Raindrop detection device and correction method therefor, correction program

Abstract

To provide a raindrop detection device which can be suppressed in reduction of accuracy of raindrop detection caused by individual difference, and a correction method therefor, a correction program.SOLUTION: A raindrop detection device 20 comprises a light source portion 22a, a light reception portion 22b, a raindrop detection portion 25a, a diameter calculation portion 25b, and a correction formula setting portion 25c. The light reception portion 22b is located at a position facing the light source portion 22a, and receives light irradiated from the light source portion 22a. The raindrop detection portion 25a detects a raindrop having passed through between the light source portion 22a and the light reception portion 22b in accordance with a change of received light amount of the light having been received by the light reception portion 22b. The diameter calculation portion 25b calculates the diameter of the raindrop detected by the raindrop detection portion 25a. The correction formula setting portion 25c sets a correction formula for correcting the value of the diameter calculated by the diameter calculation portion 25b to the value of actual diameter of a reference raindrop agent by using the diameter of a reference raindrop agent having diameter specified in advance, calculated by the diameter calculation portion 25b .SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] In recent years, tipping bucket rain gauges have been used to measure rainfall. These rain gauges are equipped with 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 arranged 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-98170 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-described conventional raindrop detection device has the following problems. In other words, although the raindrop detection device disclosed in the above publication can detect raindrops that pass through the raindrop detection area based on changes in the amount of light received by the light receiving unit, there is a risk that the accuracy of raindrop detection will decrease due to individual differences between each device. An object of the present invention is to provide a raindrop detection device capable of suppressing a decrease in raindrop detection accuracy due to individual differences, and a correction method and correction program for the same. [Means for solving the problem]

[0005] 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] Here, a reference raindrop agent whose diameter is specified in advance is used, the raindrop detection unit detects 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 becomes the actual diameter value of the reference raindrop agent. Here, the light source unit is, for example, an LED (Light Emitting Diode), and irradiates light in a predetermined direction onto the light receiving units that are arranged opposite each other with a predetermined distance therebetween.

[0007] The light receiving section is, for example, a photodiode, which receives light emitted from the light source section and outputs it as a voltage value. Detecting raindrops includes detecting, for example, 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 or the like with a known diameter, and preferably has the same diameter and light transmittance as an actual raindrop.

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

[0009] The raindrop detection device according to the 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 equation set in the correction equation setting unit. This allows the calculation results of the diameter of actually detected raindrops to be corrected using a correction formula set using a reference raindrop agent, thereby improving the accuracy of calculating the diameter of raindrops due to individual differences in the raindrop detection device.

[0010] The raindrop detection device according to the 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 in the correction processing unit. This allows the accuracy of calculating the amount of rainfall per unit time to be improved by calculating the rainfall amount 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 storage unit that stores the correction equation set in the correction equation setting unit. This allows the calculation results of the diameter of raindrops actually detected by the raindrop detection unit to be easily corrected using the correction formula stored in the storage unit.

[0012] A raindrop detection device according to 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. This allows, for example, the use of a sphere having a size, shape, and transparency similar to that of a raindrop as the reference raindrop agent to enable detection of the reference raindrop agent under conditions similar to those 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 equation setting unit sets the correction equation using a plurality of reference raindrop agents with different diameters. This allows for the detection of multiple reference raindrop agents with different diameters, calculation of the diameters, and setting a correction formula, thereby enabling the setting of an accurate correction formula regardless of the diameter of the raindrops.

[0014] A seventh aspect of the present invention provides a method for correcting a raindrop detection device, comprising the steps of: irradiating light from a light source unit in a predetermined direction; receiving the light irradiated 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 specified in advance. Here, in a correction method for a raindrop detection device that detects raindrops passing between a light source unit and a light receiving unit, a reference raindrop agent whose diameter is specified in advance is used to detect the reference raindrop agent in 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, an LED (Light Emitting Diode), and irradiates light in a predetermined direction onto the light receiving units that are arranged opposite each other with a predetermined distance therebetween.

[0015] The light receiving section is, for example, a photodiode, which receives light emitted from the light source section and outputs it as a voltage value. Detecting raindrops includes detecting, for example, 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 or the like with a known diameter, and preferably has the same diameter and light transmittance as an actual raindrop.

[0016] If the diameter value calculated by detecting a reference raindrop agent whose diameter is known in advance differs from the actual diameter value of the reference raindrop agent, this is considered to be due to variations in the detection results caused by individual differences in the raindrop detection device, so a correction formula is set to eliminate this difference. Therefore, during actual use, the calculated raindrop diameter value can be corrected using the set correction formula, thereby suppressing deterioration 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 the steps of: 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 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 specified in advance.

[0018] Here, in the correction program of the raindrop detection device that detects raindrops passing between the light source unit and the light receiving unit, a reference raindrop agent whose diameter is specified in advance is used to detect the reference raindrop agent in 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, an LED (Light Emitting Diode), and irradiates light in a predetermined direction onto the light receiving units that are arranged opposite each other with a predetermined distance therebetween.

[0019] The light receiving section is, for example, a photodiode, which receives light emitted from the light source section and outputs it as a voltage value. Detecting raindrops includes detecting, for example, 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 or the like with a known diameter, and preferably has the same diameter and light transmittance as an actual raindrop.

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

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

[0022] [Figure 1] 1 is an overall perspective view showing the configuration of a raindrop detection device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a side view of the raindrop detection device of FIG. 1. [Figure 3] FIG. 2 is a top view of the raindrop detection device of FIG. 1. [Figure 4] 4 is a cross-sectional view showing the configuration of the raindrop detection device taken along the line AA in FIG. 3. [Figure 5] 5A is a perspective view showing a substrate on which the main components of the raindrop detection device shown in FIG. 4 are arranged, and FIG. 5B is a top view thereof. [Figure 6] FIG. 5 is a control block diagram of the raindrop detection device of FIG. 4. [Figure 7] FIG. 7 is a diagram showing functional blocks generated inside the microcontroller of FIG. 6. [Figure 8] 7 is a graph showing the relationship between the change in voltage indicating raindrops detected by the raindrop detection device of FIG. 6 and the elapsed time. [Figure 9] 3 is a flowchart showing the basic flow of processing in a method for correcting a raindrop detection device according to the present invention. [Figure 10] 10 is a flowchart showing the flow of the correction process in FIG. 9. [Figure 11] 11 is a diagram showing an example of converting a detected voltage into raindrop particle diameters using the correction formula calculated by the correction process of FIG. 10 . [Figure 12] 11 is a graph illustrating the relationship between the detected voltage and the diameter of the raindrop in order to set a correction formula used in the correction process of FIG. 10. [Figure 13] 10 is a flowchart showing the flow of a process for sensing rainfall during normal times. [Figure 14] 10 is a flowchart showing the flow of a process for measuring rainfall during normal times. [Figure 15] 10 is a flowchart showing the flow of raindrop detection processing under normal circumstances. DETAILED DESCRIPTION OF THE INVENTION

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

[0024] (1) Configuration of the raindrop detection device 20 As shown in Figures 1 to 3, the raindrop detection device 20 of this embodiment detects raindrops that have passed through a predetermined opening 21a provided on the top surface of the housing unit 21, and calculates the amount of rainfall by detecting the size of the detected raindrops and the amount per unit time.

[0025] As shown in FIG. 4, the raindrop detection device 20 has 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 FIG. 4, the housing 21 is a substantially cylindrical member, and has an opening 21a, an inner wall surface 21b, a ceiling surface 21c, and an outer peripheral surface 21d.

[0026] The opening 21a is provided at approximately the center of the ceiling surface 21c, and is formed to penetrate the inside of the housing 21. The inner wall surface 21b forms the inner wall of the housing part 21 at the through portion formed by the opening part 21a. The light source part 22a and the light receiving part 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 portion 21, and has an opening 21a in its central portion. The outer peripheral surface 21d is a surface that forms the outer peripheral portion of the substantially cylindrical housing portion 21, and a gap of a predetermined size is provided between the lower end of the outer peripheral surface 21d and the base 24. The light source unit 22a and the light receiving unit 22b are arranged at positions facing each other on the inner wall surface 21b of the opening 21a, as shown in Fig. 4. Furthermore, the light source unit 22a and the light receiving unit 22b are arranged at positions facing each other on a substantially circular substrate 22c so as to sandwich the raindrop detection area A1 therebetween, as shown in Fig. 5(a) and Fig. 5(b).

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

[0029] Light is then irradiated from the light source unit 22a onto a raindrop detection area A1 (see Figure 4) formed between the light source unit 22a and the light receiving unit 22b, and part of the light detected by the light receiving unit 22b is 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 Figures 5(a) and 5(b), the substrate 22c is an approximately circular member with an opening formed in the center, and the light source unit 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 sensing area A1 and the opening 21a formed in the housing 21. Lens 22d is disposed above light source unit 22a such as an LED, and is disposed so that its multiple fan-shaped portions face light-receiving unit 22b. Lens 22d reflects the infrared light emitted from light source unit 22a by 90 degrees to convert it into parallel light, which is then emitted toward light-receiving unit 22b.

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

[0032] The base 24 is a substantially disk-shaped member, and supports the housing 21 of the raindrop detection device 20 and the like via a plurality of legs 23 erected on an upper surface 24a thereof. The microcomputer 25 is connected to the light source unit 22a and the light receiving unit 22b, and detects raindrops that have passed between the light source unit 22a and the light receiving unit 22b in accordance with 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) cutting 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. 6.

[0034] As shown in FIG. 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 section 22a is received by the light receiving section 22b, and the DC cut section 26a removes environmental components such as ambient light from the detection result detected by the light receiving section 22b.

[0035] The detection result from which the DC environmental component has been removed is amplified in amplifier 26b, then converted into a DC component in AC / DC light quantity converter 26c, and the analog signal amplified in amplifier 26d is input to microcomputer 25. The DC cut unit 26a transmits to the microcomputer 25 the data (ADRAW) of the detection result at the light receiving unit 22b before removing the disturbance light component.

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

[0037] Here, the microcomputer 25 reads various programs stored in the memory 25f and generates the functional blocks shown in FIG. 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 detector 25a detects raindrops that have passed between the light source 22a and the light receiver 22b (raindrop detection area A1) in accordance with changes in the amount of light received by the light receiver 22b.

[0038] More specifically, when a raindrop passes through the raindrop detection area A1, part of the infrared light emitted from the light source unit 22a is blocked, and the light detection result at the light receiving unit 22b changes. 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 detects the raindrop candidate as a raindrop when the peak value of the voltage corresponding to each raindrop candidate exceeds a predetermined threshold.

[0039] The detection results shown in Figure 8 show 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, so they were detected as raindrops. The differences between the three peak values in the graph shown in FIG. 8 mainly appear as differences in the diameter, transmittance, etc. of the detected raindrops. The diameter calculation unit 25b calculates the diameter of the raindrop 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 raindrops, the greater the amount of infrared light blocked by the light source unit 22a, and therefore the larger the diameter of the raindrops. The correction formula setting unit 25c sets a correction formula for correcting the value of the diameter of the reference raindrop agent calculated by the diameter calculation unit 25b to the actual diameter value of the reference raindrop agent, for which the diameter is detected by the raindrop detection unit 25a and specified in advance.

[0041] Here, 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 equation set in the correction equation 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 then integrate the volume of raindrops detected per unit time to calculate the amount of rainfall. Note that π is the circumference constant and r is the radius (= diameter R / 2).

[0043] <Method for calibrating a raindrop detector> The correction method performed by the raindrop detection device 20 of this embodiment will be described below with reference to FIGS. That is, in the correction method for the raindrop detection device 20 of this embodiment, as shown in FIG. 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 actually installed at a predetermined outdoor installation location, and in step S12, the raindrop detection device 20 senses the amount of rain. Here, the setting of the correction formula used in the correction process of the raindrop detection device 20 in step S11 will be described in detail with reference to FIG. First, as shown in FIG. 10, in step S21, a sphere (reference raindrop agent) having a diameter Φ1 is set on a predetermined jig set on the top of the raindrop detection device 20.

[0045] Next, in step S22, a plurality of spheres (reference raindrop agents) having a diameter of Φ1 are dropped from the jig through 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 average value of the detection voltage of the spheres (reference raindrop agent) having a diameter of Φ1 detected as raindrops in the raindrop detection area A1 by the raindrop detection unit 25a.

[0046] Next, in step S24, the diameter calculation unit 25b multiplies the average voltage value detected for the sphere of diameter Φ1 (reference raindrop agent) by a correction coefficient α that corrects the difference in transmittance between the sphere of diameter Φ1 (reference raindrop agent) and the raindrop. Next, in step S25, a sphere (reference raindrop agent) having a diameter of Φ2 is set on a predetermined jig set on the top of the raindrop detection device 20.

[0047] Next, in step S26, a plurality of spheres (reference raindrop agents) having a diameter of Φ2 are dropped from the jig through 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 average value of the detection voltage of the spheres (reference raindrop agent) with a diameter of Φ2 detected as raindrops in the raindrop detection area A1 by the raindrop detection unit 25a.

[0048] Next, in step S28, the diameter calculation unit 25b multiplies the average voltage value detected for the sphere of diameter Φ2 (reference raindrop agent) by a correction coefficient β that corrects the difference in transmittance between the sphere of diameter Φ2 (reference raindrop agent) and the raindrop. Next, in step S29, the correction formula setting unit 25c sets a correction formula using the average voltage × α calculated in step S24 when detecting a sphere of diameter Φ1 (reference raindrop agent) and the average voltage × β calculated in step S28 when detecting a sphere of diameter Φ2 (reference raindrop agent) so that the voltage value that should be detected when raindrops of spheres of diameter Φ1 and Φ2 (reference raindrop agent) are detected, and then ends the correction formula setting process.

[0049] Here, the voltage value that should be detected when a raindrop with a diameter of Φ1 is detected is V1, as shown in Figure 11. The voltage value that should be detected when a raindrop with a diameter of Φ2 is detected is V2, as shown in Figure 11. That is, the relationship between the detected voltage and the diameter of the raindrop is such that the detected voltage for a raindrop with a diameter of Φ1 is V1 and the detected voltage for a raindrop with a diameter of Φ2 is V2. As shown in the graph in Figure 12, the line connecting these two points is expressed by the relational expression Φ = aV + b (where a = (Φ2 - Φ1) / (V2 - V1), b = Φ1 - aV1).

[0050] <Raindrop detection method after correction processing> In the raindrop detection method of this embodiment, the variation in detection accuracy due to individual differences in the raindrop detection device 20 is eliminated by a correction process using the above-mentioned correction formula, and then raindrop detection (rainfall sensing) is performed in step S12 according to the flowcharts shown in Figures 13 to 15. As shown in FIG. 13, such rainfall sensing is performed by the microcomputer 25 repeatedly performing a process (steps S42, S43) in which the microcomputer 25 starts a PWM sequence in step S41, starts measurement in step S42, and performs rainfall calculation processing in step S43.

[0051] Here, in the rainfall sensing, the rainfall is measured according to the flowchart shown in FIG. That is, in step S51, the microcomputer 25 repeatedly determines whether the sampling interval has elapsed, for example, using a timer, and proceeds to step S52 each time the sampling interval has elapsed. Next, in step S52, the microcomputer 25 acquires data (AD values (A / D converted light receiving voltages)) indicating the measurement results of the light receiving section 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 the specified number of items have been retained. If it is determined that the specified number of items have been retained, the measurement is terminated. If it is determined that the specified number of items have not been retained, the processing from step S51 onwards is repeated.

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

[0054] Next, in step S64, since the raindrops have been determined to be raindrops in steps S62 and S63, the microcomputer 25 (rainfall calculation unit 25e) calculates the diameter of the raindrops using a correction formula. Next, in step S65, the microcomputer 25 (rainfall calculation unit 25e) adds up the volumes of the raindrops that have been 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 amount of rainfall 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.

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

[0057] [Other embodiments] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention. (A) In the above embodiment, the raindrop detection device and the raindrop detection device correction method are described as examples of realizing the present invention, but 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 above-described method for correcting a raindrop detection device. The correction program for this raindrop detection device is stored in a memory (storage unit) installed in the raindrop detection device, and the CPU reads the correction program stored in the memory and causes the hardware to execute each step. More specifically, the CPU reads the correction program and executes the above-mentioned steps, thereby achieving the same effects as those described above.

[0059] <Additional Notes> The raindrop detection device according to the first invention is a light source unit that emits light in a predetermined direction; a light receiving unit disposed opposite the light source unit and configured to receive light emitted 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 raindrop detected by the raindrop detection unit; 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 so that the diameter value of the reference raindrop agent detected by the raindrop detection unit and whose diameter is specified in advance becomes the actual diameter value of the reference raindrop agent; It is equipped with:

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

[0061] A raindrop detection device according to a fourth aspect of the present invention is the raindrop detection device according to any one of the first to third aspects of the present invention, The image forming apparatus further includes a storage unit for storing the correction formula set by the correction formula setting unit. A raindrop detection device according to a fifth aspect of the present invention is a raindrop detection device according to any one of the first to fourth aspects of the present invention, The reference raindrop is a sphere.

[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, The correction formula setting unit sets the correction formula using a plurality of the reference raindrop agents having different diameters. A raindrop detection device correction method according to a seventh aspect of the present invention includes: A step in which a light source unit emits light in a predetermined direction; a step of receiving light emitted from the light source unit by a light receiving unit; 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; 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 calculated in the step of calculating the diameter of the reference raindrop agent, the diameter of which is detected in the step of detecting raindrops and previously specified, so that the value of the diameter of the reference raindrop agent becomes the actual value of the diameter of the reference raindrop agent; It is equipped with:

[0063] A correction program for a raindrop detection device according to an eighth aspect of the present invention is A step in which a light source unit emits light in a predetermined direction; a step of receiving light emitted from the light source unit by a light receiving unit; 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; 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 calculated in the step of calculating the diameter of the reference raindrop agent, the diameter of which is detected in the step of detecting raindrops and previously specified, so that the value of the diameter of the reference raindrop agent becomes the actual value of the diameter of the reference raindrop agent; The present invention causes a computer to execute a method for correcting a raindrop detection device comprising the steps of: [Industrial Applicability]

[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. [Explanation of symbols]

[0065] 20 Raindrop detector 21 Housing 21a opening 21b Inner wall 21c Ceiling surface 21d Outer surface 22a Light source section 22b Light receiving part 22c board 22d, 22e lenses 23 Legs 24 base 24a Top side 25 Microcomputer 25a Raindrop detection part 25b Diameter calculation section 25c Correction formula setting section 25d Correction processing section 25e Rainfall calculation part 25f Memory (storage section) 26a DC cut section 26b Amplification section 26c AC / DC light intensity conversion unit 26d Amplifier 26e AC environmental component cancellation section 26f AC modulation driver 30 illuminance meter 40 Thermo-hygro-barometer A1 Raindrop detection area

Claims

1. a light source unit that emits light in a predetermined direction; a light receiving unit disposed opposite the light source unit and configured to receive light emitted 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 raindrop detected by the raindrop detection unit; 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 so that the diameter value of the reference raindrop agent detected by the raindrop detection unit and whose diameter is specified in advance becomes the actual diameter value of the reference raindrop agent; A raindrop detection device comprising:

2. Further provided is a correction processing unit that corrects the diameter of the raindrop actually detected by the raindrop detection unit using the correction formula set in the correction formula setting unit, The raindrop detection device of claim 1 .

3. The rainfall amount calculation unit calculates the amount of rainfall per unit time using the diameter of the raindrop corrected by the correction processing unit.

3. The raindrop detection device of claim 2.

4. The apparatus further includes a storage unit that stores the correction formula set by the correction formula setting unit.

3. The raindrop detection device according to claim 1 or 2.

5. The reference raindrop agent is a sphere.

3. The raindrop detection device according to claim 1 or 2.

6. The correction formula setting unit sets the correction formula using a plurality of reference raindrop agents having different diameters.

3. The raindrop detection device according to claim 1 or 2.

7. A step in which a light source unit emits light in a predetermined direction; a step of receiving light emitted from the light source unit by a light receiving unit; 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; 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 calculated in the step of calculating the diameter of the reference raindrop agent, the diameter of which is detected in the step of detecting raindrops and previously specified, so that the value of the diameter of the reference raindrop agent becomes the actual value of the diameter of the reference raindrop agent; A method for correcting a raindrop detection device comprising:

8. A step in which a light source unit emits light in a predetermined direction; a step of receiving light emitted from the light source unit by a light receiving unit; 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; 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 calculated in the step of calculating the diameter of the reference raindrop agent, the diameter of which is detected in the step of detecting raindrops and previously specified, so that the value of the diameter of the reference raindrop agent becomes the actual value of the diameter of the reference raindrop agent; A correction program that causes a computer to execute a method for correcting a raindrop detection device comprising:

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