Method for obtaining a picture and multi-camera system

• US 9,866,766 B2
• Filed: 05/05/2016
• Issued: 01/09/2018
• Est. Priority Date: 02/18/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Urfalioglu, Onay, Cordara, Giovanni
• Primary Examiner(s): Giles, Nicholas
• Application Number:
  US15/147,482
• Publication Number:
  US 20160248988A1
• Time in Patent Office: 614 Days
• CPC Class Codes: G06T 2207/20021 Dividing image into blocks, subimages or windows
• CPC Class Codes: G06T 2207/30168 Image quality inspection
• CPC Class Codes: G06T 7/00 Image analysis
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 23/60 Control of cameras or camera modules
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• CPC Class Codes: H04N 23/951 by using two or more images to influence resolution, frame rate or aspect ratio

Abstract

A method and a multi-camera system for obtaining pictures with improved image quality. At least two cameras are used for each capturing an image, and a fast shooting mode is employed. The fast shooting mode may work in a preprocessing mode, in which the captured image of highest sharpness is acquired as a final picture, or may work in a post processing mode, in which multiple captured images are acquired, and are then post-processed to obtain a final picture of high image quality. In both modes it may be automatically determined, whether to activate the fast shooting mode or not. The determination is based on a relative movement of the multi-camera system to an object of interest, or is based on a shooting behavior of the user.

Claims

1. A method for obtaining a picture with a multi-camera system, the method comprising:

detecting a fast shooting mode condition;

capturing a first image with a first camera when the fast shooting mode condition is detected;

capturing a second image with a second camera when the fast shooting mode condition is detected;

evaluating a first sharpness of a first part of the first image;

evaluating a second sharpness of a second part of the second image;

setting a first exposure time for the first camera based on the first sharpness;

setting a second exposure time for the second camera based on the second sharpness;

capturing a third image with the first exposure time;

capturing a fourth image with the second exposure time; and

obtaining the picture based on the third image and the fourth image.

2. The method of claim 1, wherein the first exposure time is set longer than the second exposure time, when the first image is less sharp than the second image.

3. The method of claim 1, wherein evaluating the first sharpness and evaluating the second sharpness comprises iteratively measuring the first sharpness and the second sharpness.

4. The method of claim 1, wherein the fast shooting mode condition comprises an autofocus process being incomplete.

5. The method of claim 1, wherein the fast shooting mode condition comprises the multi-camera system is moving.

6. The method of claim 1, wherein the fast shooting mode condition comprises an object of interest is moving relative to the multi-camera system.

7. The method of claim 1, wherein the fast shooting mode condition comprises receiving a command for obtaining the picture being detected after a time period less than a predetermined threshold value, wherein the time period is measured from activating the multi-camera system.

8. A multi-camera apparatus for obtaining a picture, the multi-camera apparatus comprising:

a first camera;

a second camera;

a processor in communication with the first camera and the second camera;

the processor configured to;

detect a fast shooting mode condition;

evaluate a first sharpness of a first part of a first image captured by the first camera when the fast shooting mode condition is detected;

evaluate a second sharpness of a second part of a second image captured by the second camera when the fast shooting mode condition is detected;

set a first exposure time for the first camera based on the first sharpness;

set a second exposure time for the second camera based on the second sharpness; and

obtain the picture based on a third image captured with the first exposure time and a fourth image captured with the second exposure time.

9. The multi-camera apparatus of claim 8, wherein the first camera and the second camera comprise an overlapping field of view.

10. A non-transitory computer readable storage medium comprising program instructions that when executed by a processor of a multi-camera apparatus cause the multi-camera apparatus to:

detect a fast shooting mode condition;

evaluate a first sharpness of a first part of a first image captured by the first camera when the fast shooting mode condition is detected;

evaluate a second sharpness of a second part of a second image captured by the second camera when the fast shooting mode condition is detected;

set a first exposure time for the first camera based on the first sharpness;

set a second exposure time for the second camera based on the second sharpness; and

obtain the picture based on a third image captured with the first exposure time and a fourth image captured with the second exposure time.