Digital image capture under conditions of varying light intensity

Patent metadata

Field	Value
Publication number	US-9538090-B2
Application number	US-201514719752-A
Country	US
Kind code	B2
Filing date	May 22, 2015
Priority date	Jun 28, 2012
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

An approach is provided to adjust a camera shutter lag. In the approach, data is collected that corresponds to an ambient light found in a physical environment with the ambient light being controlled using a pulse-width modulation (PWM). The pulse-width modulation corresponds to a PWM timing model. When an exposure request is received, the camera shutter lag is calculated using the PWM timing model. The calculated shutter lag is based on a future point in time at which the ambient light of the physical environment is predicted to be at a selected light output level, such as a power level selected by the user of a camera. When the calculated camera shutter lag has expired, a shutter of the camera is opened causing a camera lens to be exposed that results in a captured exposure.

First claim

What is claimed is:

1. A method implemented by an information handling system to adjust a camera shutter lag, the method comprising:
identifying a pulse rate of an ambient light source;
creating a plurality of sample exposures, wherein each of the sample exposures is taken at a different point in an ambient light timing model corresponding to the ambient light source;
selecting a sample light output level in the ambient light timing model, wherein the selected sample light output level corresponds to one of the plurality of sample exposures;
setting a selected light output level to the selected sample light output level;
receiving an exposure request;
in response to receiving the exposure request:
calculating a camera shutter lag based on a future point in time at which the ambient light source is predicted to be at the selected light output level; and
opening a shutter of the camera after the calculated camera shutter lag has expired, the opening causing an exposure of a sensor that results in a captured exposure.

2. The method of claim 1 wherein the ambient light source is controlled using pulse-width modulation (PWM).

3. The method of claim 1 wherein the pulse rate flickers a light from the ambient light source in order to dim the light.

4. The method of claim 1 wherein the ambient light source is a florescent light source.

5. The method of claim 1 wherein the pulse rate is determined by a frequency of an alternating current power supply that powers the ambient light source.

6. The method of claim 1 wherein the exposure request is received from a user, and further comprising:
receiving a selection from the user, wherein the user selection corresponds to the one of the plurality of sample exposures.

7. The method of claim 2 wherein the ambient light source is a light emitting diode (LED) light source.

8. The method of claim 5 wherein the ambient light source is a florescent light source.

9. An information handling system to adjust a camera shutter lag, the information handling system comprising:
one or more processors;
a memory coupled to at least one of the processors;
a shutter controlled by at least one of the processors, wherein the shutter controls exposure of a photosensitive sensor; and
a set of instructions stored in the memory and executed by at least one of the processors, wherein the set of instructions perform actions comprising:
identifying a pulse rate of an ambient light source;
creating a plurality of sample exposures, wherein each of the sample exposures is taken at a different point in an ambient light timing model corresponding to the ambient light source;
selecting a sample light output level in the ambient light timing model, wherein the selected sample light output level corresponds to one of the plurality of sample exposures;
setting a selected light output level to the selected sample light output level;
receiving an exposure request;
in response to receiving the exposure request:
calculating a camera shutter lag based on a future point in time at which the ambient light source is predicted to be at the selected light output level; and
opening a shutter of the camera after the calculated camera shutter lag has expired, the opening causing an exposure of a sensor that results in a captured exposure.

10. The information handling system of claim 9 wherein the ambient light source is controlled using pulse-width modulation (PWM).

11. The information handling system of claim 9 wherein the pulse rate flickers a light from the ambient light source in order to dim the light.

12. The information handling system of claim 9 wherein the ambient light source is a florescent light source.

13. The information handling system of claim 9 wherein the pulse rate is determined by a frequency of an alternating current power supply that powers the ambient light source.

14. The information handling system of claim 9 wherein the exposure request is received from a user, and further comprising:
receiving a selection from the user, wherein the user selection corresponds to the one of the plurality of sample exposures.

15. The information handling system of claim 10 wherein the ambient light source is a light emitting diode (LED) light source.

16. The information handling system of claim 13 wherein the ambient light source is a florescent light source.

17. A computer program product stored in a non-transitory computer readable medium, comprising functional descriptive material that, when executed by an information handling system, causes the information handling system to perform actions comprising:
identifying a pulse rate of an ambient light source;
creating a plurality of sample exposures, wherein each of the sample exposures is taken at a different point in an ambient light timing model corresponding to the ambient light source;
selecting a sample light output level in the ambient light timing model, wherein the selected sample light output level corresponds to one of the plurality of sample exposures;
setting a selected light output level to the selected sample light output level;
receiving an exposure request;
in response to receiving the exposure request:
calculating a camera shutter lag based on a future point in time at which the ambient light source is predicted to be at the selected light output level; and
opening a shutter of the camera after the calculated camera shutter lag has expired, the opening causing an exposure of a sensor that results in a captured exposure.

18. The computer program product of claim 17 wherein the ambient light source is controlled using pulse-width modulation (PWM).

19. The computer program product of claim 17 wherein the pulse rate flickers a light from the ambient light source in order to dim the light.

20. The computer program product of claim 17 wherein the ambient light source is a florescent light source.

21. The computer program product of claim 17 wherein the pulse rate is determined by a frequency of an alternating current power supply that powers the ambient light source.

22. The computer program product of claim 17 wherein the exposure request is received from a user, and further comprising:
receiving a selection from the user, wherein the user selection corresponds to the one of the plurality of sample exposures.

23. The computer program product of claim 18 wherein the ambient light source is a light emitting diode (LED) light source.

Assignees

• IBM

Inventors

• Spielberg Anthony Cappa

Classifications

• H04N23/745

  Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination · CPC title

• H04N23/71 Primary

  Circuitry for evaluating the brightness variation · CPC title

• H04N23/73 Primary

  by influencing the exposure time · CPC title

• H04N23/74

  by influencing the scene brightness using illuminating means · CPC title

• H04N23/56

  provided with illuminating means · CPC title