JPS58139107A - Automatic focusing method of optical microscope - Google Patents

Abstract

PURPOSE:To enable automatic focusing by the use of an ordinary objective lens part by projecting part of the diaphragm of an ordinary optical microscope with a TV camera, and operating the driving mechanism for the objective lens in such a way that the binary coded area of said part by an image processing unit is maximized. CONSTITUTION:When part of the diaphragm 23 of an optical microscope 22 is taken with a TV camera 24, part 33 of the diaphragm 23 appearing on the image screen 31 of a TV appears under shielded light and has therefore the darkest areas. The surface of specimens 21 is brighter than said areas. Thereupon, the electric video signal of the plane 31 is binary-coded with the electric video signal corresponding to the darkest area of the part 33 of the diaphragm 23 as a threshold value by an image processing unit 26 so that the darkest area is made level 1 and the other areas level 0. A driving mechanism 25 for an objective lens is so operated that the area of the level 1 is maximized, and if the movement of the objective lens is stopped where the area is max., that position is a focusing position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for automatically focusing an optical microscope toward a sample.

Conventionally, there was a method shown in FIG. 1 as a method for making these noodles. In the figure, (1) is the sample, (2) is the objective lens part of the optical microscope, (3) is the gas that is blown directly into the sample (1) blood through the objective lens part (2), and (4) is a pressure sensor that measures the direction of this gas (3), and (5) is an objective lens drive mechanism that moves the objective lens part (2) up and down by the pressure of gas (3) measured by this pressure sensor (4). be.

Next, a1'11. I will explain about it. Objective lens part (
The gas (3) flowing straight inside the objective lens part (
2) is released from the objective lens portion (2) and is blown onto the surface of the sample (1) to be focused. Gas (3) is supplied through an orifice. Gas (3
) is measured by the pressure sensor (4) for a total of 5II18.

When the focus is on the sample (1) surface (objective lens part (
The distance between the tip of 2) and the sample 11) is do), and the pressure of (3) is Po. If the focus is on the sample (1
) plane (distance is d, ), the flow of gas (3) released at the tip of objective lens portion (2) changes, and the pressure of gas (3) becomes p.

(kipo), therefore, a signal corresponding to the pressure difference ΔP (2Pt-Pa) measured and detected by the pressure sensor (4) is sent to the objective lens drive shaft mechanism (6), and the sign of the pressure difference Δp is The vertical movement of the objective lens part (2) according to Δp=.

If this is continued until the interval d becomes the interval, the focus will automatically be on the sample (1).

The conventional automatic focusing method of optical AM- adopts the method described above, so the shape and dimensions of the objective lens part (2) are adjusted to the fluid level in order to sensitively detect the difference in focus as a pressure difference in the gas (3). Must be considered based on mechanics1
There are disadvantages such as not being able to use the objective lens part of a normal optical microscope, and the disadvantage that the area of the sample (1) outside the field of view to be focused is carved by the pressure difference, making precise focusing difficult. Ta.

This invention was made in order to eliminate the drawbacks of the conventional methods as described above.2 Conventional optical microscopes.

It is an object of the present invention to provide a method that can automatically adjust the focus by using an 'rv camera image processing device.

An embodiment of the present invention will be described below with reference to the drawings. Kasu 2
In the figure, (c) is the sample, (b) is normal optics, 41
mkm, n are the apertures that this ordinary optical microscope has at -(2), (to) is the 'vV camera that converts the optical image magnified by the optical microscope #I@ into an electrical image, and @ is the optical Customer ad■
Objective lens drive mechanism that moves the objective lens up and down (to)
is an image processing device that processes electrical video signals from a 1゛V camera.

Next, the operation of the method of the present invention will be explained with reference to FIG. Figure 8 <a> shows the focus on the sample v.
TvlIII shows the TV plane (b) obtained with the TV camera when the aperture (2) is wide open (adjusted to the zero plane)
The sample (b) surface is projected on the i-plane 0η. If you close the aperture of the aperture (to) here, it will be Tv#lno+).

Not only the surface of the sample (b) but also part of the aperture (■) appears (Figure 8 (b)). Since the focus is set, the aperture (total)
Part (2) of the sample I2!9 is clearly imaged in the same way as the sample I2!9 side. However, when the focus shifts from the test surface, not only the four surfaces of the sample but also a part of the aperture ring become blurred and indistinct (Fig. 8(C)). This phenomenon is well known to ordinary optical observers. The method of the present invention applies this phenomenon. That is, the part of the aperture that appears on the TV screen 61 appears through light, so it has the darkest area.
Sample Ca1) The song is brighter than the area. Once, an image processing device (to) was used to process the wlt air gorge signal from the TV screen ψV,
The mosquito in the first part of the aperture is converted into 211aE as the electric video signal threshold corresponding to the piece area, and the most spraying area is
Rubel, other areas If 1 is set to '0 rubel, then
vsS (Figure 1) (d), (C) TVI@1niiGIl) which has been processed using the painting method of (f3). However, if you compare the area of the 'l level (3°) in the TVmiicn when it is in focus and the area of the 'l level of 81 when it is out of focus, you will notice that when it is placed horizontally, the part of the aperture block) is blurred. Therefore, it is smaller than the former (S+<SO). When the object is in focus, it is the maximum value of the instep level that can be obtained at a TV angle of -9 yen. Therefore, objective lens -d4 in FIG.
After moving the objective lens of the optical microscope (support) slightly upwards using the m-position, the #l Lebel surface mst of part 1 of the above-mentioned crest (2) is exposed to the TV camera ( Goods) 9 While measuring with the image processing device (to), move to F direction 11tllL
,,'1' When the level area 81 reaches so, if the objective lens drive mechanism is stopped, the focus can be automatically adjusted to the sample (C) surface.

In the above embodiment, the diaphragm (2) is equipped with an ordinary optical consultant, and the aperture is manually reduced to fit the image on the TV screen. It is also possible to vary the intensity. Also, the aperture (
Instead of 2), a part of the light shielding plate may be inserted at the position of the diaphragm 4, and the same effect as in the above embodiment can be obtained.

As described above, a part of the pattern of this invention - a normal optical microscope - is imaged with a TV camera, and the objective lens body aI is binarized by an image processing device so that th+width is maximized.
I! Since the A bridge is operated, a normal objective lens part can be used, and the area of the sample surface other than the field of view is not carved.
(I) Tight focusing (o) Sega valley gutter.

[Brief explanation of drawings]

Fig. 1 is a sectional view for explaining a conventional self-focusing method of an optical microscope, and Fig. 2 is a mlll diagram for explaining an automatic focusing method according to an embodiment of the present invention.
Figures (a) to <e> are TV screen views for explaining the operation zero effect of the automatic focusing method of the present invention. In the figure, @ is an optical microscope, @ is an aperture, (c) is a TV camera, I4 is an image processing device, (2) is an objective lens m movement mechanism,
C+a is the TV m side, and the confrontation is part of Shibori Shun m ``Or'
l is the area of a partial binarized image (s1 lebel) of the aperture (2). In FIG. 1, the same symbols indicate the same or phase tooth portions. Nobu Nishikino - Figure 1 Figure 2 Figure 3 Figure 3 (St) Procedural amendment (spontaneous) Director General of the Japan Patent Office 1. Display of 11 items Patent Application No. 1987-0101 2,
Title of invention Automatic focusing method 3 of optical convergence mirror
, Person making the amendment 6, Detailed explanation of the specification to be amended and brief explanation of the drawings -
6. The statement of contents of the amendment shall be amended as follows.

Claims (1)

[Claims] A part of the aperture of an optical microscope is imaged by a l'v camera. The optical system is characterized by converting only a part of the aperture image into a binarized image using an image processing device, and moving the original lens until the area of the binarized image is maximized. How to match.