Automatic Zooming Method and Apparatus

• US 20180081257A1
• Filed: 03/27/2015
• Published: 03/22/2018
• 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
• Granted Patent: US 10,317,777 B2
• Time in Patent Office: 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

1-16. -16. (canceled)

17. An automatic zooming method, comprising:

determining a contour of a subject of a preview image;

determining a central point of the subject according to the preview image in a preview frame on a screen;

determining a zoom parameter according to a size of the contour of the subject and a size of the preview frame when the central point of the subject overlaps a central point of the preview frame,

wherein the zoom parameter comprises 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.

18. The method according to claim 17, 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 characteristic parameter of the preview image;

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

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

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

19. The method according to claim 17, 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 characteristic parameter of the preview image;

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

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

wherein the first preset template is a preset template in the at least one preset template, and

wherein the first sub-image block is a sub-image block in the at least one sub-image block of the first preset template.

20. The method according to claim 17, 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, wherein the prompt information is used to provide instructions to move the central point of the subject to the central point of the preview frame.

21. The method according to claim 17, wherein the method further comprises:

detecting definition of the preview image;

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

detecting whether perspective distortion occurs in the captured photograph of the preview image;

performing perspective correction on the captured photograph when perspective distortion occurs in the captured photograph; and

saving the corrected captured photograph.

22. The method according to claim 21, 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.

23. The method according to claim 18, wherein the shape of the at least one preset template is a circle, a rectangle, a triangle, a regular polygon, or an irregular polygon.

24. 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, wherein the instruction cause the processor to be configured to;

determine a contour of a subject of a preview image;

determine a central point of the subject according to the preview image in a preview frame on the display screen;

determine a zoom parameter according to a size of the contour of the subject and a size of the preview frame when the central point of the subject overlaps a central point of the preview frame,

wherein the zoom parameter comprises at least one of a to-be-adjusted focal length of a camera or a zoom factor of the preview image; and

zoom the camera according to the zoom parameter.

25. The portable electronic device according to claim 24, wherein the instructions further cause the processor to be configured to:

obtain a characteristic parameter of the preview image;

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

determine that a shape comprised in a first preset template is the subject of the preview image when the characteristic parameter of the preview image successfully matches a characteristic parameter of the first preset template in the at least one preset template, wherein the first preset template is a preset template in the at least one preset template; and

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

26. The portable electronic device according to claim 24, wherein the instructions further cause the processor to be configured to:

obtain a characteristic parameter of the preview image;

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

determine that a shape comprised in a first sub-image block of the first preset template is the subject of the preview image when the characteristic parameter of the preview image successfully matches a characteristic parameter of the first sub-image block in the at least one sub-image block of the first preset template in the at least one preset template,

wherein the first preset template is a preset template in the at least one preset template, and

wherein the first sub-image block is a sub-image block in the at least one sub-image block of the first preset template.

27. The portable electronic device according to claim 24, 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, wherein the prompt information is used to provide instructions to move the central point of the subject to the central point of the preview frame.

28. The portable electronic device according to claim 24, wherein the instructions further cause the processor to be configured to:

detect definition of the preview image;

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

detect whether perspective distortion occurs in the captured photograph of the preview image;

perspective correction on the captured photograph when perspective distortion occurs in the captured photograph; and

save the corrected captured photograph.

29. The portable electronic device according to claim 28, further comprising a detector coupled to the processor and 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.

30. The portable electronic device according to claim 25, wherein the shape of the at least one preset template is a circle, a rectangle, a triangle, a regular polygon, or an irregular polygon.

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

determine a contour of a subject of a preview image;

determine a central point of the subject according to the preview image in a preview frame on a screen;

determine a zoom parameter according to a size of the contour of the subject and a size of the preview frame when the central point of the subject overlaps a central point of the preview frame,

wherein the zoom parameter comprises at least one of a to-be-adjusted focal length of a camera or a zoom factor of the preview image; and

zoom the camera according to the zoom parameter.

32. The non-transitory computer readable medium according to claim 31, wherein the computer readable medium further causes the processor to:

obtain a characteristic parameter of the preview image;

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

determine that a shape comprised in a first preset template is the subject of the preview image when the characteristic parameter of the preview image successfully matches a characteristic parameter of the first preset template in the at least one preset template, wherein the first preset template is a preset template in the at least one preset template; and

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

33. The non-transitory computer readable medium according to claim 31, wherein the computer readable medium further causes the processor to:

obtain a characteristic parameter of the preview image;

separately match the characteristic parameter of the preview image with a characteristic parameter of at least one sub-image block of each preset template in at least one preset template that is stored in advance; and

determine that a shape comprised in a first sub-image block of the first preset template is the subject of the preview image when the characteristic parameter of the preview image successfully matches a characteristic parameter of the first sub-image block in the at least one sub-image block of the first preset template in the at least one preset template,

wherein the first preset template is a preset template in the at least one preset template, and

wherein the first sub-image block is a sub-image block in the at least one sub-image block of the first preset template.

34. The non-transitory computer readable medium according to claim 31, wherein the computer readable medium 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, wherein the prompt information is used to prompt a user to move the central point of the subject to the central point of the preview frame.

35. The non-transitory computer readable medium according to claim 31, wherein the computer readable medium further causes the processor to:

detect definition of the preview image;

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

detect whether perspective distortion occurs in the captured photograph of the preview image; and

perform perspective correction on the captured photograph when the perspective distortion occurs in the captured photograph; and

save the captured corrected photograph.

36. The non-transitory computer readable medium according to claim 35, wherein the computer readable medium 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.