METHOD AND SYSTEM FOR MODIFYING A BEACON LIGHT SOURCE FOR USE IN A LIGHT BASED POSITIONING SYSTEM

• US 20130026945A1
• Filed: 06/19/2012
• Published: 01/31/2013
• Est. Priority Date: 07/26/2011
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: Bytelight, Inc. (Acuity Brands, Inc.)
• Inventors: GANICK, Aaron, RYAN, Daniel
• Granted Patent: US 9,723,676 B2
• Time in Patent Office: Days
• US Class Current: 315/246
• CPC Class Codes: G06F 2218/02 Preprocessing
• CPC Class Codes: G06F 2218/14 by matching peak patterns
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 2207/20216 Image averaging
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: H04W 4/30 Services specially adapted for particular environments, situations or purposes
• CPC Class Codes: H04W 4/33 for indoor environments, e.g. buildings
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 47/16 by timing means
• CPC Class Codes: H05B 47/175 by remote control

Abstract

In one aspect, the present disclosure related to a method for modifying a beacon light source for use in a light-based positioning system. In some embodiments, the method includes selecting a modulation scheme for the light source, determining a duty cycle for the light source based on the modulation scheme, the duty cycle having a proportion of time the light source is in an on state and a corresponding proportion of time the light source is in an off state, the proportion of time the light source is in an off state resulting in reduced luminosity of the light source, and supplying additional power to the light source to compensate for the reduced luminosity of the light source by the duty cycle.

Claims

1. A method for modifying a beacon light source for use in a light-based positioning system, the method comprising:

selecting a modulation scheme for the light source;

determining a duty cycle for the light source based on the modulation scheme, wherein the duty cycle comprises a proportion of time the light source is in an on state and a corresponding proportion of time the light source is in an off state, the proportion of time the light source is in an off state resulting in reduced luminosity of the light source; and

supplying additional power to the light source to compensate for the reduced luminosity of the light source by the duty cycle.

2. The method of claim 1, wherein a minimum proportion of time in an on state and a maximum proportion of time in an on state are determined by a sampling time of a light sensor and a desired modulation frequency of the light source.

3. The method of claim 2, wherein the minimum proportion of time in an on state comprises the desired modulation frequency multiplied by half of the sampling time of the light sensor.

4. The method of claim 2, wherein the maximum proportion of time in an on state comprises one minus the desired modulation frequency multiplied by half of the sampling time of the light sensor.

5. The method of claim 2, wherein the modulation frequency comprises between about 60 Hz and about 5000 Hz.

6. The method of claim 2, wherein the sampling frequency comprises between about 1 KHz and about 1 MHz.

7. The method of claim 1, wherein the additional power results in the modulated light source having substantially the same luminosity as an un-modulated light source.

8. The method of claim 1, wherein the additional power supplied does not exceed a manufacturer'"'"'s specifications for current and voltage applied to the modulated light source.

9. The method of claim 1, wherein the light source comprises a light-emitting diode (LED).

10. A modified beacon light source for use in a light-based positioning system comprising:

an emitter with a luminosity broadcasting a modulated signal with a duty cycle;

a modulator for receiving a modulation scheme for the light source and determining the duty cycle based on the modulation scheme, wherein the duty cycle comprises a proportion of time the light source is in an on state and a corresponding proportion of time the light source is in an off state, the proportion of time the light source is in an off state resulting in reduced luminosity of the light source; and

a power input for supplying additional power to the emitter to compensate for the reduced luminosity of the emitter by the duty cycle.

11. The light source of claim 10, wherein a minimum proportion of time in an on state and a maximum proportion of time in an on state are determined by a sampling time of a light sensor and a desired modulation frequency of the emitter.

12. The light source of claim 11, wherein the minimum proportion of time in an on state comprises the desired modulation frequency multiplied by half of the sampling time of the light sensor.

13. The light source of claim 11, wherein the maximum proportion of time in an on state comprises one minus the desired modulation frequency multiplied by half of the sampling time of the light sensor.

14. The light source of claim 11, wherein the modulation frequency comprises between about 60 Hz and about 5000 Hz.

15. The light source of claim 11, wherein the sampling frequency comprises between about 1 KHz and about 1 MHz.

16. The light source of claim 10, wherein the additional power results in the emitter having substantially the same luminosity as an emitter not broadcasting a modulated signal.

17. The light source of claim 10, wherein the additional power supplied does not exceed a manufacturer'"'"'s specifications for current and voltage applied to the light source.

18. The light source of claim 10, wherein the emitter comprises a light-emitted diode (LED).