Systems and methods for exposure control

Patent metadata

Field	Value
Publication number	US-10721409-B2
Application number	US-201916454152-A
Country	US
Kind code	B2
Filing date	Jun 27, 2019
Priority date	Dec 27, 2016
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

The present disclosure relates to systems and methods for exposure control. The systems and methods may obtain a target frame brightness value of the image. The systems and methods may also obtain an exposure mode of the electronic device. The systems and methods may also obtain an exposure table corresponding to the exposure mode. The systems and methods may also determine a target value, corresponding to the target frame brightness value, for each of the one or more exposure parameters based on the exposure table. The systems and methods may also adjust one or more of the at least one lens, the at least one exposure-time controller, and the at least one sensor according to the target values of the one or more exposure parameters.

First claim

What is claimed is:

1. A method for exposure control implemented on an electronic device having at least one lens to intake scenes, at least one exposure-time controller to control an exposure time, at least one sensor to detect a scene from the at least one lens during the exposure time, and at least one processor to receive electronic signals of an image relating to the scene from the at least one sensors during the exposure time, and control the at least one lens, the at least one exposure-time controller, and the at least one sensor, the method comprising:
obtaining, by the at least one processor, a target frame brightness value of the image;
obtaining, by the at least one processor, an exposure mode of the electronic device;
obtaining, by the at least one processor, an exposure table corresponding to the exposure mode, wherein the exposure table includes a plurality of parameter groups each of which includes a preset value of each of one or more exposure parameter of the capture device, the exposure table includes one or more parts in each of which the preset values of one of the one or more exposure parameters are different, and the preset values of each of the other exposure parameters are equal, respectively;
determining, by the at least one processor, a target value, corresponding to the target frame brightness value, for each of the one or more exposure parameters based on the exposure table; and
adjusting, by the at least one processor, one or more of the at least one lens, the at least one exposure-time controller, and the at least one sensor according to the target values of the one or more exposure parameters.

2. The method of claim 1 , wherein the determining of the target value, corresponding to the target frame brightness value, for each of the one or more exposure parameters based on the exposure table includes:
obtaining a relationship between the preset value for each of the one or more exposure parameters and a decibel (dB) value corresponding to the preset value;
for each preset value in the exposure table, determining a preset dB value based on the relationship;
for each of the plurality of parameter groups in the exposure table, determining a total dB value by determining a sum of preset dB values of the preset value of each of the one or more exposure parameters in the parameter group;
determining a target brightness dB value corresponding to the target frame brightness value; and
determining the target value for each of the one or more exposure parameters based on the total dB value for each of the plurality of parameter groups in the exposure table and the target brightness dB value.

3. The method of claim 2 , wherein the determining of the target value for each of the one or more exposure parameters based on the total dB value for each of the plurality of parameter groups in the exposure table and the target brightness dB value includes:
performing a bisection algorithm on the total dB value for each of the plurality of parameter groups in the exposure table based on the target brightness dB value.

4. The method of claim 2 , wherein the determining of the target brightness dB value corresponding to the target frame brightness value includes:
obtaining a current frame brightness value and a current value of each of the one or more exposure parameters;
determining a decibel difference between the current frame brightness value and the target frame brightness value;
determining a current dB value for each current value of the one or more exposure parameters based on the relationship; and
determining the target brightness dB value by determining a sum of the decibel difference and the current dB value for each current value of the one or more exposure parameters.

5. The method of claim 4 , wherein the decibel difference between the current frame brightness value and the target frame brightness value is determined based on a logarithm of a ratio of the target frame brightness value to the current frame brightness value.

6. A system for exposure control, comprising:
at least one lens to intake scenes;
at least one exposure-time controller to control an exposure time;
at least one sensor to detect a scene from the at least one lens during the exposure time; and
at least one processor to receive electronic signals of an image relating to the scene from the at least one sensors during the exposure time, and control the at least one lens, the at least one exposure-time controller, and the at least one sensor, wherein when executing a set of instructions, the at least one processor is directed to cause the system to:
obtain a target frame brightness value of the image;
obtain an exposure mode of the electronic device;
obtain an exposure table corresponding to the exposure mode, wherein the exposure table includes a plurality of parameter groups each of which includes a preset value of each of one or more exposure parameter of the capture device, the exposure table includes one or more parts in each of which the preset values of one of the one or more exposure parameters are different, and the preset values of each of the other exposure parameters are equal, respectively;
determine a target value, corresponding to the target frame brightness value, for each of the one or more exposure parameters based on the exposure table; and
adjust one or more of the at least one lens, the at least one exposure-time controller, and the at least one sensor according to the target values of the one or more exposure parameters.

7. The system of claim 6 , wherein to determine the target value, corresponding to the target frame brightness value, for each of the one or more exposure parameters based on the exposure table, the at least one processor is directed to cause the system to:
obtain a relationship between the preset value for each of the one or more exposure parameters and a decibel (dB) value corresponding to the preset value;
for each preset value in the exposure table, determine a preset dB value based on the relationship;
for each of the plurality of parameter groups in the exposure table, determine a total dB value by determining a sum of preset dB values of the preset value of each of the one or more exposure parameters in the parameter group;
determine a target brightness dB value corresponding to the target frame brightness value; and
determine the target value for each of the one or more exposure parameters based on the total dB value for each of the plurality of parameter groups in the exposure table and the target brightness dB value.

8. The system of claim 7 , wherein to determine the target value for each of the one or more exposure parameters based on the total dB value for each of the plurality of parameter groups in the exposure table and the target brightness dB value, the at least one processor is directed to cause the system to:
perform a bisection algorithm on the total dB value for each of the plurality of parameter groups in the exposure table based on the target brightness dB value.

9. The system of claim 7 , wherein to determine the target brightness dB value corresponding to the target frame brightness value, the at least one processor is directed to cause the system to:
obtain a current frame brightness value and a current value of each of the one or more exposure parameters;
determine a decibel difference between the current frame brightness value and the target frame brightness value;
determine a current dB value for each current value of the one or more exposure parameters based on the relationship; and
determine the target brightness dB value by determining a sum of the decibel difference and the current dB value for each current value of the one or more exposure

Assignees

• Zhejiang Dahua Technology Co

Inventors

• Zhou Yanfen
• Pan Runfa
• Li Liangcheng
• Huang Qianfeng
• Lu Erli
• Chen Mingzhu

Classifications

• H04N23/71

  Circuitry for evaluating the brightness variation · CPC title

• H04N23/741

  by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors · CPC title

• H04N23/73 Primary

  by influencing the exposure time · CPC title

• H04N23/72 Primary

  Combination of two or more compensation controls · CPC title

• H04N5/2353 Primary

  Electricity · mapped topic