical elements are separated from each other by a predetermined distance.

21. A detection system as defined in claim 4, wherein said detector and said additional detector are separated from each other by a predetermined distance.

22. A detection system as defined in claim 1, further comprising a display responsive to said electronic circuit for displaying an image representative of a range of said object.

23. A system for detecting an object within a predetermined field of view, comprising:

a radiator, for emitting radiation into the predetermined field of view;

a detector for detecting radiation reflected from within the predetermined field of view, the detector comprising;

(a) a base having a surface formed of a reflective material that defines a reflective region facing toward the predetermined field of view,

(b) a mask spaced a predetermined distance from the reflective region, said mask comprising a reflective surface facing substantially toward the reflective region of the base,

(c) a cavity having a diffusely reflective surface, the cavity being formed in one of the reflective region of the base and the reflective surface of the mask, and

(d) a sensor, responsive to incident radiation, that generates a response signal based on the intensity of radiation that it receives and that is coupled to the cavity so as to intercept radiation from within the cavity,

(e) wherein the mask is located between the base and the predetermined field of view such that the mask constructively occludes radiation incident to the detector from within the field of view with respect to the cavity so as to tailor response of light detector to the radiation reflected from within the predetermined field of view in a predetermined manner; and

an electronic circuit for processing the signal from the sensor, to detect said object.

24. A system as in claim 23, wherein the reflective region of the base is substantially diffusely reflective.

25. A system as in claim 23, wherein the reflective surface of the mask is substantially diffusely reflective.

26. A system as in claim 23, further comprising a baffle located between the base reflective region and the reflective surface of the mask and forming a plurality of optical sections with respect to light incident to the cavity, wherein the sensor comprises a plurality of radiant energy sensors each radiant energy sensor being coupled to one of the optical sections.

27. A system as in claim 23, wherein the field of view extends normal to the mask and base.

28. A system as in claim 23, wherein the mask, base and cavity are arranged to form a side-looking detector.

29. A system for detecting an object within a predetermined field of view, comprising:

a radiator, for emitting radiation into the predetermined field of view;

a detector for detecting radiation reflected from within the predetermined field of view, the detector comprising;

(a) a base configured with a detection aperture that receives light from substantially any direction within the predetermined field of view,

(b) a mask positioned within the predetermined field of view and spaced from said detection aperture so as to occlude a portion of the detection aperture with respect to the predetermined field of view,

(c) a baffle positioned in said aperture between said mask and said base, said baffle dividing said aperture into regions, and

(d) a plurality of detectors, each arranged to generate a signal representative of radiation incident through a respective region of the aperture; and

an electronic circuit for processing the signals from the detectors, to detect said object.

30. A system as in claim 29, wherein the detection aperture defines a reflective region on the base.

31. A system as in claim 30, wherein the reflective region on the base is substantially diffusely reflective.

32. A system as in claim 30, wherein the aperture comprises an opening of a cavity formed in the base, the cavity having a reflective surface.

33. A system as in claim 29, wherein the mask comprises a reflective surface facing the detection aperture.

34. A system as in claim 33, wherein the reflective surface is substantially diffusely reflective.

35. A system for detecting an object within a predetermined field of view, comprising:

a radiator, for emitting radiation into the predetermined field of view;

a detector for detecting radiation reflected from within the predetermined field of view, the detector comprising;

(a) a base having a first reflective surface,

(b) mask having a second reflective surface oriented to redirect at least some radiation toward the first reflective surface, wherein at least one of the reflective surfaces is substantially diffusely reflective,

(c) a cavity formed in one of the reflective surfaces and arranged with respect to the mask such that the mask occludes a substantial portion of an opening of the cavity with respect to radiation reflected from within the predetermined field of view, and

(d) at least one radiant energy sensor coupled to the cavity to sense radiant energy incident within the cavity; and

an electronic circuit for processing a signal from the at least one radiant energy sensor, to detect said object.

36. A system as in claim 35, further comprising a baffle located between the mask and the base to divide radiation passing between the first and second reflective surfaces into a plurality of portions, wherein the at least one radiant energy sensor comprises a plurality of sensors each of which is receptive of one of the portions of the divided radiation.