Method for automatically adjusting focus based on frequency domain comparison method

Abstract

The invention relates to a method for automatically adjusting focus based on a frequency domain comparison method. The method comprises the steps that a computer controls a mechanical telescoping lens barrel and adjusts the position of either a digital camera, or an imaging aspherical lens or a microobjective, on one hand the telescoping lens barrel conducts telescoping movement, and on the other hand the camera conducts shooting, so that K picture data I0,..., Ii,..., Ik-1 is obtained, the telescoping position of the mechanical telescoping lens barrel when focusing is needed is obtained through a series of calculation, and automatic focusing can be achieved by making the mechanical telescoping lens barrel telescope to the telescoping position. Through comparison and analysis of frequency domain components, harmful effects brought by picture noise on automatic focus adjusting precision can be avoided. The method for automatically adjusting focus based on the frequency domain comparison method is more suitable for automatic focus adjusting of transmission imaging, particularly on a noninvasive condition in which capillaries inside the human skin have periodicity in shape and distribution, and have more obvious features in the frequency domain. By means of the method for automatically adjusting focus based on the frequency domain comparison method, the focus is more accurately automatically adjusted. In the aspect of operation of devices, the devices are simpler and thus easy to use practically.

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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