System and method for improved camera flash

Patent metadata

Field	Value
Publication number	US-10409141-B2
Application number	US-201715710752-A
Country	US
Kind code	B2
Filing date	Sep 20, 2017
Priority date	Sep 20, 2017
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

Methods, systems, computer-readable media, and apparatuses for improved camera flash are presented. In some embodiments, a method includes performing an autofocus technique on a scene to obtain an autofocus output. The method also includes obtaining an ambient light measurement of the scene. The method further includes adjusting a sensitivity of an image sensor based at least in part on the autofocus output and the ambient light measurement. The method additionally includes, after adjusting the light sensitivity of the image sensor, illuminating the scene using a pre-flash.

First claim

What is claimed is:

1. A method, comprising:
performing an autofocus technique on a scene to obtain an autofocus output;
receiving light from the scene;
obtaining an ambient light measurement of the scene based on the received light;
adjusting a sensitivity of an image sensor based at least in part on the autofocus output and the ambient light measurement, wherein the sensitivity is adjusted to avoid saturation of the image sensor when illuminating the scene using a pre-flash at a first intensity;
after adjusting the sensitivity of the image sensor, illuminating the scene using the pre-flash at the first intensity;
determining a second intensity to use for a main flash, wherein the second intensity is greater than or equal to the first intensity;
illuminating the scene using the main flash at the second intensity; and
capturing, using the image sensor, the scene as illuminated by the main flash.

2. The method of claim 1 , wherein the autofocus output comprises an autofocus confidence value and a focus position pertaining to the scene.

3. The method of claim 2 , further comprising:
determining whether the autofocus confidence value is above a threshold confidence value; and
obtaining a focus position value from a look-up table (LUT), based at least in part on the focus position.

4. The method of claim 2 , further comprising:
determining whether the autofocus confidence value is below a threshold confidence value; and
in response to determining that the autofocus confidence value is below the threshold confidence value, not performing the adjusting step.

5. The method of claim 1 , wherein the autofocus output comprises a focus position pertaining to the scene.

6. The method of claim 1 , wherein the image sensor is housed within a camera device.

7. The method of claim 1 , wherein the autofocus technique comprises at least one of the following autofocus techniques: laser autofocus, phase detection autofocus, or contrast autofocus.

8. A system, comprising:
a lens;
a light source;
an image sensor coupled to a processor;
an ambient light sensor coupled to the processor and configured to receive light from a scene, wherein the processor is configured to:
perform an autofocus technique on the scene to obtain an autofocus output;
obtain an ambient light measurement of the scene based on the received light;
adjust a sensitivity of the image sensor based at least in part on the autofocus output and the ambient light measurement, wherein the processor adjusts the sensitivity to avoid saturation of the image sensor when illuminating the scene using a pre-flash at a first intensity;
after adjusting the sensitivity of the image sensor, illuminate the scene using the light source to produce the pre-flash at the first intensity;
determine a second intensity to use for a main flash, wherein the second intensity is greater than or equal to the first intensity;
illuminate the scene using the main flash at the second intensity; and
capture, using the image sensor, the scene as illuminated by the main flash.

9. The system of claim 8 , wherein the autofocus output comprises an autofocus confidence value and a focus position pertaining to the scene.

10. The system of claim 9 , wherein the processor is further configured to:
determine whether the autofocus confidence value is above a threshold confidence value; and
obtain a focus position value from a look-up table (LUT), based at least in part on the focus position.

11. The system of claim 9 , wherein the processor is further configured to:
determine whether the autofocus confidence value is below a threshold confidence value; and
in response to determining that the autofocus confidence value is below the threshold confidence value, not perform the adjusting step.

12. The system of claim 8 , wherein the autofocus output comprises a focus position pertaining to the scene.

13. The system of claim 8 , wherein the system is a camera device.

14. The system of claim 8 , wherein the autofocus technique comprises at least one of the following autofocus techniques: laser autofocus, phase detection autofocus, or contrast autofocus.

15. An apparatus, comprising:
means for performing an autofocus technique on a scene to obtain an autofocus output;
means for receiving light from the scene;
means for obtaining an ambient light measurement of the scene based on the received light;
means for adjusting a sensitivity of an image sensor based at least in part on the autofocus output and the ambient light measurement, wherein the sensitivity is adjusted to avoid saturation of the image sensor when illuminating the scene using a pre-flash at a first intensity;
means for, after adjusting the sensitivity of the image sensor, illuminating the scene using the pre-flash at the first intensity;
means for determining a second intensity to use for a main flash, wherein the second intensity is greater than or equal to the first intensity;
means for illuminating the scene using the main flash at the second intensity; and
means for capturing, using the image sensor, the scene as illuminated by the main flash.

16. The apparatus of claim 15 , wherein the autofocus output comprises an autofocus confidence value and a focus position pertaining to the scene.

17. The apparatus of claim 16 , further comprising:
means for determining whether the autofocus confidence value is above a threshold confidence value; and
in response to determining that the autofocus confidence value is below the threshold confidence value, means for not perform the adjusting step.

18. The apparatus of claim 15 , wherein the autofocus output comprises a focus position pertaining to the scene.

19. The apparatus of claim 15 , wherein the autofocus technique comprises at least one of the following autofocus techniques: laser autofocus, phase detection autofocus, or contrast autofocus.

20. One or more non-transitory computer-readable media storing computer-executable instructions that, when executed, cause one or more computing devices to:
perform an autofocus technique on a scene to obtain an autofocus output;
receive light from the scene;
obtain an ambient light measurement of the scene based on the received light;
adjust a sensitivity of an image sensor based at least in part on the autofocus output and the ambient light measurement, wherein the sensitivity is adjusted to avoid saturation of the image sensor when illuminating the scene using a pre-flash at a first intensity;
after adjusting the sensitivity of the image sensor, illuminate the scene using the pre-flash at the first intensity;
determine a second intensity to use for a main flash, wherein the second intensity is greater than or equal to the first intensity;
illuminate the scene using the main flash at the second intensity; and
capture, using the image sensor, the scene as illuminated by the main flash.

21. The non-transitory computer-readable media of claim 20 , wherein the autofocus output comprises an autofocus confidence value and a focus position pertaining to the scene.

22. The non-transitory computer-readable media of claim 21 , wherein the instructions that, when executed, further cause the one or more computing devices to:
determine whether the autofocus confidence value is above a threshold confidence value; and
obtain a focus position value from a look-up table (LUT), based at least in part on the focus position.

23. The non-transitory computer-reada

Assignees

• Qualcomm Inc

Inventors

• Nikhara Soman
• Kadambala Ravi Shankar
• Gummadi Bapineedu Chowdary

Classifications

• H04N23/67

  Focus control based on electronic image sensor signals · CPC title

• H04N23/65

  Control of camera operation in relation to power supply · CPC title

• H04N23/72

  Combination of two or more compensation controls · CPC title

• H04N23/73

  by influencing the exposure time · CPC title

• H04N23/56

  provided with illuminating means · CPC title