WO2023047851A1 - Calibration device, calibration method, and program - Google Patents

Calibration device, calibration method, and program Download PDF

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Publication number
WO2023047851A1
WO2023047851A1 PCT/JP2022/031236 JP2022031236W WO2023047851A1 WO 2023047851 A1 WO2023047851 A1 WO 2023047851A1 JP 2022031236 W JP2022031236 W JP 2022031236W WO 2023047851 A1 WO2023047851 A1 WO 2023047851A1
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calibration
sensor
calibrated
calibration target
detection values
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PCT/JP2022/031236
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French (fr)
Japanese (ja)
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宣博 石田
鉄三 原
昌宏 石井
優太 大吉
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株式会社村田製作所
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance

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  • the present disclosure relates to a calibration device, a calibration method, and a program.
  • Non-Patent Document 1 discloses a method for calibrating a capacitive soil moisture sensor.
  • Non-Patent Document 1 the soil near the sensor is collected, and the oven drying method (a method of evaporating the moisture of the soil in a drying oven and calculating the moisture content from the weight change before and after drying).
  • a calibration formula is obtained by comparing the obtained moisture content with the sensor output.
  • An object of the present disclosure is to provide a calibration device, a calibration method, and a program that can easily perform accurate calibration with less effort.
  • a calibration device includes an arithmetic circuit and a storage device,
  • the arithmetic circuit is A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium.
  • obtaining and storing in the storage device a plurality of calibrated detected values for the amount of moisture in the medium detected at the time;
  • a calibration formula for calibrating the plurality of calibration target detection values is calculated with reference to the plurality of reference detection values.
  • a calibration method comprises: A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining a plurality of calibrated sensed values for the amount of moisture in the medium sensed at a time; calculating a calibration formula for calibrating the plurality of calibration target detection values with reference to the plurality of reference detection values; including.
  • Yet another aspect of the present disclosure includes: A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining a plurality of calibrated sensed values for the amount of moisture in the medium sensed at a time; calculating a calibration formula for calibrating the plurality of calibration target detection values with reference to the plurality of reference detection values; to be executed by the arithmetic circuit.
  • FIG. 1 is a schematic diagram showing the configuration of a calibration system 100 according to a first embodiment of the present disclosure
  • FIG. 1 is a block diagram showing a configuration example of a calibration device 1 according to a first embodiment of the present disclosure
  • FIG. 4 is a flow chart for explaining the operation of the calibration device 1 according to the first embodiment of the present disclosure
  • FIG. 3 is a schematic diagram showing the configuration of a calibration system 200 according to a second embodiment of the present disclosure
  • FIG. 9 is a flow chart for explaining a calibration operation by the calibration device 1 of the calibration system 200 according to the second embodiment of the present disclosure
  • FIG. 11 is a flow chart for explaining a calibration operation by the calibration device 1 of the calibration system 200 according to the third embodiment of the present disclosure
  • a soil moisture sensor that measures soil moisture is sometimes used to determine the timing of irrigating crops.
  • a soil moisture sensor a capacitance type soil moisture sensor that measures the capacitance of soil is known.
  • Soil is mainly composed of water, air, and soil particles. Water has a dielectric constant of about 80, while air has a low dielectric constant of 1 and soil particles have a small capacitance of about 2 to 5. Therefore, the capacitance of the entire soil is There is a correlation with the moisture content of Therefore, the capacitance soil moisture sensor can detect the moisture content of the soil by measuring the capacitance of the entire soil.
  • the capacitance type soil moisture sensor generally uses a measurement frequency of several tens of MHz to 100 MHz, and is affected by the electrical conductivity of the soil. Without calibration, it may not be possible to measure the moisture content with good accuracy.
  • An example of a method for calibrating a capacitance soil moisture sensor is to collect soil near the sensor and measure the moisture content of the sampled soil in dry, wet, and intermediate conditions using an oven drying method (soil moisture content in a drying oven). is evaporated and the moisture content is calculated from the weight change before and after drying), and the moisture content between each state is compared with the sensor output to determine the calibration formula. Even if the calibration is completed once, if the ambient environment such as season, soil type, temperature, electrical conductivity, etc. changes, the calibration must be performed again to accurately measure the moisture content. Thus, it takes time and effort to accurately measure the moisture content using a capacitance type soil moisture sensor, requiring a great deal of man-hours and operating costs for calibration.
  • a TDR sensor and a TDT sensor are also known as soil moisture sensors.
  • the TDR sensor measures the dielectric constant of soil by the Time Domain Reflectometry method (TDR method) and detects the water content of the soil based on the measurement result.
  • the TDT sensor measures the dielectric constant of soil by the Time Domain Transmission method (TDT method) and detects the moisture content of the soil based on the measurement result.
  • TDR and TDT sensors which have measurement frequencies ranging from several hundred MHz to several GHz, can accurately detect the moisture content of soil without the need for time-consuming calibration, which is required for capacitance-type soil moisture sensors. It can be done, but is significantly more expensive than a capacitive soil moisture sensor.
  • the inventors conducted research to solve the above problems, and came up with a calibration device, a calibration method, and a program that can easily perform accurate calibration with less effort.
  • FIG. 1 is a schematic diagram showing the configuration of a calibration system 100 according to the first embodiment of the present disclosure.
  • the calibration system 100 includes a calibration device 1, a calibration target sensor 2 to be calibrated, and a standard sensor (reference sensor) 3 that serves as a calibration standard.
  • the calibration target sensor 2 and the reference sensor 3 are connected to the calibration device 1 by wire or wirelessly.
  • the calibration target sensor 2 and the reference sensor 3 are soil moisture sensors that are placed in the soil 4 and measure the moisture content of the soil 4, for example, the volumetric moisture content.
  • Soil 4 is an example of the "medium” of this disclosure.
  • the medium includes soil as well as substances such as powders and granules.
  • the sensor to be calibrated 2 and the reference sensor 3 are placed in the same environment, eg soil 4, which undergoes similar weather changes.
  • the sensor to be calibrated 2 and the reference sensor 3 are placed in close proximity in the soil 4, eg at a distance of less than 10 m, or eg at a distance of less than 1 m.
  • the calibration target sensor 2 is a capacitive soil moisture sensor that measures the capacitance from the charging time of the capacitor in the calibration target sensor 2 .
  • the reference sensor 3 is a TDR sensor or a TDT sensor.
  • the calibration system 100 calibrates the calibration target sensor 2 using the calibration device 1 based on the detection result of the reference sensor 3 . Details of the calibration operation will be described later. After calibration is complete, the reference sensor 3 is removed from the soil 4 and is available for calibrating other capacitive soil moisture sensors, for example.
  • the calibration target sensor 2 can be calibrated based on the accurate detection result of the reference sensor 3, and even if an inexpensive sensor is adopted as the calibration target sensor 2, the calibration target sensor 2, an accurate detection result can be obtained.
  • the excavated soil 4 is different from the soil of the place where the crops are actually cultivated, and the moisture content and the crops of the place where the calibration target sensor 2 is installed are different. There is a possibility that there will be a difference between the moisture content of the place where it is cultivated.
  • the calibration system 100 since the soil 4 near the calibration target sensor 2 is not collected, the difference between the moisture content at the location where the calibration target sensor 2 is installed and the moisture content at the location where the crops are cultivated is can be reduced.
  • FIG. 2 is a block diagram showing a configuration example of the calibration device 1 according to this embodiment.
  • the calibration device 1 includes an arithmetic circuit 11 , a storage device 12 and an input/output interface (I/F) 13 .
  • I/F input/output interface
  • the arithmetic circuit 11 performs information processing to realize the functions of the calibration device 1 . Such information processing is realized, for example, by operating the arithmetic circuit 11 according to instructions of a program stored in the storage device 12 .
  • the arithmetic circuit 11 is composed of circuits such as a CPU, MPU, and FPGA, for example.
  • the storage device 12 includes recording media for recording various information including programs and data necessary for realizing the functions of the calibration device 1 .
  • the storage device 12 stores detected values obtained from the calibration target sensor 2 and the reference sensor 3 in FIG.
  • the storage device 12 is realized by, for example, a semiconductor storage device such as a flash memory, a solid state drive (SSD), a magnetic storage device such as a hard disk drive (HDD), or other recording media alone or in combination.
  • Storage device 12 may include volatile memory such as SRAM, DRAM, and the like.
  • the input/output I/F 13 is an interface circuit that connects the calibration device 1 and external devices in order to transmit and receive information to and from external devices such as the calibration target sensor 2 and the reference sensor 3 .
  • the input/output I/F 103 may be a communication circuit that performs data communication according to existing wired communication standards or wireless communication standards.
  • FIG. 3 is a flowchart for explaining the operation of the calibration device 1 according to this embodiment. Each processing shown in the flowchart of FIG. 3 is executed by the arithmetic circuit 11 of the calibration device 1 .
  • the arithmetic circuit 11 determines whether or not the measurement start condition is satisfied (S1). For example, when the arithmetic circuit 11 receives an embedding completion signal indicating completion of embedding in the soil 4 from each of the calibration target sensor 2 and the reference sensor 3, it determines that the measurement start condition is satisfied. Such an burying completion signal is transmitted to the calibrating device 1 when the burying operator presses a predetermined button switch provided on each of the calibration target sensor 2 and the reference sensor 3 . Alternatively, when the arithmetic circuit 11 receives an burying completion signal from the information processing terminal used by the burying worker, it determines that the measurement start condition is satisfied.
  • the arithmetic circuit 11 obtains detection results from both the calibration target sensor 2 and the reference sensor 3, and the measurement start condition is satisfied. It may be determined that
  • the arithmetic circuit 11 detects calibration data detected in time series from each of the calibration target sensor 2 and the reference sensor 3 within a predetermined period after the measurement start condition is met.
  • a target detection value group and a reference detection value group are acquired (S2).
  • the predetermined period is four days, and the arithmetic circuit 11 acquires 96 calibration target detection values and reference detection values measured every hour from the calibration target sensor 2 and the reference sensor 3, respectively.
  • a plurality of calibration target detection values and reference detection values acquired in step S2 are stored in the storage device 12 after being associated with detection times.
  • the reference moisture content which is the reference detection value detected by the reference sensor 3, and the calibration target detection value detected at the same time as the reference moisture content are stored in the storage device 12 after being associated with the detection time. be done.
  • the arithmetic circuit 11 calculates a first calibration formula for calibrating the calibration target detection value group with reference to the reference detection value group acquired in step S2 (S3).
  • the storage device 12 stores the reference moisture content (y 1 , y 2 , .
  • a plurality of data sets (for example, 96 sets) of calibration target detection values (x 1 , x 2 , . . . , x n ) detected at the same time are stored. Based on these data sets, the arithmetic circuit 11 calculates a first calibration formula for fitting the calibration target detection value group to the reference detection value group. Regression analysis such as the method of least squares is used to calculate the first calibration formula.
  • the calibration equation is not limited to cubic equations as described above.
  • the arithmetic circuit 11 determines whether or not the absolute value
  • the threshold R th1 is, for example, 0.2 to 0.7.
  • the arithmetic circuit 11 When the absolute value
  • the arithmetic circuit 11 may output a signal indicating the measurement error to a display device such as a display, an LED, etc., display text indicating the measurement error, and/or flash the LED in red.
  • step S5 the notification of the measurement error allows the user to know that an abnormal situation may occur, and the abnormal situation is resolved by checking the burial site of the calibration target sensor 2 and the reference sensor 3. early opportunity to do so.
  • the arithmetic circuit 11 selects a detected value equal to or greater than the upper threshold value ⁇ max in the reference detected value group, and It is determined whether or not there is a detected value equal to or lower than the lower limit threshold ⁇ min (S6).
  • the upper threshold value ⁇ max is set to, for example, the upper saturation value of the water content or a value slightly smaller than the upper saturation value of the water content at which the water content of the soil 4 does not increase even if water is added to further moisten the soil 4 .
  • the upper threshold ⁇ max is set to 0.45, for example.
  • the lower limit threshold ⁇ min is set to the lower limit of the water content of the soil 4 or a value slightly larger than it.
  • the lower threshold ⁇ min is set to a value such as 0.1 or 0.25 that is smaller than the upper threshold ⁇ max , for example.
  • the arithmetic circuit 11 further controls the sensor 2 to be calibrated for a predetermined period. Detected values are acquired from the reference sensor 3 and a data set is accumulated (S7). That is, in the case of No in step S6, the arithmetic circuit 11 further acquires the calibration target detection value group and the reference detection value group detected in time series within a predetermined period from the calibration target sensor 2 and the reference sensor 3, respectively. . After step S7, the process proceeds to step S6.
  • step S6 if there are detected values equal to or higher than the upper threshold ⁇ max and detected values equal to or lower than the lower threshold ⁇ min in the group of reference detected values (Yes in S6), the arithmetic circuit 11 obtains in steps S2 and S7 A second calibration formula for calibrating the calibration target detection value group obtained in steps S2 and S7 is calculated using the obtained reference detection value group as a reference (S8).
  • the calculation method of the second calibration formula is the same as the calculation method of the first calibration formula in step S3.
  • the arithmetic circuit 11 determines whether or not the absolute value
  • the threshold R th2 is greater than the threshold R th1 , and ranges from 0.4 to 1, for example.
  • the arithmetic circuit 11 When the absolute value
  • a display device such as a display, LED, etc.
  • step S9 If the absolute value
  • the reference sensor 3 is removed from the soil 4 and can be used for calibrating other capacitive soil moisture sensors, for example.
  • the calibration device 1 includes the arithmetic circuit 11 and the storage device 12 .
  • the arithmetic circuit 11 obtains a plurality of reference detection values and a plurality of calibration target detection values and stores them in the storage device (S2, S7).
  • the plurality of reference detection values relate to the amount of water in the soil 4 detected at a plurality of times by the reference sensor 3 arranged in the soil 4 .
  • the plurality of calibration target detection values relate to the amount of moisture in the soil 4 detected by the calibration target sensor 2 placed in the soil 4 at times respectively corresponding to the plurality of times.
  • Arithmetic circuit 11 calibrates a plurality of calibration target detection values with reference to a plurality of reference detection values (S8).
  • the calibration can be performed while the calibration target sensor 2 is placed in the soil 4. Therefore, during calibration, the soil 4 near the calibration target sensor 2 is collected, and the collected soil 4 is dried by the oven drying method. There is no need to perform time-consuming work such as moisture content measurement. Moreover, since the soil 4 near the sensor 2 to be calibrated is not collected during calibration, there is no risk of damaging crops or the like when digging up the soil 4 .
  • the excavated soil 4 is different from the soil of the place where the crops are actually cultivated, and the moisture content and the crops of the place where the calibration target sensor 2 is installed are different. There is a possibility that there will be a difference between the moisture content of the place where it is cultivated.
  • the calibration system 100 since the soil 4 near the calibration target sensor 2 is not collected, the difference between the moisture content at the location where the calibration target sensor 2 is installed and the moisture content at the location where the crops are cultivated is can be reduced.
  • the reference sensor 3 may be a TDR sensor or a TDT sensor that detects a plurality of reference detection values by the TDR method or TDT method.
  • the calibrated sensor 2 may be a capacitive sensor that detects a plurality of calibrated detected values based on soil capacitance.
  • the calibration target sensor 2 can be calibrated based on the accurate detection result of the reference sensor 3, and even if an inexpensive capacitance sensor is adopted as the calibration target sensor 2, after calibration Accurate detection results can be obtained from the calibration target sensor 2 of .
  • FIG. 4 is a schematic diagram showing the configuration of a calibration system 200 according to a second embodiment of the present disclosure.
  • a calibration system 200 according to the present embodiment differs from the calibration system 100 (see FIG. 1) according to the first embodiment in that it includes a plurality of sensors 2 to be calibrated.
  • FIG. 4 illustrates nine sensors 2 to be calibrated.
  • the reference sensor 3 and the plurality of sensors to be calibrated 2 are both wired or wirelessly connected to the calibration device 1, but the connection lines are not shown in FIG. 4 to avoid complication of the drawing.
  • At least one of the sensors 2 to be calibrated and the reference sensor 3 are placed in close proximity in the soil 4, for example at a distance of less than 10 m, or at a distance of less than 1 m, for example.
  • Other sensors 2 to be calibrated are placed in the same environment, eg soil 4, undergoing similar weather changes.
  • Other sensors 2 to be calibrated need not be in close proximity to said at least one sensor 2 to be calibrated.
  • another sensor to be calibrated 2 may be placed in the soil 4 at a distance of several meters to several hundred meters from the at least one sensor to be calibrated 2 . Even with such a distance, the soil 4 is generally homogeneous in the field, and the environment such as the weather is often the same. can be well calibrated.
  • FIG. 5 is a flow chart for explaining the calibration operation by the calibration device 1 of the calibration system 200 according to this embodiment.
  • FIG. 5 is a flow chart for explaining the calibration operation by the calibration device 1 of the calibration system 200 according to this embodiment.
  • portions different from the operations of the calibration apparatus 1 according to the first embodiment shown in FIG. 3 will be described, and descriptions of similar operations will be omitted.
  • the arithmetic circuit 11 determines whether or not the measurement start condition is satisfied (S201). For example, when the arithmetic circuit 11 receives embedding completion signals from all of the reference sensor 3 and the plurality of calibration target sensors 2, it determines that the measurement start condition is satisfied. Alternatively, the arithmetic circuit 11 may determine that the measurement start condition is satisfied when detection results are obtained from all of the reference sensor 3 and the plurality of calibration target sensors 2 .
  • the arithmetic circuit 11 detects in time series from each of the reference sensor 3 and the plurality of calibration target sensors 2 within a predetermined period after the measurement start condition is met. A group of reference detected values and a group of detected values to be calibrated are acquired (S202).
  • the arithmetic circuit 11 calculates a third calibration formula for calibrating the average value of the calibration target detection value group based on the reference detection value group acquired in step S202 (S203).
  • the arithmetic circuit 11 determines whether or not the absolute value
  • the arithmetic circuit 11 selects a detected value equal to or greater than the upper threshold value ⁇ max in the reference detected value group, and It is determined whether or not there is a detected value equal to or lower than the lower limit threshold ⁇ min (S6). If Yes in step S6, the arithmetic circuit 11 calibrate the average value of the calibration target detection value group obtained in steps S202 and S7 with reference to the reference detection value group obtained in steps S202 and S7. A calibration formula is calculated (S208).
  • the arithmetic circuit 11 determines whether or not the absolute value
  • the arithmetic circuit 11 of the calibration device 1 calibrates a plurality of calibration target detection values detected by each calibration target sensor with reference to a plurality of reference detection values, thereby obtaining a plurality of The calibration target sensor 2 is calibrated.
  • the calibration system according to this embodiment has similar calibrations as the calibration system 200 according to the second embodiment shown in FIG. In this embodiment, the same reference numerals as in the second embodiment are used for the same components as in the second embodiment.
  • the reference sensor 3 and the plurality of calibration target sensors 2 further detect temperature in this embodiment.
  • those sensors 2 to be calibrated that detect temperature changes similar to those detected by the reference sensor 3 are configured.
  • FIG. 6 is a flow chart for explaining the calibration operation by the calibration device 1 of the calibration system 200 according to this embodiment.
  • portions different from the operations of the calibration apparatus 1 according to the second embodiment shown in FIG. 5 will be described, and descriptions of similar operations will be omitted.
  • the arithmetic circuit 11 detects in time series from each of the reference sensor 3 and the plurality of calibration target sensors 2 within a predetermined period after the measurement start condition is met.
  • the temperature, reference detection value group, and calibration target detection value group are acquired (S302).
  • the arithmetic circuit 11 selects the calibration target sensor 2 that has detected a temperature change similar to the temperature change detected by the reference sensor 3 from among the plurality of calibration target sensors 2 (S303). For example, when the difference between the temperature detected by a specific sensor to be calibrated 2 at each time and the temperature detected by the reference sensor 3 at the same time is equal to or less than a predetermined threshold, the arithmetic circuit 11 Select 2. If none of the plurality of sensors 2 to be calibrated have been selected, the flow of FIG. 6 ends.
  • the arithmetic circuit 11 calculates a fifth calibration formula for calibrating the average value of the calibration target detection value group of the calibration target sensor 2 selected in step S303, using the reference detection value group acquired in step S302 as a reference.
  • the operation after step S304 is the same as the calibration operation by the calibration device 1 of the calibration system 200 according to the second embodiment shown in FIG.
  • a sixth calibration formula for calibrating the average value of the calibration target detection value group of the calibration target sensor 2 selected in step S303 is calculated.
  • the arithmetic circuit 11 further acquires temperatures detected at a plurality of times by the reference sensor 3 and the plurality of calibration target sensors 2 (S302).
  • the arithmetic circuit 11 selects one or more sensors 2 to be calibrated from among the plurality of sensors 2 to be calibrated based on a comparison between the temperature detected by the reference sensor 3 and the temperature detected by the plurality of sensors 2 to be calibrated.
  • Select (S303).
  • the arithmetic circuit 11 calibrates the one or more calibration target sensors 2 by calibrating the calibration target detection values detected by each of the selected one or more calibration target sensors 2 with reference to a plurality of reference detection values. conduct.
  • the dielectric constant of water changes depending on the temperature. Therefore, if the temperature of the location where the calibration target sensor 2 is embedded is significantly different from the temperature of the location where the reference sensor 3 is embedded, even if the calibration target sensor 2 is calibrated using the reference sensor 3 as a reference, the calibration target sensor 2 after calibration Moisture content measurements may not be accurate. In the present embodiment, only one or more of the calibration target sensors 2 that have detected the same temperature change as the reference sensor 3 among the plurality of calibration target sensors 2 is calibrated. Calibration can be performed.
  • the calibration target sensor 2 that measures the relative permittivity of the soil and, by extension, the water content, was described, but the calibration target sensor 2 of the present disclosure may further detect temperature.
  • the dielectric constant of water changes with temperature, when converting the dielectric constant detected by the sensor 2 to be calibrated into the water content, a correction coefficient corresponding to the temperature at the time of detection is applied. Without conversion, you will not get an accurate moisture content.
  • the arithmetic circuit 11 acquires a plurality of dielectric constants detected in time series by the sensor 2 to be calibrated and the temperature at the time of detection of each of the plurality of dielectric constants. Next, the arithmetic circuit 11 converts each relative permittivity into a moisture content by applying a correction coefficient corresponding to the temperature at the time of detection to each relative permittivity obtained. Arithmetic circuit 11 calibrates a plurality of moisture contents based on a plurality of reference detection values. As a result, it is possible to obtain a more accurate moisture content according to the temperature from the detection result of the relative permittivity by the sensor 2 to be calibrated. Therefore, according to this modification, by calibrating an accurate moisture content based on the reference sensor 3, calibration can be performed with high accuracy.

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Abstract

This calibration device is provided with a calculating circuit and a storage device. The calculating circuit acquires and stores in the storage device: a plurality of reference detected values related to a moisture content of a medium, detected at each of a plurality of time points by means of a reference sensor disposed in the medium; and a plurality of calibration target detected values relating to the moisture content of the medium, detected at time points corresponding to each of the plurality of time points by means of a calibration target sensor disposed in the medium. The calculating circuit calculates a calibration formula for calibrating the plurality of calibration target detected values, on the basis of the plurality of reference detected values.

Description

較正装置、較正方法、及びプログラムCALIBRATION DEVICE, CALIBRATION METHOD, AND PROGRAM
　本開示は、較正装置、較正方法、及びプログラムに関する。 The present disclosure relates to a calibration device, a calibration method, and a program.
　土壌の水分を測定する土壌水分センサとして、土壌の静電容量を測定する静電容量式の土壌水分センサが知られている。非特許文献１は、静電容量式の土壌水分センサの較正方法を開示している。 As a soil moisture sensor that measures soil moisture, a capacitance soil moisture sensor that measures the capacitance of soil is known. Non-Patent Document 1 discloses a method for calibrating a capacitive soil moisture sensor.
　非特許文献１に開示された従来の較正方法では、センサ付近の土壌を採集し、炉乾法（乾燥炉で土壌の水分を蒸発させ、乾燥前後の重量変化から含水率を算出する方法）で求めた含水率とセンサ出力とを比較して較正式を求める。このような較正には手間がかかり、多大な工数及び運用コストが必要である。 In the conventional calibration method disclosed in Non-Patent Document 1, the soil near the sensor is collected, and the oven drying method (a method of evaporating the moisture of the soil in a drying oven and calculating the moisture content from the weight change before and after drying). A calibration formula is obtained by comparing the obtained moisture content with the sensor output. Such calibration is labor intensive and requires significant man-hours and operating costs.
　本開示の目的は、手間を省いて容易に精度の良い較正を行うことができる較正装置、較正方法、及びプログラムを提供することにある。 An object of the present disclosure is to provide a calibration device, a calibration method, and a program that can easily perform accurate calibration with less effort.
　本開示の一態様に係る較正装置は、演算回路と記憶装置とを備え、
　前記演算回路は、
　媒質中に配置された基準センサによってそれぞれ複数の時刻において検出された前記媒質中の水分量に関する複数の基準検出値と、前記媒質中に配置された較正対象センサによって前記複数の時刻にそれぞれ対応する時刻において検出された前記媒質中の水分量に関する複数の較正対象検出値と、を取得して前記記憶装置に格納し、
　前記複数の基準検出値を基準として前記複数の較正対象検出値を較正する較正式を算出する。 A calibration device according to one aspect of the present disclosure includes an arithmetic circuit and a storage device,
The arithmetic circuit is
A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining and storing in the storage device a plurality of calibrated detected values for the amount of moisture in the medium detected at the time;
A calibration formula for calibrating the plurality of calibration target detection values is calculated with reference to the plurality of reference detection values.
　本開示の他の態様に係る較正方法は、
　媒質中に配置された基準センサによってそれぞれ複数の時刻において検出された前記媒質中の水分量に関する複数の基準検出値と、前記媒質中に配置された較正対象センサによって前記複数の時刻にそれぞれ対応する時刻において検出された前記媒質中の水分量に関する複数の較正対象検出値と、を取得するステップと、
　前記複数の基準検出値を基準として前記複数の較正対象検出値を較正する較正式を算出するステップと、
　を含む。 A calibration method according to another aspect of the present disclosure comprises:
A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining a plurality of calibrated sensed values for the amount of moisture in the medium sensed at a time;
calculating a calibration formula for calibrating the plurality of calibration target detection values with reference to the plurality of reference detection values;
including.
　本開示の更に他の態様は、
　媒質中に配置された基準センサによってそれぞれ複数の時刻において検出された前記媒質中の水分量に関する複数の基準検出値と、前記媒質中に配置された較正対象センサによって前記複数の時刻にそれぞれ対応する時刻において検出された前記媒質中の水分量に関する複数の較正対象検出値と、を取得するステップと、
　前記複数の基準検出値を基準として前記複数の較正対象検出値を較正する較正式を算出するステップと、
　を演算回路に実行させるためのプログラムを提供する。 Yet another aspect of the present disclosure includes:
A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining a plurality of calibrated sensed values for the amount of moisture in the medium sensed at a time;
calculating a calibration formula for calibrating the plurality of calibration target detection values with reference to the plurality of reference detection values;
to be executed by the arithmetic circuit.
　本開示に係る較正装置、較正方法、及びプログラムによれば、手間を省いて容易に精度の良い較正を行うことができる。 According to the calibration device, calibration method, and program according to the present disclosure, it is possible to easily perform accurate calibration with less effort.
本開示の第１実施形態に係る較正システム１００の構成を示す模式図である。1 is a schematic diagram showing the configuration of a calibration system 100 according to a first embodiment of the present disclosure; FIG. 本開示の第１実施形態に係る較正装置１の構成例を示すブロック図である。1 is a block diagram showing a configuration example of a calibration device 1 according to a first embodiment of the present disclosure; FIG. 本開示の第１実施形態に係る較正装置１の動作を説明するためのフローチャートである。4 is a flow chart for explaining the operation of the calibration device 1 according to the first embodiment of the present disclosure; 本開示の第２実施形態に係る較正システム２００の構成を示す模式図である。FIG. 3 is a schematic diagram showing the configuration of a calibration system 200 according to a second embodiment of the present disclosure; FIG. 本開示の第２実施形態に係る較正システム２００の較正装置１による較正動作を説明するためのフローチャートである。9 is a flow chart for explaining a calibration operation by the calibration device 1 of the calibration system 200 according to the second embodiment of the present disclosure; 本開示の第３実施形態に係る較正システム２００の較正装置１による較正動作を説明するためのフローチャートである。FIG. 11 is a flow chart for explaining a calibration operation by the calibration device 1 of the calibration system 200 according to the third embodiment of the present disclosure; FIG.
（本開示に至った経緯）
　圃場では、農作物への灌水のタイミングを決めるために、土壌の水分を測定する土壌水分センサが利用されることがある。土壌水分センサとして、土壌の静電容量を測定する静電容量式の土壌水分センサが知られている。土壌は主に水・空気・土粒子から構成され、水の比誘電率が８０程度なのに対して、空気は１、土粒子は２～５程度と小さいため、土壌全体の静電容量は、土壌の含水率と相関がある。したがって、静電容量式の土壌水分センサは、土壌全体の静電容量を測定することで、土壌の含水率を検出することができる。 (Circumstances leading to this disclosure)
In fields, a soil moisture sensor that measures soil moisture is sometimes used to determine the timing of irrigating crops. As a soil moisture sensor, a capacitance type soil moisture sensor that measures the capacitance of soil is known. Soil is mainly composed of water, air, and soil particles. Water has a dielectric constant of about 80, while air has a low dielectric constant of 1 and soil particles have a small capacitance of about 2 to 5. Therefore, the capacitance of the entire soil is There is a correlation with the moisture content of Therefore, the capacitance soil moisture sensor can detect the moisture content of the soil by measuring the capacitance of the entire soil.
　しかしながら、静電容量式の土壌水分センサは、数十ＭＨｚ～１００ＭＨｚ程度の測定周波数を用いることが一般的であり、土壌の電気伝導度等の影響を受けるため、実際に埋設される土壌を用いて較正をしなければ、精度良く含水率を測定することができないことがある。静電容量式の土壌水分センサの較正方法の一例は、センサ付近の土壌を採集し、採集した土壌の乾燥状態、湿潤状態、及び中間状態の含水率を炉乾法（乾燥炉で土壌の水分を蒸発させ、乾燥前後の重量変化から含水率を算出する方法）で求め、各状態間の含水率とセンサ出力とを比較して較正式を求めることを含む。一度較正が完了しても、季節、土壌の土質、温度、電気伝導度等の周囲環境が変わると、含水率を正確に測定するには較正を再度行う必要がある。このように、静電容量式の土壌水分センサを使用して含水率を正確に測定するには手間がかかり、較正に多大な工数及び運用コストが必要である。 However, the capacitance type soil moisture sensor generally uses a measurement frequency of several tens of MHz to 100 MHz, and is affected by the electrical conductivity of the soil. Without calibration, it may not be possible to measure the moisture content with good accuracy. An example of a method for calibrating a capacitance soil moisture sensor is to collect soil near the sensor and measure the moisture content of the sampled soil in dry, wet, and intermediate conditions using an oven drying method (soil moisture content in a drying oven). is evaporated and the moisture content is calculated from the weight change before and after drying), and the moisture content between each state is compared with the sensor output to determine the calibration formula. Even if the calibration is completed once, if the ambient environment such as season, soil type, temperature, electrical conductivity, etc. changes, the calibration must be performed again to accurately measure the moisture content. Thus, it takes time and effort to accurately measure the moisture content using a capacitance type soil moisture sensor, requiring a great deal of man-hours and operating costs for calibration.
　一方、土壌水分センサとして、ＴＤＲセンサ及びＴＤＴセンサも知られている。ＴＤＲセンサは、時間領域反射法（Time Domain Reflectometry法，ＴＤＲ法）により土壌の比誘電率を測定し、測定結果に基づいて土壌の含水率を検出する。ＴＤＴセンサは、時間領域透過法（Time Domain Transmission法，ＴＤＴ法）により土壌の比誘電率を測定し、測定結果に基づいて土壌の含水率を検出する。数百ＭＨｚから数ＧＨｚの測定周波数を有するＴＤＲセンサ及びＴＤＴセンサは、静電容量式の土壌水分センサのように手間のかかる較正を行わなくても、精度良く土壌の含水率を検出することができるが、静電容量式の土壌水分センサに比べて著しく高価である。 On the other hand, a TDR sensor and a TDT sensor are also known as soil moisture sensors. The TDR sensor measures the dielectric constant of soil by the Time Domain Reflectometry method (TDR method) and detects the water content of the soil based on the measurement result. The TDT sensor measures the dielectric constant of soil by the Time Domain Transmission method (TDT method) and detects the moisture content of the soil based on the measurement result. The TDR and TDT sensors, which have measurement frequencies ranging from several hundred MHz to several GHz, can accurately detect the moisture content of soil without the need for time-consuming calibration, which is required for capacitance-type soil moisture sensors. It can be done, but is significantly more expensive than a capacitive soil moisture sensor.
　発明者らは、上記課題を解決するために研究を行い、手間を省いて容易に精度の良い較正を行うことができる較正装置、較正方法、及びプログラムを想到するに至った。 The inventors conducted research to solve the above problems, and came up with a calibration device, a calibration method, and a program that can easily perform accurate calibration with less effort.
　以下、添付の図面を参照して本開示に係る較正システムの実施形態を説明する。なお、以下の実施形態において、同一又は同様の構成要素については同一の符号を付している。 Hereinafter, embodiments of the calibration system according to the present disclosure will be described with reference to the attached drawings. In addition, in the following embodiment, the same code|symbol is attached|subjected about the same or similar component.
１．第１実施形態
１－１．構成例
　図１は、本開示の第１実施形態に係る較正システム１００の構成を示す模式図である。較正システム１００は、較正装置１と、較正の対象である較正対象センサ２と、較正の基準となる基準センサ（リファレンスセンサ）３とを含む。較正対象センサ２及び基準センサ３は、有線又は無線により較正装置１に接続されている。 1. First Embodiment 1-1. Configuration Example FIG. 1 is a schematic diagram showing the configuration of a calibration system 100 according to the first embodiment of the present disclosure. The calibration system 100 includes a calibration device 1, a calibration target sensor 2 to be calibrated, and a standard sensor (reference sensor) 3 that serves as a calibration standard. The calibration target sensor 2 and the reference sensor 3 are connected to the calibration device 1 by wire or wirelessly.
　較正対象センサ２及び基準センサ３は、土壌４中に配置され、土壌４の含水率、例えば体積含水率を測定する土壌水分センサである。土壌４は、本開示の「媒質」の一例である。媒質は、土壌の他、例えば粉末、顆粒等の物質を含む。較正対象センサ２及び基準センサ３は、同一の環境内、例えば同様の天候変化を経る土壌４中に配置される。較正対象センサ２及び基準センサ３は、土壌４中に近接して、例えば１０ｍ未満の距離、又は例えば１ｍ未満の距離を隔てて配置される。 The calibration target sensor 2 and the reference sensor 3 are soil moisture sensors that are placed in the soil 4 and measure the moisture content of the soil 4, for example, the volumetric moisture content. Soil 4 is an example of the "medium" of this disclosure. The medium includes soil as well as substances such as powders and granules. The sensor to be calibrated 2 and the reference sensor 3 are placed in the same environment, eg soil 4, which undergoes similar weather changes. The sensor to be calibrated 2 and the reference sensor 3 are placed in close proximity in the soil 4, eg at a distance of less than 10 m, or eg at a distance of less than 1 m.
　較正対象センサ２は、較正対象センサ２内のコンデンサの充電時間から静電容量を測定する静電容量式の土壌水分センサである。基準センサ３は、ＴＤＲセンサ又はＴＤＴセンサである。較正システム１００は、較正装置１によって、基準センサ３による検出結果を基準として、較正対象センサ２を較正する。較正動作の詳細は後述する。較正完了後は、基準センサ３は土壌４から取り除かれ、例えば他の静電容量式の土壌水分センサの較正に利用可能である。 The calibration target sensor 2 is a capacitive soil moisture sensor that measures the capacitance from the charging time of the capacitor in the calibration target sensor 2 . The reference sensor 3 is a TDR sensor or a TDT sensor. The calibration system 100 calibrates the calibration target sensor 2 using the calibration device 1 based on the detection result of the reference sensor 3 . Details of the calibration operation will be described later. After calibration is complete, the reference sensor 3 is removed from the soil 4 and is available for calibrating other capacitive soil moisture sensors, for example.
　較正システム１００によれば、正確な基準センサ３の検出結果に基づいて、較正対象センサ２を較正することができ、較正対象センサ２として安価なセンサを採用したとしても、較正後の較正対象センサ２から正確な検出結果を得ることができるようになる。 According to the calibration system 100, the calibration target sensor 2 can be calibrated based on the accurate detection result of the reference sensor 3, and even if an inexpensive sensor is adopted as the calibration target sensor 2, the calibration target sensor 2, an accurate detection result can be obtained.
　また、較正システム１００によれば、較正対象センサ２付近の土壌４の採集、土壌４の湿潤及び乾燥を含む手間のかかる較正を行う必要がない。また、較正システム１００によれば、較正対象センサ２付近の土壌４を採集しないため、土壌４を掘り起こす際に農作物等を傷つけるおそれがない。 Further, according to the calibration system 100, there is no need to perform time-consuming calibration including collection of the soil 4 near the calibration target sensor 2, wetting and drying of the soil 4. Moreover, according to the calibration system 100, since the soil 4 near the sensor 2 to be calibrated is not collected, there is no risk of damaging crops or the like when digging up the soil 4. FIG.
　さらに、土壌４を採集する従来の較正方法では、掘り起こされた土壌４が、実際に農作物を栽培する場所の土壌と土質が変わってしまい、較正対象センサ２を設置した場所の含水率と農作物を栽培する場所の含水率との間に差異が生じるおそれがある。これに対して、較正システム１００によれば、較正対象センサ２付近の土壌４を採集しないため、較正対象センサ２を設置した場所の含水率と農作物を栽培する場所の含水率との間に差異が生じるおそれを低減することができる。 Furthermore, in the conventional calibration method of collecting the soil 4, the excavated soil 4 is different from the soil of the place where the crops are actually cultivated, and the moisture content and the crops of the place where the calibration target sensor 2 is installed are different. There is a possibility that there will be a difference between the moisture content of the place where it is cultivated. On the other hand, according to the calibration system 100, since the soil 4 near the calibration target sensor 2 is not collected, the difference between the moisture content at the location where the calibration target sensor 2 is installed and the moisture content at the location where the crops are cultivated is can be reduced.
　図２は、本実施形態に係る較正装置１の構成例を示すブロック図である。較正装置１は、演算回路１１と、記憶装置１２と、入出力インタフェース（Ｉ／Ｆ）１３とを備える。 FIG. 2 is a block diagram showing a configuration example of the calibration device 1 according to this embodiment. The calibration device 1 includes an arithmetic circuit 11 , a storage device 12 and an input/output interface (I/F) 13 .
　演算回路１１は、情報処理を行って較正装置１の機能を実現する。このような情報処理は、例えば、演算回路１１が記憶装置１２に格納されたプログラムの指令に従って動作することにより実現される。演算回路１１は、例えば、ＣＰＵ、ＭＰＵ、ＦＰＧＡ等の回路で構成される。 The arithmetic circuit 11 performs information processing to realize the functions of the calibration device 1 . Such information processing is realized, for example, by operating the arithmetic circuit 11 according to instructions of a program stored in the storage device 12 . The arithmetic circuit 11 is composed of circuits such as a CPU, MPU, and FPGA, for example.
　記憶装置１２は、較正装置１の機能を実現するために必要なプログラム及びデータを含む種々の情報を記録する記録媒体を含む。例えば、記憶装置１２は、図１の較正対象センサ２及び基準センサ３から取得した各検出値を記憶する。記憶装置１２は、例えば、フラッシュメモリ、ソリッド・ステート・ドライブ（ＳＳＤ）等の半導体記憶装置、ハードディスクドライブ（ＨＤＤ）等の磁気記憶装置、その他の記録媒体単独で又はそれらを組み合わせて実現される。記憶装置１２は、ＳＲＡＭ、ＤＲＡＭ等の揮発性メモリを含んでもよい。 The storage device 12 includes recording media for recording various information including programs and data necessary for realizing the functions of the calibration device 1 . For example, the storage device 12 stores detected values obtained from the calibration target sensor 2 and the reference sensor 3 in FIG. The storage device 12 is realized by, for example, a semiconductor storage device such as a flash memory, a solid state drive (SSD), a magnetic storage device such as a hard disk drive (HDD), or other recording media alone or in combination. Storage device 12 may include volatile memory such as SRAM, DRAM, and the like.
　入出力Ｉ／Ｆ１３は、較正対象センサ２、基準センサ３等の外部装置との間で情報を送受信するために、較正装置１と外部装置とを接続するインタフェース回路である。入出力Ｉ／Ｆ１０３は、既存の有線通信規格又は無線通信規格に従ってデータ通信を行う通信回路であってもよい。 The input/output I/F 13 is an interface circuit that connects the calibration device 1 and external devices in order to transmit and receive information to and from external devices such as the calibration target sensor 2 and the reference sensor 3 . The input/output I/F 103 may be a communication circuit that performs data communication according to existing wired communication standards or wireless communication standards.
１－２．動作例
　図３は、本実施形態に係る較正装置１の動作を説明するためのフローチャートである。図３のフローチャートに示す各処理は、較正装置１の演算回路１１によって実行される。 1-2. Operation Example FIG. 3 is a flowchart for explaining the operation of the calibration device 1 according to this embodiment. Each processing shown in the flowchart of FIG. 3 is executed by the arithmetic circuit 11 of the calibration device 1 .
　まず、演算回路１１は、測定開始条件が満たされているか否かを判断する（Ｓ１）。例えば、演算回路１１は、較正対象センサ２及び基準センサ３のそれぞれから、土壌４への埋設が完了したことを示す埋設完了信号を受信した場合、測定開始条件が満たされていると判断する。このような埋設完了信号は、埋設作業者が、較正対象センサ２及び基準センサ３のそれぞれに設けられた所定のボタンスイッチを押すことにより、較正装置１に送信される。あるいは、演算回路１１は、埋設作業者が使用する情報処理端末から埋設完了信号を受信した場合、測定開始条件が満たされていると判断する。 First, the arithmetic circuit 11 determines whether or not the measurement start condition is satisfied (S1). For example, when the arithmetic circuit 11 receives an embedding completion signal indicating completion of embedding in the soil 4 from each of the calibration target sensor 2 and the reference sensor 3, it determines that the measurement start condition is satisfied. Such an burying completion signal is transmitted to the calibrating device 1 when the burying operator presses a predetermined button switch provided on each of the calibration target sensor 2 and the reference sensor 3 . Alternatively, when the arithmetic circuit 11 receives an burying completion signal from the information processing terminal used by the burying worker, it determines that the measurement start condition is satisfied.
　また、較正対象センサ２及び基準センサ３の中には、土壌４内に適切に配置されない限り測定を開始せず、検出結果を出力しないものもある。したがって、このような較正対象センサ２及び基準センサ３を使用する場合には、演算回路１１は、較正対象センサ２及び基準センサ３の両方から検出結果を取得したときに、測定開始条件が満たされていると判断してもよい。 In addition, some of the calibration target sensor 2 and the reference sensor 3 do not start measurement and do not output detection results unless they are properly placed in the soil 4 . Therefore, when using such calibration target sensor 2 and reference sensor 3, the arithmetic circuit 11 obtains detection results from both the calibration target sensor 2 and the reference sensor 3, and the measurement start condition is satisfied. It may be determined that
　測定開始条件が満たされている場合（Ｓ１でＹｅｓ）、演算回路１１は、較正対象センサ２及び基準センサ３のそれぞれから、測定開始条件の具備後の所定期間内に時系列で検出された較正対象検出値群及び基準検出値群を取得する（Ｓ２）。例えば、上記の所定期間は４日であり、演算回路１１は、較正対象センサ２及び基準センサ３のそれぞれから、１時間毎に測定された９６個の較正対象検出値及び基準検出値を取得する。ステップＳ２で取得された複数の較正対象検出値及び基準検出値は、検出時刻に関連付けられた上で、記憶装置１２に格納される。例えば、基準センサ３によって検出された基準検出値である基準含水率と、当該基準含水率と同時刻に検出された較正対象検出値とが、検出時刻に関連付けられた上で記憶装置１２に格納される。 If the measurement start condition is satisfied (Yes in S1), the arithmetic circuit 11 detects calibration data detected in time series from each of the calibration target sensor 2 and the reference sensor 3 within a predetermined period after the measurement start condition is met. A target detection value group and a reference detection value group are acquired (S2). For example, the predetermined period is four days, and the arithmetic circuit 11 acquires 96 calibration target detection values and reference detection values measured every hour from the calibration target sensor 2 and the reference sensor 3, respectively. . A plurality of calibration target detection values and reference detection values acquired in step S2 are stored in the storage device 12 after being associated with detection times. For example, the reference moisture content, which is the reference detection value detected by the reference sensor 3, and the calibration target detection value detected at the same time as the reference moisture content are stored in the storage device 12 after being associated with the detection time. be done.
　次に、演算回路１１は、ステップＳ２で取得された基準検出値群を基準として、較正対象検出値群を較正する第１の較正式を算出する（Ｓ３）。例えば、記憶装置１２には、基準センサ３によって検出された基準検出値である基準含水率（ｙ１，ｙ２，…，ｙｎ）（ｎは２以上の整数）と、当該基準含水率と同時刻に検出された較正対象検出値（ｘ１，ｘ２，…，ｘｎ）とのデータセットが複数（例えば９６セット）格納されている。演算回路１１は、これらのデータセットに基づいて、較正対象検出値群を基準検出値群にフィッティングさせる第１の較正式を算出する。第１の較正式の算出には、最小二乗法等の回帰分析が用いられる。 Next, the arithmetic circuit 11 calculates a first calibration formula for calibrating the calibration target detection value group with reference to the reference detection value group acquired in step S2 (S3). For example, the storage device 12 stores the reference moisture content (y 1 , y 2 , . A plurality of data sets (for example, 96 sets) of calibration target detection values (x 1 , x 2 , . . . , x n ) detected at the same time are stored. Based on these data sets, the arithmetic circuit 11 calculates a first calibration formula for fitting the calibration target detection value group to the reference detection value group. Regression analysis such as the method of least squares is used to calculate the first calibration formula.
　例えば、演算回路１１による第１の較正式を算出は、基準検出値群ｙ＝（ｙ１，ｙ２，…，ｙｎ）と較正対象検出値群ｘ＝（ｘ１，ｘ２，…，ｘｎ）との関係が３次式ｙ＝Ａｘ３＋Ｂｘ２＋Ｃｘ＋Ｄで表されるとき、最小二乗法によりパラメータＡ，Ｂ，Ｃ，及びＤを求めることを含む。 For example, the calculation of the first calibration formula by the arithmetic circuit 11 is based on the reference detection value group y=(y 1 , y 2 , . . . , yn ) and the calibration target detection value group x=(x 1 , x 2 , . x n ) is represented by the cubic equation y=Ax 3 +Bx 2 +Cx+D, determining the parameters A, B, C, and D by the least squares method.
　較正式は、上記のように３次式に限定されない。例えば、演算回路１１による第１の較正式を算出は、基準検出値群ｙ＝（ｙ１，ｙ２，…，ｙｎ）と較正対象検出値群ｘ＝（ｘ１，ｘ２，…，ｘｎ）とを任意の多項式近似によりフィッティングして較正式を作成することを含む。 The calibration equation is not limited to cubic equations as described above. For example, the calculation of the first calibration formula by the arithmetic circuit 11 is based on the reference detection value group y=(y 1 , y 2 , . . . , yn ) and the calibration target detection value group x=(x 1 , x 2 , . x n ) by an arbitrary polynomial approximation to create a calibration equation.
　次に、演算回路１１は、基準検出値群と較正対象検出値群との相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ１以上であるか否かを判断する（Ｓ４）。閾値Ｒｔｈ１は、例えば０．２～０．７である。 Next, the arithmetic circuit 11 determines whether or not the absolute value |R| of the correlation coefficient R between the reference detection value group and the calibration target detection value group is equal to or greater than the threshold value R th1 (S4). The threshold R th1 is, for example, 0.2 to 0.7.
　相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ１未満である場合（Ｓ４でＮｏ）、演算回路１１は、入出力Ｉ／Ｆ１３を介して、測定エラーがある旨をユーザに通知する（Ｓ５）。例えば、演算回路１１は、スピーカ等の音声出力装置に測定エラーを示す信号を出力し、警告音をスピーカに出力させる。演算回路１１は、ディスプレイ、ＬＥＤ等の表示装置に測定エラーを示す信号を出力し、測定エラーを示す旨のテキストを表示させ、及び／又はＬＥＤを赤色で点滅させてもよい。 When the absolute value |R| of the correlation coefficient R is less than the threshold value R th1 (No in S4), the arithmetic circuit 11 notifies the user that there is a measurement error via the input/output I/F 13 (S5 ). For example, the arithmetic circuit 11 outputs a signal indicating a measurement error to an audio output device such as a speaker, and causes the speaker to output a warning sound. The arithmetic circuit 11 may output a signal indicating the measurement error to a display device such as a display, an LED, etc., display text indicating the measurement error, and/or flash the LED in red.
　相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ１未満である場合、較正対象センサ２及び基準センサ３の少なくとも一方が故障している、土壌４中に適切に埋設されていない、動物等により土壌４中から掘り起こされているなど、異常事態が発生しているおそれがある。ステップＳ５では、測定エラーが通知されることにより、ユーザは、異常事態が発生しているおそれを知ることができ、較正対象センサ２及び基準センサ３の埋設現場を確認することにより異常事態を解消する機会を早期に得ることができる。 If the absolute value |R| of the correlation coefficient R is less than the threshold value R th1 , at least one of the calibration target sensor 2 and the reference sensor 3 is out of order, is not properly buried in the soil 4, or is caused by an animal or the like. There is a possibility that an abnormal situation such as being dug up from the soil 4 has occurred. In step S5, the notification of the measurement error allows the user to know that an abnormal situation may occur, and the abnormal situation is resolved by checking the burial site of the calibration target sensor 2 and the reference sensor 3. early opportunity to do so.
　ステップＳ４において相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ１以上である場合（Ｓ４でＹｅｓ）、演算回路１１は、基準検出値群の中に、上限閾値θｍａｘ以上の検出値、及び下限閾値θｍｉｎ以下の検出値があるか否かを判断する（Ｓ６）。上限閾値θｍａｘは、例えば土壌４をそれ以上湿潤させるために水を加えても土壌４の含水率が上昇しない、含水率の上限飽和値又はそれより僅かに小さい値に設定される。上限閾値θｍａｘは、例えば０．４５に設定される。下限閾値θｍｉｎは、土壌４の含水率の下限値又はそれより僅かに大きい値に設定される。下限閾値θｍｉｎは、例えば、上限閾値θｍａｘより小さい０．１，０．２５等の値に設定される。 If the absolute value |R| of the correlation coefficient R is equal to or greater than the threshold value R th1 in step S4 (Yes in S4), the arithmetic circuit 11 selects a detected value equal to or greater than the upper threshold value θ max in the reference detected value group, and It is determined whether or not there is a detected value equal to or lower than the lower limit threshold θ min (S6). The upper threshold value θ max is set to, for example, the upper saturation value of the water content or a value slightly smaller than the upper saturation value of the water content at which the water content of the soil 4 does not increase even if water is added to further moisten the soil 4 . The upper threshold θ max is set to 0.45, for example. The lower limit threshold θ min is set to the lower limit of the water content of the soil 4 or a value slightly larger than it. The lower threshold θ min is set to a value such as 0.1 or 0.25 that is smaller than the upper threshold θ max , for example.
　上限閾値θｍａｘ以上の検出値、及び下限閾値θｍｉｎ以下の検出値の両方を得るためには、土壌４が湿潤した状態と乾燥した状態の両方において測定を行う必要がある。例えば、降雨により土壌４が湿潤した状態になり、その後降雨が止んで土壌４が次第に乾燥した状態に至った場合に、土壌４が湿潤した状態と乾燥した状態の両方における測定が完了する。図３に示したフローでは、自然の降雨と乾燥を待ってもよいが、人工的に灌水して土壌４を湿潤させる手順、及び／又は人工的に土壌４を乾燥させる手順が実行されてもよい。 In order to obtain both a detected value equal to or higher than the upper threshold value θ max and a detected value equal to or lower than the lower threshold value θ min , it is necessary to carry out the measurement both when the soil 4 is wet and when it is dry. For example, when the soil 4 becomes wet due to rain, and then the rain stops and the soil 4 gradually dries, the measurement is completed when the soil 4 is both wet and dry. In the flow shown in FIG. 3, it may be possible to wait for natural rainfall and drying, but even if a procedure of artificially watering the soil 4 and/or artificially drying the soil 4 is performed, good.
　基準検出値群の中に、上限閾値θｍａｘ以上の検出値、及び下限閾値θｍｉｎ以下の検出値の少なくとも一方がない場合（Ｓ６でＮｏ）、演算回路１１は、更に所定期間較正対象センサ２及び基準センサ３から検出値を取得し、データセットを蓄積する（Ｓ７）。すなわち、ステップＳ６でＮｏの場合、演算回路１１は、較正対象センサ２及び基準センサ３のそれぞれから、所定期間内に時系列で検出された較正対象検出値群及び基準検出値群を更に取得する。ステップＳ７の後は、ステップＳ６に進む。 If at least one of the detected values equal to or higher than the upper limit threshold θ max and the detected value equal to or lower than the lower limit threshold θ min does not exist in the reference detected value group (No in S6), the arithmetic circuit 11 further controls the sensor 2 to be calibrated for a predetermined period. Detected values are acquired from the reference sensor 3 and a data set is accumulated (S7). That is, in the case of No in step S6, the arithmetic circuit 11 further acquires the calibration target detection value group and the reference detection value group detected in time series within a predetermined period from the calibration target sensor 2 and the reference sensor 3, respectively. . After step S7, the process proceeds to step S6.
　ステップＳ６において、基準検出値群の中に、上限閾値θｍａｘ以上の検出値、及び下限閾値θｍｉｎ以下の検出値がある場合（Ｓ６でＹｅｓ）、演算回路１１は、ステップＳ２及びＳ７で取得された基準検出値群を基準として、ステップＳ２及びＳ７で取得された較正対象検出値群を較正する第２の較正式を算出する（Ｓ８）。第２の較正式の算出方法は、ステップＳ３の第１の較正式の算出方法と同様である。 In step S6, if there are detected values equal to or higher than the upper threshold θ max and detected values equal to or lower than the lower threshold θ min in the group of reference detected values (Yes in S6), the arithmetic circuit 11 obtains in steps S2 and S7 A second calibration formula for calibrating the calibration target detection value group obtained in steps S2 and S7 is calculated using the obtained reference detection value group as a reference (S8). The calculation method of the second calibration formula is the same as the calculation method of the first calibration formula in step S3.
　次に、演算回路１１は、基準検出値群と較正対象検出値群との相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ２以上であるか否かを判断する（Ｓ９）。閾値Ｒｔｈ２は、閾値Ｒｔｈ１より大きく、例えば０．４～１である。 Next, the arithmetic circuit 11 determines whether or not the absolute value |R| of the correlation coefficient R between the reference detection value group and the calibration target detection value group is equal to or greater than the threshold value R th2 (S9). The threshold R th2 is greater than the threshold R th1 , and ranges from 0.4 to 1, for example.
　相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ２以上である場合（Ｓ９でＹｅｓ）、演算回路１１は、入出力Ｉ／Ｆ１３を介して、較正が完了した旨をユーザに通知する（Ｓ１０）。例えば、演算回路１１は、スピーカ等の音声出力装置に較正完了を示す信号を出力し、較正完了を示す音をスピーカに出力させる。演算回路１１は、ディスプレイ、ＬＥＤ等の表示装置に較正完了を示す信号を出力し、較正完了を示す旨のテキストを表示させ、及び／又はＬＥＤを青色で点滅させてもよい。 When the absolute value |R| of the correlation coefficient R is equal to or greater than the threshold value R th2 (Yes in S9), the arithmetic circuit 11 notifies the user that the calibration has been completed via the input/output I/F 13 (S10 ). For example, the arithmetic circuit 11 outputs a signal indicating completion of calibration to an audio output device such as a speaker, and causes the speaker to output a sound indicating completion of calibration. Arithmetic circuit 11 may output a signal indicating completion of calibration to a display device such as a display, LED, etc., display text indicating completion of calibration, and/or blink the LED in blue.
　ステップＳ９において相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ２未満である場合（Ｓ９でＮｏ）、演算回路１１は、ステップＳ７に戻り、ステップＳ７，Ｓ６，Ｓ８，及びＳ９を実行する。無限ループを避けるために、ステップＳ９でＮｏに進むことを所定回数、例えば４回繰り返した場合には、演算回路１１は、ステップＳ５のように測定エラーをユーザに通知してもよい。 If the absolute value |R| of the correlation coefficient R is less than the threshold value R th2 in step S9 (No in S9), the arithmetic circuit 11 returns to step S7 and executes steps S7, S6, S8, and S9. In order to avoid an infinite loop, the arithmetic circuit 11 may notify the user of the measurement error as in step S5 when the process proceeds to No in step S9 a predetermined number of times, for example, four times.
　較正完了後は、基準センサ３は土壌４から取り除かれ、例えば他の静電容量式の土壌水分センサの較正に利用可能である。 After the calibration is completed, the reference sensor 3 is removed from the soil 4 and can be used for calibrating other capacitive soil moisture sensors, for example.
１－３．効果等
　以上のように、本実施形態に係る較正装置１は、演算回路１１と記憶装置１２とを備える。演算回路１１は、複数の基準検出値と、複数の較正対象検出値と、を取得して記憶装置に格納する（Ｓ２，Ｓ７）。複数の基準検出値は、土壌４中に配置された基準センサ３によって複数の時刻において検出された土壌４中の水分量にそれぞれ関する。複数の較正対象検出値は、土壌４中に配置された較正対象センサ２によって前記複数の時刻にそれぞれ対応する時刻において検出された土壌４中の水分量に関する。演算回路１１は、複数の基準検出値を基準として複数の較正対象検出値を較正する（Ｓ８）。 1-3. Effect etc. As described above, the calibration device 1 according to the present embodiment includes the arithmetic circuit 11 and the storage device 12 . The arithmetic circuit 11 obtains a plurality of reference detection values and a plurality of calibration target detection values and stores them in the storage device (S2, S7). The plurality of reference detection values relate to the amount of water in the soil 4 detected at a plurality of times by the reference sensor 3 arranged in the soil 4 . The plurality of calibration target detection values relate to the amount of moisture in the soil 4 detected by the calibration target sensor 2 placed in the soil 4 at times respectively corresponding to the plurality of times. Arithmetic circuit 11 calibrates a plurality of calibration target detection values with reference to a plurality of reference detection values (S8).
　この構成によれば、較正対象センサ２を土壌４中に配置したまま較正を行うことができるため、較正の際に較正対象センサ２付近の土壌４の採集、採集した土壌４の炉乾法による含水率測定等の手間のかかる作業を行う必要がない。また、較正の際に較正対象センサ２付近の土壌４を採集しないため、土壌４を掘り起こす際に農作物等を傷つけるおそれがない。 According to this configuration, the calibration can be performed while the calibration target sensor 2 is placed in the soil 4. Therefore, during calibration, the soil 4 near the calibration target sensor 2 is collected, and the collected soil 4 is dried by the oven drying method. There is no need to perform time-consuming work such as moisture content measurement. Moreover, since the soil 4 near the sensor 2 to be calibrated is not collected during calibration, there is no risk of damaging crops or the like when digging up the soil 4 .
　さらに、土壌４を採集する従来の較正方法では、掘り起こされた土壌４が、実際に農作物を栽培する場所の土壌と土質が変わってしまい、較正対象センサ２を設置した場所の含水率と農作物を栽培する場所の含水率との間に差異が生じるおそれがある。これに対して、較正システム１００によれば、較正対象センサ２付近の土壌４を採集しないため、較正対象センサ２を設置した場所の含水率と農作物を栽培する場所の含水率との間に差異が生じるおそれを低減することができる。 Furthermore, in the conventional calibration method of collecting the soil 4, the excavated soil 4 is different from the soil of the place where the crops are actually cultivated, and the moisture content and the crops of the place where the calibration target sensor 2 is installed are different. There is a possibility that there will be a difference between the moisture content of the place where it is cultivated. On the other hand, according to the calibration system 100, since the soil 4 near the calibration target sensor 2 is not collected, the difference between the moisture content at the location where the calibration target sensor 2 is installed and the moisture content at the location where the crops are cultivated is can be reduced.
　基準センサ３は、ＴＤＲ法又はＴＤＴ法により複数の基準検出値を検出するＴＤＲセンサ又はＴＤＴセンサであってもよい。較正対象センサ２は、土壌の静電容量に基づいて複数の較正対象検出値を検出する静電容量式のセンサであってもよい。 The reference sensor 3 may be a TDR sensor or a TDT sensor that detects a plurality of reference detection values by the TDR method or TDT method. The calibrated sensor 2 may be a capacitive sensor that detects a plurality of calibrated detected values based on soil capacitance.
　この構成によれば、正確な基準センサ３の検出結果に基づいて、較正対象センサ２を較正することができ、較正対象センサ２として安価な静電容量式のセンサを採用したとしても、較正後の較正対象センサ２から正確な検出結果を得ることができる。 According to this configuration, the calibration target sensor 2 can be calibrated based on the accurate detection result of the reference sensor 3, and even if an inexpensive capacitance sensor is adopted as the calibration target sensor 2, after calibration Accurate detection results can be obtained from the calibration target sensor 2 of .
２．第２実施形態
　図４は、本開示の第２実施形態に係る較正システム２００の構成を示す模式図である。本実施形態に係る較正システム２００は、第１実施形態に係る較正システム１００（図１参照）と比較して、複数の較正対象センサ２を含む点で異なる。図４には、９個の較正対象センサ２を例示している。基準センサ３及び複数の較正対象センサ２は、いずれも有線又は無線により較正装置１に接続されているが、図４では図面が煩雑になるのを防ぐために接続線を図示していない。 2. Second Embodiment FIG. 4 is a schematic diagram showing the configuration of a calibration system 200 according to a second embodiment of the present disclosure. A calibration system 200 according to the present embodiment differs from the calibration system 100 (see FIG. 1) according to the first embodiment in that it includes a plurality of sensors 2 to be calibrated. FIG. 4 illustrates nine sensors 2 to be calibrated. The reference sensor 3 and the plurality of sensors to be calibrated 2 are both wired or wirelessly connected to the calibration device 1, but the connection lines are not shown in FIG. 4 to avoid complication of the drawing.
　較正対象センサ２のうちの少なくとも１つと、基準センサ３とは、土壌４中に近接して、例えば１０ｍ未満の距離、又は例えば１ｍ未満の距離を隔てて配置される。他の較正対象センサ２は、同一の環境内、例えば同様の天候変化を経る土壌４中に配置される。他の較正対象センサ２は、前記少なくとも１つの較正対象センサ２に近接している必要はない。例えば、他の較正対象センサ２は、前記少なくとも１つの較正対象センサ２から数ｍ～数１００ｍの距離を隔てて土壌４中に配置されてもよい。このような距離を隔てても、土壌４は圃場内で略均質であり、天候等の環境も同様であることが多いため、基準センサ３を基準とすることにより複数の較正対象センサ２を精度良く較正することができる。 At least one of the sensors 2 to be calibrated and the reference sensor 3 are placed in close proximity in the soil 4, for example at a distance of less than 10 m, or at a distance of less than 1 m, for example. Other sensors 2 to be calibrated are placed in the same environment, eg soil 4, undergoing similar weather changes. Other sensors 2 to be calibrated need not be in close proximity to said at least one sensor 2 to be calibrated. For example, another sensor to be calibrated 2 may be placed in the soil 4 at a distance of several meters to several hundred meters from the at least one sensor to be calibrated 2 . Even with such a distance, the soil 4 is generally homogeneous in the field, and the environment such as the weather is often the same. can be well calibrated.
　図５は、本実施形態に係る較正システム２００の較正装置１による較正動作を説明するためのフローチャートである。以下では、図３に示した第１実施形態に係る較正装置１の動作と異なる部分について説明し、同様の動作については説明を省略する。 FIG. 5 is a flow chart for explaining the calibration operation by the calibration device 1 of the calibration system 200 according to this embodiment. In the following, portions different from the operations of the calibration apparatus 1 according to the first embodiment shown in FIG. 3 will be described, and descriptions of similar operations will be omitted.
　まず、演算回路１１は、測定開始条件が満たされているか否かを判断する（Ｓ２０１）。例えば、演算回路１１は、基準センサ３及び複数の較正対象センサ２の全てから埋設完了信号を受信した場合、測定開始条件が満たされていると判断する。あるいは、演算回路１１は、基準センサ３及び複数の較正対象センサ２の全てから検出結果を取得したときに、測定開始条件が満たされていると判断してもよい。 First, the arithmetic circuit 11 determines whether or not the measurement start condition is satisfied (S201). For example, when the arithmetic circuit 11 receives embedding completion signals from all of the reference sensor 3 and the plurality of calibration target sensors 2, it determines that the measurement start condition is satisfied. Alternatively, the arithmetic circuit 11 may determine that the measurement start condition is satisfied when detection results are obtained from all of the reference sensor 3 and the plurality of calibration target sensors 2 .
　測定開始条件が満たされている場合（Ｓ２０１でＹｅｓ）、演算回路１１は、基準センサ３及び複数の較正対象センサ２のそれぞれから、測定開始条件の具備後の所定期間内に時系列で検出された基準検出値群及び較正対象検出値群を取得する（Ｓ２０２）。 When the measurement start condition is satisfied (Yes in S201), the arithmetic circuit 11 detects in time series from each of the reference sensor 3 and the plurality of calibration target sensors 2 within a predetermined period after the measurement start condition is met. A group of reference detected values and a group of detected values to be calibrated are acquired (S202).
　次に、演算回路１１は、ステップＳ２０２で取得された基準検出値群を基準として、較正対象検出値群の平均値を較正する第３の較正式を算出する（Ｓ２０３）。 Next, the arithmetic circuit 11 calculates a third calibration formula for calibrating the average value of the calibration target detection value group based on the reference detection value group acquired in step S202 (S203).
　次に、演算回路１１は、基準検出値群と較正対象検出値群の平均値との相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ１以上であるか否かを判断する（Ｓ４）。 Next, the arithmetic circuit 11 determines whether or not the absolute value |R| of the correlation coefficient R between the reference detection value group and the calibration target detection value group is equal to or greater than the threshold value R th1 (S4).
　ステップＳ４において相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ１以上である場合（Ｓ４でＹｅｓ）、演算回路１１は、基準検出値群の中に、上限閾値θｍａｘ以上の検出値、及び下限閾値θｍｉｎ以下の検出値があるか否かを判断する（Ｓ６）。ステップＳ６でＹｅｓの場合、演算回路１１は、ステップＳ２０２及びＳ７で取得された基準検出値群を基準として、ステップＳ２０２及びＳ７で取得された較正対象検出値群の平均値を較正する第４の較正式を算出する（Ｓ２０８）。 If the absolute value |R| of the correlation coefficient R is equal to or greater than the threshold value R th1 in step S4 (Yes in S4), the arithmetic circuit 11 selects a detected value equal to or greater than the upper threshold value θ max in the reference detected value group, and It is determined whether or not there is a detected value equal to or lower than the lower limit threshold θ min (S6). If Yes in step S6, the arithmetic circuit 11 calibrate the average value of the calibration target detection value group obtained in steps S202 and S7 with reference to the reference detection value group obtained in steps S202 and S7. A calibration formula is calculated (S208).
　次に、演算回路１１は、基準検出値群と較正対象検出値群の平均値との相関係数Ｒの絶対値|Ｒ|が閾値Ｒｔｈ２以上であるか否かを判断する（Ｓ９）。 Next, the arithmetic circuit 11 determines whether or not the absolute value |R| of the correlation coefficient R between the reference detection value group and the calibration target detection value group is equal to or greater than the threshold value R th2 (S9).
　以上のように、本実施形態に係る較正装置１の演算回路１１は、複数の基準検出値を基準として、各較正対象センサによって検出された複数の較正対象検出値を較正することにより、複数の較正対象センサ２について較正を行う。 As described above, the arithmetic circuit 11 of the calibration device 1 according to the present embodiment calibrates a plurality of calibration target detection values detected by each calibration target sensor with reference to a plurality of reference detection values, thereby obtaining a plurality of The calibration target sensor 2 is calibrated.
　この構成により、１つの基準センサ３を基準として、複数の較正対象センサ２について較正を行うことができ、数日かかる構成を較正対象センサ２の数だけ行う手間を省き、複数の較正対象センサ２の運用コストを低減することができる。 With this configuration, it is possible to calibrate a plurality of sensors 2 to be calibrated using one reference sensor 3 as a reference. operating costs can be reduced.
３．第３実施形態
　以下、本開示の第３実施形態について説明する。本実施形態に係る較正システムは、図４に示した第２実施形態に係る較正システム２００と同様の較正を有する。本実施形態では、第２実施形態と同様の構成要素について、第２実施形態と同一の符号を用いる。 3. Third Embodiment A third embodiment of the present disclosure will be described below. The calibration system according to this embodiment has similar calibrations as the calibration system 200 according to the second embodiment shown in FIG. In this embodiment, the same reference numerals as in the second embodiment are used for the same components as in the second embodiment.
　第２実施形態に係る較正システム２００と比較すると、本実施形態では、基準センサ３及び複数の較正対象センサ２は、温度を更に検出する。本実施形態に係る較正システム２００では、複数の較正対象センサ２のうち、基準センサ３によって検出された温度変化と類似する温度変化を検出した較正対象センサ２を構成する。例えば、９個の較正対象センサ２のうち、日陰になる時刻が同じ等の理由により、基準センサ３と同様の温度変化を検出した４個の較正対象センサ２のみを較正するような利用方法が考えられる。 In comparison with the calibration system 200 according to the second embodiment, the reference sensor 3 and the plurality of calibration target sensors 2 further detect temperature in this embodiment. In the calibration system 200 according to this embodiment, among the plurality of sensors 2 to be calibrated, those sensors 2 to be calibrated that detect temperature changes similar to those detected by the reference sensor 3 are configured. For example, among the nine sensors 2 to be calibrated, there is a method of use in which only four sensors 2 to be calibrated that have detected the same temperature change as the reference sensor 3 are calibrated because they are shaded at the same time. Conceivable.
　図６は、本実施形態に係る較正システム２００の較正装置１による較正動作を説明するためのフローチャートである。以下では、図５に示した第２実施形態に係る較正装置１の動作と異なる部分について説明し、同様の動作については説明を省略する。 FIG. 6 is a flow chart for explaining the calibration operation by the calibration device 1 of the calibration system 200 according to this embodiment. In the following, portions different from the operations of the calibration apparatus 1 according to the second embodiment shown in FIG. 5 will be described, and descriptions of similar operations will be omitted.
　測定開始条件が満たされている場合（Ｓ２０１でＹｅｓ）、演算回路１１は、基準センサ３及び複数の較正対象センサ２のそれぞれから、測定開始条件の具備後の所定期間内に時系列で検出された温度、基準検出値群、及び較正対象検出値群を取得する（Ｓ３０２）。 When the measurement start condition is satisfied (Yes in S201), the arithmetic circuit 11 detects in time series from each of the reference sensor 3 and the plurality of calibration target sensors 2 within a predetermined period after the measurement start condition is met. The temperature, reference detection value group, and calibration target detection value group are acquired (S302).
　次に、演算回路１１は、複数の較正対象センサ２の中から、基準センサ３によって検出された温度変化と類似する温度変化を検出した較正対象センサ２を選択する（Ｓ３０３）。例えば、各時刻において特定の較正対象センサ２によって検出された温度と、同時刻において基準センサ３によって検出された温度との差が所定の閾値以下であるとき、演算回路１１は、当該較正対象センサ２を選択する。複数の較正対象センサ２のいずれも選択されなかった場合は、図６のフローを終了する。 Next, the arithmetic circuit 11 selects the calibration target sensor 2 that has detected a temperature change similar to the temperature change detected by the reference sensor 3 from among the plurality of calibration target sensors 2 (S303). For example, when the difference between the temperature detected by a specific sensor to be calibrated 2 at each time and the temperature detected by the reference sensor 3 at the same time is equal to or less than a predetermined threshold, the arithmetic circuit 11 Select 2. If none of the plurality of sensors 2 to be calibrated have been selected, the flow of FIG. 6 ends.
　次に、演算回路１１は、ステップＳ３０２で取得された基準検出値群を基準として、ステップＳ３０３で選択された較正対象センサ２の較正対象検出値群の平均値を較正する第５の較正式を算出する（Ｓ３０４）。ステップＳ３０４以降の動作は、図５に示した第２実施形態に係る較正システム２００の較正装置１による較正動作と同様である。なお、ステップＳ３０８では、ステップＳ３０３で選択された較正対象センサ２の較正対象検出値群の平均値を較正する第６の較正式を算出する。 Next, the arithmetic circuit 11 calculates a fifth calibration formula for calibrating the average value of the calibration target detection value group of the calibration target sensor 2 selected in step S303, using the reference detection value group acquired in step S302 as a reference. Calculate (S304). The operation after step S304 is the same as the calibration operation by the calibration device 1 of the calibration system 200 according to the second embodiment shown in FIG. In step S308, a sixth calibration formula for calibrating the average value of the calibration target detection value group of the calibration target sensor 2 selected in step S303 is calculated.
　以上のように、本実施形態では、演算回路１１は、基準センサ３及び複数の較正対象センサ２によってそれぞれ複数の時刻において検出された温度を更に取得する（Ｓ３０２）。演算回路１１は、基準センサ３によって検出された温度と、複数の較正対象センサ２によって検出された温度との比較に基づいて、複数の較正対象センサ２の中から１以上の較正対象センサ２を選択する（Ｓ３０３）。演算回路１１は、複数の基準検出値を基準として、選択された１以上の較正対象センサ２のそれぞれによって検出された較正対象検出値を較正することにより、１以上の較正対象センサ２について較正を行う。 As described above, in the present embodiment, the arithmetic circuit 11 further acquires temperatures detected at a plurality of times by the reference sensor 3 and the plurality of calibration target sensors 2 (S302). The arithmetic circuit 11 selects one or more sensors 2 to be calibrated from among the plurality of sensors 2 to be calibrated based on a comparison between the temperature detected by the reference sensor 3 and the temperature detected by the plurality of sensors 2 to be calibrated. Select (S303). The arithmetic circuit 11 calibrates the one or more calibration target sensors 2 by calibrating the calibration target detection values detected by each of the selected one or more calibration target sensors 2 with reference to a plurality of reference detection values. conduct.
　水の比誘電率は温度によって変化する。したがって、較正対象センサ２の埋設場所の温度が、基準センサ３の埋設場所の温度と大きく異なる場合、基準センサ３を基準として較正対象センサ２を較正しても、較正後の較正対象センサ２による含水率の計測結果は正確でないことがある。本実施形態では、複数の較正対象センサ２のうち、基準センサ３と同様の温度変化を検出した１以上の較正対象センサ２のみを較正するため、当該１以上の較正対象センサ２について高精度に較正を行うことができる。 　The dielectric constant of water changes depending on the temperature. Therefore, if the temperature of the location where the calibration target sensor 2 is embedded is significantly different from the temperature of the location where the reference sensor 3 is embedded, even if the calibration target sensor 2 is calibrated using the reference sensor 3 as a reference, the calibration target sensor 2 after calibration Moisture content measurements may not be accurate. In the present embodiment, only one or more of the calibration target sensors 2 that have detected the same temperature change as the reference sensor 3 among the plurality of calibration target sensors 2 is calibrated. Calibration can be performed.
（変形例）
　以上、本開示の実施形態を詳細に説明したが、前述までの説明はあらゆる点において本開示の例示に過ぎない。本開示の範囲を逸脱することなく種々の改良や変形を行うことができる。例えば、以下のような変更が可能である。なお、以下では、上記実施形態と同様の構成要素に関しては同様の符号を用い、上記実施形態と同様の点については、適宜説明を省略する。以下の変形例は適宜組み合わせることができる。 (Modification)
Although the embodiments of the present disclosure have been described above in detail, the above description is merely an example of the present disclosure in every respect. Various modifications and variations can be made without departing from the scope of the disclosure. For example, the following changes are possible. In addition, below, the same code|symbol is used about the component similar to the said embodiment, and description is abbreviate|omitted suitably about the point similar to the said embodiment. The following modified examples can be combined as appropriate.
　第１実施形態では、土壌の比誘電率、ひいては含水率を測定する較正対象センサ２について説明したが、本開示の較正対象センサ２は、温度を更に検出してもよい。前述のように、水の比誘電率は温度によって変化するため、較正対象センサ２によって検出された比誘電率を含水率に変換する際には、検出時の温度に応じた補正係数を適用して変換を行わなければ、正確な含水率が得られない。 In the first embodiment, the calibration target sensor 2 that measures the relative permittivity of the soil and, by extension, the water content, was described, but the calibration target sensor 2 of the present disclosure may further detect temperature. As described above, since the dielectric constant of water changes with temperature, when converting the dielectric constant detected by the sensor 2 to be calibrated into the water content, a correction coefficient corresponding to the temperature at the time of detection is applied. Without conversion, you will not get an accurate moisture content.
　そこで、本変形例では、演算回路１１は、較正対象センサ２によって時系列で検出された複数の比誘電率と、複数の比誘電率のそれぞれの検出時の温度とを取得する。次に、演算回路１１は、取得した各比誘電率に、その検出時の温度に応じた補正係数を適用することにより各比誘電率を含水率に変換する。演算回路１１は、複数の基準検出値を基準として、複数の含水率を較正する。これにより、較正対象センサ２による比誘電率の検出結果から、温度に応じてより正確な含水率を得ることができる。したがって、本変形例によれば、正確な含水率を、基準センサ３に基づいて較正することにより、高精度に較正を行うことができる。 Therefore, in this modified example, the arithmetic circuit 11 acquires a plurality of dielectric constants detected in time series by the sensor 2 to be calibrated and the temperature at the time of detection of each of the plurality of dielectric constants. Next, the arithmetic circuit 11 converts each relative permittivity into a moisture content by applying a correction coefficient corresponding to the temperature at the time of detection to each relative permittivity obtained. Arithmetic circuit 11 calibrates a plurality of moisture contents based on a plurality of reference detection values. As a result, it is possible to obtain a more accurate moisture content according to the temperature from the detection result of the relative permittivity by the sensor 2 to be calibrated. Therefore, according to this modification, by calibrating an accurate moisture content based on the reference sensor 3, calibration can be performed with high accuracy.
　１　較正装置
　２　較正対象センサ
　３　基準センサ
　４　土壌
　１１　演算回路
　１２　記憶装置
　１３　入出力インタフェース
　１００，２００　較正システム REFERENCE SIGNS LIST 1 calibration device 2 calibration target sensor 3 reference sensor 4 soil 11 arithmetic circuit 12 storage device 13 input/ output interface 100, 200 calibration system

Claims (7)

  1. 　演算回路と記憶装置とを備え、
    　前記演算回路は、
    　媒質中に配置された基準センサによってそれぞれ複数の時刻において検出された前記媒質中の水分量に関する複数の基準検出値と、前記媒質中に配置された較正対象センサによって前記複数の時刻にそれぞれ対応する時刻において検出された前記媒質中の水分量に関する複数の較正対象検出値と、を取得して前記記憶装置に格納し、
    　前記複数の基準検出値を基準として前記複数の較正対象検出値を較正する較正式を算出する、
    　較正装置。     comprising an arithmetic circuit and a storage device,
    The arithmetic circuit is
    A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining and storing in the storage device a plurality of calibrated detected values for the amount of moisture in the medium detected at the time;
    calculating a calibration formula for calibrating the plurality of calibration target detection values based on the plurality of reference detection values;
    calibration device.
  2. 　前記演算回路は、
    　前記較正対象センサによって検出された複数の比誘電率と、前記複数の比誘電率のそれぞれの検出時の温度とを取得し、
    　各比誘電率に、対応する前記検出時の温度に応じた補正係数を適用することにより複数の含水率を算出し、
    　前記複数の基準検出値を基準として前記複数の含水率を較正する、
    　請求項１に記載の較正装置。     The arithmetic circuit is
    Acquiring a plurality of dielectric constants detected by the sensor to be calibrated and a temperature at the time of detection of each of the plurality of dielectric constants;
    calculating a plurality of water contents by applying a correction coefficient according to the corresponding temperature at the time of detection to each relative permittivity;
    calibrating the plurality of moisture contents based on the plurality of reference detection values;
    2. The calibration device of claim 1.
  3. 　前記基準センサは、ＴＤＲ法又はＴＤＴ法により前記複数の基準検出値を検出し、
    　前記較正対象センサは、前記較正対象センサ内のコンデンサの静電容量に基づいて前記複数の較正対象検出値を検出する静電容量式のセンサである、
    　請求項１又は２に記載の較正装置。     The reference sensor detects the plurality of reference detection values by a TDR method or a TDT method,
    The calibration target sensor is a capacitive sensor that detects the plurality of calibration target detection values based on the capacitance of a capacitor in the calibration target sensor.
    3. A calibration device according to claim 1 or 2.
  4. 　前記媒質中には、１つの前記基準センサと複数の前記較正対象センサが配置され、
    　前記演算回路は、前記複数の基準検出値を基準として、各較正対象センサによって検出された前記複数の較正対象検出値を較正することにより、前記複数の較正対象センサについて較正を行う、
    　請求項１～３のいずれかに記載の較正装置。     one of the reference sensors and a plurality of the calibration target sensors are arranged in the medium;
    The arithmetic circuit calibrates the plurality of calibration target sensors by calibrating the plurality of calibration target detection values detected by each calibration target sensor with reference to the plurality of reference detection values.
    A calibration device according to any one of claims 1-3.
  5. 　前記演算回路は、
    　前記基準センサ及び前記複数の較正対象センサによってそれぞれ複数の時刻において検出された温度を更に取得し、
    　前記基準センサによって検出された温度と、前記複数の較正対象センサによって検出された温度との比較に基づいて、前記複数の較正対象センサの中から１以上の較正対象センサを選択し、
    　前記複数の基準検出値を基準として、選択された前記１以上の較正対象センサのそれぞれによって検出された較正対象検出値を較正することにより、前記１以上の較正対象センサについて較正を行う、
    　請求項４に記載の較正装置。     The arithmetic circuit is
    further acquiring temperatures detected at a plurality of times by the reference sensor and the plurality of sensors to be calibrated;
    selecting one or more sensors to be calibrated from among the plurality of sensors to be calibrated based on a comparison of the temperatures sensed by the reference sensor and the temperatures sensed by the plurality of sensors to be calibrated;
    calibrating the one or more calibration target sensors by calibrating the calibration target detection values detected by each of the one or more calibration target sensors selected using the plurality of reference detection values as a reference;
    5. A calibration device according to claim 4.
  6. 　媒質中に配置された基準センサによってそれぞれ複数の時刻において検出された前記媒質中の水分量に関する複数の基準検出値と、前記媒質中に配置された較正対象センサによって前記複数の時刻にそれぞれ対応する時刻において検出された前記媒質中の水分量に関する複数の較正対象検出値と、を取得するステップと、
    　前記複数の基準検出値を基準として前記複数の較正対象検出値を較正する較正式を算出するステップと、
    　を含む較正方法。     A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining a plurality of calibrated sensed values for the amount of moisture in the medium sensed at a time;
    calculating a calibration formula for calibrating the plurality of calibration target detection values with reference to the plurality of reference detection values;
    Calibration method including.
  7. 　媒質中に配置された基準センサによってそれぞれ複数の時刻において検出された前記媒質中の水分量に関する複数の基準検出値と、前記媒質中に配置された較正対象センサによって前記複数の時刻にそれぞれ対応する時刻において検出された前記媒質中の水分量に関する複数の較正対象検出値と、を取得するステップと、
    　前記複数の基準検出値を基準として前記複数の較正対象検出値を較正する較正式を算出するステップと、
    　を演算回路に実行させるためのプログラム。     A plurality of reference detection values relating to the amount of moisture in the medium detected at a plurality of times by a reference sensor placed in the medium, and corresponding to the plurality of times by a sensor to be calibrated placed in the medium. obtaining a plurality of calibrated sensed values for the amount of moisture in the medium sensed at a time;
    calculating a calibration formula for calibrating the plurality of calibration target detection values with reference to the plurality of reference detection values;
    A program for executing the arithmetic circuit.
PCT/JP2022/031236 2021-09-27 2022-08-18 Calibration device, calibration method, and program WO2023047851A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004271494A (en) * 2003-03-11 2004-09-30 Asuzac Inc Field moisture switch
JP2012122909A (en) * 2010-12-10 2012-06-28 Univ Of Tokushima Capacitance type moisture meter and water gage
CN205808985U (en) * 2016-04-28 2016-12-14 浙江托普云农科技股份有限公司 A kind of Novel integrated soil temperature-moisture sensor
CN110579512A (en) * 2019-10-09 2019-12-17 清华大学 manufacturing and calibration method of filter type soil moisture content sensor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004271494A (en) * 2003-03-11 2004-09-30 Asuzac Inc Field moisture switch
JP2012122909A (en) * 2010-12-10 2012-06-28 Univ Of Tokushima Capacitance type moisture meter and water gage
CN205808985U (en) * 2016-04-28 2016-12-14 浙江托普云农科技股份有限公司 A kind of Novel integrated soil temperature-moisture sensor
CN110579512A (en) * 2019-10-09 2019-12-17 清华大学 manufacturing and calibration method of filter type soil moisture content sensor

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