Automatic focusing method

An automatic focusing and defocusing technology, which is applied to TVs, color TV parts, electrical components, etc., can solve problems such as large number of points, insignificant changes in high-frequency components, and small changes in image definition evaluation function values. , to achieve the effect of distinguishing sensitivity and improving accuracy

Inactive Publication Date: 2015-09-16
LASER FUSION RES CENT CHINA ACAD OF ENG PHYSICS
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Problems solved by technology

However, in digital images, we can only obtain corresponding discrete point values, so the number of points obtained at certain frequencies is large, and the number of points obtained at certain frequencies is small. If the above method is used, it cannot truly reflect the changes of high-frequency components.
Moreover, when the above method is seriously defocused, the high-frequency components of the image are very small, and the change of the high-frequency components w

Method used

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Embodiment 1

[0021] Such as figure 1 As shown, in the automatic focusing system based on image processing, the focusing unit is a motor, the imaging unit is a lens and a charge-coupled device (CCD), and the image processing unit is a microcomputer (PC). After the imaging unit is imaged, the system collects the image and inputs it into the PC, and the PC calls the image definition evaluation function to obtain the value of the image definition evaluation function to evaluate the corresponding focus, defocus and defocus amount, and then the PC gives The motor sends commands to adjust the focus using the hill climbing method. When the value of the image definition evaluation function takes the maximum value, the system is in focus.

[0022] The image sharpness evaluation function is the ratio of the amplitude sum of the high-frequency components and the amplitude sum of the low-frequency components of the image. The sum of the amplitudes of the high-frequency components is the sum of the amp...

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Abstract

The invention discloses an automatic focusing method, comprising the steps as follows: collecting an image; an image processing unit using a definition evaluation function value to evaluate defocusing amount, and controlling a focusing unit to focus according to the defocusing amount, wherein the image definition evaluation function value is a specific value of a high-frequency component amplitude and a low frequency component amplitude, and the frequency of a low frequency component is less than that of a high-frequency component, and the proportion that the low frequency component occupies the number of all frequency components obtained by calculating is 3 to 6 percents. The method of the invention improves sensitivity and accuracy of the image definition evaluation function value at a server defocusing place so as to be beneficial to realize fast and accurate automatic focusing.

Description

technical field [0001] The present invention relates to the technical field of automatic focusing based on image processing of an imaging system, in particular to an automatic focusing method. Background technique [0002] A clear image can correctly reflect the observed things, so that people can get accurate information. The imaging system is an effective tool for image acquisition. However, if the imaging system is out of focus, the image will be blurred. Therefore, it is necessary to adjust the focus so that the system is in focus to obtain a clear image. Due to its strong subjectivity and low efficiency, manual focusing has given birth to the vigorous development of automatic focusing. Nowadays, most imaging devices such as mobile phone cameras, digital cameras, video cameras, microscopes, and space telescopes require and use automatic focusing systems. [0003] Autofocus is the process of first evaluating the defocus amount of the system, and then controlling the foc...

Claims

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Application Information

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IPC IPC(8): H04N5/232
Inventor 刘仁德胡东霞邓学伟赵军普杨英代万俊张鑫袁强王德恩薛峤张小璐
Owner LASER FUSION RES CENT CHINA ACAD OF ENG PHYSICS
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