JP2016034235A - pH DETERMINATION APPARATUS, pH MEASURING INSTRUMENT, pH DETERMINATION METHOD, AND pH DETERMINATION PROGRAM - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy of pH determination based on a color image of a measurement target.SOLUTION: A pH determination apparatus 100 determines a pH value of a pH indicator-added measurement target in a vessel 20. The pH determination apparatus 100 comprises a memory unit 19 and a control unit 18. The memory unit 19 stores reference information 19a which indicates the relation between a reference hue value indicating the degree of the hue of the color of a measurement target and the pH value of the measurement target the reference hue value of which is obtained. The control unit 18 obtains the color image data of a surface of a measurement target in the vessel 20, then obtains, from the color image data, the measured hue value indicating the degree of the hue of the color of the measurement target in the vessel 20, and determines the pH value of the measurement target in the vessel 20 from the measured hue value on the basis of the reference information 19a.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a pH determination device, a pH measurement device, a pH determination method, and a pH determination program for measuring the pH of a measurement object (for example, a culture medium containing cultured cells).

Conventionally, methods for measuring the pH of various solutions and the like are known.
For example, in the field of cell culture, a method of observing whether or not the culture of a cell placed in a culture vessel is progressing by measuring the pH of a medium in which the cell to be measured is placed is used. It has been. The pH of the medium was measured one by one using a pH sensor. However, in recent years, it is possible to measure the pH of a medium containing cells without using a sensor or the like in order to increase the number of recesses (wells) for holding cells in a culture vessel and improve work efficiency. Measurement equipment is required.

In such a pH measurement device, a color change-type pH indicator (eg, phenol red, methyl orange, phenolphthalein, litmus, etc.) is added to a medium containing cells as measurement objects, and the color change of the pH indicator is detected. The pH measurement can be performed by referring to a table that shows the relationship between the detected pH value and color information (RGB values, etc.).
For example, a method for displaying a pH value obtained by converting a color image of a measurement object uniformly mixed with a pH indicator into a signal and comparing the measurement object with a calibration curve prepared in advance is disclosed. (For example, refer to Patent Document 1). In this method, the calibration curve is created based on the correspondence relationship between the value based on RGB of the color image and the pH value.

JP 2001-343328 A

However, the conventional method has the following problems.
That is, in the method disclosed in Patent Document 1, the calibration curve is created based on the correspondence between the RGB value (for example, the y value in the CIE chromaticity diagram) of the color image data acquired by the camera and the pH value. Is done.
However, since the RGB values of the color image data acquired by the camera change depending on the luminance, that is, the change in the amount of light from the measurement object, even the same measurement object changes depending on its thickness (amount). Therefore, in the conventional method, accurate pH cannot be measured unless the amount of the measurement object is kept constant.

Also, since the RGB value of the color image data acquired by the camera changes due to the change in the amount of light, the brightness changes due to the deterioration of the light source of the device, the presence or absence of a lid of the container in which the measurement object is put, the material and processing of the container This difference also affects the pH measurement results, leading to a decrease in pH measurement accuracy.
Therefore, an object of the present invention is to provide a pH determination device, a pH measurement device, a pH determination method, and a pH determination program capable of improving the measurement accuracy of pH based on a color image of a measurement object.

  A pH determination apparatus according to one aspect of the present invention is a pH determination apparatus for determining a pH value of a measurement object to which a pH indicator in a container is added, and indicates a degree of hue of a color of the measurement object. A storage unit for storing reference information indicating the relationship between the hue value and the pH value of the measurement object from which the reference hue value is obtained, and obtaining color image data of the surface of the measurement object in the container, from the color image data A control unit that obtains a measured hue value indicating the degree of hue of the color of the measurement object in the container and determines a pH value of the measurement object in the container from the measurement hue value based on the reference information.

  Here, the pH of the measurement object is determined based on the relationship between the degree of hue and the pH value acquired in advance. Therefore, unlike pH determination based on color information (for example, RGB values) including luminance that varies depending on changes in the amount of light when the measurement object is imaged, pH determination is not affected by the thickness (amount) of the measurement object. The result can be obtained. That is, according to the pH determination apparatus according to the present invention, factors that cause a change in the amount of light, such as the thickness (amount) of the measurement object, the presence or absence of the lid of the container in which the measurement object is placed, the material and shape of the container, Since there is little influence by a difference, stable pH determination can be performed.

A pH measurement device according to another aspect of the present invention includes the pH determination device, and an imaging unit that images the surface of the measurement object in the container and transmits or transmits the captured color image to the pH determination device. .
A pH determination method according to still another aspect of the present invention is a pH determination method for determining a pH value of a measurement object to which a pH indicator in a container is added, and indicates the degree of hue of the color of the measurement object. The reference information indicating the relationship between the reference hue value and the pH value of the measurement object from which the reference hue value is obtained is read from the storage unit, the color image data of the surface of the measurement object in the container is acquired, and the acquired color image A measurement hue value indicating the degree of hue of the color of the measurement object in the container is acquired from the data, and the pH value of the measurement object in the container is determined from the measurement hue value based on the reference information.

  A pH determination program according to still another aspect of the present invention is a pH determination program for causing a computer to execute a process for determining a pH value of a measurement object to which a pH indicator in a container is added, wherein the pH indicator is The reference information indicating the reference hue value indicating the degree of hue of the color of the added measurement object and the pH value of the measurement object from which the reference hue value is obtained is read from the storage unit, and the surface of the measurement object in the container Color image data is obtained, a measurement hue value indicating the degree of hue of the color of the measurement object in the container is obtained from the obtained color image data, and the measurement object in the container is obtained from the measurement hue value based on the reference information. The pH value of is determined.

  The present invention can improve the accuracy of pH determination based on a color image of a measurement object.

The front view which shows the structure of the pH measuring device which concerns on one Embodiment of this invention. The perspective view which shows the state which took out the main structures of the pH measuring machine of FIG. 1 from the housing | casing part. The top view of the container (well plate) which concerns on the same embodiment. The schematic block diagram of the pH determination apparatus which concerns on this embodiment. The figure for demonstrating the relationship of each parameter in a color system. The figure which shows the verification result of the change of the hue angle of the color of the measuring object by the change of quantity. The graph which shows the relationship between the hue angle of the color of the measuring object which concerns on this embodiment, and pH value. The flowchart of pH determination operation | movement by the same pH determination apparatus. The figure of the example of a screen output by the pH determination apparatus. The figure of the example of a screen output by the pH determination apparatus.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.
In addition, the inventors provide the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and these are intended to limit the subject matter described in the claims. is not.

(Embodiment)
[1. Constitution]
[1-1. Configuration of pH measuring device 10]
FIG. 1 shows an appearance of a pH measuring device 10 (an example of a pH measuring device) according to an embodiment.
The pH measuring device 10 according to the present embodiment is configured to change the pH of a medium (an example of a measurement object) that changes according to the growth state of the cells C placed in a well plate 20 (an example of a container; see FIG. 3). Is detected by image processing.

As shown in FIG. 1, the pH measuring device 10 includes a housing unit 11, a mounting base 12, a light source unit 13, a container mounting unit 14 (an example of a container mounting surface), a Fresnel lens 16, and a camera. (An example of an imaging unit) 17 and a pH determination device 100 (see FIG. 4) described later are provided.
<Case 11>
The casing 11 has two doors (not shown) with double doors (not shown) on the front side of the box shape, and forms a dark room inside by closing the two doors. Moreover, the housing | casing part 11 stores the principal part structure, such as the mounting stand 12, the light source part 13, the container mounting part 14, the Fresnel lens 16, and the camera 17, as shown in FIG.

In the present embodiment, the pH measurement is performed in a state where the main part for measuring the pH is housed in the housing part 11. Thereby, while being able to implement pH measurement without being influenced by ambient light, the power of the light source unit 13 can also be saved. Furthermore, by carrying out pH measurement in a dark box, it is possible to suppress changes in temperature and CO ₂ concentration due to the influence of wind.

As in the present embodiment, when the main configuration of the pH measuring device 10 is installed in a dark box and a power supply device, a USB hub, or the like is disposed under the casing unit 11, the power supply device or the like is cooled. Therefore, the arrangement may be devised so that the cooling air does not flow in the direction of the well plate 20.
In the present embodiment, by detecting the change in pH of the medium containing the cells C held in the well plate 20 using the light irradiated from the light source unit 13 in the dark room formed in the housing unit 11, A highly accurate pH determination can be performed without being affected by ambient light.

<Mounting base 12>
As shown in FIG. 2, the mounting base 12 is a base on which the light source unit 13, the container mounting unit 14, the camera 17, and the like are mounted. The base unit 12a, the support unit 12b, the two support columns 12c and 12c, and the camera It has a mounting portion 12d.
The base 12a is a flat member that is placed on the installation surface on which the pH measuring device 10 is installed and forms a base portion of the pH measuring device 10, and the light source unit 13 is disposed therein. Yes. A well plate 20 is placed on the portion of the base 12a where the light source unit 13 is disposed.

The support part 12b is a flat plate-like member attached above the upper surface of the base part 12a via a predetermined gap, and is formed in a through-hole formed in a part facing the well plate 20 in the Fresnel lens 16. Is inserted.
As shown in FIG. 2, the two support columns 12c and 12c are erected along a substantially vertical direction on the side opposite to the front side where the well plate 20 is introduced in the base portion 12a. Moreover, the camera support part 12d to which the camera 17 is attached to the upper end part is fixed to the two support columns 12c and 12c.

As shown in FIG. 2, the camera attachment portion 12d is a substantially T-shaped member in plan view, and is supported by the upper ends of the two columns 12c and 12c. In addition, a camera 17 arranged toward the well plate 20 is attached to a substantially T-shaped tip portion of the camera attachment portion 12d.
<Light source unit 13>
The light source part 13 is comprised by white LED, and irradiates light toward the well plate 20 arrange | positioned upwards from the base part 12a.

As the light source unit 13, other light sources such as a halogen lamp may be used. However, for example, when a halogen lamp is used as the light source, the environmental temperature rises due to heat generation, and the temperature in the housing 11 also rises. In this case, there is a possibility that the cells placed in each well 20a of the well plate 20 will die in a high temperature environment.
Therefore, as the light source unit, it is preferable to use an LED having a small calorific value as in the present embodiment.

<Container placement unit 14>
The container mounting part 14 is a flat plate-like member having a through hole installed on the base part 12a, and the well plate 20 is placed in this through part. The penetration part of the container mounting part 14 is formed according to the size of the well plate 20.
Thus, when the well plate 20 is placed on the container placement portion 14, the well plate 20 is placed in a state of being aligned with a predetermined location on the base portion 12a.

<Fresnel lens 16>
As shown in FIGS. 1 and 2, the Fresnel lens 16 is arranged between the well plate 20 placed on the base portion 12 a and the camera 17 in the vertical direction. The Fresnel lens 16 is a lens having telecentricity and has a characteristic that the optical axis and the principal ray can be regarded as parallel at the position of the camera 17 that forms an image.

<Camera 17>
The camera 17 is an imaging device capable of acquiring a color image, and is fixed above the Fresnel lens 16 while being supported by the camera mounting portion 12d of the mounting base 12 described above, as shown in FIGS. Has been.
Further, the camera 17 is disposed at a position away from the upper surface of the Fresnel lens 16 by a predetermined distance so that the range including the well plate 20 can be photographed via the Fresnel lens 16.

Furthermore, the camera 17 changes an optical image into an electrical signal using an imaging device such as a CCD or a CMOS, digitizes the electrical signal, and transmits or transmits it as color image data to the control unit 18 of the pH determination device 100. .
<Well plate 20>
In the pH measuring device 10 of this embodiment, as shown in FIG. 3, a well plate 20 having a total of 48 wells 20a (an example of concave portions) of 8 columns and 6 rows formed on the surface thereof is used. Cells C and medium are put in each well 20a of the well plate 20 to culture the cells.

The well plate 20 is a culture container for culturing cells C in a high temperature and high humidity culture space formed in an incubator (not shown), and resin injection molding is performed so that 48 wells 20a are formed on the surface. Is formed by.
Each well 20a contains cells C together with a medium containing phenol red as a pH indicator.

As shown in FIG. 2, the well plate 20 is placed on the container placement portion 14 formed on the base portion 12 a of the mounting base 12 so that the surface thereof faces the camera 17.
[1-2. Configuration of pH determination apparatus 100]
FIG. 4 shows a schematic configuration of the pH determination device 100. The pH determination device 100 is a computer device connected to the pH measuring device 10, and includes a control unit 18, a storage unit 19 connected to the control unit 18, and a display unit 30 connected to the control unit 18.

<Control unit 18>
As shown in FIG. 4, the control unit 18 includes functions of an image data acquisition unit 181, a color information analysis unit 183, a hue angle calculation unit 185, a pH determination unit 187, a display image generation unit 189, and the like. The control unit 18 is configured by a processor such as a CPU that reads a predetermined program stored in the storage unit 19 and executes each function.

The image data acquisition unit 181 acquires the color image data acquired by the camera 17, and sequentially executes predetermined image processing on the image data of the surface of the well 20a that is each pH measurement site included in the color image data. Hereinafter, the well 20a targeted for pH determination is referred to as a target well 20a.
The color information analysis unit 183 acquires RGB image information included in the image data of the target well 20a subjected to the image processing, and acquires color information (hue) from the image information. Specifically, the color information analysis unit 183 performs color space conversion and acquires color information. The following formula shows a formula for conversion from RGB to XYZ color system.

In the above formula, a conversion matrix M is obtained from RGB coordinate values and white point values, and conversion from RGB to the XYZ color system is performed.
The color information analysis unit 183 further performs conversion from the XYZ color system to the L * a * b * color system. A mathematical formula for performing this conversion is, for example, as follows.

X _n , Y _n and Z _n are the coordinates of the white point.
Further, the color information analysis unit 183 obtains a value of the L * C * h color system that is the polar coordinate system of the L * a * b * color system.
The hue angle calculation unit 185 calculates the value of h indicating the hue angle among the values of the L * C * h color system acquired by the color information analysis unit 183.

  FIG. 5 shows the relationship between the parameter values of L * C * h in the L * C * h color system. L indicates lightness, which is the same as the lightness L * of the L * a * b * color system. C * represents saturation. Note that a * and b * indicate the chromaticity of the L * a * b * color system, and C * of the L * C * h color system is obtained by the following equation.

The hue angle h (θ) of the L * C * h color system is obtained by tan ⁻¹ (b * / a *).
The pH determination unit 187 refers to a calibration table 19a (an example of reference information) in the memory 19 described later, and acquires a pH value corresponding to the hue angle h obtained by the hue angle calculation unit 185. The pH determination unit 187 stores the acquired pH value in the memory 19 in association with the identification information of the target well 20a.

The display image generation unit 189 generates an image to be displayed when the pH determination of all the wells 20a in the well plate 20 is completed.
<Storage unit 19>
The storage unit 19 includes a memory (RAM, ROM, etc.) connected to the control unit 18. The storage unit 19 stores a calibration table 19a. The calibration table 19a will be described later.

<Display unit 30>
The display unit 30 is configured by a display such as a liquid crystal or an organic EL, and displays the image data generated by the display image generation unit 189 of the control unit 18 on the screen.
<Input unit 40>
The input unit 40 is a keyboard, a mouse, a touch panel, or the like connected to the control unit 18. The input unit 40 is operated by a user to input information.

[1-3. Calibration table 19a]
The calibration table 19a is a table storing calibration data in which the hue value of the color of the measurement object measured in advance and the pH value of the measurement object are associated with each other.
The present inventors have found a correlation between hue and pH value among the colors of the measurement object. Since the pH is determined based on the hue that does not affect the brightness (luminance) by determining the pH based on the correlation between the hue and the pH value, the liquid volume and thickness of the same measurement object The pH value is not affected by this difference.

FIG. 6 shows the result of measuring the hue value by changing the amount of the medium having the same pH value. As shown in the figure, the saturation C * varies depending on the liquid volume of the culture medium, but it can be seen that the hue angle h is substantially constant.
The calibration table creation procedure will be described below.
First, a plurality of measurement objects respectively prepared in the plurality of wells 20a of the well plate 20 are prepared. Here, the plurality of objects to be measured are solutions having various predetermined pH values, for example, a medium adjusted to an arbitrary pH value by adding a diluent, to which a pH indicator is added. . The pH value of the medium adjusted according to the ratio of the diluted solution and the medium is measured using a commercially available pH meter, and the color of the medium containing a pH indicator (for example, phenol red) is photographed to obtain the pH value and color. Detect the relationship. Specifically, the surface of the well plate 20 is photographed to obtain color image data. Then, from the same color image data, the color information of the medium color of each well 20a (the value of h in the L * C * h color system) is obtained through color space conversion in the same manner as the processing by the control unit 18 described above. get. The acquired hue information is associated with the pH value of the corresponding well 20a to create a calibration table 19a.

FIG. 7 shows an example of calibration data created by the above procedure. The pH value corresponding to the hue angle from the color image obtained by actually imaging the surface of the medium is calculated with reference to the calibration table 19a obtained by tabulating the calibration data. Note that the calibration data in FIG. 7 is data obtained by using phenol red as a pH indicator in order to obtain data around a pH value of 7.
Therefore, the pH measuring device 10 digitizes the hue of the pH measurement site, refers to the calibration table 19a stored in the storage unit 19, and obtains the pH value corresponding to the numeric value of the hue of the pH measurement site. The growth state of the cells C in each well 20a of the plate 20 can be determined. As a result, when the pH value is low, that is, when the number of cells increases and the medium is acidified, the cells C in the well 20a are dispensed into the other wells 20a and are again cultured in the incubator. By placing it in the space, the culture of the cell C can be promoted.

  On the other hand, if the pH value is not low as a result of pH measurement, that is, if the medium is not acidified, it means that the growth of the cells C in the well 20a has not progressed. Therefore, in this case, operations such as medium replacement can be performed in order to eliminate a factor that can be considered as the cause of the cell C not growing. As a result, by performing the treatment so that the growth of the cells C is promoted, the growth of the cells C in all the wells 20a can be advanced.

[2. Operation]
[2-1. ph judgment operation]
FIG. 8 is a flowchart of the pH determination operation mainly executed by the control unit 18 according to the present embodiment.
S 101: Color image data captured by the camera 17 of the pH measuring device 10 is acquired by the image data acquisition unit 181. Here, image data corresponding to an image of the entire surface of the well plate 20 is acquired.

S102: Each well 20a is specified from the acquired image data by the image data acquisition unit 181. The well 20a is identified based on position information set in advance.
The position of each well 20a is set by prior adjustment. For example, the position of each well 20a may be determined or adjusted while viewing the image of the entire surface of the well plate (the image display area 301 of the screen 300 in FIG. 10). At this time, a person who adjusts (for example, a service person or an inspection worker) operates the input unit 40 while viewing the image 20i of the entire surface of the well plate 20 displayed on the screen. The measurement position of the well 20a may be adjusted. At this time, a mark indicating the measurement area may be displayed in a circle of each well 20a of the well plate 20 displayed in the image display area 301 so that the measurement position of the well 20a is known. The measurement area may be adjusted in size.

  S103: When the well 20a is specified, the color information analysis unit 183 analyzes the color information of the color image data on the surface of the target well 20a. Specifically, each value (Y, x, y) in the XYZ color system is calculated from the RGB values acquired from the color image data by the color space conversion described above, and L * a is calculated from each value in the XYZ color system. * b * Color system values (L *, a *, b *) are calculated, and L *, C *, and h color system values are acquired.

S104: The hue angle calculation unit 185 calculates the value of the hue angle h (an example of the measured hue value) among the values of the L *, C *, and h color systems.
S105: The calibration table 19a is referred to by the pH determination unit 187.
S106: The pH determination unit 187 acquires a pH value corresponding to the acquired hue angle h value (an example of a reference hue value) from the referenced calibration table 19a.

S107: The acquired pH value is stored in the storage unit 19 in association with the identification information of the target well 20a.
S108: The pH determination unit 187 determines whether there is an unmeasured well 20a among the wells 20a of the imaged well plate 20. If there is an unmeasured well 20a, the process returns to step S103, and if there is no unmeasured well 20a, the process proceeds to step S109.

S109: Based on the pH value corresponding to the well identification information stored in the storage unit 19, the display image generation unit 189 generates an image including the pH value for each well 20a as described later.
S110: The generated image is displayed on the display unit 30.
The control flow is an example, and the order and timing are not limited to the above.

[2-2. ph judgment screen]
FIG. 9 shows an example of a screen 300 displayed on the display unit 30 as a result of the pH determination operation.
The screen 300 includes a pH value display area 302.
The pH value display area 302 displays an array table 304 (8 columns × 6 rows) composed of cells 304c arranged in the same manner as the array of the wells 20a. The position of the cell 304 c in the array table 304 corresponds to the position of the well 20 a in the well plate 20. That is, the array table 304 includes columns 1 to 8 and cells 304c in rows A to F. The array table 304 displays pH values measured for the wells 20a corresponding to the respective cells 304c.

  As described above, the screen 300 of the display unit 30 displays the array table 304 corresponding to the array of the wells 20a in the well plate 20 and displays the determined pH value in the cell 304c corresponding to each well 20a. The user can immediately grasp the pH value of each well 20a. The user grasps the culture state of the measurement object by comparing the pH value of each well 20a with a predetermined threshold value, and determines what processing (medium replacement, dispensing, etc.) is to be performed next. be able to.

FIG. 10 shows another example of a screen 300 displayed on the display unit 30 as a result of the pH determination operation. This screen is mainly used by a service person or an inspection worker who adjusts the pH measuring device 10 or the like.
The screen 300 includes an image display area 301, a well display area 303, a switching tab 307, and the like.

The image display area 301 displays at least the image 20 i of the well plate 20.
The well display area 303 displays an array table 304 (8 columns × 6 rows) composed of cells 304c arranged in the same manner as the well 20a array as in FIG. The array table 304 further displays numerical values of color information (lightness L *, saturation *, and hue angle h), in addition to the pH value of the well 20a corresponding to each cell 304c.

The switching tab 307 switches to a screen in which parameter values of different color systems (L * a * b * color system and RGB color system) and corresponding pH values are displayed for each well 20a when selected. Can do.
[3. Effect]
<3-1>
The pH determination apparatus 100 according to the present embodiment is a pH determination apparatus that determines the pH value of a measurement object to which a pH indicator in a container (well plate 20) is added, and includes a storage unit 19, a control unit 18, and the like. . The storage unit 19 is a relationship between a reference hue value (h value of the L * C * h color system) indicating the degree of hue of the color of the measurement object and the pH value of the measurement object from which the reference hue value is obtained. Is stored as reference information (calibration table 19a). The control unit 18 obtains color image data of the surface of the measurement object in the container, and measures a hue value (L * C * h table) indicating the degree of hue of the color of the measurement object in the container from the color image data. Color system h value) is obtained, and the pH value of the measurement object in the container is determined from the measured hue value based on the reference information.

  For this reason, since the pH determination apparatus 100 according to the present embodiment determines the pH value based on the relationship between the degree of hue and the pH value, it includes luminance that varies depending on the change in the amount of light when the measurement object is imaged. Unlike pH determination based on color information, it is possible to obtain a pH determination result that does not depend on the amount of the measurement object. That is, since the influence of the change in the light amount due to the factor causing the change in the light amount, for example, the thickness (amount) of the measurement object is small, stable pH determination can be performed. Further, even if there is a change in the amount of light due to the difference in the material of the well plate 20, there is an advantage that the influence on the pH determination result is also small.

<3-2>
In the pH determination apparatus 100 according to the present embodiment, the container (well plate 20) includes a plurality of recesses (wells 20a) each storing and arranging a measurement object, and the control unit 18 includes the plurality of recesses. From the color image data including the surface of the measurement object, measurement hue values (h in the L * C * h color system) indicating the degree of hue of the color of the measurement object in each recess are obtained, respectively. Based on (calibration table 19a), the pH value for the measurement object in each recess is determined from the measured hue value.

For this reason, since the pH value of many measuring objects can be determined collectively, the working efficiency of pH determination can be improved.
<3-3>
The pH determination apparatus 100 according to the present embodiment further includes a display unit 30 connected to the control unit 18, and the control unit 18 corresponds to the arrangement of the plurality of recesses (wells 20a) of the container (well plate 20). An array table 304 including a plurality of arranged cells 304c is generated, and the display unit 30 displays the array table 304. Each cell 304c of the displayed array table 304 includes a measurement object in each corresponding recess. pH value is included.

For this reason, the user can confirm the pH values of a large number of measurement objects at a time, and the next step (for example, medium conversion or dispensing when the measurement object is a medium in which cells are cultured). Therefore, it is possible to improve the working efficiency for the measurement object.
<3-4>
The pH measuring device 10 according to the present embodiment has an imaging unit (camera 17) that images the surface of a measurement target in a container (well plate 20) and transmits or transmits the captured color image data to the pH determination device 100. And a container placement surface on which the container is placed so as to face the imaging unit. The container has a colorless and permeable lid that covers the surface side of the measurement object in the container, and the imaging unit is placed inside the container with the lid covering the surface side of the measurement object in the container. The color image data of the surface of the measurement object is acquired.

  For this reason, in the pH determination apparatus 100 according to the present embodiment, the container can be measured with a lid (colorless and transparent). In other words, by covering, there is little influence on the pH determination result due to the change in the amount of light when the measurement object is imaged. Therefore, it is not necessary to remove the lid to take an image for pH determination, thus preventing contamination of the measurement object in the recess (for example, medium in which cells are cultured) and changes in temperature and humidity in the container. Can do.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of invention.
(A)
In the above embodiment, the L * C * h color system is used to calculate the hue, but the degree of hue may be calculated using the L * a * b * color system. In this case, the degree of hue is the hue angle θ,
θ = tan ⁻¹ (b * / a *)
Can be calculated.

Further, the present invention is not limited to the above color system, and a parameter indicating the degree of hue may be used for other color systems.
(B)
In the above embodiment, in the screen examples of FIGS. 9 and 10, the measured pH value of the well 20a is set to the next step (for example, medium conversion or dispensing when the measurement target is a medium in which cells are cultured). You may make it display so that the comparison result with the threshold value used as the judgment reference may be reflected. For example, the control unit 18 may display so as to emphasize the measured pH value of the well 20a that has reached a standard that requires medium replacement or dispensing as a result of comparison with the threshold (for example, by different colors). Display, reverse display, flashing display, etc.).

(C)
In the above embodiment, an example in which the present invention is applied to the pH determination device 100 has been described. However, the present invention is not limited to this.
In the above embodiment, the pH determination device 100 includes the display unit 30, but may include only the control unit 18 and the storage unit 19. Further, the pH determination device 100 may be incorporated in the pH measuring device 10.

Moreover, you may implement this invention as a pH determination method performed according to the control flow (refer FIG. 8) mentioned above, or a pH determination program which makes a computer perform the pH determination method, for example.
(D)
In the embodiment described above, an example in which the well plate 20 including a plurality of wells (concave portions) 20a is used as a container for storing cells has been described. However, the present invention is not limited to this.

For example, a petri dish or the like may be used as the culture container.
However, the cell culture efficiency can be improved by putting cells in a plurality of wells like a well plate and confirming the growth state of the cells, so that the cell culture efficiency can be improved as in the above-described embodiment. In addition, it is more preferable to use a culture vessel capable of performing cell culture at a plurality of locations.

(E)
In the above-described embodiment, an example in which the number of wells (recesses) 20a is 48 columns × 6 rows in total 48 well plates 20 has been described. However, the present invention is not limited to this.
For example, a well plate including a smaller number or a larger number of wells such as 4 columns × 3 rows in total 12 wells and 40 columns × 90 rows in total 3600 wells may be used.

Even in this case, it is possible to efficiently determine the pH regardless of the number of wells by acquiring an image with a camera or the like disposed above the well plate.
(F)
In the above embodiment, an example in which a Fresnel lens is used as the lens of the telecentric optical system has been described. However, the present invention is not limited to this.

For example, instead of the Fresnel lens, another telecentric optical system may be used.
(G)
In the said embodiment, the example which performs pH determination in the dark room formed inside the housing | casing part 11 was given and demonstrated. However, the present invention is not limited to this.

For example, the pH determination may be performed in a room where the brightness is constant in consideration of measurement errors due to ambient brightness.
(H)
In the above embodiment, in order to recognize a change in pH as a change in color, an example in which phenol red is used as a pH indicator added to a medium containing cells has been described. However, the present invention is not limited to this.

  For example, in addition to phenol red, pH indicators such as methyl orange, phenolphthalein, litmus, promophenol blue, promocresol green, promothymol blue, and thymol blue may be used.

  Since the present invention has an effect of improving the accuracy of pH measurement based on a color image of a measurement object, it can be widely applied as an apparatus, a method, a computer program, etc. for performing pH measurement.

10 pH measuring machine (an example of pH measuring machine)
DESCRIPTION OF SYMBOLS 11 Case part 12 Mounting base 12a Base part 12b Support part 12c Support | pillar 12d Camera mounting part 13 Light source part 14 Container mounting part (an example of a container mounting surface)

16 Fresnel lens 17 Camera (an example of an imaging unit)
18 Control unit (an example of a control unit)
19 Storage unit (an example of a storage unit)
19a Calibration table (an example of reference information)
20 well plate (example of container)
20a well (an example of a recess)
100 pH determination device (an example of a pH determination device)
C cells

Claims (18)

A pH determination device for determining a pH value of a measurement object to which a pH indicator in a container is added,
A storage unit for storing reference information indicating a relationship between a reference hue value indicating a degree of hue of a color of the measurement object and a pH value of the measurement object from which the reference hue value is obtained;
Obtaining color image data of the surface of the measurement object in the container, obtaining a measurement hue value indicating the degree of hue of the color of the measurement object in the container from the color image data, and based on the reference information A control unit for determining the pH value of the measurement object in the container from the measured hue value;
A pH determination device. The reference information includes calibration table information created based on the correlation between the reference hue value and the pH value of the measurement object from which the reference hue value was obtained.
The pH determination apparatus according to claim 1. The degree of the hue corresponds to a parameter value indicating the hue in a predetermined color space.
The pH determination apparatus according to claim 1 or 2. The degree of the hue corresponds to the hue angle h in the L * C * h color system.
The pH determination apparatus according to claim 3. The degree of the hue is a hue angle θ,
θ = tan ⁻¹ (b * / a *)
The pH determination apparatus according to claim 3, which is acquired by the following.
However, a * is the chromaticity a * in the L * a * b * color system, and b * is the chromaticity b * in the L * a * b * color system. The container includes a plurality of recesses each storing and arranging a measurement object,
The control unit obtains a measured hue value indicating the degree of hue of the color of the measurement object in each recess from color image data including the surfaces of the measurement objects in the plurality of recesses, and uses the reference information as the reference information. Based on the measured hue value based on the measured pH value for each measurement object in each recess, respectively.
The pH determination apparatus according to any one of claims 1 to 5. A display unit connected to the control unit;
The control unit generates an array table including a plurality of cells arranged corresponding to the array of the plurality of recesses of the container,
The display unit displays the sequence table, and each cell of the displayed sequence table includes a pH value of a measurement object in each corresponding recess.
The pH determination apparatus according to claim 6. The display unit further displays one image including all surfaces of the measurement object in the plurality of recesses together with the arrangement table.
The pH determination apparatus according to claim 7. A pH determination device according to any one of claims 4 and 5,
An imaging unit that images the surface of the measurement object in the container and transmits the captured color image to the pH determination device;
A pH measuring machine. A container mounting surface on which the container is mounted so as to face the imaging unit;
Further comprising
The container has a colorless and permeable lid that covers the surface side of the measurement object in the container,
The imaging unit images the surface of the measurement object in the container in a state where the lid part covers the surface side of the measurement object in the container.
The pH measuring device according to claim 9. A pH determination method for determining a pH value of a measurement object to which a pH indicator in a container is added,
Reading reference information indicating the relationship between the reference hue value indicating the degree of hue of the color of the measurement object and the pH value of the measurement object from which the reference hue value was obtained from the storage unit,
Obtaining color image data of the surface of the measurement object in the container;
Obtaining a measurement hue value indicating the degree of hue of the color of the measurement object in the container from the obtained color image data;
Based on the reference information, the pH value of the measurement object in the container is determined from the measured hue value.
pH determination method. The degree of the hue corresponds to a parameter value indicating the hue in a predetermined color space.
The pH determination method according to claim 11. The degree of the hue corresponds to the hue angle h in the L * C * h color system.
The pH determination method according to claim 12. The degree of the hue is a hue angle θ,
θ = tan ⁻¹ (b * / a *)
The pH determination method according to claim 12, which is obtained by:
However, a * is the chromaticity a * in the L * a * b * color system, and b * is the chromaticity b * in the L * a * b * color system. A pH determination program for causing a computer to execute a process for determining a pH value of a measurement object to which a pH indicator in a container is added,
Read out from the storage unit reference information indicating the reference hue value indicating the degree of hue of the color of the measurement object to which the pH indicator is added and the pH value of the measurement object from which the reference hue value is obtained,
Obtaining color image data of the surface of the measurement object in the container;
Obtaining a measurement hue value indicating the degree of hue of the color of the measurement object in the container from the obtained color image data;
Based on the reference information, the pH value of the measurement object in the container is determined from the measured hue value.
pH determination program. The degree of the hue corresponds to a parameter value indicating the hue in a predetermined color space.
The pH determination program according to claim 15. The degree of the hue corresponds to the hue angle h in the L * C * h color system.
The pH determination program according to claim 16. The degree of the hue is a hue angle θ,
θ = tan ⁻¹ (b * / a *)
The pH determination program according to claim 16, which is acquired by:
However, a * is the chromaticity a * in the L * a * b * color system, and b * is the chromaticity b * in the L * a * b * color system.

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