Method for detecting objects with visible light

• US 8,319,949 B2
• Filed: 06/18/2008
• Issued: 11/27/2012
• Est. Priority Date: 06/18/2007
• Status: Active Grant

• Current Assignee: LeddarTech, Inc.
• Original Assignee: LeddarTech, Inc.
• Inventors: Cantin, Daniel, Gallant, Pascal, Babin, François
• Primary Examiner(s): RATCLIFFE, LUKE D
• Application Number:
  US12/141,282
• Publication Number:
  US 20080309914A1
• Time in Patent Office: 1,623 Days
• Field of Search: 356 401- 515, 356/28, 356/141.2, 356/141.5
• US Class Current: 356/4.01
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32

Abstract

A method for detecting an object using visible light comprises providing a visible-light source having a function of illuminating an environment. The visible-light source is driven to emit visible light in a predetermined mode, with visible light in the predetermined mode being emitted such that the light source maintains said function of illuminating an environment. A reflection/backscatter of the emitted visible light is received from an object. The reflection/backscatter is filtered over a selected wavelength range as a function of a desired range of detection from the light source to obtain a light input. The presence or position of the object is identified with the desired range of detection as a function of the light input and of the predetermined mode.

Claims

1. A method for detecting an object using visible light, comprising:

providing a white solid-state visible-light source having a function of illuminating an environment;

driving the visible-light source to emit visible light in a predetermined pulse mode, with visible light in the predetermined pulse mode being emitted such that the light source maintains said function of illuminating an environment;

receiving a reflection/backscatter of the emitted visible light from an object;

filtering the reflection/backscatter over a selected wavelength range of 400 nm to 750 nm as a function of a desired range of detection from the light source to obtain a light input having a shorter pulse on a time scale than a Pulse of the visible light;

detecting the light input with the shorter pulse; and

identifying at least one of a presence and a position of the object with the desired range of detection solely as a function of the detected light input with the shorter pulse and of the predetermined pulse mode.

2. The method according to claim 1, wherein providing the light source comprises providing at least one phosphor-converted light-emitting diode.

3. The method according to claim 2, wherein filtering the reflection/backscatter comprises obtaining the light input in blue emission ranging between 400 nm to 500 nm from the phosphor-converted light-emitting diode for detection at short range.

4. The method according to claim 2, wherein filtering the reflection/backscatter comprises obtaining the light input in broadband luminescent emission from the phosphor-converted light-emitting diode for detection at long range.

5. The method according to claim 1, wherein filtering the reflection/backscatter comprises filtering with an optical interference filter.

6. The method according to claim 1, wherein driving the visible-light source in the predetermined mode comprises driving the visible-light source in a pulse-width modulation.

7. The method according to claim 1, wherein filtering the reflection/backscatter over a selected wavelength range to obtain a light input comprises obtaining the light input in a visible wavelength.

8. The method according to claim 1, wherein driving the visible-light source comprises driving the visible-light source to emit light in pulse-width modulation, identifying at least one of a presence and a position of the object comprises identifying rapid transients in the reflection/backscatter, and further comprising calculating a distance of the object from the rapid transients received and rapid transients from the pulse-width modulation.