GB2138240A

GB2138240A - Method to superimpose a reference standard onto the image of a microscope

Info

Publication number: GB2138240A
Application number: GB08407099A
Authority: GB
Inventors: Jurgen Tuente; Olaf Simon
Original assignee: Carl Zeiss AG
Current assignee: Carl Zeiss AG
Priority date: 1983-04-09
Filing date: 1984-03-19
Publication date: 1984-10-17
Also published as: GB2138240B; GB8407099D0; DE3312779C2; CH665034A5; DE3312779A1

Abstract

The method is intended for the quick judgement of microscopic specimens by an observer with the aid of standardized reference images. The reference standards to be superimposed, such as metallographic grain-size patterns (9) complying with ASTM or VDEh standards, are filed as digital information in a non-volatile memory (EPROM 8a-d). For display on the television screen (7) the desired standards are read out from the selected memory (8a) and as a television-compatible signal sequence mixed into the video signal of the camera which is mounted on the microscope (1). <IMAGE>

Description

SPECIFICATION Method to superimpose a reference standard onto the image of a microscope For a quick judgement of microscopic specimens, e.g. in metallographic or medical test series, a standard is generally superimposed onto the micro scopic image, which the observer compares with the specimen. Some of these standards are standardized. For polished-metal sections, for example, so-called grain-size patterns are available, which comply with ASTM and VDEh.

Such standards are known to be designed as so-called standard-series disks, i.e. eyepiece reticles on which the standard is engraved. The standardseries disks are combined in several turrets, which are exchangeably mounted on the microscope tube so that the plates can be swung into the microscope's intermediate-image plane.

According to the present state of the art the line figures are also designed as projection disks for a projection apparatus which is mounted on the microscope.

It is furthermore known from DE-PS 2407 270 that a reference standard in theform of a slide is brought into the microscope beam path by means of a separate projection system attached to the microscope.

All these known solutions have the disadvantages that manipulations are necessary in the microscope beam path, and, frequently, considerable accessory attachments and/or constructions. The manufacture of the standards often requires considerable outlay.

Furthermore, the exchange of the standards is time-consuming, and their storage not unproblematic.

For some time already microscopes with television cameras are offered, which allow confortable, fatigue-free observation of the microscopic image. In such television microscopes, too, the reference standard has so far been superimposed optically, i.e.

by means of reticles which are superimposed onto the microscopic intermediate image which is picked up by the camera.

It is an object of the invention herein specified to indicate a simplified method suitablefortelevision microscopes to superimpose reference standards onto the microscopic image seen by the observer.

According to the characterizing part of the main claim, this object is met by using a reference standard, which is filed as digital information in a non-volatile storage module, reading out the storage contents and mixing it into the video signal of the television image.

This solution has the advantage that manipulations in the optical system of the microscope are not necessary. The images of specimen and standard are superimposed electronically, for example, by a multiplexer connected into the line between the television camera on the microscope and the monitor which, in turn, is connected with the read feature of the image memory where the digital information is filed, which represents the reference standard.

According to this invention every television microscope can be converted into a comparison microscope. The mechanical precision workmanship required so farforthe manufacture of reference standards in the form of reticles is no longer necessary.

Suitably programmable, erasable, read only memories (PROMs or EPROM) can be used. Such storage modules are available at reasonable prices.

Depending on the information density of the reference standards and the capacity of the storage module, several standards can be filed in one and the same storage module. The memories are offered as plug-in modules, and are easily exchangeable for other storage sets which contain the patterns required for a specific task.

A magnetic storage disk, e.g. a mini disk, is recommended for applications where a great number of reference standards must frequently be exchanged. The mini disk is best operated by a computer with a working storage of adequate capacity, where the required reference standard is temporarily stored.

It may also be useful to use an optical data medium, e.g. a video disk or a so-called optical disk as memory. Such memories allow static image display, so that a temporary storage is not necessary.

When the reference standard is electronically superimposed, the brightness of the superimposed pattern is easily controlled, and it is possible to change between positive and negative display of the reference standard.

Quite frequently, the reference standard should not be superimposed over all the specimen image, but both should be visible side-by-side. To achieve this, the video signal of the specimen supplied by the television camera of the microscope should be suppressed in the area covered by the reference standard.

Besides reference standards in the proper sense of the word, such as the aforementioned ASTM grainsize patterns, other auxiliary objects can be filed in corresponding memories, e.g. scale bars, integrating fields, etc., which until now have also been designed as eyepiece reticles.

Further advantages of the invention are explained below in the description of Figures 1 and 2 of the attached drawings, where: Figure lisa block diagram of a prototype of the invention Figure 2 is a reference standard designed as eyepiece reticle.

In Figure 1, item 1 refers to a microscope with a television camera 2 mounted on its tube. The signal supplied by this camera 2 is relayed to a monitor 7 for the display of an image of the specimen to be examined. A multiplexer 6 is connected between monitor 7 and camera 2, where the camera signal is mixed into a second signal from a processor 5, which supplies the image of a reference standard. A synchronous signal obtained from the video signal of camera 2 via a synchronizing-pulse separator 3 is relayed to processor 5.

Via data lines processor 5 is connected with a non-volatile storage module 8 which contains four plug-in read only memories (ROM), 8a, b, c, and d.

This module may be an erasable, programmable, read only memory (EPROM) by Messrs. Intel, type designation D27128, which has a capacity of 16 kbyte, adequate for a binary image with a resolution of 128 000 points.

To superimpose the reference standard filed in the storage modules 8a-8d onto the screen of monitor 7, the corresponding storage module is selected and processor 5 read out at the pulse of the video frequency. The stored signal sequence is relayed to multiplexer 6.

The prototype shown can be modified in that the processor 5 is replaced by a computer with working storage of its own, into which the desired reference image or, rather, the contents of the corresponding storage module is read, and where it is temporarily stored. The temporarily stored image can be modified by a corresponding control of the computer, e.g. the image can be shifted or further symbols, text, etc. added.

A mini disk storage unit can be connected to the computer instead of the read only memory, where the reference images are stored, and which can be used to document the data the observer obtains from the television image, or to file specific specimen images.

Figure 2 shows a reference standard designed as conventional eyepiece reticle. Shown in the pattern of ferrite grain sizes 1:1, complying with steel-iron test certificate No. 1510-61.Ascan be seen, line pattern 9 is applied to one half of plate 10 only. The specimen image to be compared with pattern 9 will appear in the other half of the intermediate image covered by plate 10. This area also contains a field 11 where the identification data of pattern 9 are engraved.

In accordance with the invention, pattern 9 and field 11 are filed in one of the storage modules 8a-8d of the prototype shown in Figure 1 after having been reduced to the format of the television screen.

Pattern 9 is, for example, filed in the memory in that a sample of pattern 9 is recorded by a television camera, converted into a binary image and read into the storage module by means of a processor which is programmed accordingly. The type of storage is not limited to writing continuously into the memory the bright/dark information of the successive picture points. It is also possible, for example, and recommended in particular for standards of low information density, to file only the coordinates of those points which in the image appear bright or dark.

Claims

1. Method to superimpose a reference standard (grain-size pattern 9) onto the image of a microscope (1) displayed on a television screen (7), characterized by the fact that a reference standard is used, which is filed as digital information in a non-volatile storage module (8), and that the storage contents is read out and mixed into the video signal of the television image.

2. Method according to claim 1, characterized by the fact that the reference standard is temporarily taken over into the working storage of a computer (5) on-line with the storage module.

3. Method according to claims 1-2, characterized by the fact that the storage module is a programmable read only memory (PROM, EPROM 8).

4. Method according to claims 1-2, characterized by the fact that the storage module is a magnetic disk (mini disk).

5. Method according to claims 1-2, characterized by the fact that the storage module is an optical disk.

6. Method according to claims 1-5, characterized by the fact that the reference standard (9) covers only part of screen (7), and that the video signal supplied bythetelevision camera (2) of microscope (1) is suppressed in the area covered by the reference standard.

7. Method according to claims 1-6, characterized by the fact that the reference standard consists of images of grain-size disks and/or grain-size patterns (9) of polished-metal sections complying with ASTM1 12 and VDEh-standard (steel-iron test certificate).