Image device auto exposure

Patent metadata

Field	Value
Publication number	US-10757342-B1
Application number	US-201815962314-A
Country	US
Kind code	B1
Filing date	Apr 25, 2018
Priority date	Apr 25, 2018
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

An auto exposure method for an image capture device includes the steps of gathering ambient light data using an ambient light sensor of the image capture device, selecting a frame rate corresponding to the gathered ambient light data, and determining an optimal image capture frame rate for the image capture device. The auto exposure method determines the optimal image capture frame rate by executing an auto exposure algorithm with a processor using the selected frame rate as an initialization parameter for the auto exposure algorithm.

First claim

What is claimed is:

1. An auto exposure method for an image capture device having an ambient light sensor and an imager separate from the ambient light sensor, the method comprising:
gathering ambient light data using the ambient light sensor of the image capture device;
selecting a frame rate corresponding to the gathered ambient light data;
determining optimal image capture parameters including sensor gain and exposure time for the imager of the image capture device by executing an auto exposure algorithm with a processor using the selected frame rate as an initialization parameter for the auto exposure algorithm and then using iteratively gathered imaging data from the imager by the auto exposure algorithm to determine the optimal image capture parameters for the imager, wherein the ambient light data corresponding to the selected frame rate is gathered prior to execution of the auto exposure algorithm.

2. The method of claim 1 , further comprising:
iteratively gathering imaging data using an imager of the image capture device at the selected frame rate; and
determining the optimal image capture parameters by utilizing the selected frame rate as the initialization parameter and utilizing the iteratively gathered imaging data, the auto exposure algorithm executed by the processor to compare the iteratively gathered imaging data to a threshold value and to determine the optimal image capture parameters upon the iteratively gathered imaging data conforming to the threshold value.

3. The method of claim 1 , wherein the selecting step comprises:
comparing the ambient light data to a plurality of ambient light ranges in a look up table, each ambient light range associated with a frame rate; and
selecting the frame rate corresponding to the ambient light range that encompasses the ambient light data.

4. The method of claim 3 , wherein the plurality of ambient light ranges includes at least two ambient light ranges, each of the plurality of ambient light ranges corresponding to a mode.

5. The method of claim 4 , wherein the plurality of ambient light ranges includes at least three ambient light ranges.

6. The method of claim 2 , further comprising:
iteratively determining, using the processor, an input signal strength from the gathered imaging data; and
converging the auto exposure algorithm utilizing the iteratively determined input signal strength.

7. The method of claim 6 , wherein the processor switches the imager to a record mode upon convergence of the auto exposure algorithm, the imager configured to gather data in real time during the record mode.

8. The method of claim 7 , further comprising activating the imager to capture at least one image.

9. The method of claim 8 , wherein the imager is activated by pressing a button on the image capture device.

10. The method of claim 1 , further comprising:
using the selected frame rate for capturing a still image.

11. An image capture device comprising:
an ambient light sensor configured to gather ambient light data;
an imager separate from the ambient light sensor and configured to capture an image; and
a processor configured to determine an optimal image capture frame rate for the imager by executing the following steps:
selecting a frame rate corresponding to the gathered ambient light data,
determining optimal image capture parameters including sensor gain and exposure time for the image capture device by executing an auto exposure algorithm with a processor using the selected frame rate as an initialization parameter for the auto exposure algorithm and then using iteratively gathered imaging data from the imager by the auto exposure algorithm to determine the optimal image capture frame rate, wherein the ambient light data corresponding to the selected frame rate is gathered prior to execution of the auto exposure algorithm;

wherein the imager is controlled by the processor to capture the image at the optimal image capture frame rate.

12. The image capture device of claim 11 , wherein the imager is further configured to iteratively gather imaging data at the selected frame rate; and
wherein the processor is further configured to determine the optimal image capture parameters by utilizing the selected frame rate as the initialization parameter and utilizing the iteratively gathered imaging data, the auto exposure algorithm executed to compare the iteratively gathered imaging data to a threshold value and to determine the optimal image capture parameters upon the iteratively gathered imaging data conforming to the threshold value.

13. The image capture device of claim 11 , wherein the processor is further configured to:
compare the ambient light data to a plurality of ambient light ranges in a look up table, each ambient light range associated with a frame rate, and
select the frame rate corresponding to the ambient light range that encompasses the ambient light data.

14. The image capture device of claim 13 , wherein the plurality of ambient light ranges includes at least two ambient light ranges, each of the plurality of ambient light ranges corresponding to a mode.

15. The image capture device of claim 14 , wherein the plurality of ambient light ranges includes at least three ambient light ranges.

16. The image capture device of claim 12 , wherein the processor is further configured to:
iteratively determine, using the processor, an input signal strength from the gathered imaging data, and
converge the auto exposure algorithm utilizing the iteratively determined input signal strength.

17. The image capture device of claim 16 , wherein the processor is further configured to switch the imager to a record mode upon convergence of the auto exposure algorithm, the imager configured to gather data in real time during the record mode.

18. The image capture device of claim 11 , wherein the imager is configured to be activated by a depression of a button on the image capture device.

19. The image capture device of claim 11 , wherein the image capture device is eyewear.

20. The image capture device of claim 11 , wherein the processor is further configured to use the selected frame rate for capturing a still image with the imager.

Assignees

• Ding Bo
• Ryuma Dmitry
• Snap Inc

Inventors

• Ding Bo
• Ryuma Dmitry

Classifications

• H04N23/71 Primary

  Circuitry for evaluating the brightness variation · CPC title

• H04N23/72

  Combination of two or more compensation controls · CPC title

• H04N23/73 Primary

  by influencing the exposure time · CPC title

• G02B2027/0138

  comprising image capture systems, e.g. camera · CPC title

• G02B27/017

  Head mounted · CPC title