Optical object detection system incorporating fiber optic coupling

• US 5,291,261 A
• Filed: 02/06/1990
• Issued: 03/01/1994
• Est. Priority Date: 02/06/1990
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Dahl, Randy, Ghaem, Sanjar
• Primary Examiner(s): Wallace, Linda J.
• Application Number:
  US07/475,543
• Time in Patent Office: 1,484 Days
• Field of Search: 356/1, 356/41, 340/435, 340/904, 250/208.2, 250/208.3, 250/222.1, 250/561, 250/578.1, 250/341, 250/233, 250/349, 250/232, 250/350
• US Class Current: 356/3.02
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4818 using optical fibres

Abstract

A system (4) for use in an automobile (2) for the detection of objects comprising: a light source (6); a plurality of spaced transmitter ports (10, 12) for respectively transmitting light to a plurality of fields of illumination (18, 20); an optical fiber coupling the light source to the transmitter ports; a plurality of receiver ports (10, 12) embracing respectively a plurality of fields of reception (34, 36) each having an area of overlap (38, 40, 42, 44) with each of the plurality of fields of illumination so as to receive light transmitted from one of the transmitter ports and reflected by an object present in an area of overlap; a receiver (22) for receiving light and for producing a signal representative thereof; an optical fiber (24) coupling the receiver ports to the receiver; and processing means (52) for sequentially activating each of the transmitter ports with each of the receiver ports, and for processing the signal produced by the receiver in response to each activation to detect the presence of an object in each of the areas of overlap.

Claims

1. A system for the detection of objects comprising:

a source of optical energy;

a first transmitter port at a first transmitter location for transmitting optical energy to a first field of illumination;

first fiber optic coupling means coupling the source of optical energy to the first transmitter port;

a second transmitter port at a second transmitter location spaced from the first transmitter location for transmitting optical energy to a second field of illumination;

second fiber optic coupling means coupling the source of optical energy to the second transmitter port;

at least one receiver port embracing a field of reception having a first are of overlap with the first field of illumination and having a second area of overlap with the second field of illumination so as to receive optical energy transmitted from the first or second transmitter port and reflected by an object present in the first or second area of overlap;

a receiver coupled to the at least one receiver port for producing a signal representative of the optical energy received thereat;

means for sequentially activating the first and second transmitter ports during each cycle of activation of the system; and

processing means for processing the signal produced by the receiver to sequentially direct the presence of an object in the first or second area of overlap.

2. A system according to claim 1 wherein the means for sequentially activating the first and second transmitter ports includes shutter means respectively associated with each transmitter port for selectively passing optical energy from the respective transmitter ports.

3. A system according to claim 2 wherein the shutter means each comprise a member movable between first and second positions, the member being substantially transmissive to optical energy from its respective transmitter port in its first position and being substantially non-transmissive to optical energy from its respective transmitter port in its second position.

4. A system according to claim 1 further comprising means for beam shaping associated respectively with each of the ports.

5. A system according to claim 4 wherein each means for beam shaping comprises a lens.

6. A system according to claim 1 wherein the optical energy is visible light.

7. A system according to claim 1 wherein the optical energy is infra-red radiation.

8. A system according to claim 1 wherein the optical energy is ultra-violet radiation.

9. A system according to claim 1 further comprising correlator means for correlating the signal produced by the receiver with a transmission signal so as to reduce detection error.

10. A system according to claim 9 wherein the correlator means comprises:

mixer means for mixing the transmission signal with the signal produced by the receiver to produce a mixed signal; and

low-pass filter means for low-pass filtering the mixed signal to reduce non-correlated components therein.

11. A system according to claim 1 further comprising integrator means for integrating the signal produced by the receiver so as to reduce detection error.

12. A system according to claim 1 wherein the source of optical energy comprises a light emitting diode.

13. A system for the detection of objects comprising:

a source of optical energy;

at least one transmitter port coupled to the source of optical energy for transmitting optical energy to a field of illumination;

a first receiver port located at a first location and embracing afield field of reception having a first area of overlap with the field of illumination so as to receive optical energy transmitted form the at least one transmitter port and reflected by an object present in the first area of overlap;

a second receiver port located at a second location spaced from the first location and embracing a second field of reception having a second area of overlap with the field of illumination so as to receive optical energy transmitted by the at lest one transmitter and reflected by an object present in the second area of overlap;

a receiver for receiving optical energy and for producing a signal representative thereof;

fiber optic coupling means coupling to the first and second receiver ports to the receiver;

means for sequentially activating the first and second receiver ports during each cycle of activation of the system; and

processing means for processing the signal produced by the receiver to sequentially detect the presence of an object in the first or second area of overlap.

14. A system according to claim 13 wherein the means for sequentially activating the first and second receiver ports includes shutter means respectively associated with each receiver port for selectively passing optical energy to the respective receiver ports.

15. A system according to claim 14 wherein the shutter means each comprise a member movable between first and second positions, the member being substantially transmissive to optical energy to its respective receiver port in its first position and being substantially non-transmissive to optical energy to its respective receiver port in its second position.

16. A system according to claim 13 further comprising means for beam shaping associated respectively with each of the ports.

17. A system according to claim 13 wherein each means for beam shaping comprises a lens.

18. A system according to claim 13 wherein the optical energy is visible light.

19. A system according to claim 13 wherein the optical energy is infra-red radiation.

20. A system according to claim 13 wherein the optical energy is ultra-violet radiation.

21. A system according to claim 13 further comprising correlator means for correlating the signal produced by the receiver with a transmission signal so as to reduce detection error.

22. A system according to claim 21 wherein the correlator means comprises:

mixer means for mixing the transmission signal with the signal produced by the receiver to produce a mixed signal; and

a low-pass filter means for low-pass filtering the mixed signal to reduce non-correlated components therein.

23. A system according to claim 13 further comprising integrator means for integrating the signal produced by the receiver so as to reduce detection error.

24. A system according to claim 13 wherein the source of optical energy comprises a light emitting diode.

25. A system for use in a vehicle to detect objects in the vicinity of the vehicle, the system comprising:

a source of optical energy;

a plurality of spaced transmitter ports for respectively transmitting optical energy to a plurality of fields of illumination;

transmission fiber optic coupling means coupling the source of optical energy to the plurality of transmitter ports;

a plurality of receiver ports embracing respectively a plurality of fields of reception each having an area of overlap in the vicinity of the vehicle with each of the plurality of fields of illumination so as to receive optical energy transmitted from one of the plurality of transmitter ports and reflected by an object present in an area of overlap;

a receiver for receiving optical energy and for producing a signal representative thereof;

reception fiber optic coupling means coupling the plurality of receiver ports to the receiver;

means for sequentially activating each of the plurality of transmitter ports with each of the plurality of receiver ports during each cycle of activation of the system; and

processing means for processing the signal produced by the receiver in response to each activation to sequentially detect the presence of an object in each of the areas of overlap in the vicinity of the vehicle.