A Method of Automatic Focus Adjustment Based on Frequency Domain Comparison Method

Abstract

The invention relates to a method for automatically adjusting focus based on a frequency domain comparison method, which includes the following process: a computer controls a mechanical telescopic lens barrel, adjusts the position of a digital camera, or an imaging aspheric lens, or a microscopic objective lens, and adjusts one side of the telescopic lens barrel Carry out telescopic movement, the camera shoots while acquiring K image data I 0 ,...,I i ,...,I j ,...,I k‑1 , After obtaining the telescopic position of the mechanical lens barrel for focusing through a series of calculations, and controlling the telescopic position of the mechanical lens barrel to this position, automatic focusing can be realized. Through the comparison and analysis of frequency domain components, it is possible to avoid the negative impact of image noise on the accuracy of automatic focus adjustment, and it is more suitable for automatic focus adjustment of transmission imaging, especially for the microvessels inside the human skin under non-invasive conditions, whose shape and distribution have special characteristics. The periodicity is more obvious in the frequency domain, so the automatic focus adjustment of the present invention is more accurate. In terms of device operation, this method is more convenient and easy to use in practice.

Description

technical field [0001] The invention relates to the field of image processing, in particular to a method for automatically adjusting focus based on a frequency domain comparison method. Background technique [0002] Micro-lens systems and cameras can realize image acquisition, but during the image acquisition process, due to the problem of inaccurate focus, the acquired image will be blurred, which cannot achieve the meaning of image acquisition. Therefore, the adjustment of focus is very important. [0003] In order to facilitate the user to adjust the focus and improve the use efficiency of the equipment, a telescopic lens barrel with mechanical brake is added to the equipment. The distance between the micro-objective and the aspheric lens used for imaging. Although the telescopic lens barrel with mechanical brake can reduce the complexity of equipment focusing to a certain extent, it is still difficult for users who have no experience in microscopic observation to confi...

AI Technical Summary

Problems solved by technology

In the existing image contrast automatic focus adjustment methods, most of the image edge detection algorithms such as Laplacian image filter are used to realize the automatic detection of sharpness. It is also very sensitive to noise, so accurate automatic focus adjustment cannot be achieved in noisy image situations such as imaging the interior of an object through a surface

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