LED object detection system and method combining complete reflection traces from individual narrow field-of-view channels

• US 8,242,476 B2
• Filed: 11/18/2010
• Issued: 08/14/2012
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: LeddarTech, Inc.
• Original Assignee: LeddarTech, Inc.
• Inventors: Mimeault, Yvan, Gallant, Pascal, Cantin, Daniel
• Primary Examiner(s): Bui Pho, Pascal M
• Application Number:
  US12/949,212
• Publication Number:
  US 20110205521A1
• Time in Patent Office: 635 Days
• Field of Search: 250/221, 250/208.1, 250/214.R, 250/214.1, 250/559.19, 250/559.2, 250/559.21, 250/559.22, 250/559.24, 250/338.1, 250/339.01, 250/339.02, 250/339.06, 250/339.11, 250/205, 250/559.29, 250/559.38, 250/559.4, 356/2, 356 3- 316, 356/4.01, 356601-614, 356/625, 356/627, 356/628, 356634-640, 356/237.1, 340/500, 340/540, 340/541, 340555-557, 340/552, 340/567, 235/435, 235/439, 235/440, 235/454, 235/462.01, 235/462.11, 235/462.16, 235/462.17, 235/462.24, 235/462.41, 235/462.42, 235/468
• US Class Current: 250/559.29
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 7/4814 of transmitters alone

Abstract

A multi-channel LED object detection system and a method for detecting an object are provided. The method includes providing and orienting a light source having a wide field-of-illumination to encompass the width of the environment; providing and orienting a detector having a wide field-of-view to encompass the width of the environment, the detector having a plurality of sub-detectors with individual narrow field-of-views, driving the LED source into emitting light to illuminate the width of the environment; receiving and acquiring an individual complete trace of a reflection/backscatter of the emitted light on the object at each sub-detector; converting the acquired individual complete trace into an individual digital signal; and detecting and identifying a presence of an object, a position of the object, a distance between the object and the LED source and/or a visibility, using the emitted light waveform and an individual digital signal.

Claims

1. A method for detecting an object located in an environment, said environment having a width, comprising:

providing a Light-Emitting-Diode (LED) light source having a wide field-of-illumination and orienting said LED light source for said wide field-of-illumination to encompass said width of said environment;

providing an optical detector having a wide field-of-view and orienting said optical detector for said wide field-of-view to encompass said width of said environment, said optical detector having a plurality of sub-detectors, each having an individual narrow field-of-view, each individual narrow field-of-view creating a channel in said wide field-of-view;

driving the LED light source into emitting light toward the environment, said width of said environment being illuminated by said light, said light having an emitted light waveform, said emitted light waveform having short light pulses, each light pulse having a width of less than 50 ns and an amplitude greater than a nominal value of said LED light source and said waveform having a low duty cycle;

receiving and acquiring an individual complete temporal waveform trace of a reflection/backscatter of the emitted light on the object in the environment at each sub-detector of said plurality, thereby combining said individual narrow field-of-view to create said wide field-of-view encompassing said width of said environment and thereby receiving and acquiring an individual complete trace for each channel, said individual complete temporal waveform trace being acquired from a moment when said emitting begins over a length of time continuing after said emitting has ended and ending before emission of a next one of said short light pulses, said acquiring including acquiring and storing multiple time-spaced sampling points at each sub-detector to acquire and store said individual complete temporal waveform trace;

converting said acquired individual complete trace of said reflection/backscatter into an individual digital signal; and

detecting and identifying at least one of a presence of an object in the environment, a position of the object in the environment, a distance between the object and the LED light source and a visibility in said environment, using said emitted light waveform and at least one of said individual digital signal.

2. The method as claimed in claim 1, wherein said providing a LED light source comprises providing an invisible LED light source and said driving said invisible LED light source comprises illuminating said environment using non-visible light for said detection.

3. The method as claimed in claim 1, wherein said providing a LED light source comprises providing a visible LED light source and said driving said visible LED light source comprises at least one of illuminating said environment using visible light for said detection and emitting a signal to a person in the environment.

4. The method as claimed in claim 1, wherein the step of driving the LED light source comprises at least one of pulsating and modulating the light.

5. The method as claimed in claim 1, wherein said providing a LED light source comprises providing at least one visible LED light source and at least one invisible LED light source and wherein said driving said LED light source comprises driving said invisible LED light source for illuminating said environment using non-visible light for said detection and driving said visible LED light source for at least one of illuminating said environment using visible light for said detection and emitting a signal to a person in the environment.

6. The method as claimed in claim 1, wherein said step of providing a LED light source comprises providing a plurality of LED light sources, each having an individual narrow field-of-illumination, wherein said step of driving the LED light source comprises driving said plurality of LED light sources to emit light in combination, thereby combining said individual narrow field-of-illumination to create said wide field-of-illumination encompassing said width of said environment.

7. The method as claimed in claim 6, wherein said driving said plurality of LED light sources includes driving said LED light sources to emit light one of in sequence and simultaneously.

8. The method as claimed in claim 1, wherein said step of detecting and identifying further comprises combining information obtained from at least two individual digital signals to detect and identify.

9. The method as claimed in claim 1, wherein said detecting and identifying said distance comprises measuring a time delay between said driving the LED light source to emit the light and said receiving said complete trace.

10. The method as claimed in claim 1, further comprising repeating said steps of driving, receiving and acquiring, converting and detecting and identifying to cumulate a plurality of time-spaced digital signals for said detector.

11. The method as claimed in claim 10, further comprising analyzing said plurality of time-spaced digital signals to determine at least one of a displacement speed of said object, a shape of said object and a dimension of said object.

12. The method as claimed in claim 1, wherein said visibility is an environmental condition, said environmental condition being a presence of one of fog, rain, snow, dust, smoke, gas, smog.

13. A multi-channel LED object detection system for detecting an object located in an environment, said environment having a width, comprising:

a Light-Emitting-Diode (LED) light source having a wide field-of-illumination oriented for said wide field-of-illumination to encompass said width of said environment;

a source controller for said LED light source for driving said LED light source into emitting light toward the environment, said width of said environment being illuminated by said light, said light having an emitted light waveform, said emitted light waveform having short light pulses, each light pulse having a width of less than 50 ns and an amplitude greater than a nominal value of said LED light source and said waveform having a low duty cycle;

an optical detector having a wide field-of-view oriented for said wide field-of-view to encompass said width of said environment, said optical detector having a plurality of sub-detectors, each having an individual narrow field-of-view, each individual narrow field-of-view creating a channel in said wide field-of-view, said optical detector receiving an individual complete temporal waveform trace of a reflection/backscatter of the emitted light on the object in the environment at each sub-detector of said plurality, thereby combining said individual narrow field-of-view to create said wide field-of-view encompassing said width of said environment and thereby receiving and acquiring an individual complete trace for each channel, said individual complete temporal waveform trace being acquired from a moment when said source controller drives said LED light source to emit and over a length of time continuing after said source controller has stopped driving said LED light source to emit and ending before said source controller drives said LED light source to emit a next one of said short light pulses, said optical detector acquiring and storing multiple time-spaced sampling points at each sub-detector to acquire and store said individual complete temporal waveform trace;

an analog-to-digital converter for converting each said individual complete trace of said reflection/backscatter into an individual digital signal;

a memory for acquiring and storing each said individual complete trace; and

a signal processor for detecting and identifying at least one of a presence of an object in the environment, a position of the object in the environment, a distance between the object and the LED light source and a visibility in said environment, using said emitted light waveform and at least one of said individual digital signal and outputting a data output associated to the object.

14. The multi-channel LED object detection system as claimed in claim 13, wherein said LED light source is an invisible LED light source and said width of said environment is illuminated by non-visible light for said detection.

15. The multi-channel LED object detection system as claimed in claim 14, wherein said invisible LED light source is an infrared LED light source.

16. The multi-channel LED object detection system as claimed in claim 13, wherein said LED light source comprises a plurality of LED light sources, each having an individual narrow field-of-illumination, and wherein said source controller drives said plurality of LED light sources to emit light in combination, thereby combining said individual narrow field-of-illumination to create said wide field-of-illumination encompassing said width of said environment.

17. The multi-channel LED object detection system as claimed in claim 16, wherein said plurality of LED light sources is multiple small clusters of LEDs.

18. The multi-channel LED object detection system as claimed in claim 13, further comprising a lens and a diffuser, said lens for collimating the power of said light source, said diffuser for diffusing said collimated power to illuminate said environment.

19. The multi-channel LED object detection system as claimed in claim 13, wherein said plurality of optical sub-detectors is arranged in a detector array, said detector array is one of a linear array, a 2D type array, an APD array, a photodiode array, a CCD sensor and a CMOS sensor.

20. The multi-channel LED object detection system as claimed in claim 13, wherein said object is at least one of a vehicle, a truck, a boat, a car, a motorcycle, a tricycle, a bicycle, a person, a pavement, a sidewalk, a ground surface, a particle, an environmental particle, a wall, a post, a stationary object and a moving object.

21. The multi-channel LED object detection system as claimed in claim 13, wherein said wide field-of-illumination has an angular range of more than 10 degrees.

22. The multi-channel LED object detection system as claimed in claim 21, wherein said angular range of said field-of-illumination is between 15 and 180 degrees.