Low power glare sensor

• US 7,586,079 B2
• Filed: 05/13/2006
• Issued: 09/08/2009
• Est. Priority Date: 05/13/2005
• Status: Active Grant

• Current Assignee: Dynamic Fax Inc., The Research Foundation for The State University of New York (State University of New York)
• Original Assignee: Dynamic Fax Inc.
• Inventors: Bhagavathula, Kiriti, Mullin, Christopher, Titus, Albert H.
• Primary Examiner(s): Epps; Georgia Y
• Assistant Examiner(s): WILLIAMS, DON J
• Application Number:
  US11/434,599
• Publication Number:
  US 20070012869A1
• Time in Patent Office: 1,214 Days
• Field of Search: 250/214.R, 250/201.1, 250/204, 250/206, 250/214.1, 250/214.D, 250/205, 333/181, 359/265, 359/267, 359/843, 359601-610, 385/12, 385/14, 385/101, 356300-303, 345/77, 345/84, 345/90, 219/121.61, 219/121.62
• US Class Current: 250/214.00R
• CPC Class Codes: G01J 1/1626 Arrangements with two photodetectors, the signals of which are compared
• CPC Class Codes: G01J 1/18 using comparison with a reference electric value
• CPC Class Codes: G01J 1/26 adapted for automatic variation of the measured or reference value regulation of light intensity G05D25/00
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G01J 2001/0276 Protection
• CPC Class Codes: H03F 2203/45674 the LC comprising one current mirror
• CPC Class Codes: H03F 3/082 with FET's H03F3/085 takes precedence
• CPC Class Codes: H03F 3/45183 Long tailed pairs H03F3/4521, H03F3/45237 take precedence

Abstract

The invention may be embodied as a glare detection system or as a method of detecting glare. In a system according to the invention, there may be a light receiving surface, a first input channel, a second input channel, a glare signaling circuit and a glare reducing circuit. The first input channel may provide an indication of the amount of light impinging on a first portion of the light receiving surface. The second input channel may provide an indication of the amount of light impinging on a second portion of the light receiving surface. The glare signaling circuit (“GSC”) may have a first input port in communication with the first input channel, a second input port in communication with the second input channel, a logic-or gate capable of producing an output signal when the logic-or gate detects that the first input channel or the second input channel indicates glare on the light receiving surface. The glare reducing circuit (“GRC”) may be in communication with the logic-or gate, and may be capable of reacting when the logic-or gate produces the output signal. For example, the GRC may react by determining where on the light receiving surface glare exists.

Claims

1. A glare detection system, comprising:

a light receiving surface;

a first input channel providing an indication of the amount of light impinging on a first portion of the light receiving surface;

a second input channel providing an indication of the amount of light impinging on a second portion of the light receiving surface;

a glare signaling circuit (“

GSC”

) having;

(a) a first input port in communication with the first input channel,

(b) a second input port in communication with the second input channel,

(c) a logic-or gate capable of producing an output signal when the logic-or gate detects that the first input channel or the second input channel indicates glare on the light receiving surface; and

a glare reducing circuit (“

GRC”

) in communication with the logic-or gate, the GRC being capable of reacting when the logic-or gate produces the output signal.

2. The glare detection system of claim 1, further comprising a glare determination circuit (“

GDC”

) having;

(a) an input in communication with the first input channel,

(b) a threshold input, and

(c) an output in communication with the GSC first input port, wherein the GDC provides a glare signal via the GDC output when the first input channel indication is not in an acceptable range relative to the threshold input.

3. The glare detection system of claim 2, wherein the GDC provides the glare signal when the first input channel indication is above the threshold input.

4. The glare detection system of claim 2, wherein the GDC accepts an analog signal at the GDC input and the glare signal is a digital signal.

5. The glare detection system of claim 2, further comprising circuitry for transmitting the glare signal to a switch which controls the provision of information from the first input channel to the GRC when the glare signal is received by the switch.

6. The glare detection system of claim 2, wherein a signal on the threshold input may vary with time.

7. The glare detection system of claim 2 wherein the first portion is comprised of at least two pixels, and if the logic-or gate does not detect glare on any of the pixels of the first portion, then information from the pixels is not transmitted beyond the GDC.

8. The glare detection system of claim 1, wherein the GRC reacts by determining where on the light receiving surface glare exists.

9. The glare detection system of claim 1, further comprising an apparatus that maintains the GRC in a low-power mode until the glare signal is provided.

10. The glare detection system of claim 9, wherein the apparatus places the GRC in the low-power mode after the glare signal has not been received for a predetermined amount of time.

11. The glare detection system of claim 1, wherein the light receiving surface includes pixels, and the first portion corresponds to one of the pixels.

12. The glare detection system of claim 1, wherein the light receiving surface includes an array of pixels, and the first portion corresponds to at least two pixels.

13. The glare detection system of claim 12, wherein the at least two pixels are arranged as a column of pixels.

14. A method of detecting glare, comprising:

providing a light receiving surface;

receiving a first indication of the amount of light impinging on a first portion of the light receiving surface;

receiving a second indication of the amount of light impinging on a second portion of the light receiving surface;

determining whether the first indication or the second indication indicates glare on the light receiving surface;

providing an output signal when the first indication or the second indication indicates glare on the light receiving surface, wherein the output signal does not indicate where on the light receiving surface glare exists; and

reacting to the output signal by determining where on the light receiving surface glare exists.

15. The method of claim 14, wherein determining whether glare is indicated on the light receiving surface, includes determining whether the first indication is in an acceptable range.

16. The method of claim 15, wherein the first indication is not in an acceptable range when the first input is greater than a threshold value.

17. The method of claim 16, wherein the threshold value may vary with time.

18. The method of claim 14, wherein the first indication is received in the form of an analog signal.

19. The method of claim 14, wherein the output signal is provided as a digital signal.

20. The method of claim 14, wherein the light receiving surface includes pixels, and the first portion corresponds to one of the pixels.

21. The method of claim 14, wherein the light receiving surface includes an array of pixels, and the first portion corresponds to at least two pixels in the array.

22. The method of claim 21, wherein the part of the may is a column of pixels.

23. The method of claim 21, wherein if glare is detected in the column, then information from pixels in the column is used to determine where on the light receiving surface glare exists.

24. A glare detection system, comprising:

a first light sensor having an output channel;

a second light sensor having an output channel;

a glare signaling circuit (GSC) having a first input in communication with the output channel of the first light sensor, and having a second input in communication with the output channel of the second light sensor, the GSC having a logic-or gate capable of providing an indication of glare when glare is detected on the first light sensor or the second light sensor.

25. The glare detection system of claim 24, further comprising a glare determination circuit (“

GDC”

) having;

(a) an input in communication with the first light sensor output channel,

(b) a threshold input, and

(c) an output in communication with the GSC first input, wherein the GDC provides a glare signal via the GDC output when the output channel of the first light sensor is not in an acceptable range relative to the threshold input.

26. The glare detection system of claim 25, wherein the GDC provides the glare signal when the first input channel indication is greater than a signal on the threshold input.

27. The glare detection system of claim 26, wherein the signal on the threshold input may vary with time.

28. The glare detection system of claim 25, wherein the GDC accepts an analog signal at the GDC input and the glare signal is a digital signal.

29. The glare detection system of claim 24, wherein the first light sensor includes at least two pixels.

30. The glare detection system of claim 29, wherein the at least two pixels are arranged as a column of pixels.

31. The glare detection system of claim 29 wherein if glare is indicated on the first light sensor, then information from the two pixels is used to determine where on the first light sensor glare exists.