Auto-focusing method and apparatus, electronic device, and medium

Patent metadata

Field	Value
Publication number	US-12549852-B2
Application number	US-202118260187-A
Country	US
Kind code	B2
Filing date	Dec 8, 2021
Priority date	Dec 30, 2020
Publication date	Feb 10, 2026
Grant date	Feb 10, 2026

Abstract

Provided are an auto-focusing method and apparatus, an electronic device, and a medium. The method includes: determining image block change information of a current frame image relative to a reference frame image in a scene monitoring area, where the scene monitoring area includes a pre-divided image effective area in a photographing picture; determining, according to the image block change information, whether to trigger a focusing operation on the scene monitoring area; and in response to determining to trigger the focusing operation, determining a focusing area of interest triggered by the movement of an object relative to the scene monitoring area, and performing the focusing operation on the focusing area of interest.

First claim

What is claimed is:

1 . An auto-focusing method, comprising:
determining image block change information of a current frame image relative to a reference frame image in a scene monitoring area, wherein the scene monitoring area comprises a pre-divided image effective area in a photographing picture; determining, according to the image block change information, whether to trigger a focusing operation on the scene monitoring area; and in response to determining to trigger the focusing operation, determining a focusing area of interest triggered by movement of an object relative to the scene monitoring area, and performing the focusing operation on the focusing area of interest; wherein the scene monitoring area comprises at least one image block, and determining the image block change information of the current frame image relative to the reference frame image in the scene monitoring area comprises: determining first image block feature information of the current frame image mapped at each image block location in the scene monitoring area and second image block feature information of the reference frame image mapped at each image block location in the scene monitoring area, respectively; and determining, according to the first image block feature information and the second image block feature information at each image block location, the image block change information of the current frame image relative to the reference frame image in the scene monitoring area; and wherein the first image block feature information and the second image block feature information each comprise an image block definition evaluation value and an image block color evaluation value, respectively, and the image block change information comprises a number of change blocks and a change trend evaluation value.

2 . The method of claim 1 , wherein determining, according to the first image block feature information and the second image block feature information at each image block location, the image block change information of the current frame image relative to the reference frame image in the scene monitoring area comprises:
determining, according to the first image block feature information and the second image block feature information at each image block location, an image block feature change value of the current frame image relative to the reference frame image at each image block location in the scene monitoring area; and in response to determining that an image block feature change value at any image block location is greater than or equal to a preset image block feature change threshold, using an image block at the any image block location as a change block, and counting a number of change blocks of the current frame image relative to the reference frame image in the scene monitoring area; wherein the image block feature change value is used for indicating a change of the image block definition evaluation value and a change of the image block color evaluation value.

3 . The method of claim 1 , wherein determining, according to the first image block feature information and the second image block feature information at each image block location, the image block change information of the current frame image relative to the reference frame image in the scene monitoring area comprises:
counting, according to the image block definition evaluation value indicated by the first image block feature information at each image block location and the image block definition evaluation value indicated by the second image block feature information at each image block location, a number of first change blocks of the current frame image relative to the reference frame image in the scene monitoring area and a number of second change blocks of the current frame image relative to the reference frame image in the scene monitoring area, wherein the first change blocks comprise an image block where an image definition evaluation value becomes small, and the second change blocks comprise an image block where an image definition evaluation value becomes large; and calculating, according to the number of the first change blocks, the number of the second change blocks and a number of image blocks in the scene monitoring area, the change trend evaluation value of the current frame image relative to the reference frame image in the scene monitoring area.

4 . The method of claim 3 , wherein the image block definition evaluation value comprises pieces of high-frequency information of the image blocks, wherein a piece of high-frequency information of each image block of the image blocks represents a degree of detail richness of the each image block such that a definition of the each image block is evaluated using the high-frequency information of the each image block.

5 . The method of claim 1 , wherein determining, according to the image block change information, whether to trigger the focusing operation on the scene monitoring area comprises:
determining, according to the number of the change blocks indicated by the image block change information, whether the scene monitoring area satisfies a first focusing condition, wherein the first focusing condition is used for determining whether a change degree of a photographing picture in the scene monitoring area is obvious; determining, according to the change trend evaluation value indicated by the image block change information, whether the scene monitoring area satisfies a second focusing condition, wherein the second focusing condition is used for determining whether a change trend of the photographing picture in the scene monitoring area is consistent; and determining, based on a determination result that the scene monitoring area satisfies both the first focusing condition and the second focusing condition, to trigger the focusing operation on the scene monitoring area.

6 . The method of claim 5 , further comprising:
not triggering, based on a determination result that the scene monitoring area satisfies the first focusing condition and does not satisfy the second focusing condition, the focusing operation on the scene monitoring area; and determining a location area where the object is located after the object moves in the scene monitoring area, and using the location area where the object is located after the object moves in the scene monitoring area as a new scene monitoring area; and determining, according to an intersection result of the new scene monitoring area and a pre-divided image core area in the photographing picture, whether to update the first focusing condition and the reference frame image for a next focusing monitoring phase.

7 . The method of claim 1 , wherein determining the focusing area of interest triggered by the movement of the object relative to the scene monitoring area comprises:
calculating, according to the image block color evaluation value indicated by the first image block feature information at each image block location and the image block color evaluation value indicated by the second image block feature information at each image block location, an image block color evaluation value change amount of the current frame image relative to the reference frame image at each image block location in the scene monitoring area; and using a location area where an absolute value of an image block color evaluation value change amount is greater than a preset color evaluation value change amount threshold in the scene monitoring area as the focusing area of interest triggered by the object; wherein the focusing area of interest comprises a location area where the object is located after the object moves into the scene monitoring area or a location area where the object is located before the object moves out of the scene monitoring area.

Assignees

• Zhejiang Uniview Tech Co Ltd

Inventors

• Gong Zhidong
• Shi Fei

Classifications

• H04N23/61

  based on recognised objects · CPC title

• G06T7/248

  involving reference images or patches · CPC title

• H04N23/62

  Control of parameters via user interfaces · CPC title

• H04N23/675 Primary

  comprising setting of focusing regions · CPC title

• H04N23/67 Primary

  Focus control based on electronic image sensor signals · CPC title