Balancing exposure and gain at an electronic device based on device motion and scene distance

Patent metadata

Field	Value
Publication number	US-10154190-B2
Application number	US-201715730278-A
Country	US
Kind code	B2
Filing date	Oct 11, 2017
Priority date	Oct 21, 2015
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

An electronic device balances gain and exposure at an imaging sensor of the device based on detected image capture conditions, such as motion of the electronic device, distance of a scene from the electronic device, and predicted illumination conditions for the electronic device. By balancing the gain and exposure, the quality of images captured by the imaging sensor is enhanced, which in turn provides for improved support of location-based functionality.

First claim

What is claimed is:

1. A method comprising:
generating, at an electronic device, one or more feature descriptors for one or more spatial features identified in imagery captured at one or more imaging sensors and one or more non-visual sensors of the electronic device, wherein each of the generated feature descriptors describes one or more of an orientation, gravity direction, and scale of one or more of the identified spatial features;
identifying, at the electronic device, motion of the electronic device based on the generated feature descriptors; and
balancing a gain and an exposure associated with the one or more imaging sensors based on the identified motion.

2. The method of claim 1 , wherein the one or more non-visual sensors comprise a gyroscope of the electronic device.

3. The method of claim 1 , wherein identifying motion based on the generated feature descriptors comprises:
identifying a first spatial feature based on a first image captured at the electronic device; and
identifying the motion based on a difference between a first position of the first spatial feature in the first image and a second position of the first spatial feature in a second image captured at the electronic device.

4. The method of claim 3 wherein identifying motion based on the generated feature descriptors comprises:
selecting the first spatial feature based on a distance of the first spatial feature from the electronic device.

5. The method of claim 1 , wherein balancing the gain and the exposure comprises:
balancing the gain and the exposure further based on a depth of a scene indicated by the imagery.

6. The method of claim 5 , further comprising:
identifying the depth of the scene based on information captured by a depth camera of the electronic device.

7. The method of claim 1 , wherein balancing the gain and the exposure comprises:
predicting an illumination based on the identified motion of the electronic device; and
balancing the gain and the exposure further based on the predicted illumination.

8. The method of claim 7 , wherein predicting the illumination comprises:
identifying a current pose of the electronic device based on the generated feature descriptors and based on data received from the one or more non-visual sensors;
predicting a future pose of the electronic device based on the identified motion of the electronic device; and
predicting the illumination based on the predicted future pose of the electronic device.

9. The method of claim 1 , wherein balancing the gain and the exposure comprises:
increasing the gain and reducing the exposure in response to an increase in motion of the electronic device; and
reducing the gain and increasing the exposure in response to a decrease in motion of the electronic device.

10. A method, comprising,
generating, at an electronic device, one or more feature descriptors for one or more spatial features identified in imagery captured at one or more imaging sensors of the electronic device, wherein each of the generated feature descriptors describes one or more of an orientation, gravity direction, and scale of one or more of the identified spatial features;
identifying, at the electronic device, one or more capture conditions for the one or more imaging sensors based on the one or more feature descriptors, the capture conditions comprising one or more of motion of the electronic device, a distance of the one or more spatial features from the electronic device, and an illumination in an environment of the electronic device; and
balancing a gain associated with the one or more imaging sensors and an exposure associated with the one or more imaging sensors based on the identified capture conditions.

11. The method of claim 10 , wherein identifying the distance of the one or more spatial features comprises:
identifying a first feature based on a first image captured at the electronic device; and
identifying the distance based on a matched known feature descriptor associated with the first feature.

12. The method of claim 10 , wherein balancing the gain and the exposure comprises:
balancing the gain and the exposure further based on the identified motion of the electronic device.

13. The method of claim 12 , wherein the identified motion comprises a rotational velocity of the electronic device.

14. An electronic device comprising:
an imaging sensor to capture imagery;
a gain control module to control a gain of the imaging sensor;
an exposure control module to control an exposure of the imaging sensor;
non-visual sensors to capture non-visual pose information for the electronic device; and
a processor to
generate one or more feature descriptors for one or more spatial features identified in imagery captured, wherein each of the generated feature descriptors describes one or more of an orientation, gravity direction, and scale of one or more of the identified spatial features;
compare the one or more generated feature descriptors to one or more known feature descriptors to identify a matched known feature descriptor;
identify motion of the electronic device based on the imagery and based on the non-visual pose information; and
balance the gain and the exposure based on the identified motion.

15. The electronic device of claim 14 , wherein the processor is to identify motion based on imagery by:
identifying a first feature based on a first image captured at the electronic device; and
identifying the motion based on a difference between a first position of the first feature in the first image and a second position of the first feature in a second image captured at the electronic device.

16. The electronic device of claim 15 , wherein the processor is to identify motion based on imagery by:
selecting the first feature based on a distance of the first feature from the electronic device.

17. The electronic device of claim 14 , wherein the processor is to balance the gain and the exposure by:
balancing the gain and the exposure further based on a depth of a scene indicated by the imagery.

18. The electronic device of claim 17 , wherein the processor is to:
identify the depth of the scene based on information captured by a depth camera of the electronic device.

19. The electronic device of claim 14 , wherein the processor is to balance the gain and the exposure by:
predicting an illumination based on the motion of the electronic device; and
balancing the gain and the exposure further based on the predicted illumination.

20. The electronic device of claim 19 , wherein the processor is to predict the illumination by:
identifying a current pose of the electronic device based on the imagery captured at the electronic device and based on received non-visual pose information;
predicting a future pose of the electronic device based on the identified motion of the electronic device; and
predicting the illumination based on the predicted future pose of the electronic device.

Assignees

• Google Llc

Inventors

• Hesch Joel
• Fung James

Classifications

• H04N23/6812

  based on additional sensors, e.g. acceleration sensors · CPC title

• H04N23/88

  for colour balance, e.g. white-balance circuits or colour temperature control · CPC title

• H04N23/684

  performed by controlling the image sensor readout, e.g. by controlling the integration time · CPC title

• H04N23/698

  for achieving an enlarged field of view, e.g. panoramic image capture · CPC title

• H04N23/6811

  based on the image signal · CPC title