Raindrop detection device and correction method, correction program for same

Abstract

A raindrop detection device (20) comprises a light source unit (22a), a light reception unit (22b), a raindrop detection unit (25a), a diameter calculation unit (25b), and a correction formula setting unit (25c). The light reception unit (22b) is provided at a position that is opposite the light source unit (22a) and receives light emitted from the light source unit (22a). The raindrop detection unit (25a) detects raindrops that have passed between the light source unit (22a) and the light reception unit (22b) in accordance with the change in the amount of light received at the light reception unit (22b). The diameter calculation unit (25b) calculates the diameter of the raindrops detected at the raindrop detection unit (25a). The correction formula setting unit (25c) uses the diameter, as calculated at the diameter calculation unit (25b), of a reference raindrop agent that has a pre-identified diameter to set a correction formula for correcting the value of the diameter calculated at the diameter calculation unit (25b) to the actual value of the diameter of the reference raindrop agent.

Description

Raindrop detection device and its correction method and correction program

[0001] The present invention relates to a raindrop detection device for detecting raindrops, and a correction method and correction program for the same.

[0002] In recent years, tipping bucket rain gauges have been used to measure rainfall, and the rain gauge includes a receiver that receives falling rainwater, a filter that drips the rainwater received in the receiver, and a tipping bucket that tips over to collect the rainwater dripping from the filter. For example, Patent Document 1 discloses a raindrop detection device in which a light source unit and a light receiving unit are positioned opposite each other, and when raindrops pass through a raindrop detection area formed between the light source unit and the light receiving unit, the amount of light received by the light receiving unit decreases, and the device detects raindrops based on this decreased amount of light received.

[0003] JP 2023-98170 A

[0004] However, the conventional raindrop detection device described above has the following problems. Although the raindrop detection device disclosed in the publication can detect raindrops passing through the raindrop detection area based on changes in the amount of light received by the light-receiving unit, there is a risk of raindrop detection accuracy being reduced due to individual differences between devices. The present invention aims to provide a raindrop detection device and a correction method and program therefor that can suppress the reduction in raindrop detection accuracy due to individual differences.

[0005] (Means for Solving the Problem) A raindrop detection device according to a first aspect of the present invention includes a light source unit, a light receiving unit, a raindrop detection unit, a diameter calculation unit, and a correction formula setting unit. The light source unit emits light in a predetermined direction. The light receiving unit is positioned opposite the light source unit and receives the light emitted from the light source unit. The raindrop detection unit detects raindrops that pass between the light source unit and the light receiving unit in accordance with changes in the amount of light received by the light receiving unit. The diameter calculation unit calculates the diameter of the raindrops detected by the raindrop detection unit. The correction formula setting unit sets a correction formula for correcting the diameter value of a reference raindrop agent, the diameter of which is detected by the raindrop detection unit and whose diameter is specified in advance, to the actual diameter value of the reference raindrop agent.

[0006] In this method, a reference raindrop agent whose diameter is specified in advance is detected by the raindrop detection unit, the diameter of the detected reference raindrop agent is calculated, and a correction formula is set to correct the calculation result so that it becomes the actual diameter value of the reference raindrop agent. Here, the light source unit is, for example, a light emitting diode (LED), and irradiates light in a predetermined direction to a light receiving unit arranged opposite to the light source unit at a predetermined distance.

[0007] The light receiving unit is, for example, a photodiode that receives light irradiated from the light source unit and outputs it as a voltage value. Raindrop detection includes, for example, detecting the diameter of the raindrop, the volume of one raindrop, the amount of rainfall per unit time, and the speed of the raindrop. The reference raindrop agent used to set the correction formula is, for example, a sphere with a known diameter, preferably having the same diameter and light transmittance as an actual raindrop.

[0008] Therefore, if the diameter value calculated by detecting a reference raindrop agent whose diameter is known in advance differs from the diameter value of the actual reference raindrop agent, it is considered that the variation in detection results is due to individual differences in the raindrop detection device, so a correction formula is set to eliminate the difference. Therefore, during actual use, the calculated raindrop diameter value can be corrected using the set correction formula, thereby suppressing the decrease in raindrop detection accuracy due to individual differences.

[0009] A raindrop detection device according to a second aspect of the present invention is the raindrop detection device according to the first aspect of the present invention, further comprising a correction processing unit that corrects the diameter of raindrops actually detected by the raindrop detection unit using the correction formula set in the correction formula setting unit. By correcting the calculation result of the diameter of the actually detected raindrops using the correction formula set using the reference raindrop agent, the accuracy of calculating the diameter of raindrops due to individual differences in the raindrop detection device can be improved.

[0010] The raindrop detection device according to a third aspect of the present invention is the raindrop detection device according to the second aspect of the present invention, further comprising a rainfall calculation unit that calculates the amount of rainfall per unit time using the raindrop diameter corrected by the correction processing unit. This improves the accuracy of calculating the amount of rainfall per unit time by calculating the amount of rainfall per unit time using the raindrop diameter value corrected using the correction formula.

[0011] A raindrop detection device according to a fourth aspect of the present invention is the raindrop detection device according to the first or second aspect of the present invention, further comprising a memory unit that stores the correction formula set in the correction formula setting unit, thereby making it possible to easily correct the calculation results of the diameters of raindrops actually detected by the raindrop detection unit using the correction formula stored in the memory unit.

[0012] A fifth aspect of the present invention is the raindrop detection device according to the first or second aspect of the present invention, wherein the reference raindrop agent is a sphere. By using a sphere having a size, shape, and transparency similar to that of a raindrop as the reference raindrop agent, the reference raindrop agent can be detected under conditions similar to those used when detecting actual raindrops.

[0013] A raindrop detection device according to a sixth aspect of the present invention is the raindrop detection device according to the first or second aspect of the present invention, wherein the correction formula setting unit sets the correction formula using a plurality of reference raindrop agents with different diameters. By detecting a plurality of reference raindrop agents with different diameters, calculating the diameters, and setting the correction formula, an accurate correction formula can be set regardless of the diameter of the raindrops.

[0014] A seventh aspect of the present invention provides a raindrop detection device correction method, comprising the steps of: irradiating light from a light source unit in a predetermined direction; receiving the light emitted from the light source unit with a light receiving unit; detecting raindrops that have passed between the light source unit and the light receiving unit according to changes in the amount of light received by the light receiving unit; calculating the diameter of the detected raindrops; and setting a correction formula for correcting the diameter value of the reference raindrop agent calculated in the diameter calculation step to the actual diameter value of the reference raindrop agent, for a reference raindrop agent whose diameter is detected in the raindrop detection step and whose diameter is specified in advance. In this method for correcting a raindrop detection device that detects raindrops passing between the light source unit and the light receiving unit, the raindrop detection unit detects the reference raindrop agent using a reference raindrop agent whose diameter is specified in advance, calculates the diameter of the detected reference raindrop agent, and sets a correction formula for correcting the calculation result to the actual diameter value of the reference raindrop agent.

[0015] Here, the light source unit is, for example, an LED (Light Emitting Diode) that emits light in a predetermined direction toward a light receiving unit arranged opposite the light source unit at a predetermined distance. The light receiving unit is, for example, a photodiode that receives the light emitted from the light source unit and outputs it as a voltage value. Raindrop detection includes, for example, detecting the diameter of the raindrop, the volume of one raindrop, the amount of rainfall per unit time, and the speed of the raindrop. The reference raindrop agent used to set the correction formula is, for example, a sphere with a known diameter, and preferably has the same diameter and light transmittance as an actual raindrop.

[0016] Therefore, if the diameter value calculated by detecting a reference raindrop agent whose diameter is known in advance differs from the diameter value of the actual reference raindrop agent, it is considered that the variation in detection results is due to individual differences in the raindrop detection device, so a correction formula is set to eliminate the difference. Therefore, during actual use, the calculated raindrop diameter value can be corrected using the set correction formula, thereby suppressing the decrease in raindrop detection accuracy due to individual differences.

[0017] A correction program for a raindrop detection device according to an eighth aspect of the present invention includes a step of irradiating light from a light source unit in a predetermined direction, a step of receiving the light irradiated from the light source unit by a light receiving unit, a step of detecting raindrops that have passed between the light source unit and the light receiving unit according to changes in the amount of light received by the light receiving unit, a step of calculating the diameter of the detected raindrops, and a step of setting a correction formula for correcting the diameter value of the reference raindrop agent calculated in the diameter calculation step to the actual diameter value of the reference raindrop agent, for a reference raindrop agent whose diameter is detected in the raindrop detection step and specified in advance.

[0018] In this example, a correction program for the raindrop detection device detects raindrops passing between a light source unit and a light receiving unit. The program uses a reference raindrop agent whose diameter is specified in advance to have the raindrop detection unit detect the reference raindrop agent, calculates the diameter of the detected reference raindrop agent, and sets a correction formula to correct the calculation result so that it matches the actual diameter of the reference raindrop agent. Here, the light source unit is, for example, a light-emitting diode (LED), which irradiates light in a predetermined direction toward the light receiving unit, which is arranged opposite the light source unit at a predetermined distance.

[0019] The light receiving unit is, for example, a photodiode that receives light irradiated from the light source unit and outputs it as a voltage value. Raindrop detection includes, for example, detecting the diameter of the raindrop, the volume of one raindrop, the amount of rainfall per unit time, and the speed of the raindrop. The reference raindrop agent used to set the correction formula is, for example, a sphere with a known diameter, preferably having the same diameter and light transmittance as an actual raindrop.

[0020] Therefore, if the diameter value calculated by detecting a reference raindrop agent whose diameter is known in advance differs from the diameter value of the actual reference raindrop agent, it is considered that the variation in detection results is due to individual differences in the raindrop detection device, so a correction formula is set to eliminate the difference. Therefore, during actual use, the calculated raindrop diameter value can be corrected using the set correction formula, thereby suppressing the decrease in raindrop detection accuracy due to individual differences.

[0021] Effect of the Invention The raindrop detection device according to the present invention can suppress a decrease in raindrop detection accuracy due to individual differences.

[0022] 1 is an overall perspective view showing the configuration of a raindrop detection device according to an embodiment of the present invention. It is a side view of the raindrop detection device of FIG. 1. It is a top view of the raindrop detection device of FIG. 1. It is a cross-sectional view showing the configuration of the raindrop detection device at the cross-sectional view of line A-A of FIG. 3. (a) is a perspective view showing a board on which the main components of the raindrop detection device of FIG. 4 are arranged. (b) is a top view thereof. It is a control block diagram of the raindrop detection device of FIG. 4. It is a diagram showing functional blocks generated inside the microcomputer of FIG. 6. It is a graph showing the relationship between elapsed time and changes in voltage indicating raindrops detected in the raindrop detection device of FIG. 6. It is a flowchart showing the basic flow of processing of a correction method for the raindrop detection device of the present invention. It is a flowchart showing the flow of the correction process of FIG. 9. It is a diagram showing an example in which the detected voltage is converted into raindrop particle diameter using the correction formula calculated by the correction process of FIG. 10. It is a graph explaining the relationship between the detected voltage and the diameter of raindrops in order to set the correction formula used in the correction process of FIG. 10. It is a flowchart showing the flow of processing for rainfall sensing under normal conditions. It is a flowchart showing the flow of processing for rainfall measurement under normal conditions. It is a flowchart showing the flow of processing for raindrop detection under normal conditions.

[0023] A raindrop detection device 20 according to one embodiment of the present invention will be described below with reference to FIGS. 1 to 15. In this embodiment, unnecessary detailed explanations may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following explanation and to facilitate understanding by those skilled in the art.

[0024] Furthermore, the applicant provides the accompanying drawings and the following description to enable those skilled in the art to fully understand the present invention, and they are not intended to limit the subject matter described in the claims.

[0025] (1) Configuration of Raindrop Detection Device 20 As shown in Figures 1 to 3, the raindrop detection device 20 according to this embodiment detects raindrops that pass through a predetermined opening 21a provided in the top surface of a housing 21, and calculates the amount of rainfall by detecting the size of the detected raindrops and the amount per unit time. As shown in Figure 4, the raindrop detection device 20 includes a housing 21, a light source 22a and a light receiving unit 22b provided inside the housing 21, legs 23, a base (foundation) 24, and a microcomputer 25. As shown in Figure 4, the housing 21 is a substantially cylindrical member and includes an opening 21a, an inner wall surface 21b, a ceiling surface 21c, and an outer circumferential surface 21d.

[0026] The opening 21a is provided at approximately the center of the ceiling surface 21c and is formed to penetrate the interior of the housing 21. The inner wall surface 21b forms the inner wall of the housing 21 at the penetration portion formed by the opening 21a. The light source unit 22a and the light receiving unit 22b are arranged at positions facing each other on the inner wall surface 21b.

[0027] The ceiling surface 21c is a substantially disk-shaped portion that forms the ceiling portion of the substantially cylindrical housing 21, and an opening 21a is provided in its central portion. The outer peripheral surface 21d is a surface that forms the outer peripheral portion of the substantially cylindrical housing 21, and a predetermined gap is provided between the lower end of the outer peripheral surface 21d and the base 24. As shown in FIG. 4, the light source unit 22a and the light receiving unit 22b are arranged in opposing positions on the inner wall surface 21b of the opening 21a. As shown in FIGS. 5(a) and 5(b), the light source unit 22a and the light receiving unit 22b are arranged in opposing positions on the substantially circular substrate 22c so as to sandwich the raindrop detection area A1.

[0028] The light source unit 22a is, for example, an LED (Light Emitting Diode), and irradiates infrared light toward the light receiving unit 22b via a lens 22d that collimates the light, as shown in Figures 5(a) and 5(b). The light receiving unit 22b is, for example, a photodiode, and is disposed opposite the light source unit 22a, as shown in Figures 5(a) and 5(b), and receives light condensed via a lens 22e that condenses the light radiated from the light source unit 22a.

[0029] The light source 22a emits light onto a raindrop detection area A1 (see FIG. 4) formed between the light source 22a and the light receiving unit 22b. The light is partially blocked by raindrops, reducing the amount of light received by the light receiving unit 22b, thereby detecting the presence or absence of raindrops. As shown in FIGS. 5(a) and 5(b), the substrate 22c is a substantially circular member with an opening in the center, and the light source 22a, the light receiving unit 22b, and the lenses 22d and 22e are arranged on its upper surface.

[0030] An opening formed in the center of the substrate 22c corresponds to the raindrop detection area A1 and the opening 21a formed in the housing 21. The lens 22d is disposed above the light source 22a, such as an LED, with its multiple fan-shaped portions facing the light receiving unit 22b. The lens 22d reflects the infrared light emitted from the light source 22a at 90 degrees to collimate it and emits it toward the light receiving unit 22b.

[0031] The lens 22e is disposed above the light receiving unit 22b such as a photodiode, with its multiple fan-shaped portions facing the light source unit 22a. The lens 22e collects the infrared light emitted from the light source unit 22a, reflects it at an angle of 90 degrees, and directs it to the light receiving unit 22b disposed directly below. The multiple legs 23 are provided on the upper surface of the base 24.

[0032] The base 24 is a substantially disk-shaped member that supports the housing 21 of the raindrop detection device 20 via a plurality of legs 23 erected on its upper surface 24a. The microcomputer 25 is connected to the light source 22a and the light receiving unit 22b, and detects raindrops that pass between the light source 22a and the light receiving unit 22b in response to changes in the amount of light received by the light receiving unit 22b.

[0033] More specifically, in addition to the light source unit 22a and the light receiving unit 22b, the raindrop detection device 20 includes a microcomputer 25, a memory (storage unit) 25f, a DC (direct current) cut unit 26a, an amplifier unit 26b, an AC (alternating current) / DC (direct current) light quantity conversion unit 26c, an amplifier unit 26d, an AC (alternating current) environmental component cancellation unit 26e, and an AC modulation drive unit 26f, as shown in FIG.

[0034] 6, the microcomputer 25 is connected to a memory 25f, and reads various programs and data stored in the memory 25f to control each part of the raindrop detection device 20 and to implement a correction method for the raindrop detection device 20, which will be described later. Here, the infrared light emitted from the light source unit 22a is received by the light receiving unit 22b, and the DC cut unit 26a removes environmental components such as ambient light from the detection result detected by the light receiving unit 22b.

[0035] The detection result from which the DC environmental component has been removed is amplified by amplifier 26b, and then converted into a DC component by AC / DC light intensity converter 26c. The analog signal amplified by amplifier 26d is input to microcomputer 25. Note that data (ADRAW) of the detection result from light receiving unit 22b before the removal of the disturbance light component is transmitted to microcomputer 25 as is from DC cutter 26a.

[0036] The microcomputer 25 receives the detection result from the light receiving unit 22b, controls the AC / DC light intensity converter 26c to perform AC / DC conversion processing by PWM (Pulse Width Modulation) control, and controls the AC modulation driver 26f to switch the light intensity of the light source unit 22a. A signal indicating the light intensity level converted into an AC component by the AC / DC light intensity converter 26c is sent to an AC environmental component canceller 26e, which removes the AC voltage component that drives the light source unit 22a, such as an LED, and sends the signal to the AC modulation driver 26f, where it is used to adjust the output of the light source unit 22a.

[0037] The microcomputer 25 loads various programs stored in the memory 25f and generates the functional blocks shown in Fig. 7. That is, as shown in Fig. 7, the microcomputer 25 has a raindrop detection unit 25a, a diameter calculation unit 25b, a correction formula setting unit 25c, a correction processing unit 25d, and a rainfall calculation unit 25e. The raindrop detection unit 25a detects raindrops that pass between the light source unit 22a and the light receiving unit 22b (raindrop detection area A1) in accordance with changes in the amount of light received by the light receiving unit 22b.

[0038] More specifically, when raindrops pass through the raindrop detection area A1, part of the infrared light emitted from the light source unit 22a is blocked, causing a change in the light detection result at the light receiving unit 22b. As shown in Fig. 8, the raindrop detection unit 25a regards the change in voltage value (peak value) obtained by amplifying the detection result at the light receiving unit 22b as a raindrop candidate, and if the peak value of the voltage corresponding to each raindrop candidate exceeds a predetermined threshold, the raindrop candidate is detected as a raindrop.

[0039] The detection result shown in FIG. 8 illustrates an example in which three raindrop candidates were detected within the measurement time, and all of the raindrop candidates had peak values ​​exceeding the threshold, resulting in their detection as raindrops. The difference between the three peak values ​​in the graph shown in FIG. 8 primarily manifests as differences in the diameter, transmittance, and other characteristics of the detected raindrops. The diameter calculation unit 25b calculates the diameter of the raindrops detected by the raindrop detection unit 25a. Specifically, the diameter calculation unit 25b calculates the diameter of the voltage value having a peak value corresponding to the raindrop detected by the raindrop detection unit 25a using a table or the like showing the relationship between the voltage value and the diameter.

[0040] Here, assuming that the transmittance of raindrops is approximately constant, the larger the diameter of the raindrop, the greater the amount of infrared light blocked by the light source unit 22a, resulting in a larger diameter of the raindrop. The correction formula setting unit 25c sets a correction formula for correcting the diameter value of the reference raindrop agent calculated by the diameter calculation unit 25b so that it becomes the actual diameter value of the reference raindrop agent, for a reference raindrop agent whose diameter is detected by the raindrop detection unit 25a and specified in advance.

[0041] The reference raindrop agent is a sphere whose diameter is specified in advance and is used to set the correction formula. The process of calculating the diameter of the reference raindrop agent detected by actually dropping the reference raindrop agent into the raindrop detection area A1 of the raindrop detection device 20 and setting the correction formula will be described in detail later. The correction processing unit 25d corrects the diameter of the raindrops actually detected by the raindrop detection unit 25a using the correction formula set in the correction formula setting unit 25c.

[0042] The rainfall calculation unit 25e calculates the amount of rainfall per unit time using the diameter of the raindrops corrected by the correction processing unit 25d. Specifically, the rainfall calculation unit 25e calculates the volume V (= 4 / 3 × π × r) of each raindrop from the diameter R of the raindrops that have passed through the raindrop detection area A1. ３ ) and integrate the volume of raindrops detected per unit time to calculate the amount of rainfall. Note that π is the ratio of the circumference of a circle to its diameter, and r is the radius (= diameter R / 2).

[0043] <Raindrop Detection Device Correction Method> The correction method performed by the raindrop detection device 20 of this embodiment will be described below with reference to Figures 9 to 12. That is, in the correction method for the raindrop detection device 20 of this embodiment, as shown in Figure 9, a correction process is performed in step S11 as an initial setting before the raindrop detection device 20 is actually installed outdoors, in order to eliminate individual differences between the raindrop detection devices 20.

[0044] The raindrop detection device 20 after the correction process is then installed at a predetermined outdoor installation location, and the raindrop amount is sensed in step S12. The setting of the correction formula used in the correction process of the raindrop detection device 20 in step S11 will now be described in detail with reference to FIG. 10. First, as shown in FIG. 10, in step S21, the diameter Φ １ The sphere (reference raindrop agent) is set on a predetermined jig set on the top of the raindrop detection device 20.

[0045] Next, in step S22, a plurality of diameters Φ １ The sphere (reference raindrop agent) is dropped from the opening 21a of the housing 21 of the raindrop detection device 20 so as to pass through the raindrop detection area A1. Next, in step S23, the diameter calculation unit 25b calculates the diameter Φ １ The sphere (reference raindrop agent) with a diameter Φ １ The average value of the detected voltage of the sphere (reference raindrop agent) is calculated.

[0046] Next, in step S24, the diameter calculation unit 25b calculates the diameter Φ １ The average voltage value detected for a sphere (reference raindrop agent) of diameter Φ １ Next, in step S25, the difference in transmittance between the sphere (reference raindrop agent) and the raindrop is multiplied by a correction coefficient α. ２ The sphere (reference raindrop agent) is set on a predetermined jig set on the top of the raindrop detection device 20.

[0047] Next, in step S26, a plurality of diameters Φ ２ The sphere (reference raindrop agent) is dropped from the opening 21a of the housing 21 of the raindrop detection device 20 so as to pass through the raindrop detection area A1. Next, in step S27, the diameter calculation unit 25b calculates the diameter Φ ２ The sphere (reference raindrop agent) with a diameter Φ ２ The average value of the detected voltage of the sphere (reference raindrop agent) is calculated.

[0048] Next, in step S28, the diameter calculation unit 25b calculates the diameter Φ２ The average voltage value detected for a sphere (reference raindrop agent) of diameter Φ ２ Next, in step S29, the correction formula setting unit 25c multiplies the diameter Φ calculated in step S24 by a correction coefficient β that corrects the difference in transmittance between the sphere (reference raindrop agent) and the raindrop. １ The average voltage × α detected for the sphere (reference raindrop agent) and the diameter Φ calculated in step S28 ２ Using the average voltage × β detected for a sphere (reference raindrop agent) of diameter Φ １ , diameter Φ ２ The correction formula is set so that the voltage value that should be detected when raindrops on the sphere (reference raindrop agent) are detected is obtained, and the correction formula setting process is terminated.

[0049] Here, the diameter Φ １ As shown in FIG. 11, the voltage value to be detected when a raindrop of V １ Diameter Φ ２ As shown in FIG. 11, the voltage value to be detected when a raindrop of V ２ That is, the relationship between the detected voltage and the diameter of the raindrop is １ The detection voltage of raindrops is V １ , diameter Φ ２ The detection voltage of raindrops is V ２ Therefore, as shown in the graph of FIG. 12, the line connecting these two points is expressed by the relational expression Φ=aV+b (where a=(Φ ２ -Φ １ ) / (V ２ -V １ ), b = Φ １ -aV １ ).

[0050] <Raindrop Detection Method After Correction Processing> In the raindrop detection method of this embodiment, the above-described correction formula is used to perform the correction processing to eliminate variations in detection accuracy due to individual differences in the raindrop detection device 20, and then raindrop detection (rainfall sensing) is performed in step S12 according to the flowcharts shown in Figures 13 to 15. As shown in Figure 13, this rainfall sensing is performed by the microcomputer 25 repeatedly performing the following processes (steps S42 and S43): starting a PWM sequence in step S41, starting measurement in step S42, and performing rainfall calculation processing in step S43.

[0051] Here, in rainfall sensing, rainfall is measured according to the flowchart shown in Fig. 14. That is, in step S51, the microcomputer 25 repeatedly determines whether a sampling interval has elapsed, for example, using a timer, and proceeds to step S52 each time the interval has elapsed. Next, in step S52, the microcomputer 25 acquires data (AD values ​​(received light voltages converted from analog to digital)) indicating the measurement results of the light receiving unit 22b.

[0052] Next, in step S53, the microcomputer 25 stores the AD value acquired in step S52 in the memory 25f. Next, in step S54, the microcomputer 25 determines whether or not a predetermined number of AD values ​​have been stored. If it is determined that the AD values ​​have been stored, the measurement is terminated. If it is determined that the AD values ​​have not been stored, the process from step S51 onward is repeated.

[0053] 15, in the raindrop detection process, in step S61, the microcomputer 25 repeats steps S61 to S66 until a specified number (AD value) is reached. Next, in step S62, if the microcomputer 25 detects raindrops exceeding the threshold, the process proceeds to step S63. Next, in step S63, the microcomputer 25 determines whether the time during which the raindrops exceeding the threshold passed through the raindrop detection area A1 was less than T (variable). Here, if it is less than T (variable), it is determined to be raindrops, and the process proceeds to step S64. If it is equal to or greater than T (variable), it is determined not to be raindrops, and the process returns to step S62.

[0054] Next, in step S64, the microcomputer 25 (rainfall calculation unit 25e) calculates the raindrop diameter using a correction formula because the raindrops were determined to be raindrops in steps S62 and S63. Next, in step S65, the microcomputer 25 (rainfall calculation unit 25e) adds up the volume of the raindrops determined to be raindrops. Next, in step S66, the microcomputer 25 repeats the processes of steps S61 to S66 until the number of processed AD values ​​reaches a specified number. Next, in step S67, the rainfall amount per unit time is calculated using the raindrop volume calculated in step S65.

[0055] <Major Features> The raindrop detection device 20 of this embodiment includes a light source unit 22a, a light receiving unit 22b, a raindrop detection unit 25a, a diameter calculation unit 25b, and a correction formula setting unit 25c. The light source unit 22a emits light in a predetermined direction. The light receiving unit 22b is positioned opposite the light source unit 22a and receives the light emitted from the light source unit 22a. The raindrop detection unit 25a detects raindrops that pass between the light source unit 22a and the light receiving unit 22b in response to changes in the amount of light received by the light receiving unit 22b. The diameter calculation unit 25b calculates the diameter of the raindrop detected by the raindrop detection unit 25a. The correction formula setting unit 25c sets a correction formula that corrects the diameter value calculated by the diameter calculation unit 25b to the actual diameter value of the reference raindrop agent, using the diameter calculated by the diameter calculation unit 25b of a reference raindrop agent whose diameter is specified in advance.

[0056] As a result, if the diameter value calculated by detecting a reference raindrop agent whose diameter is known in advance differs from the diameter value of the actual reference raindrop agent, a correction formula is set to eliminate the difference, since this is considered to be due to variations in the detection results caused by individual differences in the raindrop detection device 20. Therefore, during actual use, by correcting the calculated raindrop diameter value using the set correction formula, it is possible to suppress a decrease in raindrop detection accuracy caused by individual differences.

[0057] [Other Embodiments] While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit and scope of the invention. (A) In the above embodiment, an example in which the present invention is realized as a raindrop detection device and a raindrop detection device correction method has been described. However, the present invention is not limited to this.

[0058] For example, the present invention may be realized as a correction program that causes a computer to execute the raindrop detection device correction method described above. The raindrop detection device correction program is stored in a memory (storage unit) installed in the raindrop detection device, and a CPU loads the correction program stored in the memory and causes the hardware to execute each step. More specifically, the CPU loads the correction program and executes the above-described steps, thereby achieving the same effects as described above.

[0059] <Note> The raindrop detection device according to the first aspect of the present invention includes: a light source unit that irradiates light in a predetermined direction; a light receiving unit that is disposed opposite the light source unit and receives the light irradiated from the light source unit; a raindrop detection unit that detects raindrops that have passed between the light source unit and the light receiving unit according to a change in the amount of light received by the light receiving unit; a diameter calculation unit that calculates the diameter of the raindrops detected by the raindrop detection unit; and a correction formula setting unit that sets a correction formula for correcting the diameter value of the reference raindrop agent calculated by the diameter calculation unit to the actual diameter value of the reference raindrop agent, for a reference raindrop agent that is detected by the raindrop detection unit and has a diameter specified in advance.

[0060] A raindrop detection device according to a second aspect of the present invention is the raindrop detection device according to the first aspect of the present invention, further comprising a correction processing unit that corrects the diameter of raindrops actually detected by the raindrop detection unit using the correction formula set in the correction formula setting unit.A raindrop detection device according to a third aspect of the present invention is the raindrop detection device according to the second aspect of the present invention, further comprising a rainfall calculation unit that calculates the amount of rainfall per unit time using the raindrop diameter corrected by the correction processing unit.

[0061] A fourth aspect of the present invention is the raindrop detection device according to any one of the first to third aspects, further comprising a storage unit that stores the correction formula set by the correction formula setting unit.A fifth aspect of the present invention is the raindrop detection device according to any one of the first to fourth aspects, further comprising a storage unit that stores the correction formula set by the correction formula setting unit.A fifth aspect of the present invention is the raindrop detection device according to any one of the first to fourth aspects, further comprising a storage unit that stores the correction formula set by the correction formula setting unit.

[0062] A raindrop detection device according to a sixth aspect of the present invention is the raindrop detection device according to any one of the first to fifth aspects of the present invention, wherein the correction equation setting unit sets the correction equation using a plurality of reference raindrop agents with different diameters.A correction method for a raindrop detection device according to a seventh aspect of the present invention includes: a light source unit irradiating light in a predetermined direction; a light receiving unit receiving the light irradiated from the light source unit; detecting raindrops that have passed between the light source unit and the light receiving unit according to changes in the amount of light received by the light receiving unit; calculating the diameters of the detected raindrops; and setting a correction equation for a reference raindrop agent whose diameter is detected in the raindrop detection step and whose diameter is specified in advance, to correct the diameter value of the reference raindrop agent calculated in the diameter calculation step to the actual diameter value of the reference raindrop agent.

[0063] A correction program for a raindrop detection device according to an eighth aspect of the present invention causes a computer to execute a correction method for a raindrop detection device, the method comprising: a step of irradiating light in a predetermined direction from a light source unit; a step of receiving the light irradiated from the light source unit by a light receiving unit; a step of detecting raindrops that have passed between the light source unit and the light receiving unit according to a change in the amount of light received by the light receiving unit; a step of calculating the diameter of the detected raindrops; and a step of setting a correction formula for correcting the value of the diameter of the reference raindrop agent calculated in the diameter calculation step to the actual value of the diameter of the reference raindrop agent, for a reference raindrop agent that is detected in the raindrop detection step and has a diameter specified in advance.

[0064] The raindrop detection device of the present invention has the effect of suppressing a decrease in raindrop detection accuracy due to individual differences, and is therefore widely applicable to raindrop detection devices mounted on weather sensors and the like.

[0065] 20 Raindrop detection device 21 Housing 21a Opening 21b Inner wall surface 21c Ceiling surface 21d Outer surface 22a Light source unit 22b Light receiving unit 22c Substrate 22d, 22e Lens 23 Leg 24 Base 24a Top surface 25 Microcomputer 25a Raindrop detection unit 25b Diameter calculation unit 25c Correction formula setting unit 25d Correction processing unit 25e Rainfall calculation unit 25f Memory (storage unit) 26a DC cut unit 26b Amplification unit 26c AC / DC light quantity conversion unit 26d Amplification unit 26e AC environmental component cancellation unit 26f AC modulation drive unit 30 Illuminance meter 40 Temperature, humidity, and pressure gauge A1 Raindrop detection area

Claims

1. A raindrop detection device comprising: a light source unit that irradiates light in a predetermined direction; a light receiving unit that is disposed at a position facing the light source unit and receives the light irradiated from the light source unit; a raindrop detection unit that detects raindrops passing between the light source unit and the light receiving unit in response to a change in the amount of light received by the light receiving unit; a diameter calculation unit that calculates the diameter of the raindrops detected by the raindrop detection unit; and a correction formula setting unit that sets a correction formula for correcting the value of the diameter of a reference raindrop agent, which is detected by the raindrop detection unit and has a predetermined diameter, so as to be the actual value of the diameter of the reference raindrop agent.

2. The raindrop detection device according to claim 1, further comprising a correction processing unit that corrects the diameter of the raindrops actually detected by the raindrop detection unit using the correction formula set by the correction formula setting unit.

3. The raindrop detection device according to claim 2, further comprising a rainfall amount calculation unit that calculates the rainfall amount per unit time using the diameter of the raindrops corrected by the correction processing unit.

4. The raindrop detection device according to claim 1 or 2, further comprising a storage unit that stores the correction formula set by the correction formula setting unit.

5. The raindrop detection device according to claim 1 or 2, wherein the reference raindrop agent is a sphere.

6. The raindrop detection device according to claim 1 or 2, wherein the correction formula setting unit sets the correction formula using a plurality of reference raindrop agents having different diameters.

7. A correction method for a raindrop detection device, comprising: a step of irradiating light in a predetermined direction by a light source unit; a step of receiving the light irradiated from the light source unit by a light receiving unit; a step of detecting raindrops passing between the light source unit and the light receiving unit in response to a change in the amount of light received by the light receiving unit; a step of calculating the diameter of the detected raindrops; and a step of setting a correction formula for correcting the value of the diameter of a reference raindrop agent, which is detected in the step of detecting the raindrops and has a predetermined diameter, so as to be the actual value of the diameter of the reference raindrop agent in the step of calculating the diameter.

8. A step of irradiating light in a predetermined direction by a light source unit; a step of receiving the light irradiated from the light source unit by a light receiving unit; a step of detecting raindrops that have passed between the light source unit and the light receiving unit according to a change in the amount of light received by the light receiving unit; a step of calculating the diameter of the detected raindrops; a step of setting a correction formula for correcting the value of the diameter of the reference raindrop agent whose diameter is specified in advance and detected in the step of detecting the raindrops so as to be the value of the diameter of the actual reference raindrop agent; A correction program that causes a computer to execute a correction method for a raindrop detection device including the above steps.

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