Remote control systems that can distinguish stray light sources

• US 8,658,995 B2
• Filed: 12/14/2009
• Issued: 02/25/2014
• Est. Priority Date: 11/07/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven Porter, King, Nicholas Vincent, Kerr, Duncan Robert, Low, Wing Kong
• Primary Examiner(s): Sohn, Seung C
• Application Number:
  US12/637,246
• Publication Number:
  US 20100094585A1
• Time in Patent Office: 1,534 Days
• Field of Search: 250/226, 250/578.1, 340/825.72, 340/825.57, 345/158, 345/163, 345/169
• US Class Current: 250/578.1
• CPC Class Codes: G01J 1/16 using electric radiation detectors G01J1/20 takes precedence
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G08C 2201/32 Remote control based on movements, attitude of remote control device
• CPC Class Codes: G08C 23/04 using light waves, e.g. infrared
• CPC Class Codes: H04N 21/42204 User interfaces specially adapted for controlling a client device through a remote control device; Remote control devices therefor constructive details of casings for the remote control device H01H9/0235; user interfaces for controlling a tuning device of a television receiver through a remote control H03J9/00; remote control of peripheral devices connected to a television receiver through the remote control device of the television receiver H04B1/205
• CPC Class Codes: H04N 21/42221 Transmission circuitry, e.g. infrared [IR] or radio frequency [RF]

Abstract

Remote control systems that can distinguish predetermined light sources from stray light sources, e.g., environmental light sources and/or reflections are provided. The predetermined light sources can be disposed in asymmetric substantially linear or two-dimensional patterns. The predetermined light sources also can output waveforms modulated in accordance with one or more signature modulation characteristics. The predetermined light sources also can output light at different signature wavelengths.

Claims

1. A method for distinguishing a plurality of predetermined light sources from stray light sources, the method comprising:

providing light from the plurality of predetermined light sources, wherein the predetermined light sources are disposed in a target pattern;

generating photodetector data representative of detected light using a photodetector;

identifying a plurality of detected light sources from the photodetector data;

determining positional characteristics of the detected light sources using the photodetector data; and

selecting a subset of the detected light sources based on the positional characteristics and the target pattern.

2. The method of claim 1, wherein selecting the subset comprises choosing a predetermined number of the detected light sources, and wherein the predetermined number corresponds to the number of predetermined light sources.

3. The method of claim 1, wherein selecting the subset comprises identifying a derivative pattern of light sources from the plurality of detected light sources, and wherein the derivative pattern is indicative of the target pattern.

4. The method of claim 1, wherein selecting the subset comprises:

identifying a plurality of permutations of the detected light sources;

iteratively determining how well each of the permutations matches the target pattern; and

selecting one of the permutations as the subset of detected light sources.

5. The method of claim 1, wherein the target pattern comprises an asymmetric substantially linear pattern.

6. The method of claim 1, wherein the target pattern comprises a two-dimensional pattern that is asymmetric about at least one of a longitudinal axis and an axis orthogonal to the longitudinal axis.

7. The method of claim 1, further comprising determining the position of the photodetector with respect to the predetermined light sources using the subset of detected light sources.

8. A method for distinguishing at least one predetermined light source from stray light sources, wherein the at least one predetermined light source provides light exhibiting a signature modulation characteristic, the method comprising:

(a) accepting photodetector data from a photodetector, wherein the photodetector data is indicative of light detected by the photodetector;

(b) identifying one or more detected light sources from the photodetector data;

(c) determining a modulation characteristic for each of the one or more detected light sources;

(d) correlating the determined modulation characteristics to the signature modulation characteristic of the at least one predetermined light source; and

(e) identifying, based on the correlating, at least one of the detected light sources that approximate the signature modulation characteristic.

9. The method of claim 8, wherein determining a modulation characteristic comprises:

tracking the detected light sources for a predetermined number of frames; and

determining the modulation characteristics based on the tracking.

10. The method of claim 8, wherein correlating comprises computing at least one correlation coefficient for each of the detected light sources, and wherein the correlation coefficient indicates how well a modulation characteristic matches a signature modulation characteristic.

11. The method of claim 8, wherein identifying the one or more detected light sources comprises determining positional characteristics of each of the detected light sources.

12. The method of claim 8, further comprising:

repeating steps (a)-(e); and

comparing the at least one of the detected light sources identified in step (e) with a previous solution.

13. The method of claim 8, further comprising determining the position of the photodetector with respect to the at least one predetermined light source using the at least one of the detected light sources.

14. A system comprising:

a plurality of predetermined light sources each configured to emit light using different signature modulation characteristics, wherein the predetermined light sources are disposed in a target pattern;

at least one photodetector configured to detect light; and

a controller configured to identify the light associated with the predetermined light sources based on both the signature modulation characteristics and the target pattern.

15. The method of claim 14, wherein the target pattern comprises an asymmetric substantially linear pattern.

16. The method of claim 15, wherein the target pattern comprises a two-dimensional pattern that is asymmetric about at least one of a longitudinal axis and an axis orthogonal to the longitudinal axis.

17. The system of claim 14, wherein the predetermined light sources are each configured to turn ON and OFF in accordance with a respective signature modulation characteristic.

18. The system of claim 14, wherein the predetermined light sources are each configured to adjust a signal strength of an output waveform in a predetermined manner in accordance with a respective signature modulation characteristic.

19. The system of claim 14, wherein the signature modulation characteristic associated with each of the predetermined light sources comprises at least one of a predetermined frequency at which an output wavelength is modulated, a predetermined duty cycle at which an output waveform is modulated, and a phase shift.

20. The system of claim 14, wherein the at least one photodetector is further configured to demodulate photodetector data in accordance with the signature modulation characteristics.

21. The system of claim 14, wherein the at least one photodetector comprises a first photodetector and a second photodetector, and wherein the first photodetector is configured to detect a first wavelength in accordance with a first signature modulation characteristic and the second photodetector is configured to detect a second wavelength in accordance with a second signature modulation characteristic.

22. The system of claim 14, further comprising a remote control within which the at least one photodetector is disposed.

23. The system of claim 14, further comprising a display, wherein the predetermined light sources are disposed proximate to the display.

24. The system of claim 14, wherein the controller is further configured to determine the position of the at least one photodetector with respective to the predetermined light sources.