Image Frame Synchronization For Dynamic Image Frame Rate In Dual-Camera Applications

Patent metadata

Field	Value
Publication number	US-2016366398-A1
Application number	US-201615245177-A
Country	US
Kind code	A1
Filing date	Aug 24, 2016
Priority date	Sep 11, 2015
Publication date	Dec 15, 2016
Grant date	—

Abstract

Techniques and examples pertaining to frame synchronization for dynamic frame rate in dual-camera applications are described. A change in brightness in ambient lighting may be detected when an electronic apparatus operates in a dual-camera mode utilizing images captured by a first image sensor and a second image sensor. In response to the detected change in brightness in the ambient lighting, frame rates of the first image sensor and the second image sensor may be synchronized.

First claim

What is claimed is:

1 . A method, comprising:
detecting a change in brightness in ambient lighting when an electronic apparatus operates in a dual-camera mode utilizing images captured by a first image sensor and a second image sensor; and synchronizing frame rates of the first image sensor and the second image sensor responsive to the detecting.

2 . The method of claim 1 , wherein the synchronizing of the frame rates of the first image sensor and the second image sensor comprises:
determining, by a synchronization driver circuit, the first frame rate of the first image sensor, the second frame rate of the second image sensor, and a difference between the first frame rate and the second frame rate; communicating, by the synchronization driver circuit to an automatic exposure (AE) circuit, the first frame rate, the second frame rate, and the difference between the first frame rate and the second frame rate; adjusting, by the AE circuit, an exposure time associated with the first image sensor and the second image sensor from a first exposure time to a second exposure time responsive to the detecting; and providing, by the AE circuit to a synchronization driver circuit, an indication that the exposure time is adjusted.

3 . The method of claim 2 , wherein, responsive to the AE circuit adjusting the exposure time, the second frame rate of the second image sensor changes from a first value corresponding to the first exposure time to a second value corresponding to the second exposure time, and wherein the synchronizing of the frame rates of the first image sensor and the second image sensor further comprises:
adjusting, by the synchronization driver circuit, the first frame rate to match the second frame rate.

4 . The method of claim 1 , wherein the synchronizing of the frame rates of the first image sensor and the second image sensor comprises:
adjusting an exposure time associated with the first image sensor and the second image sensor from a first exposure time to a second exposure time responsive to the detecting, wherein, responsive to the adjusting of the exposure time, a second frame rate of the second image sensor changes from a first value corresponding to the first exposure time to a second value corresponding to the second exposure time; determining a difference between a first frame rate of the first image sensor and the second frame rate of the second image sensor; determining whether the difference between the first frame rate and the second frame rate is greater than a first threshold; responsive to a determination that the difference between the first frame rate and the second frame rate is greater than the first threshold, determining whether the difference between the first frame rate and the second frame rate is less than a second threshold which is greater than the first threshold; and responsive to a determination that the difference between the first frame rate and the second frame rate is less than the second threshold and greater than the first threshold, adjusting the first frame rate to match the second frame rate.

5 . The method of claim 4 , wherein the synchronizing of the frame rates of the first image sensor and the second image sensor further comprises:
responsive to a determination that the difference between the first frame rate and the second frame rate is less than the first threshold or greater than the second threshold, monitoring a change in the difference between the first frame rate and the second frame rate; and adjusting the first frame rate to match the second frame rate upon the difference between the first frame rate and the second frame rate falling within a range between the first threshold and the second threshold.

6 . The method of claim 1 , wherein the synchronizing of the frame rates of the first image sensor and the second image sensor comprises:
adjusting an exposure time associated with the first image sensor and the second image sensor from a first exposure time to a second exposure time responsive to the detecting.

7 . The method of claim 6 , wherein, responsive to the adjusting of the exposure time, a second frame rate of the second image sensor changes from a first value corresponding to the first exposure time to a second value corresponding to the second exposure time, and wherein the synchronizing of the frame rates of the first image sensor and the second image sensor further comprises:
determining a first frame rate of the first image sensor, the second frame rate of the second image sensor, and a difference between the first frame rate and the second frame rate; and adjusting the first frame rate to match the second frame rate.

8 . A method, comprising:
launching a dual-camera application that utilizes images captured by a first image sensor and a second image sensor; detecting a change in brightness in ambient lighting; and synchronizing a first frame rate of the first image sensor and a second frame rate of the second image sensor responsive to the detecting.

9 . The method of claim 8 , wherein the synchronizing comprises:
determining a change in the second frame rate as a result of a change in an exposure time due to the detected change in brightness in the ambient lighting; and adjusting the first frame rate to synchronize the first frame rate and the second frame rate.

10 . The method of claim 9 , wherein the adjusting of the first frame rate to synchronize the first frame rate and the second frame rate comprises:
determining a difference between the first frame rate and the second frame rate; determining whether the difference between the first frame rate and the second frame rate is greater than a first threshold; responsive to a determination that the difference between the first frame rate and the second frame rate is greater than the first threshold, determining whether the difference between the first frame rate and the second frame rate is less than a second threshold which is greater than the first threshold; and responsive to a determination that the difference between the first frame rate and the second frame rate is less than the second threshold and greater than the first threshold, adjusting the first frame rate to match the second frame rate.

11 . The method of claim 10 , wherein the adjusting of the first frame rate to synchronize the first frame rate and the second frame rate further comprises:
responsive to a determination that the difference between the first frame rate and the second frame rate is less than the first threshold or greater than the second threshold, monitoring a change in the difference between the first frame rate and the second frame rate; and adjusting the first frame rate to match the second frame rate upon the difference between the first frame rate and the second frame rate falling within a range between the first threshold and the second threshold.

12 . The method of claim 9 , wherein the adjusting of the first frame rate to synchronize the first frame rate and the second frame rate comprises:
determining the first frame rate, the second frame rate, and a difference between the first frame rate and the second frame rate; and adjusting the first frame rate to match the second frame rate.

13 . The method of claim 8 , wherein the synchronizing comprises:
determining, by a synchronization driver circuit, the first frame rate of the first image sensor, the second frame rate of the second image sensor, and a difference between the first frame rate and the second frame rate; communicating, by the synchronization driver circuit to an automatic exposure (AE) circuit, the first frame rate, the sec

Assignees

• Mediatek Inc

Inventors

• Chen Chih-Kai
• Wu Tung-Hai
• Chan Cheng-Che
• Liu Jung-Mao

Classifications

• H04N23/76

  by influencing the image signals · CPC title

• H04N23/73

  by influencing the exposure time · CPC title

• H04N23/71

  Circuitry for evaluating the brightness variation · CPC title

• H04N23/60 Primary

  Control of cameras or camera modules · CPC title

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title