Automatic focusing method and device

Abstract

The invention discloses an automatic focusing method and device. The automatic focusing method comprises the following steps that illumination light emitted by a light source is reflected to pilot light in a sample; the pilot light is divided into first and second pilot light by semi-reflection semi-transmission, the reflected first pilot light is obtained behind a reflection light focusing position, and the reflected second pilot light is obtained in front of a transmitted light focusing position; a driving signal S is obtained by calculation; the defocusing quantity of the sample is calculated according to the driving signal S; and an object lens is driven to focus according to the defocusing quantity. The pilot light reflected by the sample is divided into two paths of pilot light, thetwo paths of pilot light are obtained in different positions, two signals are obtained after processing, the defocusing quantity of the sample is obtained by calculating a difference of the two signals, and the object lens is driven to implement accurate focusing after that the defocusing quantity is known. The focusing method and device simplify design of the optical path, signal calculating is simpler, the defocusing quantity can be calculated rapidly and accurately, and the object lens can be focused automatically, rapidly and accurately.

Description

technical field [0001] The invention relates to microscopic imaging technology, in particular to an automatic focusing method and device for a gene sequencer or a microscope. Background technique [0002] With the development of biotechnology, the requirements for microscopic imaging are getting higher and higher, and the target needs to be scanned and imaged. However, the depth of field of the objective lens with high magnification and large numerical aperture is very small, usually only a few microns, and the fluctuation of the sample surface has a great influence on the imaging, so a fast and high-precision real-time autofocus device is required. [0003] At present, the autofocus methods used in microscopes and gene sequencers are roughly divided into two types. One is to use image analysis methods to find the best focal plane. This method requires post-image processing. The disadvantage is that it is slow, and the cost of hardware and algorithms is high. , unable to fo...

AI Technical Summary

Problems solved by technology

However, the depth of field of the objective lens with high magnification and large numerical aperture is very small, usually only a few microns, and the fluctuation of the sample surface has a great impact on imaging, so a fast and high-precision real-time autofocus device is required

[0003] At present, the autofocus methods used in microscopes and gene sequencers are roughly divided into two types. One is to use image analysis methods to find the best focal plane. This method requires post-image processing. The disadvantage is that it is slow, and the cost of hardware and algorithms is high. , unable to focus in real time

Especially for gene sequencers, the chip has quenching properties, and it is not possible to take multiple pictures; the other is to use laser triangulation ranging method, the disadvantage of which is low accuracy

[0004] In the prior art, there is a focusing method that uses different algorithms to post-process the images after collecting multiple images, and then determines the position of the focal plane. The disadvantages of this method are high cost, slow speed, and inability to focus in real time.

[0005] Another focusing method in the prior art is to measure and calculate the vertical distance between the objective lens and the sample by a distance measuring sensor to realize automatic focus adjustment. The distance measuring sensor used in this method is located on the side of the objective lens. Short, the measuring beam cannot approach the objective lens

This method is actually delayed focusing, and the accuracy is not high

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