Image gray scale based automatic focusing method and its system

A technology of automatic focus and image grayscale, applied in the field of automatic focus based on image grayscale and its system, can solve the problems of inconvenientness and low measurement accuracy of automatic focus technology, and achieve improved detection quality and efficiency, automatic Easy and quick effect of focusing

Inactive Publication Date: 2008-07-09
THE 45TH RES INST OF CETC
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to provide an automatic focusing method and system based on image grayscale, to solve the technical problems of low measurement accuracy and inability to obtain accurate resolution easily and quickly in existing automatic focusing technology

Method used

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  • Image gray scale based automatic focusing method and its system
  • Image gray scale based automatic focusing method and its system
  • Image gray scale based automatic focusing method and its system

Examples

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Embodiment

[0042] Example: This automatic focusing method based on image grayscale:

[0043] As shown in Figure 1, use a glass plate 5 with a length of 30 mm, an interval of 1 mm on the lithography, and a width of 1 mm with accurate black stripes as a correction reference for focusing, and place it directly below the imaging system, and the black stripes on the glass plate The target surface of the line scan CCD must be strictly perpendicular to ensure the authenticity of the imaging data.

[0044] The image is captured by the lens, and the CCD imager, that is, the charge coupled device (charge coupled device), captures the image information of the glass plate stripes passing through the lens, and the image acquisition card inputs the image signal into the microprocessor, and the image information is converted into digital electronics. Signal, transforming the image information into a grayscale change curve. Figure 2 is a schematic diagram of the grayscale change curve of the black strip...

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Abstract

The invention relates to an automatic focusing method based on image grayscale and a system thereof, comprising the following steps of: using a glass plate with black stripes distributed thereon as a correction reference for focusing, the black stripes being vertical to a target surface; acquiring image information by a lens and a CCD imager, transmitting the image information to a motion control card, calculating the probable object and image positions for desired rate, and adjusting the lens and the CCD imager to the positions to acquire a clear image; scanning at the rate to obtain an image, using the average value of the grayscale of the image as the binary threshold, and calculating the rate of the lens according to the falling edge of the black stripes under the threshold; then adjusting the lens and the CCD imager to acquire a clear image again, and calculating the rate again; and repeating the above steps until acquiring the accurate rate and the clearest image. The method is simple, convenient, fast and accurate.

Description

(1) Technical field [0001] The invention relates to an automatic focusing optical imaging method and system thereof. (2) Background technology [0002] The existing auto-focus technology can be divided into two categories in principle: one is the distance measurement method based on the distance measurement between the lens and the object to be photographed, and the other is the focus detection method based on the clear image on the focusing screen . There are five commonly used focusing methods based on image evaluation: 1. High-frequency component method, that is, perform Fourier transform on the image and extract the high-frequency component as the focal length evaluation function. This method has a large amount of calculation and is not suitable for general situations. Fast, real-time measurement; 2. Smoothing method, that is, calculating the smoothness of adjacent pixels on the image, and then summing the entire image surface as the focus evaluation function, the maxim...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B7/36G02B7/28H04N5/232
Inventor 付纯鹤魏祥英连军莉黄晓鹏
Owner THE 45TH RES INST OF CETC
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