Non-destructive moisture measurement device

Abstract

To provide a portable, low-cost non-destructive moisture measurement device capable of always measuring the moisture state of a plant in a non-destructive manner.SOLUTION: A non-destructive moisture measurement device 1 comprises an optical sensor (near-infrared LED 131 and PD 132) that irradiates a plant stem being a measurement target with near-infrared light including at least a wavelength of 1450 nm, and always measures a reflected light amount at the wavelength of 1450 nm from the plant stem. The non-destructive moisture measurement device 1 further comprises: a storage unit 170 that stores calibration curve data indicating a correlation between a moisture state of a plant and the reflected light amount; moisture state measurement units 141, 142 that measure the moisture state of the plant being the measurement target by using the calibration curve data and the measured reflected light amount; and an output unit that outputs the measured moisture state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a non-destructive moisture measurement device, and more particularly to a portable non-destructive moisture measurement device that can constantly measure the moisture status of plants non-destructively using near-infrared spectroscopy. [Background technology]

[0002] Conventionally, plant irrigation management has been indirectly carried out by measuring the moisture status of the soil in which the plants are grown, based on the fact that plants absorb most of the water they need from the soil. However, because the moisture status of the soil and the moisture status of the plant are not the same, it is difficult to optimally manage plant irrigation based solely on the measured soil moisture status, and it has largely relied on the experience and intuition of skilled workers. Therefore, there has been a demand for a way to measure the moisture status of plants.

[0003] Therefore, in order to perform timely irrigation management for plants, a device has been disclosed that non-destructively measures the water status of plants in real time (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-017624 Summary of the Invention [Problem to be solved by the invention]

[0005] In plant irrigation management, there is a demand for timely management by measuring the water status of plants in real time, as well as a demand for continuous measurement of the water status of plants to manage it over time. However, the technology disclosed in Patent Document 1 is a device that measures the water status of plants in real time, and it is difficult to leave it attached to the plant and measure it constantly. Furthermore, conventional optical sensors such as near-infrared spectroscopy can also measure non-destructively, but they are expensive and the devices are large, making it difficult to leave them attached to the plant and measure it constantly.

[0006] Therefore, an object of the present invention is to provide a portable, non-destructive moisture measuring device that can constantly measure the moisture status of plants non-destructively using near-infrared spectroscopy and that can be manufactured at low cost. [Means for solving the problem]

[0007] The present invention provides Attach it to the plant stem to be measured. A non-destructive moisture measuring device is provided that is equipped with an optical sensor that irradiates the plant stem with near-infrared light having a wavelength of at least 1450 nm and constantly measures the amount of light reflected from the plant stem at the wavelength of 1450 nm.

[0008] The present invention also provides The optical sensor a near-infrared LED that emits near-infrared light having a wavelength of at least 1450 nm; a photodiode that receives the reflected light having a wavelength of 1450 nm; A non-destructive moisture measuring device is provided.

[0009] The present invention provides a storage unit that stores calibration curve data that indicates the correspondence relationship between the water status of a plant and the amount of reflected light; a water status measurement unit that measures the water status of the measurement target plant using the calibration curve data and the measured amount of reflected light; an output unit that outputs the measured moisture state; A non-destructive moisture measuring device is provided.

[0010] The present invention provides a non-destructive moisture measuring device in which the output section outputs the measured moisture status over time.

[0011] The present invention also provides a non-destructive moisture measuring device that uses the reflected light intensity or reflectance instead of the reflected light amount.

[0012] The present invention also provides a non-destructive water content measuring device, wherein the water state is at least one of the water content, water amount, and water potential of the plant.

[0013] Further, the present invention provides a method for measuring the amount of reflected light at the wavelength of 1450 nm and the amount of reflected light at the second wavelength, wherein the optical sensor irradiates near-infrared light having at least a wavelength of 1450 nm and near-infrared light having a second wavelength that is not absorbed by water onto a plant stem to be measured, and measures the amount of reflected light at the wavelength of 1450 nm and the amount of reflected light at the second wavelength; the storage unit stores calibration curve data indicating a correspondence relationship between the water status of a plant and the ratio of the amount of reflected light at the wavelength of 1450 nm to the amount of reflected light at the second wavelength; The moisture status measuring unit measures the moisture status of the plant to be measured using the calibration curve data and the ratio between the measured amount of reflected light at the wavelength of 1450 nm and the amount of reflected light at the second wavelength.

[0014] Furthermore, the present invention provides a method for producing the calibration curve data for each plant type or each plant variety, The non-destructive moisture measuring device is provided in which the storage unit stores the calibration curve data for each type of plant and / or each variety of plant.

[0015] The present invention also provides A measuring instrument equipped with at least the optical sensor and attached to the plant stem; a battery device including at least a battery for operating the measuring instrument; a mobile communication terminal including at least the output unit; A non-destructive moisture measuring device is provided.

[0016] In addition, in the non-destructive moisture measuring device of the present invention, The device is in the form of a clip, The optical sensor provides a non-destructive moisture measuring device that is provided on the clamping surface that clamps the plant stem.

[0017] The present invention also provides a method executed by a non-destructive moisture measuring device, comprising: An optical sensor irradiates near-infrared light having a wavelength of at least 1450 nm onto the plant stem to be measured, and constantly measures the amount of reflected light of the wavelength of 1450 nm from the plant stem; storing calibration curve data indicating a correspondence relationship between the water status of the plant and the amount of reflected light in a storage unit; measuring the water status of the measurement target plant using the calibration curve data and the measured amount of reflected light; outputting the measured moisture status; The present invention provides a method having the following structure:

[0018] The present invention also provides a non-destructive moisture measuring device, an optical sensor that irradiates near-infrared light having a wavelength of at least 1450 nm onto a plant stem to be measured and constantly measures the amount of reflected light of the wavelength of 1450 nm from the plant stem; a storage unit that stores calibration curve data that indicates the correspondence relationship between the water status of the plant and the amount of reflected light; a water status measurement unit that measures the water status of the measurement target plant using the calibration curve data and the measured amount of reflected light; an output unit that outputs the measured moisture state; We provide a program that functions as a [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a portable, non-destructive moisture measuring device that can constantly measure the moisture status of plants non-destructively using near-infrared spectroscopy and that has low manufacturing costs. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram of a non-destructive moisture measuring device according to a first embodiment of the present invention. [Figure 2]1 is a diagram showing the functional configuration of a measuring instrument according to a first embodiment of the present invention. [Figure 3] 1A and 1B are diagrams illustrating a structure of an optical sensor according to a first embodiment of the present invention. [Figure 4] FIG. 1 shows an example of an Ariadne calibration curve. [Figure 5] FIG. 10 is a diagram showing a modified example of the functional configuration of a measuring instrument according to the first embodiment of the present invention. [Figure 6] FIG. 2 is a diagram showing a flowchart of a continuous measurement process of the water status of a plant stem S in the non-destructive water-measuring device according to the first embodiment of the present invention. [Figure 7] 4 is an example of a calibration curve selection / setting screen of the mobile communication terminal according to the first embodiment of the present invention. [Figure 8] 3 is an example of a measurement main screen of the mobile communication terminal according to the first embodiment of the present invention. [Figure 9] FIG. 2 is a flowchart showing the process of measuring the water content of a plant stem in the measuring instrument 100 according to the first embodiment of the present invention. [Figure 10] FIG. 4 is a flowchart showing a reflected light amount measurement process performed by a measurement control unit according to the first embodiment of the present invention. [Figure 11] 1 is a conceptual diagram showing an example of application of the non-destructive moisture measuring device 1 according to the first embodiment of the present invention. [Figure 12] FIG. 10 is a diagram showing the functional configuration of a measuring instrument according to a second embodiment of the present invention. [Figure 13] 5A and 5B are diagrams illustrating the structure of an optical sensor according to a second embodiment of the present invention. [Figure 14] FIG. 10 is a flowchart showing the process of measuring the water content of a plant stem in the measuring instrument 100 according to the second embodiment of the present invention. [Figure 15] FIG. 10 is a diagram showing another example of an Ariadne calibration curve. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention (hereinafter referred to as "embodiments") will be described in detail with reference to the accompanying drawings. In the following drawings, the same elements are designated by the same numbers or symbols throughout the description of the embodiments.

[0022] First Embodiment [Basic concept / basic configuration] FIG. 1 is a schematic diagram of a non-destructive moisture measuring device 1 according to a first embodiment of the present invention. The non-destructive moisture measuring device 1 is a device that is attached to a plant stem S and constantly measures the water status of the plant in a non-destructive manner, and includes a measuring instrument 100 and a mobile communication terminal 200.

[0023] The measuring instrument 100 clamps the plant stem S between the clamping parts 11a and 11b, and constantly measures the results of irradiating the plant stem S with near-infrared light from optical sensors provided inside the clamping parts 11a and 11b. The measuring instrument 100 also constantly measures the water status of the plant based on the constantly measured irradiation results. The irradiation results are data that are the basis for measuring the water status of the plant, i.e., data that reflects the water status of the plant. Therefore, since a user or the like can infer fluctuations in the water status of the plant from fluctuations in the irradiation results, the measuring instrument 100 may measure only the irradiation results. In this embodiment, the water status of a plant is expressed by at least one of water content, water amount, and water potential.

[0024] The plant stem S held by the measuring instrument 100 may be any stem of the plant, and may be a main axis or a side axis. It is desirable to attach the measuring instrument 100 to a position where the plant itself will not fall over or the stem will not break, and it is not desirable to attach the measuring instrument 100 to the top of the main axis or a side axis above the main axis.

[0025] The measuring device 100 is in the form of a clip, and a pair of clip halves 10 a and 10 b are connected by a connecting portion 12 . In the natural state where no external force is applied, the pair of clip halves 10a, 10b are in a closed state with the clamping portions 11a, 11b abutting against each other. On the other hand, when the gripping portions 13a, 13b are held with fingers and a force is applied in the direction that brings them closer to each other, the clamping portions 11a, 11b move apart and enter an open state.

[0026] The clamping parts 11a and 11b have grooves 14a and 14b on their opposing surfaces, which are parallel to the short side direction. The grooves 14a and 14b are positioned opposite each other, and in the closed state, the grooves 14a and 14b form a space that can surround and clamp the plant stem S. This reduces damage to the plant stem S when the measuring device 10 is attached to the plant stem S. Since the plant stem S is nearly circular, it is desirable that the grooves 14a, 14b have a semicircular cross section, but as long as a space can be formed, they may have any shape such as a U-shaped or C-shaped cross section.

[0027] On the side of clip half 10a opposite clip half 10b, there is provided a display 160 that displays the measurement values ​​of the optical sensor (described later) and the remaining charge of battery 121, as well as a button 15 that is used to turn the power of measuring device 100 on and off, turn display 160 on and off, or update display 160.

[0028] The configuration of the measuring instrument 100 described above is merely an example, and any configuration is sufficient as long as the measuring instrument 100 can be attached to the plant stem, i.e., can maintain a state in which the measuring instrument 100 is held by the plant stem.

[0029] The mobile communication terminal 200 is installed with a measurement application that operates the measuring instrument 100 and outputs the time-dependent and / or current moisture status measured by the measuring instrument 100, the optical sensor measurement value when the moisture status is measured, the temperature of the optical sensor, the measured illuminance, the measured wavelength, etc.

[0030] The measuring instrument 100 and the mobile communication terminal 200 may be connected wirelessly using Bluetooth (registered trademark) or may be connected by wire using an OTG cable. In this embodiment, the description will be given assuming that they are connected wirelessly.

[0031] [Function Configuration] FIG. 2 is a diagram showing an example of the functional configuration of the measuring instrument 100 according to the first embodiment. The measuring instrument 100 includes a communication unit 110 , a power supply unit 120 , a measurement unit 130 , a control unit 140 , a sensor 150 , a display unit 160 , and a memory unit 170 .

[0032] Communication unit 110 performs wireless communication between control unit 140 and mobile communication terminal 200, and is a Bluetooth module in this embodiment. Among wireless communication standards, Bluetooth supports a sleep mode and is excellent in terms of low power consumption, as it returns from the sleep mode in response to an instruction from mobile communication terminal 200, transfers information to mobile communication terminal 200, and then transitions back to the sleep mode.

[0033] The power supply unit 120 includes a battery 121 and supplies power to each component of the measuring instrument 100 via the control unit 140. The battery 121 may be a lithium ion battery, a nickel-metal hydride battery, or the like, and may be either a primary battery or a secondary battery.

[0034] The measurement unit 130 performs measurements to measure the moisture status of the plant to be measured, with the plant stem S clamped between the clamping units 11a and 11b, and is equipped with an optical sensor consisting of a near-infrared LED 131 and a photodiode (PD) 132, and an AD converter 133. In this embodiment, the optical sensor is a reflective optical sensor because the stem has thickness, and may be a diffuse reflection type, a retro-reflection type, a narrow field of view reflection type, etc., and may also be combined with a transmissive optical sensor as appropriate.

[0035] The near-infrared LED 131 is used as a light-emitting element, and irradiates the plant stem S with near-infrared light of 1450 nm or near-infrared light including 1450 nm. The PD 132 is used as a light receiving element, and detects the reflected light that is reflected without passing through the plant leaves S out of the near-infrared light irradiated from the near-infrared LED 131 as a current (received light current) of an analog signal. The AD converter converts the voltage converted by the resistor from the current of the analog signal detected by the PD 132 into a digital value. The reflected light amount is a digital value of the voltage when the near-infrared LED 131 is turned on, and the dark correction value (described later) is a digital value of the voltage when the LED is not turned on.

[0036] Here, the use of an optical sensor in which the near-infrared LED 131 is a light-emitting element and the PD 132 is a light-receiving element will be described. The 1450 nm wavelength included in the near-infrared light emitted by the near-infrared LED 131 is an absorption wavelength of water. In addition to 1450 nm, water also absorbs wavelengths at 1940 nm. The plant stem S is a living organism, and the more water there is in the organism, the more easily near-infrared light with wavelengths of 1450 nm and 1940 nm, which are absorption wavelengths of water, is absorbed. Therefore, by measuring the intensity of the wavelengths absorbed by water that are transmitted or reflected without being absorbed by the plant stem S, the water status of the plant stem S, i.e., the water status of the plant, can be measured.

[0037] As mentioned above, water has two absorption wavelengths, 1450 nm and 1940 nm, but water absorbs the 1940 nm wavelength more than the 1450 nm wavelength. Therefore, moisture content is generally measured using a wavelength of 1940 nm, with a light source such as a tungsten lamp or halogen lamp and a near-infrared spectrometer that uses a spectrometer that applies MEMS. However, the above-mentioned near-infrared spectrometer has the problem that the measured values ​​fluctuate over time after the lamp is turned on, and that the lamp becomes expensive when an attempt is made to make it smaller.Furthermore, since tungsten lamps emit light in a wide band from visible to infrared, the output also includes light in a wavelength range that is not involved in water absorption, resulting in low energy utilization efficiency.

[0038] Incidentally, in the case of plant stems S, the moisture content of plant stems S is high at about 40% to 90%, so sufficient results can be obtained even if the moisture status is measured using 1450 nm, which has weaker absorption than 1940 nm.

[0039] These findings indicate that the water status of plants can be measured using an optical sensor equipped with a light-emitting element that emits light at the 1450 nm wavelength absorbed by water and a light-receiving element that receives light at the 1450 nm wavelength absorbed by water.

[0040] Therefore, in this embodiment, a near-infrared LED is used as the light-emitting element (light source), which is small and inexpensive and can emit near-infrared light with a wavelength of 1450 nm absorbed by water or near-infrared light including 1450 nm. For example, the infrared LED L13895 series (Hamamatsu Photonics K.K.) can be used as the near-infrared LED. In this embodiment, since the emission spectrum is limited to a certain wavelength range by using a near-infrared LED as the light-emitting element, a PD is used instead of a spectroscope as the light-receiving element. Furthermore, since the near-infrared LED irradiates near-infrared light of 1450 nm or near-infrared light including 1450 nm, a PD sensitive to 800 to 1700 nm can be used, which is less expensive than a PD sensitive to a wide band. For example, an InGaAs PIN photodiode (Hamamatsu Photonics) can be used as the PD.

[0041] In this way, by using an optical sensor with the near-infrared LED 131 as a light-emitting element and the PD 132 as a light-receiving element, it is possible to reduce manufacturing costs and realize a compact, portable non-destructive moisture measuring device.

[0042] FIG. 3 shows the structure of the above-mentioned optical sensor. An optical lens 16 is provided between the near-infrared LED 131 and the PD 132 and the plant stem S. The optical lens 16 is a bandpass filter that functions as a filter that transmits the 1450 nm near-infrared light detected by the PD 132. The optical lens 16 is not required, but is preferably provided to eliminate individual differences between the near-infrared LEDs 131, such as variations in the emission intensity and wavelength, and to improve measurement accuracy. Note that a portion of the surface of the optical lens 16 forms part of the groove 14a.

[0043] Near-infrared light (1450 nm or including 1450 nm) emitted from the near-infrared LED 131 passes through the optical lens 16 and is irradiated onto the plant stem S (white arrow). Part of the near-infrared light irradiated onto the plant stem S is absorbed by the water in the plant stem S (gray arrow), and the remaining light that is not absorbed is reflected, passes through the optical lens 16, and is detected by the PD 132 (hatched arrow).

[0044] A temperature / humidity sensor 150a is provided near the near-infrared LED 131 and the PD 132. This is to measure the temperature and humidity used when correcting the amount of reflected light, which will be described later.

[0045] Returning to Figure 2, the control unit 140 controls the communication unit 110, power supply unit 120, measurement unit 130, sensor 150, display unit 160, and memory unit 170, and is equipped with an appropriate microcomputer chip equipped with a CPU, ROM, RAM, etc., as well as various circuits such as oscillator circuits for each unit, and is connected to each of the above-mentioned units.

[0046] The control unit 140 also includes, as functional components realized by the CPU executing a program, a measurement control unit 141, a moisture status measurement unit 142, and an output control unit 143. Details of the measurement control unit 141, moisture status measurement unit 142, and output control unit 143 will be described later.

[0047] The sensor 150 is a variety of sensors such as a temperature / humidity sensor 150a provided near the above-mentioned infrared LED 131 and PD 132, a sensor (e.g., GPS) that acquires location information of the measuring instrument 100, and an illuminance sensor that acquires the illuminance at the time of measurement, and is a sensor that acquires information necessary for calculating the moisture status of the target plant and for use in irrigation management using the calculated moisture status.

[0048] The display unit 160 is composed of an LED panel, a liquid crystal panel, or the like, and displays the amount of reflected light (digital value) acquired by the measurement control unit 141, the remaining charge of the battery 121, the sensor measurement value measured by the sensor 150, etc. The display unit 160 can turn the display on / off and update or switch the display content by pressing a button 15 provided on the side of the display unit 160.

[0049] The memory unit 170 holds memory information necessary for the operation of the measuring instrument 100, and also holds at least the calibration curve data for the plant on which the measuring instrument 100 is attached. The memory unit 170 may hold calibration curve data for multiple types of plants and multiple varieties of plants, and the user can add to or rewrite the held calibration curve data as needed.

[0050] Taking advantage of the fact that there is a certain relationship between the moisture status of stems (plants) and the amount of reflected light at a wavelength of 1450 nm, the calibration curve data is created in advance for multiple stems for each plant type or plant variety based on the stem moisture status measured by destructive measurement and the amount of reflected light measured using the measuring instrument 100. The calibration curve data is, for example, a linear regression equation or a quadratic curve equation. As described above, the water status of a plant is expressed by at least one of the water content, water amount, and water potential, so calibration curve data is created for each of the water content, water amount, and water potential.

[0051] Figure 4 shows an example of a calibration curve for the moisture content of Ariadne stems. The vertical axis represents the moisture content (wt%), and the horizontal axis represents the amount of reflected light at 1450 nm. In the figure, the dots represent measured values ​​that correspond to the amount of reflected light measured for Ariadne stems using the optical sensor described above and the moisture content obtained by destructive measurement after the measurement. The solid line represents the calibration curve calculated by regression analysis from the measured values, and is expressed as a linear regression equation.

[0052] Because calibration curves differ depending on the type and variety of plant, calibration curve data must be created in advance for each type of plant or each variety of plant. The previously created calibration curve data is stored in the memory unit 170 or a memory unit (not shown) of the mobile communication terminal 200. In this way, by measuring the amount of reflected light at a wavelength of 1450 nm from the stems of plants grown in a field or the like using the measuring instrument 100, the water status of the measured plants can be immediately detected using the calibration curve data stored in the memory unit 170 or the like.

[0053] A modified example of the functional configuration of the measuring device 100 according to the first embodiment will be described with reference to Fig. 5. Note that parts that perform the same functions as the functional parts of the measuring unit 100 are given the same reference numerals, and duplicated explanations will be omitted as appropriate.

[0054] Measuring instrument 100V includes a measuring unit 130 and a display unit 160. Measuring instrument 100V is connected to battery device 300 by wire, and battery device 300 includes communication unit 110, power supply unit 120, control unit 140, and memory unit 170, which were included in measuring instrument 100. 5 is a functional configuration in which some of the functional units of the measuring instrument 100 shown in FIG. 2 are separated into a battery device 300 connected by wire. Note that the measuring instrument 100V only needs to include at least the measurement unit 130, and the other functional units can be separated into one or more devices such as the battery device 300.

[0055] In this way, by providing some of the functions of the measuring device 100 in a separate device such as the battery device 300, the measuring device 100 can be made lighter, and the number of locations on a plant where it can be attached and the number of plants to which it can be attached can be increased. Furthermore, by providing a separate device such as the battery device 300, it is possible to increase the capacity of the battery 121, making it possible to continue constant measurement for a long period of time. Increasing the capacity of the battery 121 makes the battery device 300 heavier, so it is desirable to attach it to a location sturdier than the stem, such as a stem near the base of the plant stem S on which the measuring device 100V is attached, or a plant support or other pole near the plant stem S on which the 100V is attached.

[0056] Next, the continuous measurement process of the water status of the plant stem S in the non-destructive water-measuring device 1 according to this embodiment will be described using the case where the water content is measured as the water status as an example. The same applies to the case where the water amount or water potential is measured as the water status.

[0057] [Continuous moisture status measurement processing] FIG. 6 is a flowchart showing the process of constantly measuring the water status of the plant stem S in the non-destructive water-measuring device 1. In this process, it is assumed that the power of the measuring instrument 100 is ON, but if the power of the measuring instrument 100 is OFF, the power can be turned ON by operating the button 15, or by operating the mobile communication terminal 200.

[0058] First, when the measurement app is launched, mobile communication terminal 200 determines whether measurement has already started (S1). Whether measurement has already started is determined, for example, by whether measurement data acquired from measuring instrument 100 is stored in a storage unit (not shown) of mobile terminal 200. If measurement has not yet started, the process proceeds to S2, whereas if measurement has already started, the process proceeds to S5.

[0059] The mobile communication terminal 200 displays the calibration curve selection and setting screen of the measurement application (S2), and transmits the calibration curve of the plant selected by the user on the screen to the measuring instrument 100 (S3). FIG. 7 shows an example of a calibration curve selection and setting screen of the mobile communication terminal 200 of this embodiment. The center of the calibration curve selection and setting screen displays a list of plant types and plant varieties for which calibration curves are registered in the memory of mobile communication terminal 200, allowing the user to select the plant to be measured from the list. When the user selects "Ariadne," he or she checks the check box to the left of the "Ariadne" row. After checking the check box, when the user presses the measurement start button, mobile communication terminal 200 transmits the calibration curve for the selected plant to measuring instrument 100, and measuring instrument 100 begins continuous measurement of the water content.

[0060] When registering a calibration curve for a new plant type or variety, clicking the gear icon to the right of the "Not set" row displays a screen (not shown) for setting the type or variety of plant for which the calibration curve is to be performed, the formula and coefficients of the calibration curve, etc., and the new calibration curve can be registered by entering the information on the screen. For calibration curves that have already been registered, the formula and coefficients of the calibration curve can be changed.

[0061] Returning to Figure 6, measuring instrument 100 starts the moisture content measurement process and transmits the moisture content, which is the measurement process result, together with the measurement date and time to mobile communication terminal 200 (S4). Once measuring instrument 100 starts the moisture content measurement process, it continuously measures the moisture content and transmits it to mobile communication terminal 200. Note that measuring instrument 100 may transmit the moisture content after each measurement, or at predetermined intervals. Additionally, measuring instrument 100 may transmit the sensor measurement value measured by sensor 150 of measuring instrument 100 along with the moisture content to mobile communication terminal 200. The moisture content measurement process will be described later.

[0062] Mobile communication terminal 200 associates the moisture content received from measuring instrument 100 with the measurement date and time and stores them in the memory unit (S5). When mobile communication terminal 200 also receives a sensor measurement value from measuring instrument 100, it also associates the moisture content with the measurement date and time and stores them in the memory unit.

[0063] The mobile communication terminal 200 acquires the moisture content and measurement date and time stored in the storage unit, and also the sensor measurement value in some cases, and displays the measurement main screen of the measurement application (S6).

[0064] FIG. 8 shows an example of the measurement main screen of the mobile communication terminal 200 of this embodiment. The main measurement screen displays the moisture content of the plant in real time at the top center. The moisture content is also displayed as a graph with time on the horizontal axis, allowing you to see how the moisture content changes over time.

[0065] The sensor temperature measured by the temperature / humidity sensor 150a can be displayed on the bottom left of the center of the screen. The right-hand bottom center of the screen displays the amount of reflected light at 1450 nm, measured by the optical sensor, in real time. It is also possible to alternate between the moisture content and the amount of reflected light. It is also possible to display the sensor illuminance of the optical sensor during measurement, and whether dark compensation is enabled or disabled. The bottom of the screen has a "Calibration Curve" button for switching to the calibration curve selection and setting screen shown in Figure 7, and a "Start / End Measurement" button for instructing the measuring instrument 100 to start / end measurement, and can also display the current status (in the figure, "Continuous measurement in progress").

[0066] Returning to Fig. 6, mobile communication terminal 200 determines whether the measurement app has been terminated (S7). If the measurement app has not been terminated, the process returns to S5. On the other hand, if the measurement app has been terminated, the process ends. Note that measuring instrument 100 that has started measurement continues measurement even if the measurement app is terminated, and the measurement results are sent to mobile communication terminal 200 even if the measurement app is not running.

[0067] To stop measurement by the measuring instrument 100, the power of the measuring instrument 100 can be turned off from the mobile communication terminal 200, or by performing an operation such as pressing and holding the button 15 on the measuring instrument 100 to turn off the power of the measuring instrument 100. If the power of the measuring instrument 100 is turned off during this process, even if the measurement application is not terminated, the moisture content will not be saved in S5 because the moisture status and other information will not be received from the measuring instrument 100.

[0068] Next, the water content measurement process of the plant stem S in the measuring instrument 100 will be described with reference to the flowchart shown in Figure 9, along with details of each functional configuration of the control unit 140. The water content measurement process starts when the mobile communication terminal 200 issues a measurement start instruction to the measuring instrument 100, and ends when the measuring instrument 100 is powered off.

[0069] The measurement control unit 141 of the measuring instrument 100 first performs a dark measurement and acquires a dark correction value for a wavelength of 1450 nm (S11). Here, dark measurement, also known as dark current measurement or dark calibration, measures the current / voltage (voltage in this embodiment) of the PD 132 without lighting the near-infrared LED 131, and obtains a dark correction value that corrects for deviations due to the characteristics of the PD. Because a small amount of current flows through the PD even when it is not exposed to light, and because the current fluctuates with temperature, the measured value deviates from the true value, and therefore needs to be corrected using a dark correction value.

[0070] The measurement control unit 141 receives, with the PD 132, the light reflected by the plant stem S out of the near-infrared light irradiated from the near-infrared LED 131, and acquires the amount of reflected light at a wavelength of 1450 nm. Furthermore, the measurement control unit 141 acquires the temperature of the optical sensor from the temperature / humidity sensor 150a (S12) in conjunction with the irradiation of near-infrared light from the near-infrared LED 131. Note that the measurement control unit 141 may also acquire sensor values ​​from other sensors.

[0071] The measurement control unit 141 calculates a temperature correction coefficient based on the optical sensor temperature acquired in S12 (S13). Since the light intensity of an LED varies depending on the temperature, temperature correction can improve measurement accuracy. Specifically, the temperature correction coefficient is calculated by substituting the light sensor temperature obtained in S12 into a regression equation obtained by performing a regression analysis of the correlation between the LED light intensity and temperature measured in advance. Note that the regression equation is determined for each LED product, for example. The measurement control unit 141 corrects the amount of reflected light acquired in S12 based on the dark correction value acquired in S11 and the temperature correction ratio calculated in S13, and calculates a measurement value (S14).

[0072] The output control unit 143 of the measuring instrument 100 displays the measurement value calculated in S14 on the display unit 160 (S15). Note that the processing of S15 does not have to be performed after S14, but may be performed after S16 or S17. Furthermore, the output control unit 143 may display the measurement value calculated at the time that the button 15 is pressed on the display unit 160.

[0073] The moisture status measurement unit 142 of the measuring instrument 100 calculates the moisture content based on the calibration curve data of the plant to be measured received from the mobile communication terminal 200 and stored in the memory unit 170 and the measurement value calculated in S14 (S16). The output control unit 143 of the measuring instrument 100 transmits the sensor measurement values, including the moisture content calculated in S15 and the temperature of the optical sensor acquired in S12, to the mobile communication terminal 20 (S17), and stores them in the memory unit of the mobile communication terminal 200.

[0074] FIG. 10 is a flowchart showing the process of measuring the amount of reflected light acquired in S12 by the measurement control unit 141 according to this embodiment. First, the measurement control unit 141 instructs the near-infrared LED 131 to emit near-infrared light, that is, near-infrared light with a wavelength of 1450 nm or near-infrared light with a wavelength including 1450 nm (S21). The near-infrared LED 131 emits near-infrared light having a wavelength of 1450 nm or near-infrared light having a wavelength of 1450 nm (S22).

[0075] In response to receiving the reflected near-infrared light, the PD 132 detects the reflected light as a current (received light current) of an analog signal (S23). The AD converter 133 digitally converts the voltage obtained by converting the current of the analog signal detected by the PD 132 through the resistor in S23, and obtains the digital value of the voltage, that is, the amount of reflected light (S24). During dark measurement, the measurement control unit 141 does not turn on the near-infrared LED 131, but causes the PD 132 to detect the current of the analog signal, and the AD converter 133 converts the voltage converted by the resistor from the current of the analog signal detected by the PD 132 into a digital value, and obtains the digital value of the voltage, i.e., the dark correction value.

[0076] The measurement control unit 141 may cause the near-infrared LED 131 to irradiate near-infrared light for a predetermined time (for example, 5 seconds), and may use the average value of the reflected light amount acquired by the AD converter 133 for the predetermined time as the reflected light amount of the measurement result. Alternatively, the average value of the reflected light amount obtained by performing the processes of S21 to S24 a predetermined number of times of measurement may be used as the reflected light amount of the measurement result. The number of times of measurement may be set by the mobile communication terminal 200, or may be set in advance.

[0077] [Example of use] FIG. 11 is a conceptual diagram showing an example of application of the non-destructive moisture measuring device 1 according to the first embodiment. The non-destructive moisture measuring device 1 is connected to a programmable computer 2 that constitutes an automatic irrigation control system that automatically irrigates plants in a field. Although the figure shows one programmable computer 2, there may be multiple programmable computers.

[0078] Specifically, the moisture status measured by the non-destructive moisture measuring device 1 is automatically or manually transmitted to the programmable computer 2, and based on the real-time moisture status, the programmable computer 2 can open and close the solenoid valve 21 that supplies water to the plants, and can activate or stop the motor 22 that turns the greenhouse ventilation system on and off and opens and closes the windows. This allows for automatic irrigation management of the field. Note that in FIG. 11, the programmable computer 2 includes the solenoid valve 21 and the motor 22, but is not limited to these, and can include other devices used for irrigation management in the field.

[0079] In addition, the moisture status over time measured by the non-destructive moisture measuring device 1 is automatically / manually transmitted to the programmable computer 2, and based on the moisture status over time, the programmable computer 2 can open and close the solenoid valve 21 that supplies water to the plants, and can operate or stop the motor 22 that turns the greenhouse ventilation system on and off and opens and closes the windows.

[0080] Programmable computer 2 transmits the opening / closing history of solenoid valve 21 and the operation history of motor 22 to mobile communication terminal 200. Mobile communication terminal 200 then stores the water status of the plant and the opening / closing history and operation history. Based on the data stored in mobile communication terminal 200, the user can change the settings of programmable computer 2, thereby enabling appropriate irrigation management.

[0081] As described above, the non-destructive moisture measuring device of this embodiment can constantly measure the moisture status of a plant stem using a measuring instrument attached to the plant stem, measuring the amount of reflected light when near-infrared light including 1450 nm is irradiated onto the plant stem, and using pre-created calibration curve data. In addition, the non-destructive moisture measuring device of this embodiment allows users to estimate the moisture status of a plant by irradiating the plant stem with near-infrared light including 1450 nm using a measuring instrument attached to the plant stem and constantly measuring the amount of reflected light. By using the water absorption wavelength of 1450 nm, it becomes possible to use an LED as the light-emitting element and a PD as the light-receiving element, making it possible to realize a small and inexpensive device.

[0082] [Second embodiment] A second embodiment of the present invention will be described using Figures 12 to 14. The non-destructive moisture measuring device of the second embodiment includes an LED that emits near-infrared light at 1450 nm and an LED that emits near-infrared light at a wavelength other than 1450 nm that is not absorbed by water (hereinafter referred to as the reference wavelength), and differs from the first embodiment in that it uses a calibration curve that shows the correspondence relationship between the ratio of the amount of reflected light at 1450 nm to the amount of reflected light at other wavelengths and the moisture status of the stem (plant) instead of the amount of reflected light at 1450 nm. Since the second embodiment is otherwise similar in configuration to the first embodiment, parts that perform the same functions as those in the first embodiment described above are designated by the same reference numerals, and redundant explanations will be omitted where appropriate.

[0083] [Function Configuration] 12 is a diagram showing the functional configuration of a measuring instrument 110 according to the second embodiment. As with the measuring instrument 100 according to the first embodiment, the functional units of the measuring instrument 110 according to the second embodiment other than the measurement unit 130 can be separate devices such as a battery device 300.

[0084] The measurement unit 130 performs measurements to measure the moisture status of a plant to be measured, with the plant stem S clamped between the clamping units 11a and 11b, and is equipped with an optical sensor consisting of a near-infrared LED 131, a photodiode (PD) 132, and a near-infrared LED 134, and an AD converter 133.

[0085] The near-infrared LED 134 is used as a light-emitting element, and irradiates the plant stem S with near-infrared light of a wavelength other than 1450 nm irradiated by the near-infrared LED 131 and which is not absorbed by water (reference wavelength), or near-infrared light including the reference wavelength. The reference wavelength is, for example, 850 nm, which is a wavelength absorbed by other components contained in the stem, such as sugars and amino acids, so that the state of other components in the plant stem S can be measured in addition to the water state. The PD 132 is used as a light receiving element, and detects the amount of near-infrared light irradiated from the near-infrared LED 131 and the near-infrared LED 134 that is reflected without passing through the plant leaves S as a current (received light current) of an analog signal.

[0086] FIG. 13 shows the structure of the above-mentioned optical sensor. An optical lens 17 is provided between the near-infrared LED 131, the PD 132, and the near-infrared LED 134 and the plant stem S. The optical lens 17 is a so-called multi-band pass filter that functions as a filter that transmits near-infrared light of 1450 nm detected by the PD 132 and a reference wavelength (850 nm in this embodiment). The optical lens 17 is not necessarily provided, but is preferably provided to eliminate individual differences between the near-infrared LEDs 131 and 134, such as variations in the emission intensity and wavelength, and to improve measurement accuracy. Note that a portion of the surface of the optical lens 17 forms part of the groove 14a.

[0087] The near-infrared light (at or including the reference wavelength) emitted from the infrared LED 134 passes through the optical lens 17 and is irradiated onto the plant stem S (dotted white arrow), similar to the near-infrared light irradiated from the infrared LED 131. The near-infrared light irradiated onto the plant stem S is reflected by the plant stem S, passes through the optical lens 17, and is detected by the PD 132 (dotted diagonal arrow).

[0088] [Moisture content measurement processing] FIG. 14 is a flowchart showing the process of measuring the water content of the plant stem S in the measuring instrument 110.

[0089] The measurement control unit 141 of the measuring instrument 110 first performs dark measurement and acquires a dark correction value for a wavelength of 1450 nm and a dark correction value for a reference wavelength (S31).

[0090] The measurement control unit 141 measures the reflected light from the plant stem S out of the near-infrared light irradiated from the near-infrared LED 131 using the PD 132, and obtains the amount of reflected light at a wavelength of 1450 nm. The measurement control unit 141 also measures the reflected light from the plant stem S out of the near-infrared light irradiated from the near-infrared LED 134 using the PD 132, and obtains the amount of reflected light at a reference wavelength. Furthermore, the measurement control unit 141 acquires the temperature of the optical sensor from the temperature / humidity sensor 150a (S32) in conjunction with the irradiation of near-infrared light from the near-infrared LED 131 and the near-infrared LED 134. Note that the measurement control unit 141 may also acquire sensor values ​​from other sensors.

[0091] The measurement control unit 141 corrects the amount of reflected light at a wavelength of 1450 nm acquired in S32 based on the dark correction value at a wavelength of 1450 nm acquired in S11 and the temperature correction coefficient calculated in S13, and calculates a measurement value at a wavelength of 1450 nm. In addition, the measurement control unit 141 corrects the amount of reflected light of the reference wavelength acquired in S32 based on the dark correction value of the reference wavelength acquired in S11 and the temperature correction coefficient calculated in S13, and calculates the measurement value of the reference wavelength (S33).

[0092] The measurement control unit 141 calculates the ratio of the measurement value at a wavelength of 1450 nm calculated in S33 to the measurement value at the reference wavelength (S34). Specifically, the measurement value used in the calibration curve is calculated by dividing the measurement value at the reference wavelength by the measurement value at a wavelength of 1450 nm. The moisture status measurement unit 142 of the measuring instrument 100 calculates the moisture content based on the calibration curve data of the measurement target plant received from the mobile communication terminal 200 and stored in the memory unit 170 and the measurement value calculated in S14 (S35). An example of the calibration curve data used in this embodiment is shown in FIG.

[0093] As described above, the non-destructive moisture measuring device of this embodiment can constantly measure the moisture status of a plant stem using a measuring instrument attached to the plant stem, based on the ratio of the amount of reflected light measured by irradiating the plant stem with near-infrared light including 1450 nm to the amount of reflected light measured by irradiating the plant stem with near-infrared light of wavelengths other than 1450 nm that are not absorbed by water, and based on pre-created calibration curve data. By using the ratio of the amount of reflected light measured when near-infrared light including 1450 nm is irradiated onto a plant stem and measured to the amount of reflected light measured when near-infrared light of wavelengths other than 1450 nm that are not absorbed by water is irradiated onto the plant stem as the reference value of the calibration curve, it is possible to measure the measurement value of only the moisture content as much as possible, thereby improving the accuracy of measuring the moisture status.

[0094] (Variation 1) In the first embodiment, the reference value for the calibration curve was the amount of reflected light, and in the second embodiment, it was the ratio between the amount of reflected light measured by irradiating the plant stem with near-infrared light including 1450 nm and the amount of reflected light measured by irradiating the plant stem with near-infrared light having a wavelength other than 1450 nm and including a wavelength that is not absorbed by water.However, instead of these, reflection intensity or reflectance may be used. In this case, the measurement control unit 141 calculates the reflection intensity or reflectance as the measurement value.

[0095] (Variation 2) Multiple measuring devices 10V may be connected to one battery device 300 described in the first embodiment. In this case, the moisture status may be measured for each measuring device 10V, or the average moisture status of the multiple measuring devices 10V may be measured. By reducing the number of battery devices 300, a more inexpensive device can be realized. Furthermore, the effort required for battery replacement and charging can be reduced.

[0096] (Variation 3) In the first and second embodiments, the irradiation angles of the near-infrared LED 131 / near-infrared LEDs 131, 134 may be automatically changed to measure the amount of reflected light at multiple points on the plant stem S, and the average value of the measured amounts of reflected light may be obtained as the amount of reflected light. This can improve the measurement accuracy.

[0097] (Variation 4) In the first and second embodiments, the functions of the control unit 140 of the measuring device 100, 110 may be provided in the mobile communication terminal 20, and the calculation of the moisture status and the control of the near-infrared LEDs 131, 134 and the PD 132 may be performed by the mobile communication terminal 20.

[0098] (Variation 5) In addition, in this embodiment, the moisture content is weight moisture content, but it may be volume moisture content.

[0099] Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention. In the above embodiments, the present invention has been described as a non-destructive moisture measuring device as an invention of a product, but it can also be considered as an invention of a method executed by the non-destructive moisture measuring device in the present invention, or a program that causes the non-destructive moisture measuring device to function as various means. [Explanation of symbols]

[0100] 1. Non-destructive moisture measuring device 100, 100V, 110 Measuring Instrument 200 Mobile communication terminals 110 Communications Department 120 Power supply section 121 Battery 130 Measurement Unit 131,134 Near-infrared LED 132 Photodiode (PD) 133 AD converter 140 Control Unit 141 Measurement control section 142 Moisture status measurement unit 143 Output control section 150 sensors 160 Display section 170 Memory Department

Claims

1. Attach it to the plant stem to be measured. A non-destructive moisture measuring device equipped with an optical sensor that irradiates the plant stem with near-infrared light having a wavelength of at least 1450 nm and constantly measures the amount of light reflected from the plant stem at the wavelength of 1450 nm.

2. The optical sensor a near-infrared LED that emits near-infrared light having a wavelength of at least 1450 nm; a photodiode that receives the reflected light having a wavelength of 1450 nm; The non-destructive moisture measuring device according to claim 1 .

3. a storage unit that stores calibration curve data that indicates the correspondence relationship between the water status of a plant and the amount of reflected light; a water status measurement unit that measures the water status of the measurement target plant using the calibration curve data and the measured amount of reflected light; an output unit that outputs the measured moisture state; The non-destructive moisture measuring device according to claim 1 .

4. 4. The non-destructive moisture measuring device according to claim 3, wherein the output unit outputs the measured moisture status over time.

5. 4. A non-destructive moisture measuring device according to claim 3, wherein the reflected light intensity or reflectance is used instead of the reflected light amount.

6. 4. The non-destructive moisture measuring device according to claim 3, wherein the moisture state is at least one of the moisture content, moisture amount, and water potential of the plant.

7. The optical sensor irradiates the plant stem with near-infrared light having a wavelength of at least 1450 nm and near-infrared light having a second wavelength that is not absorbed by water, and measures the amount of reflected light at the wavelength of 1450 nm and the amount of reflected light at the second wavelength; the storage unit stores calibration curve data indicating a correspondence relationship between the water status of a plant and the ratio of the amount of reflected light at the wavelength of 1450 nm to the amount of reflected light at the second wavelength; 4. The non-destructive moisture measuring device according to claim 3, wherein the moisture status measuring unit measures the moisture status of the plant being measured using the calibration curve data and the ratio between the measured amount of reflected light at the wavelength of 1450 nm and the amount of reflected light at the second wavelength.

8. The calibration curve data is for each plant type or each plant variety, 4. The non-destructive moisture measuring device according to claim 3, wherein the storage unit stores the calibration curve data for each plant type and / or each plant variety.

9. A measuring instrument equipped with at least the optical sensor and attached to the plant stem; a battery device including at least a battery for operating the measuring instrument; a mobile communication terminal including at least the output unit; 4. The non-destructive moisture measuring device according to claim 3, comprising:

10. 2. The non-destructive moisture measuring device according to claim 1, The device is in the form of a clip, The optical sensor is a non-destructive moisture measuring device provided on the clamping surface that clamps the plant stem.

11. A method performed by a non-destructive moisture measurement device, comprising: An optical sensor irradiates near-infrared light having a wavelength of at least 1450 nm onto the plant stem to be measured, and constantly measures the amount of reflected light of the wavelength of 1450 nm from the plant stem; storing calibration curve data indicating a correspondence relationship between the water status of the plant and the amount of reflected light in a storage unit; measuring the water status of the measurement target plant using the calibration curve data and the measured amount of reflected light; outputting the measured moisture status; A method having the following.

12. Non-destructive moisture measuring device, an optical sensor that irradiates near-infrared light having a wavelength of at least 1450 nm onto a plant stem to be measured and constantly measures the amount of reflected light of the wavelength of 1450 nm from the plant stem; a storage unit that stores calibration curve data that indicates the correspondence relationship between the water status of the plant and the amount of reflected light; a water status measurement unit that measures the water status of the measurement target plant using the calibration curve data and the measured amount of reflected light; an output unit that outputs the measured moisture state; A program that functions as a

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