Automatic zooming method and apparatus

• US 10,317,777 B2
• Filed: 03/27/2015
• Issued: 06/11/2019
• Est. Priority Date: 03/27/2015
• 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: Qin, Chao, Gao, Wenmei
• Primary Examiner(s): Haskins, Twyler L
• Assistant Examiner(s): Bhuiyan, Fayez
• Application Number:
  US15/561,361
• Publication Number:
  US 20180081257A1
• Time in Patent Office: 1,537 Days
• CPC Class Codes: G03B 13/36 Autofocus systems
• CPC Class Codes: G06T 1/0007 Image acquisition
• CPC Class Codes: G06T 2207/10148 Varying focus
• CPC Class Codes: G06T 2207/20116 Active contour; Active surface; Snakes
• CPC Class Codes: G06T 7/13 Edge detection
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: H04N 23/632 for displaying or modifying preview images prior to image capturing, e.g. variety of image resolutions or capturing parameters
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/80 Camera processing pipelines; Components thereof
• CPC Class Codes: H04N 5/2628 Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

An automatic zooming method and an apparatus includes determining a contour of a subject of a preview image and a central point of the subject according to the preview image in a preview frame on a screen; when the central point of the subject overlaps a central point of the preview frame, determining a zoom parameter according to a size of the contour of the subject and a size of the preview frame, where the zoom parameter includes at least one of a to-be-adjusted focal length of a camera or a zoom factor of the preview image; and zooming the camera according to the zoom parameter.

Claims

1. An automatic zooming method, comprising:

determining a contour of a subject of a preview image in a preview frame on a screen of an electronic device;

determining a central point of the subject of the preview image;

determining a zoom parameter according to a size of the contour of the subject of the preview image and a size of the preview frame when the central point of the subject of the preview image overlaps a central point of the preview frame, the zoom parameter comprising at least one of a to-be-adjusted focal length of a lens of a camera of the electronic device or a zoom factor of the preview image;

zooming the camera according to the zoom parameter;

detecting a definition of the preview image;

capturing a photograph of the preview image when the definition of the preview image meets a preset threshold;

detecting whether the photograph of the preview image includes perspective distortion;

performing perspective correction on the photograph of the preview image when the photograph of the preview image includes perspective distortion; and

saving the photograph of the preview image with the perspective correction.

2. The method of claim 1, wherein determining the contour of the subject of the preview image and the central point of the subject of the preview image in the preview frame on the screen comprises:

obtaining a first characteristic parameter of the preview image;

separately matching the first characteristic parameter of the preview image with a second characteristic parameter in at least one preset template that is prestored;

determining shape comprised in a first preset template of the at least one preset template is a shape of the subject of the preview image when the first characteristic parameter of the preview image matches the second characteristic parameter in the at least one preset template; and

determining the contour of the subject and the central point of the subject according to the first characteristic parameter of the preview image.

3. The method of claim 1, wherein determining the contour of the subject of the preview image and the central point of the subject according to the preview image in the preview frame on the screen comprises:

obtaining a first characteristic parameter of the preview image;

separately matching the first characteristic parameter of the preview image with a second characteristic parameter of at least one sub-image block in at least one preset template that is prestored; and

determining that a shape comprised in a first sub-image block of a first preset template of the at least one preset template is a shape of the subject of the preview image when the first characteristic parameter of the preview image matches the second characteristic parameter of the at least one sub-image block in the at least one preset template, and the first sub-image block being a sub-image block in the at least one sub-image block of the first preset template.

4. The method of claim 1, wherein before determining the zoom parameter according to the size of the contour of the subject and the size of the preview frame, the method further comprises:

displaying the central point of the subject and the central point of the preview frame in the preview image; and

displaying prompt information, the prompt information comprising instructions to move the central point of the subject to the central point of the preview frame.

5. The method of claim 1, wherein after capturing the photograph of the preview image, the method further comprises:

detecting whether the preview image is changed;

maintaining the zoom parameter of the camera to be unchanged when the preview image is not changed; and

restoring the zoom parameter of the camera to an initial value when the preview image is changed.

6. The method of claim 2, wherein the shape of the first preset template is a circle, a rectangle, a triangle, a regular polygon, or an irregular polygon.

18. The method of claim 3, wherein the shape of the first preset template is a circle, a rectangle, a triangle, a regular polygon, or an irregular polygon.

7. A portable electronic device, comprising:

a display comprising a touch-sensitive surface and a display screen;

a memory comprising instructions; and

a processor coupled to the memory and the display, the processor being configured to execute the instructions, the instructions causing the processor to be configured to;

determine a contour of a subject of a preview image in a preview frame on the display screen;

determine a central point of the subject of the preview image;

determine a zoom parameter according to a size of the contour of the subject of the preview image and a size of the preview frame when the central point of the subject of the preview image overlaps a central point of the preview frame, the zoom parameter comprising at least one of a to-be-adjusted focal length of a lens of a camera of the electronic device or a zoom factor of the preview image;

zoom the camera according to the zoom parameter;

detect a definition of the preview image;

capture a photograph of the preview image when the definition of the preview image detected meets a preset threshold;

detect whether the photograph of the preview image has perspective distortion;

perform perspective correction on the photograph of the preview image when the photograph of the preview image includes perspective distortion; and

save the photograph of the preview image with the perspective correction.

8. The portable electronic device of claim 7, wherein the instructions further cause the processor to be configured to:

obtain a first characteristic parameter of the preview image;

separately match the first characteristic parameter of the preview image with a second characteristic parameter in at least one preset template that is prestored;

determine that a shape within a first preset template of the at least one preset template is a shape of the subject of the preview image when the first characteristic parameter of the preview image matches the second characteristic parameter in the at least one preset template; and

determine the contour of the subject and the central point of the subject according to the first characteristic parameter of the preview image.

9. The portable electronic device of claim 7, wherein the instructions further cause the processor to be configured to:

obtain a first characteristic parameter of the preview image;

separately match the first characteristic parameter of the preview image with a second characteristic parameter of at least one sub-image block in at least one preset template that is prestored; and

determine that a shape within a first sub-image block of a first preset template of the at least one preset template is a shape of the subject of the preview image when the first characteristic parameter of the preview image matches the second characteristic parameter of the at least one sub-image block, and the first sub-image block being a sub-image block in the at least one sub-image block of the first preset template.

10. The portable electronic device of claim 7, wherein the instructions further cause the processor to be configured to:

display the central point of the subject and the central point of the preview frame in the preview image; and

display prompt information, the prompt information comprising instructions to move the central point of the subject to the central point of the preview frame.

11. The portable electronic device of claim 7, further comprising a detector coupled to the processor, the detector being configured to:

detect whether the preview image is changed;

maintain the zoom parameter of the camera to be unchanged when the preview image is not changed; and

restore the zoom parameter of the camera to an initial value when the preview image is changed.

12. The portable electronic device of claim 8, wherein the shape of the first preset template is a circle, a rectangle, a triangle, a regular polygon, or an irregular polygon.

19. The portable electronic device of claim 9, wherein the shape of the first preset template is a circle, a rectangle, a triangle, a regular polygon, or an irregular polygon.

13. A non-transitory computer readable medium including at least one computer program code stored for automatic zooming on a device associated with a computing device, the program code when executed on a processor, causes the processor to be configured to:

determine a contour of a subject of a preview image in a preview frame on a screen;

determine a central point of the subject of the preview image;

determine a zoom parameter according to a size of the contour of the subject of the preview image and a size of the preview frame when the central point of the subject of the preview image overlaps a central point of the preview frame, the zoom parameter comprising at least one of a to-be-adjusted focal length of a lens of a camera of the device or a zoom factor of the preview image;

zoom the camera according to the zoom parameter;

detect a definition of the preview image;

capture a photograph of the preview image when the definition of the preview image detected meets a preset threshold;

detect whether the photograph of the preview image has perspective distortion;

perform perspective correction on the photograph of the preview image when the photograph of the preview image includes perspective distortion; and

save the photograph of the preview image with perspective correction.

14. The non-transitory computer readable medium of claim 13, wherein the program code further causes the processor to be configured to:

obtain a first characteristic parameter of the preview image;

separately match the first characteristic parameter of the preview image with a second characteristic parameter in at least one preset template that is prestored;

determine that a shape within a first preset template is a shape of the subject of the preview image when the first characteristic parameter of the preview image matches the second characteristic parameter in the at least one preset template; and

determine the contour of the subject and the central point of the subject according to the first characteristic parameter of the preview image.

15. The non-transitory computer readable medium of claim 13, wherein the program code further causes the processor to:

obtain a first characteristic parameter of the preview image;

separately match the first characteristic parameter of the preview image with a second characteristic parameter in at least one sub-image block in at least one preset template stored; and

determine that a shape within a first sub-image block of a first preset template is a shape of the subject of the preview image when the first characteristic parameter of the preview image matches the second characteristic parameter in the at least one sub-image block in the at least one preset template, and the first sub-image block being a sub-image block in the at least one sub-image block of the first preset template.

16. The non-transitory computer readable medium of claim 13, wherein the program code further causes the processor to:

display the central point of the subject and the central point of the preview frame in the preview image; and

display prompt information, the prompt information comprising instructions to move the central point of the subject to the central point of the preview frame.

17. The non-transitory computer readable medium of claim 13, wherein the program code further causes the processor to:

detect whether the preview image is changed after capturing the photograph of the preview image;

maintain the zoom parameter of the camera to be unchanged when the preview image is not changed; and

restore the zoom parameter of the camera to an initial value when the preview image is changed.