JPH0795897A - Method for recognizing inhibition circle on measurement of potency and device thehrefor - Google Patents

Abstract

PURPOSE:To enable to determine the position of an inhibition circle and rapidly judge the potency of a tested substance by utilizing an imaging device without increasing a sensor, etc. CONSTITUTION:This method for recognizing an inhibition circle formed on the central coaxial circles of a Petri dish comprises relatively moving the Petri dish or an imaging device so that the center of the imaged picture coincides with the center of the Petri dish, imaging at least one inhibition circle at the moved position, subjecting the imaged picture to a picture treatment to calculate a point on a circle nearest from the center of the Petri dish, relatively moving the Petri dish or the imaging device so that the center of the picture coincides with the intersection point of the coaxial circle with a direct line binding the calculated point to the center of the Petri dish, and subsequently imaging the first inhibition circle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention recognizes a region (inhibition circle) in which bacteria or spores (hereinafter referred to as "bacteria") could not be killed or grown by image processing when an antibiotic titer test was automated. For more details on the method and the apparatus,
The position of each of the blocking circles to be imaged is individually determined, and the blocking circles are identified.

[0002]

2. Description of the Related Art A cylinder is erected (or perforated) on an agar medium to dispense an antibiotic to form a bacterial growth inhibition region (inhibition circle) in which bacteria or the like could not be killed or grown. Measuring the titer of an antibiotic by measuring its diameter is stipulated in the "Japanese Standards for Antibiotics". For example, in the cylindrical plate method in this titer test, as shown in FIG. 6 and FIG. A seed layer agar plate 5 is formed. Then, four cylinders 7 are placed on the circumference of a radius of 25 mm from the center of the petri dish 1 so that the center angle is 90 °, and the cylinders 7 are filled with a diluting solution of chemicals having different concentrations. The diluent high concentration standards customary dilutions S _H, low concentration standards customary dilutions S _L, high concentration sample liquid U _H, is defined as the low-concentration sample solution U _L. Then, after culturing for a predetermined time in a state of being maintained in a constant temperature range, the diameter of the inhibition circle is measured,
The titer is calculated by the relational expression based on the measured size. In addition, the measurement of the inhibition circle is performed on five or more Petri dishes for each sample, and is performed 40 times in total.

Conventionally, the diameter of the blocking circle has been visually measured using a caliper, but in recent years, a method of photographing the blocking circle and measuring it by image processing has been adopted due to advances in image technology. Came to. In the case of using the automatic device, the Petri dish to be photographed is automatically conveyed to the photographing place by the conveying means (not shown). And the cylinder 7
The four blocking circles formed by the concentric circles are, for example, simultaneously photographed on one screen, image-processed, and then measured by the image measuring means, or the individual blocking circles are manually positioned at the photographing positions, One stop circle was enlarged and measured.

[0004]

However, in the case of image processing, if an optical system in which four blocking circles fit in one screen is used, the image becomes rough and the accuracy of image measurement is reduced. In addition, in order to increase the image accuracy, it is necessary to use a zoom optical system if the blocking circles are individually photographed, and it is possible to block one petri dish that has been conveyed at irregular rotation positions by the transporting means. Each time the circle had to be manually positioned so that it was placed at the shooting position, which was complicated and the processing speed was slow. Further, as a method of positioning one blocking circle at the photographing position, for example, marking a petri dish and detecting it with a sensor to position the petri dish is conceivable. Dedicated sensors and devices are required, resulting in increased cost and increased failure factors. The present invention has been made in view of the above circumstances, and provides a method and an apparatus for recognizing an obstruction circle that can quickly locate and determine an obstruction circle by using an imaging device without adding a sensor or the like. The purpose is to do.

[0005]

In order to achieve the above object, a method of recognizing a blocking circle at the time of measuring a titer according to the present invention is a plurality of concentric circles whose center is the center of a Petri dish and are formed at predetermined intervals. Is a method for recognizing the stop circle of the above, wherein either the Petri dish or the photographing device is moved so that the center of the screen and the center of the Petri dish coincide with each other, and at least one formed on the Petri dish at this moving position. Shoot the arc of two blocking circles,
The point on the arc that is the shortest distance from the center of the Petri dish is calculated by image processing of this captured image, and the center of the screen is located at the intersection of the concentric circle and the straight line connecting the point on the arc and the center of the Petri dish. Either the petri dish or the photographing device is moved so that the two coincide with each other, and the first stop circle is photographed at this moving position. Further, in the configuration of the blocking circle recognition device according to the present invention, the petri dish and the photographing device are provided so as to be movable relative to each other, and when the photographing device aligns the center of the screen of the photographing device with the center of the petri dish, the concentric circle An image processing means is connected to the image capturing device, in which an arc of at least one of the plurality of block circles formed in the above has an image capturing range that enters the field, and the relative movement amount between the Petri dish and the image capturing device is calculated. However, an image measuring means for measuring the blocking circle extracted by the image processing means is connected to the image processing means.

[0006]

In the blocking circle recognition method, the photographing device or the petri dish is relatively moved so that the center of the screen coincides with the center of the petri dish, and in this state, at least one arc of the blocking circle is photographed, and then the petri dish. The point on the arc that is the shortest distance from the center of the is calculated by image processing, and the center of the screen is made to coincide with the intersection of the straight line connecting this point and the center of the Petri dish and the concentric circle where the blocking circle is formed. The first blocking circle will be positioned, and the relative movement of the photographing device or the Petri dish for recognizing the blocking circle is performed at the shortest distance. In the blocking circle recognition device, the blocking circle is positioned by image processing, and it is not necessary to additionally install a sensor or the like for positioning the blocking circle, and the photographing device does not need to be a zoom optical system. If the size of the screen is large enough that the arc of at least one blocking circle can be seen when the center of the screen coincides with the center of the Petri dish, the device is simple and compact. Can be realized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a method and apparatus for recognizing a blocking circle at the time of measuring a titer according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a flow chart showing a procedure of a method of recognizing a blocking circle of the present invention, and FIG. 2 is a plan view showing a photographing situation of a blocking circle. The same members as those shown in FIGS. 6 and 7 are designated by the same reference numerals, and a duplicate description will be omitted. In the case of using an automatic device, the petri dish 1 to be photographed is conveyed by a conveyance means (not shown) without being restricted in position in the rotation direction, so that the petri dish 1 is arranged at the photographing place at irregular rotation positions. Become. In this state, first, the camera is moved so that the center p of the screen s coincides with the center p of the Petri dish 1 (st. 1).

Next, in this state, an image of the Petri dish 1 including at least one arc of the blocking circle is photographed (st. 3),
The point t on the arc v that is the shortest distance from the center of the screen s, that is, the center p of the Petri dish 1 is obtained by image processing (st.
5). The center q of the blocking circle 11 is located on the straight line u connecting this point t and the center p of the Petri dish 1. Since the center q of the blocking circle 11 is the center of the cylinder 7, it is specified by the radius r (25 mm according to the conventional example) from the center p of the Petri dish 1 on which the cylinder 7 is arranged. Therefore, if the camera arranged at the center p of the Petri dish 1 is moved on the straight line u toward the point t by a radius r (st.
7), the center q of the blocking circle 11 is made to coincide with the center of the screen s, and the first blocking circle 11 can be photographed (st.
9). If the center q of the first blocking circle 11 is specified, the other three blocking circles 1 that are in a relative positional relationship with the blocking circle 11
3, 15, 17 can calculate the amount of movement to the center,
A total of 5 shots will result in each stop circle being shot individually.

Next, it is identified which dilution liquid the four blocking circles photographed in this way are. Here, the cylinders 7 facing each other across the center p are filled with the high-concentration standard regular diluent S _H and the low-concentration standard regular diluent S _L ,
The remaining two opposite cylindrical 7 high concentration sample liquid U _H, are supposed to be a low concentration sample solution U _L is satisfied. Therefore, in the clockwise direction of the center p, for example, U _H , S _H , U _L , S
_It can be specified that they are arranged in the order of _L. In addition, since the diameter of the inhibition circle is large for highly concentrated chemicals, U _H > _UL and S
The relationship of _H > S _L is established. Under the above conditions, if the captured stop circles are the first stop circle, the second stop circle, the third stop circle, and the fourth stop circle in the clockwise direction, the first stop circle, the third stop circle, and the second stop circle. Comparing the 4th and 4th stop circles respectively, two larger stop circles were found and the two are lined up. Therefore, the first of the two stop circles in the clockwise direction is identified as U _H, and what it can be identified in clockwise direction S _H, U _L, and S _L.

FIG. 3 and FIG. 4 are explanatory views of the blocking circle identifying method. For example, as shown in FIG. 3, the first blocking circle is 18.1.
mm, the third blocking circle is 24.3 mm, the third blocking circle is large, the second blocking circle is 24.0 mm, and the fourth blocking circle is 18.7.
When the second blocking circle in mm is large, the first of greater in the clockwise direction i.e., the second inhibition circle is S _H, U _L, S _L in U _H next, the clockwise direction as after. Further, as shown in FIG. 4, the first blocking circle is 24.3 mm and the third blocking circle is 1
The first stop circle is large at 8.1 mm and the second stop circle is 18.
If the fourth blocking circle is 7 mm and the fourth blocking circle is 24.0 mm, and the fourth blocking circle is large, the first large one in the clockwise direction, that is, the fourth blocking circle becomes U _H , and the latter one is S _H , U in the clockwise direction. _L ,
It becomes S _L.

The recognizing device for realizing the above recognizing method can be configured as described below. Figure 5
FIG. 3 is a block diagram showing a schematic configuration of a blocking circle recognition device.
The image processing means 21 includes a photographing device (black and white CCD camera, etc.)
23 is connected, and the photographing device 23 uses the Petri dish 1 arranged below as a subject. The screen s (see FIG. 2) of the image capturing device 23 has such a size that a part (arc) v of at least one blocking circle (for example, blocking circle 11) can be seen when the center coincides with the center p of the Petri dish. Has become. Also,
The imaging device 23 can be moved relative to the Petri dish 1 at an arbitrary position. This movement is performed with high accuracy by using, for example, a step motor.
Furthermore, the imaging device 23 need only have at least one single-focus optical system, and does not need to have a zoom function. An illumination device 25 is provided below the petri dish 1, and the illumination device 25 illuminates the petri dish 1 with dark field transmission illumination. Therefore, in the image photographed from above by the photographing device 23, the region in which the bacteria or the like cannot be killed or grown cannot be seen uniformly dark.

The image processing means 21 is provided with, for example, an image differential absolute value processing means, an image binarization processing means, an image expansion processing means and an image contraction processing means. It can be extracted. An image measuring means 27 is connected to the image processing means 21, and the image measuring means 27 can measure its size based on the boundary of the extracted blocking circle. The image processing unit 21 has, for example, a horizontal pixel count of 51.
2, vertical 480, and a luminance value of 8 bits / pixel are used. The image processing means 21, the photographing device 23, and the image measuring means 27 constitute a recognition device 29.

In the recognizing device 29 thus constructed,
Since the blocking circle is positioned by image processing, a sensor or the like for positioning the blocking circle is not required, and the automation device is not complicated. Further, the photographing device 23 does not need to be a zoom optical system as long as it has a monofocal optical system, and the screen s is centered at the center p of the Petri dish.
Since it suffices that the arc v of at least one blocking circle can be seen when the above condition is satisfied, the imaging device 23 can also be of low cost. As a result, according to the recognition device 29 described above, it is possible to quickly and accurately recognize the blocking circle without increasing the cost of the device.

In the above-mentioned embodiment, the photographing device 23 is explained as moving, but since the photographing device 23 and the petri dish 1 need only be able to move relative to each other, the petri dish 1 is opposite to the above-mentioned embodiment. It may be moved.

[0015]

As described in detail above, according to the method of recognizing a blocking circle for measuring a titer according to the present invention, the center of the blocking circle is obtained by image processing, and an image is taken for recognizing the blocking circle. Since the relative movement of the device or the Petri dish is performed at the shortest distance, the stop circle can be recognized quickly without adding a sensor or the like. Further, according to the blocking circle recognition device, a sensor or the like is not necessary, and the optical system only needs to have a single focal point, and the screen has such a size that at least one circular arc of the blocking circle can be seen. Therefore, the device can be configured easily and compactly, the cause of failure can be reduced, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of a blocking circle recognition method of the present invention.

FIG. 2 is a plan view showing an imaging situation of a blocking circle.

FIG. 3 is an explanatory diagram of a blocking circle identification method.

FIG. 4 is an explanatory diagram of a blocking circle identification method.

FIG. 5 is a block diagram showing a schematic configuration of a blocking circle recognition device.

FIG. 6 is a plan view illustrating a cylindrical plate method in a titer test.

7 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 Petri Dish 11 Blocking Circle 21 Image Processing Means 23 Imaging Device 27 Image Measuring Means 29 Blocking Circle Recognition Device p Center of Petri Dish s Screen t Point on Arc u Straight Line v Arc of Blocking Circle

Claims (2)

[Claims] 1. A method of recognizing a plurality of blocking circles formed at predetermined intervals on concentric circles having the center of the petri dish as the same center, wherein the center of the screen and the center of the petri dish coincide with each other. Either the plate or the photographing device is moved to photograph the arc of at least one blocking circle formed on the petri dish at the movement position, and the photographed image is image-processed to determine the shortest distance from the center of the petri dish. On a straight line connecting the point on the arc and the center of the Petri dish,
Either the Petri dish or the imaging device is moved so that the center of the screen coincides with the intersection with the concentric circle, and the first blocking circle is imaged at the moving position. Circle recognition method. 2. A petri dish and a photographing device are provided so as to be movable relative to each other, and when the photographing device matches a screen center of the photographing device with a center of the petri dish, a plurality of blocking portions formed on concentric circles are provided. An image processing means, in which an arc of at least one blocking circle of the circle has an imaging range that enters the field, and an amount of relative movement between the Petri dish and the imaging device is calculated, is connected to the imaging device. An apparatus for recognizing a blocking circle, characterized in that image measuring means for measuring the blocking circle extracted by the means is connected to the image processing means.