Patent
Automatic focusing method in large defocus state
Wang Quanqiang
- 12 Jul 2019
2
TL;DR: In this article, an automatic focusing algorithm in a large defocus state was proposed to meet the requirement that an optical large-magnification zoom camera can be properly used in complex application scenarios of education recording and playing.
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Abstract: The invention provides an automatic focusing algorithm in a large defocus state so as to meet the requirement that an optical large-magnification zoom camera can be properly used in complex application scenarios of education recording and playing, video conferences and the like, simplify focusing operation of an operator during magnification changing and scenario switching, enhance product use experience, and promote application of an automatic focusing algorithm in a real scenario. The method comprises the following steps: step 1, respectively calculating a high-frequency domain image definition value FV1 and a low-frequency domain image definition value FV2 by using high-pass filtering and low-pass filtering; step 2, judging whether the image is in a large defocus state according to theFV1 and the FV2; step 3, starting an automatic focusing algorithm in the large defocus state by utilizing the delta(FV); and step 4, an automatic focusing algorithm is as follows: (1) analyzing an initial search direction; and (2) changing the forward speed of the Focus motor frame by frame by using FV1, determining the position of the Focus motor corresponding to the clearest image after repeatedly returning the motion direction of the Focus motor based on a hill climbing algorithm, i.e., the fixed focus.
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Citations
Patent
Automatic focusing method for human face region in high-magnification shallow depth-of-field state
Wang Quanqiang,Liu Hongyan,Mao Haibin +2 more
- 19 May 2020
TL;DR: In this article, the authors proposed an automatic focusing method for a human face region in a high-magnification shallow depth-of-field state, which can perform human face detection, region optimization and automatic focusing in a camera product with insufficient computing power.
Patent
Automatic focusing method, blood cell analyzer and computer readable storage medium
Zheng Luyi,Hu Shuang,Liu Lei,Cai Tao +3 more
- 14 Feb 2020
TL;DR: In this paper, an automatic focusing method, a blood cell analyzer and a computer readable storage medium are presented. But the method comprises the steps of resetting after starting; moving an objective table downwards by a first preset amplitude, and determining a next direction according to image definition before and after movement; moving the objective table by the second preset amplitude in a determined direction; and if yes, continuing to move the objective tables by the third amplitude for a preset numberof times in a direction opposite to the moving direction of the last second amplitude; and obtaining a focused image according to
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Patent
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TL;DR: In this article, an image definition evaluation function is designed on the basis of improved discrete cosine transformation (DCT) to represent detail information of the image and highlight high frequency energy, and the relative definition is brought in by consideration of a close relation between the definition of an image and the brightness and the gray scale of the images.
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TL;DR: In this paper, a method and device for focusing a camera is described, where the sizes, positions and priorities of two focusing windows can be set to solve errors of a lens structure, so that the searching speed and accuracy of the optimized focusing position can be improved.
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Patent
Zooming tracking method and apparatus
Sun Shaohui
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TL;DR: In this paper, a zooming tracking method consisting of dividing a simulated zooming curve of a Zooming motor into a first zooming zone, a second Zooming zone and a third Zooming Zone is presented.
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Patent
Method and device for triggering camera to perform automatic focusing
Li Kai
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TL;DR: In this article, a method and device for triggering a camera to perform automatic focusing is presented, which includes the following steps that: the values of the focusing definition and the brightness values of each frame of an image in a plurality of continuous frames of images are obtained; whether a scene changes is judged according to the value of focusing definitions and brightness values; the change rate of the definition of focusing definition is determined according to brightness values, and if the definition is larger than a change rate threshold value, it is judged that an image is moving; and when the scene changes, the
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Patent
Improved Sobel operator based dynamic automatic focusing algorithm
Lou Xiaoping,Chu Xiang,Meng Xiaochen,Zhu Lianqing,Dong Mingli,Pan Zhikang,Fan Fan +6 more
- 08 Mar 2017
TL;DR: In this article, an improved Sobel operator based dynamic automatic focusing algorithm is described, where the actual focusing implementation process comprises the steps of searching a in large-step manner towards a current increasing direction within a drive current range of a liquid varifocal lens when a system starting position is located at a remote focus, and recording a corresponding evaluation function value.
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