Measurement method, program, and measuring device

Abstract

To suppress an influence of noise or the like included in electromagnetic waves used for measuring a moisture content.SOLUTION: A measurement method for measuring a water content of a measurement object SA by using electromagnetic waves comprises the steps of: applying electromagnetic waves having a predetermined setting frequency to the measurement object SA; receiving electromagnetic waves transmitted through the measurement object SA; calculating a first calculation parameter for calculating a moisture content on the basis of electromagnetic waves before and after being transmitted through the measurement object SA; calculating first multiple calculation parameters for multiple different setting frequencies by changing a setting frequency; and calculating the moisture content of the measurement object SA on the basis of the first multiple calculation parameters calculated for multiple setting frequencies.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a measurement method for measuring the moisture content of an object using electromagnetic waves, a program for causing a computer to execute the measurement method, and a measurement device. [Background technology]

[0002] A measuring device is known that uses electromagnetic waves to measure the moisture content of a predetermined object. The measurement of moisture content using electromagnetic waves utilizes the fact that the dielectric constant of the object changes depending on the moisture content. Therefore, this measuring device includes an irradiating unit that irradiates the object with electromagnetic waves and a receiving unit that receives the electromagnetic waves that have passed through the object, and measures the moisture content from the dielectric constant of the object, which is calculated based on the change in amplitude and the phase delay of the received electromagnetic waves (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-012128 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional methods for measuring moisture content using electromagnetic waves use electromagnetic waves of a specific frequency. In this case, the electromagnetic waves used to measure moisture content may contain noise, making it difficult to measure the moisture content accurately. For example, the electromagnetic waves used to measure moisture content may interfere with other electromagnetic waves having a frequency close to the electromagnetic waves used to measure moisture content, causing noise to be included in the electromagnetic waves used to measure moisture content.

[0005] An object of the present invention is to suppress the influence of noise and the like contained in electromagnetic waves when measuring the moisture content of an object using the electromagnetic waves. [Means for solving the problem]

[0006] A measurement method according to one aspect of the present invention is a method for measuring the moisture content of a measurement object using electromagnetic waves. The measurement method includes the following steps. (a) A step of irradiating an electromagnetic wave having a predetermined set frequency onto an object to be measured. (b) receiving the electromagnetic waves that have passed through the object to be measured; (c) calculating a first calculation parameter for calculating the moisture content based on the electromagnetic wave before and after passing through the object to be measured; (d) calculating a plurality of first calculation parameters for a plurality of different set frequencies by changing the set frequency; (e) calculating the moisture percentage of the object to be measured based on the plurality of first calculation parameters calculated for the plurality of set frequencies;

[0007] A program according to another aspect of the present invention is a program for causing a computer to execute the above-described measurement method.

[0008] A measurement device according to yet another aspect of the present invention measures the moisture content of a measurement object using electromagnetic waves. The measurement device includes an irradiation unit, a receiving unit, and an information processing unit. The irradiation unit irradiates the measurement object with electromagnetic waves having a predetermined set frequency. The receiving unit receives the electromagnetic waves that have passed through the measurement object. The information processing unit calculates a first calculation parameter for calculating the moisture content based on the electromagnetic waves before and after passing through the measurement object, changes the set frequency to calculate multiple first calculation parameters for multiple different set frequencies, and calculates the moisture content of the measurement object based on the multiple first calculation parameters calculated for the multiple set frequencies. [Effects of the Invention]

[0009] In the above-described measurement method and measurement device, the set frequency of the electromagnetic waves irradiated onto the object is changed to calculate a plurality of first calculation parameters for calculating the moisture content of the object for a plurality of different set frequencies, and the moisture content of the object is calculated based on the plurality of first calculation parameters calculated for the plurality of set frequencies. In this way, the moisture content calculated based on the plurality of first calculation parameters for the plurality of set frequencies is calculated with errors contained in the first calculation parameters averaged. Therefore, even if the electromagnetic waves of a particular set frequency contain noise or the like and the first calculation parameters for that set frequency contain large errors, the moisture content calculated based on the plurality of first calculation parameters is accurate because the errors are averaged and small. In other words, the influence of noise or the like of the electromagnetic waves of a particular set frequency is reduced by the first calculation parameters calculated based on the electromagnetic waves of other set frequencies, allowing the moisture content of the object to be calculated with high accuracy. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a measurement device. [Figure 2] 10 is a flowchart showing a method for selecting a set frequency used to measure the moisture content of a measurement object. [Figure 3] FIG. 10 is a diagram showing an example of a calibration curve showing the relationship between the amount of amplitude change / phase delay and moisture content. [Figure 4] FIG. 4 is a diagram showing an example of a calibration curve showing the relationship between a first calculation parameter and moisture content. [Figure 5] 1 is a flowchart showing a method for measuring the moisture content of a measurement object. DETAILED DESCRIPTION OF THE INVENTION

[0011] (1) Measuring device configuration A moisture content measuring device 100 according to one embodiment will be described below with reference to the drawings. The measuring device 100 is a device for measuring the moisture content of a measurement object SA using electromagnetic waves. The measuring device 100 is installed, for example, in a food manufacturing factory.

[0012] As shown in FIG. 1, the measuring device 100 includes an irradiation unit 1, a receiving unit 3, and an information processing unit 5. FIG. 1 is a diagram showing the configuration of the measuring device 100. The irradiation unit 1 is disposed on top of a transport device 7 that transports the measurement object SA. The transport device 7 is, for example, a belt conveyor. The irradiation unit 1 irradiates electromagnetic waves onto the measurement object SA that has been transported by the transport device 7 to the arrangement position of the irradiation unit 1. The irradiation unit 1 is, for example, a horn antenna.

[0013] The receiving unit 3 is disposed at a position facing the irradiating unit 1 and separated by a predetermined distance d, with the transport device 7 in between. The receiving unit 3 receives the electromagnetic waves irradiated from the irradiating unit 1 and passing through the measurement target SA placed on the transport device 7. The receiving unit 3 is, for example, a horn antenna.

[0014] The irradiating unit 1 is movable in a direction toward or away from the receiving unit 3. That is, the distance d between the irradiating unit 1 and the receiving unit 3 is changeable. The movement of the irradiating unit 1 can be realized by a moving mechanism such as a jack, for example.

[0015] The information processing unit 5 controls the measuring device 100 and executes various information processing. The information processing unit 5 has an electromagnetic wave measuring unit 51 and an information processing device 53. The electromagnetic wave measuring unit 51 is connected to the irradiating unit 1 and outputs a high-frequency signal to the irradiating unit 1 for outputting an electromagnetic wave from the irradiating unit 1. The electromagnetic wave measuring unit 51 also inputs the electromagnetic wave received by the receiving unit 3 as a high-frequency signal. The electromagnetic wave measuring unit 51 measures the amount of change in the amplitude of the electromagnetic wave received by the receiving unit 3 relative to the amplitude of the electromagnetic wave irradiated from the irradiating unit 1, and the phase delay of the electromagnetic wave received by the receiving unit 3 relative to the phase of the electromagnetic wave irradiated from the irradiating unit 1. The electromagnetic wave measuring unit 51 is, for example, a vector network analyzer (VNA). The electromagnetic wave irradiated from the irradiating unit 1 has a frequency, for example, on the order of gigahertz (GHz).

[0016] The information processing device 53 is a computer system configured with a CPU, a storage device (RAM, ROM, SSD, hard disk, etc.), various interfaces, and a display device. The information processing device 53 is, for example, a personal computer, a tablet terminal, or a mobile terminal. The information processing device 53 performs various information processes related to the measuring device 100. The information processing device 53 realizes various information processes related to the measuring device 100 by executing programs stored in the storage device that configures the information processing device 53.

[0017] The information processing device 53 is connected to the electromagnetic wave measuring unit 51 and is capable of receiving from the electromagnetic wave measuring unit 51 the above-mentioned change in amplitude and phase delay measured by the electromagnetic wave measuring unit 51. The information processing device 53 calculates the moisture content of the measurement object SA based on a first calculation parameter calculated based on the electromagnetic wave irradiated from the irradiating unit 1 to the measurement object SA (i.e., the electromagnetic wave before passing through the measurement object SA) and the electromagnetic wave that has passed through the measurement object SA and is received by the receiving unit 3 (i.e., the electromagnetic wave after passing through the measurement object SA). As will be described later, in this embodiment, the first calculation parameter is a standardized variate of the ratio of the change in amplitude of the electromagnetic wave after passing through the measurement object SA relative to the electromagnetic wave before passing through the measurement object SA and the phase delay of the electromagnetic wave after passing through the measurement object SA relative to the electromagnetic wave before passing through the measurement object SA (i.e., amplitude change / phase delay).

[0018] In addition, the information processing device 53 irradiates electromagnetic waves having a plurality of different set frequencies onto the measurement object SA, calculates a plurality of first calculation parameters for the different set frequencies, and measures the moisture content of the measurement object SA based on the calculated plurality of first calculation parameters.

[0019] (2) Moisture content measurement method (2-1) How to select the set frequency A method for measuring the moisture content of the measurement object SA using the above-described measurement device 100 will be described below. As described above, the measurement device 100 of this embodiment measures the moisture content of the measurement object SA based on a plurality of first calculation parameters calculated for a plurality of different set frequencies. First, a method for selecting a set frequency to be used in measuring the moisture content of the measurement object SA will be described with reference to Fig. 2. Fig. 2 is a flowchart showing a method for selecting a set frequency to be used in measuring the moisture content of the measurement object SA.

[0020] First, a sample having a known moisture content is placed on the transport device 7, and the sample is placed between the irradiator 1 and the receiver 3 (step S11). Next, the irradiator 1 irradiates the sample with electromagnetic waves having a predetermined frequency (step S12). The receiver 3 receives the electromagnetic waves irradiated by the irradiator 1 and having passed through the sample (step S13). At this time, the irradiator 1 may irradiate the sample with electromagnetic waves having the same frequency multiple times, so that the receiver 3 receives the electromagnetic waves having passed through the sample multiple times.

[0021] Thereafter, the information processing device 53 receives information about the electromagnetic wave irradiated from the irradiating unit 1 (i.e., the electromagnetic wave before passing through the sample) and information about the electromagnetic wave received by the receiving unit 3 (i.e., the electromagnetic wave after passing through the sample) from the electromagnetic wave measuring unit 51, and calculates, based on this information, the ratio of the change in amplitude of the electromagnetic wave after passing through the sample relative to the electromagnetic wave before passing through the sample and the phase delay of the electromagnetic wave after passing through the sample relative to the electromagnetic wave before passing through the sample (amplitude change / phase delay) as second calculation parameters (step S14). Furthermore, the information processing device 53 associates the second calculation parameter with the moisture percentage of the sample, and generates data points consisting of the second calculation parameter and the moisture percentage.

[0022] The information processing device 53 changes the known moisture percentage and repeats steps S11 to S14 above until multiple data points are calculated for multiple types of known moisture percentages (i.e., while step S15 returns "No"), thereby calculating multiple second calculation parameters for multiple different moisture percentages and generating multiple data points.

[0023] After generating the above-mentioned multiple data points, the information processing device 53 uses the generated multiple data points to calculate the selection calibration curve that best matches the multiple data points and the degree of match between the selection calibration curve and the multiple data points (step S16).

[0024] For example, if the selection calibration curve is defined as a linear equation for amplitude change / phase lag, y=a*x+b (x: amplitude change / phase lag, y: moisture content, a, b: constants), the selection calibration curve can be calculated by, for example, fitting the above-mentioned multiple data points to y=a*x+b using the least squares method to determine the constants a and b. Furthermore, the degree of agreement between the calculated selection calibration curve and the multiple data points can be, for example, the correlation coefficient calculated in the above-mentioned fitting.

[0025] In this manner, a selection calibration curve can be calculated for one specific frequency. The information processing device 53 repeatedly executes steps S11 to S16 described above while changing the frequency of the electromagnetic waves irradiated onto the sample (while step S17 returns "No"), and calculates multiple selection calibration curves and degrees of coincidence for multiple frequencies. The more frequencies there are to calculate the selection calibration curve, the better. For example, by changing the frequency of the electromagnetic waves in increments of tens of megahertz (MHz) within a range of several gigahertz (GHz), it is possible to calculate hundreds of selection calibration curves and degrees of coincidence.

[0026] After calculating the degree of agreement with the multiple selection calibration curves, the information processing device 53 selects, from the multiple frequencies at which the degree of agreement with the selection calibration curve was calculated, the frequency at which the degree of agreement was calculated to be greater than or equal to a predetermined threshold, as the setting frequency to be used for measuring the moisture content of the measurement object SA (step S18).

[0027] (2-2) Calculation of the calibration curve The selection calibration curve, calculated by executing steps S11 to S17 above, which shows the relationship between the amplitude change amount / phase delay and the moisture content, differs depending on the frequency irradiated onto the sample, as shown in FIG. 3, for example. Specifically, the range of values ​​that the amplitude change amount / phase delay can take differs depending on the frequency (f1, f2) of the electromagnetic wave. In other words, when using the selection calibration curve, it is difficult to calculate the moisture content of the measurement object SA using common calculation parameters. FIG. 3 shows an example of a calibration curve showing the relationship between the amplitude change amount / phase delay and the moisture content.

[0028] Therefore, in this embodiment, a common calculation parameter that is independent of the frequency of the electromagnetic wave is set as the first calculation parameter for calculating the moisture percentage of the measurement object SA. Then, a calibration curve (referred to as a calculation calibration curve) that represents the relationship between the first calculation parameter that is independent of the frequency of the electromagnetic wave and the moisture percentage is calculated, and the moisture percentage of the measurement object SA is calculated using the first calculation parameter obtained by irradiating the measurement object SA with the electromagnetic wave and the calculation calibration curve.

[0029] A method for calculating the calculation calibration curve will be described below. First, the information processing device 53 converts the multiple amplitude change amounts / phase delays used in calculating the selection calibration curve in steps S11 to S17 above into standardized variables with an average value of 0 and a standard deviation of 1, and generates multiple data points made up of the standardized variables and moisture percentages. Thereafter, the information processing device 53 calculates the calculation calibration curve using the multiple data points.

[0030] For example, when the calculation calibration curve is defined as Y = A*X + B (X: standardized variable, Y: moisture content, A, B: constants), the information processing device 53 can calculate the calculation calibration curve by determining the constants A and B by fitting the above-mentioned multiple data points and Y = A*X + B by the least squares method. By repeatedly performing this for the multiple set frequencies selected in step S18 above, multiple calculation calibration curves can be calculated for the multiple set frequencies.

[0031] The standardized variable of the calibration curve for calculation calculated as described above, that is, the standardized variable obtained by converting the amplitude change amount / phase delay, is used as the first calculation parameter for calculating the moisture percentage of the measurement object SA.

[0032] In this way, by converting the amplitude change amount / phase lag into a standardized variable and using it as the first calculation parameter for calculating the moisture percentage of the object SA to be measured, the range of values ​​that the first calculation parameter can take is approximately the same regardless of the set frequency, as shown in Fig. 4, and the calculation calibration curve showing the relationship between the first calculation parameter and the moisture percentage does not change significantly depending on the set frequency. In other words, by converting the amplitude change amount / phase lag into a standardized variable and using it as the first calculation parameter, the moisture percentage can be calculated using a common first calculation parameter for multiple set frequencies. Fig. 4 is a diagram showing an example of a calibration curve showing the relationship between the first calculation parameter, which is a standardized variable of the amplitude change amount / phase lag, and the moisture percentage.

[0033] (2-3) Method for measuring the moisture content of the object A method for measuring the moisture content of a measurement object SA in the measurement device 100 will be described below with reference to Fig. 5. Fig. 5 is a flowchart showing the method for measuring the moisture content of a measurement object SA. In the following description, it is assumed that n (n: an integer of 2 or more) set frequencies (f1, f2, ... fn) are selected, and n calculation calibration curves (Y = A1 * X + B1, Y = A2 * X + B2, ... Y = An * X + Bn) are calculated for each set frequency.

[0034] First, the measurement object SA is placed on the transport device 7, and the measurement object SA is placed between the irradiation unit 1 and the receiving unit 3 (step S21). Next, the irradiation unit 1 irradiates the measurement object SA with electromagnetic waves having the k-th set frequency (step S23). Furthermore, the electromagnetic waves that have passed through the measurement object SA are received by the receiving unit 3 (step S24). Note that k is 1 immediately after step S21 is performed (step S22).

[0035] In the above steps S23 to S24, the electromagnetic waves having the same kth set frequency may be emitted from the irradiating unit 1 a plurality of times, so that the electromagnetic waves that have passed through the measurement object SA are received by the receiving unit 3 a plurality of times.

[0036] The information processing device 53 receives information about the electromagnetic waves irradiated from the irradiation unit 1 (i.e., the electromagnetic waves before passing through the object to be measured SA) and information about the electromagnetic waves received by the receiving unit 3 (i.e., the electromagnetic waves after passing through the object to be measured SA) from the electromagnetic wave measuring unit 51, and calculates a first calculation parameter for the kth set frequency based on this information (step S25).

[0037] Specifically, based on information regarding the electromagnetic wave before passing through the object to be measured SA and information regarding the electromagnetic wave after passing through the object to be measured SA, the information processing device 53 converts the ratio (amplitude change / phase delay) of the change in amplitude of the electromagnetic wave after passing through the object to be measured SA relative to the electromagnetic wave before passing through the object to be measured SA into a standardized variable with an average value of 0 and a standard deviation of 1, and sets it as the first calculation parameter.

[0038] After calculating the first calculation parameter for the kth set frequency, the information processing device 53 calculates the calculated moisture content for the kth set frequency by substituting the first calculation parameter calculated for the kth set frequency into the calculation calibration curve for the kth set frequency (step S26). For example, if the calculation calibration curve for the kth set frequency is calculated as Y=Ak*X+Bk, the calculated moisture content can be calculated as Ak*Xk+Bk (Xk: first calculation parameter for the kth set frequency) by substituting the first calculation parameter for the kth set frequency for X in the formula.

[0039] After calculating the calculated moisture content for the kth set frequency, the information processing device 53 determines whether or not the above steps S23 to S26 have been executed for all selected set frequencies (step S27). If steps S23 to S26 have not been executed for all set frequencies ("No" in step S27), the information processing device 53 increments k by 1 (k=k+1) (step S28) and executes the above steps S23 to S26 for the next k+1th set frequency.

[0040] On the other hand, if steps S23 to S26 have been executed for all set frequencies ("Yes" in step S27), that is, if n calculated moisture percentages corresponding to n set frequencies have been calculated, the information processing device 53 calculates the average value of the multiple (n) calculated moisture percentages as the moisture percentage of the measurement object SA (step S29). For example, if n calculated moisture percentages have been calculated as Y1 (= A1 * X1 + B1), Y2 (= A2 * X2 + B2), ... Yn (= An * Xn + Bn), the information processing device 53 can calculate the moisture percentage of the measurement object SA as (Y1 + Y2 + ... Yn) / n.

[0041] In the above-mentioned moisture content measurement method, by changing the set frequency of the electromagnetic waves irradiated to the object to be measured SA, multiple first calculation parameters for calculating the moisture content of the object to be measured are calculated for multiple different set frequencies, and the moisture content of the object to be measured SA is calculated based on the multiple first calculation parameters calculated for the multiple set frequencies.

[0042] In this way, the moisture content calculated based on multiple first calculation parameters for multiple set frequencies is calculated with errors included in the first calculation parameters averaged. Therefore, even if, for example, the electromagnetic waves of a specific set frequency contain noise or the like and the first calculation parameters for that set frequency contain large errors, the moisture content calculated based on multiple first calculation parameters will be accurate because the errors have been averaged and are small. In other words, the influence of noise or the like in the electromagnetic waves of a specific set frequency is reduced by the first calculation parameters calculated based on electromagnetic waves of other set frequencies, allowing the moisture content of the measurement object to be calculated with high accuracy.

[0043] For example, even if the calculated moisture content calculated based on the first calculation parameters for a specific set frequency is calculated as a value significantly different from the true moisture content due to an error contained in the first calculation parameters, the errors contained in the first calculation parameters for other set frequencies are small, so the calculated moisture content calculated for the other set frequencies will have small errors. Therefore, by averaging the multiple calculated moisture content values ​​calculated for multiple set frequencies as the final moisture content, the errors contained in the calculated moisture content are averaged, and the effects of noise and other factors contained in the electromagnetic waves of the specific set frequency can be reduced. As a result, the final moisture content will be accurate and have few errors.

[0044] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0045] The processing order and / or processing contents of each step in the flowcharts shown in FIGS. 2 and 5 can be changed as appropriate without departing from the gist of the invention. For example, steps S23 to S26 in FIG. 5 are not limited to being repeatedly executed in the order of the first set frequency, the second set frequency, ..., the nth set frequency, and the set frequency for which steps S23 to S26 are executed can be arbitrarily determined as long as the set frequencies do not overlap.

[0046] The irradiating unit 1 may irradiate the measurement object SA with a first electromagnetic wave, and receive the electromagnetic wave reflected by a reflecting member or the like after passing through the measurement object SA. In other words, the irradiating unit 1 may also have the function of the above-mentioned receiving unit 3. In this case, the receiving unit 3 can be omitted.

[0047] For example, the relationship between the first calculation parameter and the moisture content is not limited to a calibration curve that expresses the moisture content as a linear expression of the first calculation parameter. The relationship may be, for example, a calibration curve that expresses the moisture content as a higher-order expression for the first calculation parameter (for example, Y=C1*X+C2*X 2 +···+D1 (X: first calculation parameter, Y: moisture content, C1, C2, . . . , D1: constant)).

[0048] Furthermore, the relationship between the first calculation parameter and the moisture content may be expressed as a trained model obtained by machine learning (e.g., learning by artificial intelligence such as deep learning) based on at least the first calculation parameter and the moisture content. For example, the relationship may be a trained model in which the first calculation parameter is used as an input and the moisture content is used as an output. Other parameters, such as a set frequency, may also be used as inputs to this trained model.

[0049] Even when using a trained model for the relationship between the first calculation parameter and moisture content, electromagnetic waves having a predetermined frequency are irradiated onto a sample having a known moisture content, and the second calculation parameter is calculated based on the electromagnetic waves before and after passing through the sample.By changing the moisture content of the sample, multiple second calculation parameters can be calculated for multiple different moisture content values, and multiple trained models representing the relationship between the second calculation parameter and moisture content can be generated for multiple frequencies based on the multiple second calculation parameters and multiple moisture content values.

[0050] In this case, the degree of agreement between the value output when the second calculation parameter is input into one of the multiple trained models and the moisture content is expressed as a score, and the frequency that generated the trained model whose score is above a predetermined threshold can be selected as the set frequency.

[0051] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0052] (First Aspect) The measurement method is a method for measuring the moisture content of a measurement object using electromagnetic waves. The measurement method includes the following steps. The order of the steps (a) to (e) below is not limited to any particular order. (a) A step of irradiating an electromagnetic wave having a predetermined set frequency onto a measurement object (for example, measurement object SA). (b) receiving the electromagnetic waves that have passed through the object to be measured; (c) calculating a first calculation parameter for calculating the moisture content based on the electromagnetic wave before and after passing through the object to be measured; (d) calculating a plurality of first calculation parameters for a plurality of different set frequencies by changing the set frequency; (e) calculating the moisture percentage of the object to be measured based on the plurality of first calculation parameters calculated for the plurality of set frequencies;

[0053] In the measurement method according to the first aspect, the set frequency of the electromagnetic waves irradiated onto the object is changed to calculate a plurality of first calculation parameters for calculating the moisture content of the object for a plurality of different set frequencies, and the moisture content of the object is calculated based on the plurality of first calculation parameters calculated for the plurality of set frequencies. In this way, the moisture content calculated based on the plurality of first calculation parameters for the plurality of set frequencies is calculated with errors contained in the first calculation parameters averaged. Therefore, even if the electromagnetic waves of a particular set frequency contain noise or the like and the first calculation parameters for that set frequency contain large errors, the moisture content calculated based on the plurality of first calculation parameters is accurate because the errors are averaged and small. In other words, the influence of noise or the like of the electromagnetic waves of a particular set frequency is reduced by the first calculation parameters calculated based on electromagnetic waves of other set frequencies, allowing the moisture content of the object to be calculated with high accuracy.

[0054] (Second Aspect) The measurement method of the first aspect may further comprise the following steps: The following steps (f) to (l) do not limit the order of the steps. (f) irradiating a sample having a known moisture content with electromagnetic waves having a predetermined frequency. (g) receiving the electromagnetic waves that have passed through the sample; (h) calculating a second calculation parameter based on the electromagnetic wave before and after passing through the sample; (i) calculating a plurality of second calculation parameters for a plurality of different moisture percentages by changing the moisture percentage of the sample; (j) A step of calculating the degree of agreement between a model representing the relationship between the second calculation parameters and the moisture content, based on the plurality of second calculation parameters and the plurality of moisture content, and the data points used in calculating the model. (k) calculating a plurality of degrees of coincidence for a plurality of different frequencies by changing the frequency; (l) A step of determining, as a set frequency, a frequency among the plurality of frequencies when a degree of match equal to or greater than a predetermined threshold is calculated.

[0055] In the measurement method according to the second aspect, the frequency at which the model representing the relationship between the second calculation parameter and the moisture content closely matches the data points used to calculate the model is set as the set frequency used to measure the moisture content of the object, so that electromagnetic waves of a set frequency suitable for measuring the moisture content of the object can be used to measure the moisture content of the object, thereby enabling more accurate measurement of the moisture content of the object.

[0056] (Third Aspect) In the measurement method of the first or second aspect, the step of calculating the moisture content of the measurement object may include the following steps, where the steps (m) and (n) below do not limit the order of the steps: (m) calculating the calculated moisture content by inputting the first calculation parameter calculated for each set frequency into a calculation model that represents the relationship between the first calculation parameter for each set frequency and the moisture content; (n) A step of repeating the step of calculating the calculated moisture percentages the number of times equal to the set frequencies, and setting the average value of the calculated moisture percentages as the moisture percentage.

[0057] In the measurement method according to the third aspect, even if the calculated moisture content calculated based on the first calculation parameter for a specific set frequency is calculated as a value significantly different from the true moisture content due to an error contained in the first calculation parameter, the error contained in the first calculation parameter for other set frequencies is small, so the calculated moisture content calculated for the other set frequencies will have a small error. Therefore, by averaging the multiple calculated moisture content values ​​calculated for multiple set frequencies as the final moisture content, the error contained in the calculated moisture content is averaged, and the influence of noise and the like contained in the electromagnetic waves of the specific set frequency can be reduced. As a result, the final moisture content is accurate and has a small error.

[0058] (Fourth Aspect) In the measurement method of the third aspect, the calculation model may be a calculation calibration curve that represents the relationship between the first calculation parameter and the moisture content, thereby enabling an accurate calculated moisture content to be calculated.

[0059] (Fifth Aspect) In the measurement method of the third aspect, the calculation model may be a trained model obtained by machine learning based on at least the first calculation parameter and the moisture content. In the measurement method according to the fifth aspect, the calculated moisture content can be calculated simply by inputting the first calculation parameter into the trained model.

[0060] (Sixth Aspect) In the measurement method of any one of the first to fifth aspects, the first calculation parameter may be a standardized variable of the ratio between the change in amplitude of the electromagnetic wave after passing through the object to the electromagnetic wave before passing through the object, and the phase delay of the electromagnetic wave after passing through the object to the electromagnetic wave before passing through. In the measurement method according to the sixth aspect, the moisture content can be calculated for a plurality of set frequencies using a common first calculation parameter that is independent of the set frequencies.

[0061] (Seventh Aspect) A program of the seventh aspect is a program that causes a computer to execute the measurement method according to any one of the first to sixth aspects.

[0062] (Eighth Aspect) A measurement device (e.g., measurement device 100) is a measurement device that measures the moisture content of a measurement object using electromagnetic waves. The measurement device includes an irradiation unit (e.g., irradiation unit 1), a receiving unit (e.g., receiving unit 3), and an information processing unit (e.g., information processing unit 5). The irradiation unit irradiates the measurement object with electromagnetic waves having a predetermined set frequency. The receiving unit receives the electromagnetic waves that have passed through the measurement object. The information processing unit calculates a first calculation parameter for calculating the moisture content based on the electromagnetic waves before and after passing through the measurement object, changes the set frequency to calculate multiple first calculation parameters for multiple different set frequencies, and calculates the moisture content of the measurement object based on the multiple first calculation parameters calculated for the multiple set frequencies.

[0063] In a measurement device according to an eighth aspect, the moisture content of the object to be measured is calculated based on a plurality of first calculation parameters calculated for a plurality of set frequencies. In this way, the moisture content calculated based on a plurality of first calculation parameters for a plurality of set frequencies is calculated with errors contained in the first calculation parameters averaged. Therefore, even if the electromagnetic waves of a particular set frequency contain noise or the like, and the first calculation parameters for that set frequency contain large errors, the moisture content calculated based on the plurality of first calculation parameters is accurate because the errors have been averaged and are small. In other words, the influence of noise or the like of the electromagnetic waves of a particular set frequency is reduced by the first calculation parameters calculated based on the electromagnetic waves of other set frequencies, allowing the moisture content of the object to be calculated with high accuracy. [Explanation of symbols]

[0064] 100: Measuring equipment 1: Irradiation unit 3: Receiving section 5: Information Processing Section 51: Electromagnetic wave measurement section 53: Information processing equipment 7:Transportation device SA: Measurement object

Claims

1. A measurement method for measuring the moisture content of a measurement object using electromagnetic waves, comprising: irradiating the object to be measured with electromagnetic waves having a predetermined set frequency; receiving an electromagnetic wave that has passed through the object to be measured; calculating a first calculation parameter for calculating the moisture percentage based on the electromagnetic waves before and after passing through the measurement object; calculating a plurality of first calculation parameters for a plurality of different set frequencies by changing the set frequency; calculating a moisture percentage of the object to be measured based on a plurality of first calculation parameters calculated for a plurality of set frequencies; A measurement method comprising:

2. irradiating a sample having a known moisture content with electromagnetic waves having a predetermined frequency; receiving the electromagnetic wave that has passed through the sample; calculating a second calculation parameter based on the electromagnetic wave before and after passing through the sample; calculating a plurality of second calculation parameters for a plurality of different moisture percentages by changing the moisture percentage of the sample; a step of calculating a degree of agreement between a model representing the relationship between the second calculation parameters and the moisture percentages and data points used to calculate the model, based on the second calculation parameters and the moisture percentages; calculating a plurality of degrees of coincidence for a plurality of different frequencies by changing the frequency; determining, as the set frequency, a frequency among a plurality of frequencies at which the degree of coincidence equal to or greater than a predetermined threshold is calculated; The measurement method of claim 1 further comprising:

3. The step of calculating the moisture content of the measurement object includes: a step of calculating a calculated moisture content by inputting the first calculation parameter calculated for each set frequency into a calculation model that represents the relationship between the first calculation parameter for each set frequency and the moisture content; a step of repeating the step of calculating the calculated moisture percentage by the number of set frequencies and setting the average value of the calculated moisture percentages as the moisture percentage; The measurement method of claim 1 , comprising:

4. The measurement method according to claim 3 , wherein the calculation model is a calculation calibration curve that represents the relationship between the first calculation parameter and the moisture content.

5. The measurement method according to claim 3 , wherein the calculation model is a trained model obtained by machine learning based on at least the first calculation parameter and the moisture content.

6. 2. The measurement method according to claim 1, wherein the first calculation parameter is a standardized variate of a ratio between an amplitude change of the electromagnetic wave after passing through the object to the electromagnetic wave before passing through the object, and a phase delay of the electromagnetic wave after passing through the object to the electromagnetic wave before passing through the object.

7. A program that causes a computer to execute the measurement method according to any one of claims 1 to 6.

8. A measuring device for measuring the moisture content of a measurement object using electromagnetic waves, an irradiation unit that irradiates the measurement object with electromagnetic waves having a predetermined set frequency; a receiving unit that receives electromagnetic waves that have passed through the object to be measured; an information processing unit that calculates a first calculation parameter for calculating the moisture percentage based on the electromagnetic waves before and after passing through the object to be measured, calculates a plurality of first calculation parameters for a plurality of different set frequencies by changing the set frequency, and calculates the moisture percentage of the object to be measured based on the plurality of first calculation parameters calculated for the plurality of set frequencies; A measuring device comprising:

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