WO2020110729A1

WO2020110729A1 - Color measuring apparatus and process achievement degree determination apparatus

Info

Publication number: WO2020110729A1
Application number: PCT/JP2019/044548
Authority: WO
Inventors: Norio Matsui; Motohiro Furusawa; Yasuhiro Kawasaki
Original assignee: Canon Kabushiki Kaisha
Priority date: 2018-11-28
Filing date: 2019-11-13
Publication date: 2020-06-04
Also published as: JP2020085740A

Abstract

A determination apparatus (1) that determines an achievement degree of a predetermined process using a test paper (2) having a discoloration region whose color changes in accordance with the achievement degree of the predetermined process is provided. The determination apparatus (1) includes: measuring means (3) for measuring an optical characteristic value of a measurement region including the discoloration region of the test paper (2); holding means (9) for holding a determination information indicating a relationship between an area of the discoloration region in the measurement region and the optical characteristic value, for each of a plurality of achievement degrees of the predetermined process; and determining means (10) for determining the achievement degree of the predetermined process based on the optical characteristic value of the measurement region of the test paper measured by the measuring means, and the determination information.

Description

COLOR MEASURING APPARATUS AND PROCESS ACHIEVEMENT DEGREE DETERMINATION APPARATUS

The present invention relates to a color measuring technique, and a technique for determining the achievement degree of a predetermined process.

Sterilization of a sterilization target inside a container has been performed by exposing the sterilization target to such an atmosphere as high-pressure steam and hydrogen peroxide. At this time, in order to determine an achievement degree of a sterilization process for the sterilization target, a so-called chemical indicator (hereinafter, CI) for sterilization is used. The CI has a discoloration region that changes in color in accordance with a degree of achievement of a condition necessary for the sterilization process that uses a sterilizing agent (e.g., steam and hydrogen peroxide). An achievement degree of the sterilization process is determined by determining a change in the color of the discoloration region of the CI; however, when the determination is made visually, an error may occur in the determination. For this reason, Japanese Patent Laid-Open No. 2003-325646 discloses a measurement apparatus that measures an achievement degree of a sterilization process by optically reading the color of a discoloration region of a CI.

There are cases where the discoloration region of the CI is formed in a character shape or in a shape of a plurality of dots in order for a user to recognize the discoloration region. When the color of such a discoloration region of the CI is measured by the measurement apparatus disclosed in Japanese Patent Laid-Open No. 2003-325646, it is possible that the measurement result (color measurement result) may differ depending on the ratio between the discoloration region (color measurement target region) and its base that are included in the measurement region of the measurement apparatus. This results in erroneous determination with respect to the achievement degree of a predetermined process such as a sterilizing process. In order to reduce the likelihood of erroneous determination, it is necessary to suppress reduction of accuracy of the color measurement result, even if the ratio of the base included in the measurement region changes.

According to an aspect of the present invention a determination apparatus that determines an achievement degree of a predetermined process using a test paper having a discoloration region whose color changes in accordance with the achievement degree of the predetermined process is provided. The determination apparatus includes: measuring means for measuring an optical characteristic value of a measurement region including the discoloration region of the test paper; holding means for holding a determination information indicating a relationship between an area of the discoloration region in the measurement region and the optical characteristic value, for each of a plurality of achievement degrees of the predetermined process; and determining means for determining the achievement degree of the predetermined process based on the optical characteristic value of the measurement region of the test paper measured by the measuring means, and the determination information.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

FIGS. 1A to 1C are configuration diagrams of a determination apparatus according to one embodiment.

FIG. 2 is a diagram illustrating a CI according to one embodiment.

FIG. 3 is a diagram illustrating a method of determining the achievement degree according to one embodiment.

FIG. 4 is a diagram illustrating a relationship between the CI and a measurement region according to one embodiment.

FIG. 5 is a diagram illustrating spectral reflectance of a discoloration region with respect to a plurality of area ratios of the base inside a measurement region.

FIG. 6 is a diagram illustrating determination information according to one embodiment.

FIG. 7 is a diagram illustrating a CI according to one embodiment.

FIG. 8 is a diagram illustrating spectral reflectance of the discoloration region in each achievement degree.

FIG. 9 is a diagram illustrating determination information according to one embodiment.

FIG. 10 is a diagram illustrating a CI according to one embodiment.

Hereinafter, illustrative embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are illustrative and do not limit the present invention to the contents of the embodiments. Also, in the following diagrams, constituent elements that are not required for describing the embodiments are omitted.

First embodiment
FIGS. 1A and 1B are a side view and a front view of a determination apparatus 1 that determines an achievement degree of the sterilizing process, according to the embodiment. Also, FIG. 1C is a cross-sectional view thereof taken along line A-A in FIG. 1B. The determination apparatus 1 includes an insertion portion 4 for a CI 2, and a conveyance roller pair 6 that conveys the CI 2 inserted into the insertion portion 4 to a measurement position on a downstream side. As shown in FIG. 1A, upon a measurer having inserted the CI 2 from the insertion portion 4, the conveyance roller pair 6 conveys the CI 2 to the measurement position indicated by the solid line in FIG. 1C. A spectrometer 3 is arranged so as to oppose the measurement position. The spectrometer 3 measures the spectral reflectance of a discoloration region of the CI 2 by emitting light 7 to the surface of the CI 2 and receiving the reflected light. After the measurement, the CI 2 is discharged from the determination apparatus 1 by rotating the conveyance roller pair 6 in a reverse direction. A control unit 8 controls the determination apparatus 1. The control unit 8 includes a storage unit 9 for storing various pieces of information used for color measurement and achievement degree determination of the sterilizing process, and a computation processing unit 10 that performs various types of computation processing and the like. Also, the determination apparatus 1 includes a display unit 5. The control unit 8 evaluates the determination result, for example the achievement degree of the sterilizing process, in a predetermined number of levels, and displays the result in the display unit 5 as a sterilization level.

FIG. 2 illustrates the CI 2 according to the present embodiment. The CI 2 is a sheet-like test paper, and includes a discoloration region 21 in which a chemical treatment is performed on the surface thereof. In the example in FIG. 2, the discoloration region 21 is a character portion in which the alphabetic characters "TEST" are displayed. The color of the discoloration region 21 changes in accordance with the achievement degree of the sterilizing process. As shown in FIG. 3, in the present embodiment, the discoloration region 21 of the CI 2 is assumed to be configured such that the discoloration region 21 has a color C#1 in an initial state, and the color thereof changes from the color C#1 to color C#2 and so on, to color C#9 in accordance with the achievement degree of the sterilizing process, and ultimately stabilizes at a color C#10. Hereinafter, the condition achievement degree when the discoloration region 21 has a color C#k (k is an integer from one to ten) is denoted as an achievement degree #k. Note that the color of the discoloration region 21 does not take one of a predetermined number of colors (ten in FIG. 3, namely C#1 to C#10) as shown in FIG. 3, and continuously changes from the color C#1 to C#10. That is, the discoloration region 21 may take a color between a color C#m (m is an integer from one to nine) and a color C#m+1. In the present embodiment, the achievement degree of the sterilizing process is evaluated in nine levels. Specifically, if the color of the discoloration region 21 measured by the spectrometer 3 is in a range from C#m to C#m+1, the level of the sterilizing process is determined to be level#m. Also, level#8 and level#9 are OK levels, and level#1 to level#7 are NG levels, for example. Therefore, the level of the sterilizing process being level#m means that the achievement degree of the sterilizing process is in a range from #m to #m+1.

Here, the region (hereinafter, referred to as a "measurement region") of the CI 2 measured by the spectrometer 3 is a portion of the discoloration region 21 of the CI 2. FIG. 4 shows an example of a relationship between the measurement region 31 and the discoloration region 21. In the present embodiment, it is assumed that, in a state in which the CI 2 has been conveyed to the measurement position by the conveyance roller pair 6, the measurement region 31 is located in the vicinity of the vertical line of a character "T", as shown in FIG. 4. However, the relative positional relationship between the measurement region 31 and the CI 2 may differ for each measurement due to variation in the conveyance state of the CI 2 at the measurement position, variation in the size of the individual CIs 2, and the like. For example, sometimes the region indicated by the broken line square in FIG. 4 may be the measurement region. Here, the spectral reflectance measured by the spectrometer 3 differs depending on the area size of the discoloration region 21 (character portion) and the area size of a base or substrate region (portion in which no character is present) inside the measurement region 31. Therefore, in the present embodiment, a lookup table (LUT), which will be described later, is created as determination information, and the created LUT is stored in the storage unit 9 of the control unit 8 in advance. Also, the computation processing unit 10 of the control unit 8 determines the level of the sterilizing process using the LUT. The method of creating the LUT will be described in the following.

First, the spectral reflectance of the base portion of the CI 2 alone (base 100%), and the spectral reflectance of the discoloration region 21 (character portion) alone (base 0%) with respect to the respective ten stages of achievement degrees #1 to #10, that is, the spectral reflectance of the respective colors C#1 to C#10 are measured. Then, with respect to each of the achievement degrees #1 to #10, the spectral reflectance of the base portion (base 100%) and the spectral reflectance of the color C#k (k is an integer from 1 to 10) (base 0%) are divided into a predetermined number of regions at equal intervals. In the present embodiment, the number of the regions is ten. With this, the spectral reflectance with respect to each of the base ratios 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% for each of the achievement degrees can be obtained, as shown in FIG. 5. Note that the graph in FIG. 5 is for one achievement degree, the achievement degree is evaluated in ten degrees in the present embodiment, and therefore the graph in FIG. 5 is obtained for each of the achievement degrees #1 to #10. Then, the color space value (hereinafter, referred to as a "color value") L*a*b* is obtained from the pieces of spectral reflectance with respect to the respective base ratios at the respective achievement degrees, and the LUT shown in FIG. 6 is created. As shown in FIG. 6, the LUT is information indicating the relationship between the ratio of the area of the base (or the area of the discoloration region 21) inside the measurement region 31 and the color value with respect to each of the plurality of achievement degrees of the sterilizing process.

Next, the method of determining the level of the sterilizing process based on the LUT shown in FIG. 6 will be described. First, the control unit 8 measures the spectral reflectance of the measurement region 31 on the CI 2 using the spectrometer 3, and obtains a color value Ct as the measurement result. The control unit 8 obtains a color difference ΔE* between the color value Ct and each color value in the LUT, and determines the achievement degree and the base ratio corresponding to the color value, of the LUT, whose color difference is minimum. For example, assume that the color value at the achievement degree #2 and the base ratio of 20% has the minimum color difference from the measured color value Ct. In this case, the control unit 8 provisionally determines that the color value Ct is in either of the range from the achievement degree #1 to the achievement degree #2 or the range from the achievement degree #2 to the achievement degree #3. Also, the control unit 8 determines that the base ratio is 20%. In order to determine which of the range from the achievement degree #1 to the achievement degree #2 and the range from the achievement degree #2 to the achievement degree #3, the control unit 8 compares the color difference ΔE*1 between the color value Ct and the color value at the achievement degree #1 and the base ratio of 20% with the color difference ΔE*3 between the color value Ct and the color value at the achievement degree #3 and the base ratio of 20%. Note that the reason why the color difference from the color value at the base ratio of 20% in the LUT is obtained is because the base ratio at which the color difference from the measured color value Ct is minimum is 20%. For example, if ΔE*1 is 12.7 and ΔE*3 is 13.5, the control unit 8 selects the achievement degree #1 with respect to which the color difference is smaller, and finally determines that the color value Ct is in a range from the achievement degree #1 to the achievement degree #2, that is level#1.

Note that if the color difference from the color value Ct is minimum at the achievement degree #1, the control unit 8 makes a final determination that the level is level#1 without making a provisional determination. Similarly, if the color difference from the color value Ct is minimum at the achievement degree #10, the control unit 8 makes final determination that the level is level#9 without making provisional determination. On the other hand, if, with respect to the achievement degree at which the color difference from the color value Ct is minimum, both achievement degrees that are lower and higher than the achievement degree are present in the LUT, the control unit 8 makes final determination as described above. Also, if the color difference from the color value Ct is minimum at the base ratio of 100%, it is highly possible that the discoloration region 21 is not included in the measurement region 31, and therefore the control unit 8 determines that a measurement error has occurred, and can display this fact in the display unit 5.

With the configuration described above, the influence of the base of the CI 2 inside the measurement region 31 can be suppressed, and the achievement degree of the sterilizing process can be determined with high accuracy. That is, the achievement degree of the sterilizing process can be determined with high accuracy, regardless of the shape of the discoloration region 21 of the CI 2 to be used. Note that, in the present embodiment, the level of the sterilizing process is determined by the level in nine stages, as shown in FIG. 3. However, the sterilizing process can also be determined in ten stages of the achievement degree #1 to the achievement degree #10. In this case, the achievement degree at which the color difference from the color value Ct is minimum can be determined as the achievement degree of the sterilizing process as is, for example. Also, in the present embodiment, color values are used in the LUT, and the achievement degree of the sterilizing process is determined based on the color value measured by the spectrometer 3 and the LUT. However, a configuration can be adopted in which any optical characteristic value obtained from the spectral reflectance is used. Moreover, the spectral reflectance itself can be used as the optical characteristic value. Also, the control unit 8 can determine the achievement degree based on one color value Ct obtained by one measurement performed by the spectrometer 7, or can determine the achievement degree based on an average value of a plurality of color values Ct obtained by a plurality of measurements performed by the spectrometer 7.

Note that the determination apparatus 1 can be constituted by an apparatus that determines the achievement degree, and a color measuring apparatus that transmits a color measurement result to the apparatus, for example. The configuration of the color measuring apparatus is similar to the configuration of the determination apparatus 1 shown in FIG. 1. The color measuring apparatus holds/retains an LUT in which, in the field denoted as the achievement degree #1 to the achievement degree #10 shown in FIG. 6, color values of the discoloration region 21 (color measurement target region) of the respective achievement degrees are stored in place of the achievement degrees #1 to #10. Hereinafter, the color values (ten color values) stored in the LUT in place of the achievement degrees #1 to #10 are referred to as reference color values. Also, the control unit 8 of the color measuring apparatus measures the spectral reflectance of the measurement region 31 on the CI 2 using the spectrometer 3, and obtains a color value Ct as the measurement result. The control unit 8 obtains a color difference ΔE* between the color value Ct and each of the color values in the LUT, and determines the reference color value corresponding to the color value in the LUT at which the color difference is minimum. Also, the control unit 8 outputs the reference color value to the apparatus that determines the achievement degree as the color measurement result. With this configuration, even if the ratio of the base included in the measurement region 31 changes, the reduction in accuracy of the color measurement result can be suppressed.

Note that the color measuring apparatus can also output the base ratio that can be determined from the LUT to the apparatus that determines the achievement degree of the sterilizing process in addition to the color measurement result. Also, the apparatus that determines the achievement degree determines, based on the color measurement result or based on both of the color measurement result and the base ratio, the achievement degree of the sterilizing process. Note that the LUT retained in the color measuring apparatus is not limited to the table in which color values corresponding to respective combinations of the reference color value and the base ratio are shown. For example, the LUT retained by the color measuring apparatus may be a table that shows any optical characteristic value corresponding to each of the combinations of the reference color value and the base ratio. Moreover, the spectral reflectance itself can be used as the optical characteristic value.

Second embodiment
Next, a second embodiment will be described focusing on the difference from the first embodiment. FIG. 7 shows a CI 2 according to the present embodiment. In the CI 2 according to the present embodiment, a discoloration region 21 is configured as a plurality of dots.

In the present embodiment as well, the spectral reflectance of a base alone, and the spectral reflectance of the discoloration region 21 alone in each achievement degree are measured in advance. FIG. 8 shows a measurement result. Next, two wavelengths, namely a first wavelength and a second wavelength are selected based on the measurement result of the spectral reflectance of the base and the discoloration region 21 at each achievement degree. Note that how the first wavelength and the second wavelength are to be selected will be described later. In this example, 450 nm is selected as the first wavelength, and 530 nm is selected as the second wavelength. Next, with respect to each achievement degree, the difference between the spectral reflectance of the base and the spectral reflectance of the discoloration region 21 at the first wavelength is obtained as a first difference. Similarly, with respect to each achievement degree, the difference between the spectral reflectance of the base and the spectral reflectance of the discoloration region 21 at the second wavelength is obtained as a second difference. Then, determination information indicating the ratio between the first difference and the second difference at the same achievement degree is created with respect to each achievement degree. FIG. 9 shows the determination information. The determination information shown in FIG. 9 and base information indicating the spectral reflectance of the base at the first wavelength and the second wavelength are stored in the control unit 8 in advance as an LUT.

Next, the method of determining the sterilization level based on the LUT including the base information and the determination information shown in FIG. 9 will be described. First, the control unit 8 measures the spectral reflectance of a measurement region 31 on the CI 2 using the spectrometer 3. Next, the control unit 8 obtains a first difference between the spectral reflectance of the base at the first wavelength indicated by the base information and the spectral reflectance at the first wavelength of the measured spectral reflectance, and a second difference between the spectral reflectance of the base at the second wavelength indicated by the base information and the spectral reflectance at the second wavelength of the measured spectral reflectance. Then, the control unit 8 determines the level of the sterilizing process by comparing the ratio between the first difference and the second difference with the determination information shown in FIG. 9. For example, if the ratio between the obtained first difference and second difference is 0.88, the value falls between the achievement degree #3 and the achievement degree #4, and therefore level#3 is determined. Note that the configuration may be such that the achievement degree #3, which is closest to 0.88, is determined.

Next, the method of selecting the first wavelength and the second wavelength will be described. First, the first wavelength and the second wavelength are selected such that the ratio between the first difference and the second difference differs in each achievement degree. As a result of using the ratio between the first difference at the first wavelength and the second difference at the second wavelength, the first and second wavelengths being selected in this way, the influence due to the area ratio between the dot pattern and the base inside the measurement region 31 is canceled, and the sterilization level can be determined with high accuracy regardless of the size of the discoloration region 21 inside the measurement region 31.

Therefore, as shown in FIG. 8, the first wavelength and the second wavelength can be selected such that the difference between the spectral reflectance of the base at the first wavelength and the spectral reflectance of the base at the second wavelength is less than a third predetermined value. With this, the influence due to the area ratio of the base inside the measurement region 31 can further be suppressed. Also, the first wavelength is selected from wavelengths at which the difference in spectral reflectance between any two achievement degrees is less than a first predetermined value, and the second wavelength is selected from wavelengths at which the difference in spectral reflectance between any two achievement degrees is larger than a second predetermined value, for example. With this, the ratio between the first difference and the second difference can be changed.

Note that, for example, in the vicinity of wavelength 500 nm and in the vicinity of wavelength 600 nm in FIG. 8, although the spectral reflectance differs depending on the achievement degree, the change in spectral reflectance due to the change in wavelength is large. If the second wavelength is selected from wavelengths in such a region, the variation in measurement results of the spectral reflectance increases with the number of measurements. Therefore, a configuration can be adopted in which the second wavelength is selected from a region in which the change (slope) of the spectral reflectance due to the change in wavelength is smaller than a second change amount, for example from the region from the wavelength 520 nm to the wavelength 570 nm in FIG. 8. Note that, in the present embodiment, the change amount means the amount of change in spectral reflectance relative to the change in wavelength, which can be determined from the graph illustrating the relationship between the wavelength and the spectral reflectance shown in FIG. 8. In other words, the second wavelength can be selected such that the difference between a maximum value and a minimum value of the spectral reflectance in a predetermined wavelength range that is centered on the second wavelength is equal to or less than a fourth predetermined value for each achievement degree.

Note that, in FIG. 8, the change in spectral reflectance due to the change in wavelength is small in a wavelength region in which the difference in spectral reflectance due to the achievement degree is small (wavelength 460 nm or less, wavelength 650 nm or more). That is, in FIG. 8, a wavelength range is not present in which the difference in spectral reflectance due to the achievement degree is small, but the change in spectral reflectance due to the change in wavelength is large. However, even if such a wavelength range is present, if the first wavelength is selected from such a wavelength range, the variation in the measurement result of the spectral reflectance increases with the number of measurements. Therefore, a configuration may be adopted in which the first wavelength is also selected from a region in which the change in spectral reflectance due to the change in wavelength is smaller than a first change amount. In other words, the first wavelength can be selected such that the difference between a maximum value and a minimum value of the spectral reflectance in a predetermined wavelength range that is centered on the first wavelength is equal to or less than a fifth predetermined value for each achievement degree. The same applies to the spectral reflectance of the base.

Other embodiments
Note that the CI 2 including the discoloration region 21 in a shape of a plurality of dots that is shown in the second embodiment can be used in the determination of the achievement degree of the sterilizing process according to the first embodiment. Similarly, the CI 2 including the discoloration region 21 in a character shape shown in the first embodiment can be used in the determination of the achievement degree of the sterilizing process according to the second embodiment. More generally, in each of the embodiments described above, the achievement degree of the sterilizing process can be determined while suppressing the influence of the base area inside the measurement region 31, and as a result, the shape of the discoloration region 21 is not limited, and a CI 2 having a discoloration region 21 in any shape can be used. For example, the CI 2 shown in FIG. 10 can be used in the determination of the achievement degree of the sterilizing process according to the first embodiment and the second embodiment. In the CI 2 in FIG. 10, a character (number) "0" and a character "X" are formed on a base, and the character "X" is the discoloration region 21. On the other hand, the character "0" indicates the color of the discoloration region 21 at a predetermined achievement degree, and serves as a reference when visually determining the color of the discoloration region 21.

Also, in each of the embodiments described above, the CI 2 includes the discoloration region 21 whose color is different from that of the base, and the color of the discoloration region 21 changes in accordance with the achievement degree of the sterilizing process. Note that the color of the discoloration region 21 includes transparency. That is, a case where the discoloration region 21 is initially transparent, and a color appears in accordance with the achievement degree of the sterilizing process is included in the case of the change in color of the discoloration region 21 of the present invention. Similarly, a case where the discoloration region 21 is not initially transparent, but the discoloration region 21 becomes transparent in accordance with the achievement degree of the sterilizing process is included in the case of the change in color of the discoloration region 21 of the present invention. Moreover, the base portion may be transparent.

Also, for example, the color of the discoloration region 21 may be initially the same as that of the base. Moreover, the entirety of the discoloration region 21 need not uniformly change in color in accordance with the achievement degree of the sterilizing process. For example, the entirety of the discoloration region 21 initially has the same color as the base, and a portion having a length corresponding to the achievement degree of the sterilizing process may change to a color different from the color of the base. Note that the mode may be such that the discoloration region 21 initially has a portion whose color is different from the color of the base, and the length of a portion having a color different from the color of the base increases in accordance with the achievement degree of the sterilizing process. Conversely, the mode may be such that the length of a portion having a color different from the color of the base decreases as the achievement degree of the sterilizing process increases.

Also, in each of the embodiments described above, the present invention has been described taking the determination apparatus that determines the achievement degree of the sterilizing process as an example. However, the present invention can be applied to the determination of achievement degree of any process in which a test paper having a discoloration region whose color changes in accordance with the achievement degree of the process is used. Moreover, the color measuring apparatus described in the first embodiment can be used to measure the color of any color measurement target.

Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a 'non-transitory computer-readable storage medium') to perform the functions of one or more of the above-described embodiments and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiments, and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiments and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiments. The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)^TM), a flash memory device, a memory card, and the like.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2018-222687, filed on November 28, 2018, which is hereby incorporated by reference herein in its entirety.

Claims

A determination apparatus that determines an achievement degree of a predetermined process using a test paper having a discoloration region whose color changes in accordance with the achievement degree of the predetermined process, the determination apparatus comprising:
measuring means for measuring an optical characteristic value of a measurement region including the discoloration region of the test paper;
holding means for holding a determination information indicating a relationship between an area of the discoloration region in the measurement region and the optical characteristic value, for each of a plurality of achievement degrees of the predetermined process; and
determining means for determining the achievement degree of the predetermined process based on the optical characteristic value of the measurement region of the test paper measured by the measuring means, and the determination information.
The determination apparatus according to claim 1, wherein the optical characteristic value of the measurement region is spectral reflectance of the measurement region.
The determination apparatus according to claim 1, wherein the optical characteristic value of the measurement region is a color value obtained from spectral reflectance of the measurement region.
The determination apparatus according to any one of claims 1 to 3, wherein the determining means determines a first optical characteristic value, of optical characteristic values indicated by the determination information, that is closest to the optical characteristic value of the measurement region of the test paper measured by the measuring means, and determines the achievement degree of the predetermined process based on a first achievement degree corresponding to the first optical characteristic value.
The determination apparatus according to claim 4,
wherein if both of a second achievement degree that is higher in achievement degree of the predetermined process than the first achievement degree and a third achievement degree that is lower in achievement degree of the predetermined process than the first achievement degree are present in the plurality of achievement degrees,
the determining means determines which of a second optical characteristic value at the second achievement degree, indicated by the determination information, when the area of the discoloration region in the measurement region is a first area corresponding to the first optical characteristic value, and a third optical characteristic value at the third achievement degree, indicated by the determination information, when an area of the discoloration region in the measurement region is the first area, is closer to the first optical characteristic value,
if the second optical characteristic value is closer to the first optical characteristic value than the third optical characteristic value is, determines that the achievement degree of the predetermined process is in a range from the first achievement degree to the second achievement degree, and
if the third optical characteristic value is closer to the first optical characteristic value than the second optical characteristic value is, determines that the achievement degree of the predetermined process is in a range from the first achievement degree to the third achievement degree.
A determination apparatus that determines an achievement degree of predetermined process using a test paper having a discoloration region whose color changes in accordance with the achievement degree of the predetermined process, the determination apparatus comprising:
measuring means for measuring spectral reflectance of a measurement region including the discoloration region of the test paper;
holding means for holding base information indicating first spectral reflectance at a first wavelength and second spectral reflectance at a second wavelength, of a base of the test paper, and determination information indicating, for each of a plurality of achievement degrees of the predetermined process, a ratio between a first difference between spectral reflectance of a color of the discoloration region corresponding to an achievement degree at the first wavelength and the first spectral reflectance, and second difference between spectral reflectance of the color of the discoloration region corresponding to the achievement degree at the second wavelength and the second spectral reflectance; and
determining means for determining the achievement degree of the predetermined process based on a ratio between a third difference between the first spectral reflectance and spectral reflectance at the first wavelength measured by the measuring means and a fourth difference between the second spectral reflectance and spectral reflectance at the second wavelength measured by the measuring means, and the determination information.
The determination apparatus according to claim 6, wherein the determining means determines the achievement degree of the predetermined process based on an achievement degree corresponding to the ratio, of ratios indicated by the determination information, which is closest to a ratio between the third difference and the fourth difference.
The determination apparatus according to claim 6 or 7, wherein the first wavelength is a wavelength at which a difference in spectral reflectance between a plurality of colors of the discoloration region corresponding to the plurality of achievement degrees is less than a first predetermined value.
The determination apparatus according to any one of claims 6 to 8, wherein the second wavelength is a wavelength at which a difference in spectral reflectance between a plurality of colors of the discoloration region corresponding to the plurality of achievement degrees is larger than a second predetermined value.
The determination apparatus according to any one of claims 6 to 9, wherein, with respect to a color of the discoloration region at each of the plurality of achievement degrees, an amount of change in spectral reflectance of the color by wavelength at the first wavelength is less than a first change amount.
The determination apparatus according to any one of claims 6 to 10, wherein, with respect to a color of the discoloration region at each of the plurality of achievement degrees, an amount of change in spectral reflectance of the color by wavelength at the second wavelength is less than a second change amount.
The determination apparatus according to any one of claims 6 to 11, wherein the difference between the first spectral reflectance and the second spectral reflectance is less than a third predetermined value.
The determination apparatus according to any one of claims 1 to 12, wherein the predetermined process is a sterilizing process.
A color measuring apparatus comprising:
measuring means for measuring an optical characteristic value of a measurement region including a color measurement target region;
holding means for holding determination information indicating, for each of a plurality of reference colors, a relationship between an area of the color measurement target region in the measurement region and the optical characteristic value; and
selecting means for selecting one of the plurality of reference colors, as a color measurement result of the color measurement target region, based on the optical characteristic value of the measurement region measured by the measuring means and the determination information.
The color measuring apparatus according to claim 14, wherein the optical characteristic value of the measurement region is spectral reflectance of the measurement region.
The color measuring apparatus according to claim 14, wherein the optical characteristic value of the measurement region is a color value obtained from spectral reflectance of the measurement region.
The color measuring apparatus according to any one of claims 14 to 16, wherein the selecting means determines a first optical characteristic value closest to the optical characteristic value of the measurement region measured by the measuring means, of optical characteristic values indicated by the determination information, and selects a reference color corresponding to the first optical characteristic value.