Optical non-contact speedometer calibration system and optical non-contact speedometer calibration method

Abstract

To provide a calibration system of an optical non-contact speedometer which does not need a reference measurement object with a known length.SOLUTION: A calibration system of an optical non-contact speedometer comprises: a pipeline 20 which is transparent to inspection light emitted by an optical non-contact speedometer 10 being a calibration object; a fluid supply device 30 which supplies fluid to the pipeline 20; a flow rate sensor 40 which is provided in the pipeline 20 to measure the speed of the fluid flowing in the pipeline 20 as a reference speed; and a calibration signal generation unit 301 which generates a calibration signal for calibrating the measurement speed of the optical non-contact speedometer 10 on the basis of the measurement speed of the fluid measured by the optical non-contact speedometer 10 and the reference speed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a system and method for calibrating an optical non-contact speed meter. [Background technology]

[0002] A non-contact speedometer can measure the speed of an object without contact, and is used to measure the conveying speed of sheets such as films and nonwoven fabrics. In order to maintain the accuracy of a non-contact speedometer, a method for calibrating the non-contact speedometer has been proposed.

[0003] Japanese Patent Laid-Open Publication No. 8-304452 describes a method of calibrating a non-contact speedometer by placing a material to be measured of a known length, using a moving device to move a non-contact speedometer in parallel with the material to be measured at an arbitrary speed, measuring the relative speed with respect to the material to be measured using the non-contact speedometer, calculating the measured length of the material to be measured from the speed measured by the non-contact speedometer, and comparing the measured length with the known length of the material to be measured.

[0004] Japanese Patent Laid-Open Publication No. 9-113526 describes a method of calibrating a non-contact speedometer by placing an endless belt of a known length between a pair of pulleys, calculating a reference speed of the endless belt from the number of revolutions of the endless belt and the known length, measuring the speed of the endless belt with a non-contact speedometer, and comparing the speed measured by the non-contact speedometer with the reference speed.

[0005] Japanese Patent Application Laid-Open No. 2017-173216 describes a method of calibrating a non-contact velocimeter by detecting scattered light from a moving surface platen using a non-contact velocimeter to calculate the period of the beat signal, and then dividing the moving distance of the surface platen by the period of the beat signal to calculate the interval between interference fringes formed by the non-contact velocimeter in the measurement area. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-304452 [Patent Document 2] Japanese Patent Application Publication No. 9-113526 [Patent Document 3] Japanese Patent Application Publication No. 2017-173216 Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional calibration methods for non-contact speed meters use a reference measurement object of known length, but during calibration, it may be necessary to measure or set an accurate measurement time when calculating length from speed. Therefore, one object of the present invention is to provide a calibration system and a calibration method for an optical non-contact speed meter that do not require a reference measurement object of known length. [Means for solving the problem]

[0008] A calibration system for an optical non-contact speedometer according to an aspect of the present invention includes a pipe that is transparent to inspection light emitted by the optical non-contact speedometer to be calibrated, a fluid supply device that supplies fluid to the pipe, a flow velocity sensor provided in the pipe that measures the speed of the fluid flowing through the pipe as a reference speed, and a calibration signal generation unit that generates a calibration signal for calibrating the measured speed of the optical non-contact speedometer based on the measured speed of the fluid measured by the optical non-contact speedometer and the reference speed.

[0009] The above-described calibration system for an optical non-contact speedometer may further include a holder for holding the optical non-contact speedometer.

[0010] In the above-described calibration system for an optical non-contact speed meter, the holder may hold the optical non-contact speed meter so that the test light is irradiated onto a position facing the flow velocity sensor.

[0011] In the above-described optical non-contact velocity meter calibration system, the fluid supply device may supply fluid to the piping at a plurality of different supply velocities.

[0012] The above-described calibration system for an optical non-contact speed meter may further include a temperature control device that controls the temperature of the pipe.

[0013] The above-described calibration system for an optical non-contact speedometer may further include a calibration signal transmitting unit for transmitting a calibration signal to the optical non-contact speedometer.

[0014] In the above-described calibration system for an optical non-contact speed meter, the calibration signal may be configured to bring the measured speed closer to the reference speed.

[0015] In the above-described calibration system for an optical non-contact speed meter, the piping and the fluid supply device may be configured so that the flow of the fluid in the piping is a laminar flow.

[0016] A method for calibrating an optical non-contact velocimeter according to an aspect of the present invention includes supplying a fluid to a pipe that is transparent to an inspection light emitted by the optical non-contact velocimeter to be calibrated, measuring the velocity of the fluid flowing through the pipe as a measurement velocity with the optical non-contact velocimeter, measuring the velocity of the fluid flowing through the pipe as a reference velocity with a flow velocity sensor provided in the pipe, and generating a calibration signal for calibrating the measurement velocity based on the measurement velocity and the reference velocity.

[0017] The above-described method for calibrating an optical non-contact velocimeter may further include positioning the optical non-contact velocimeter so that test light is irradiated at a position facing the flow velocity sensor.

[0018] In the above-described method for calibrating an optical non-contact velocimeter, the fluid may be supplied to the pipe at a plurality of different supply velocities.

[0019] The above-described method for calibrating an optical non-contact speed meter may further include controlling the temperature of the pipe.

[0020] The above-described method for calibrating an optical non-contact speedometer may further include transmitting a calibration signal to the non-contact speedometer.

[0021] In the above-described method for calibrating an optical non-contact speed meter, the calibration signal may be configured to bring the measured speed closer to the reference speed.

[0022] In the above-described method for calibrating an optical non-contact velocimeter, the fluid may be caused to flow through the pipe so that the flow of the fluid in the pipe becomes a laminar flow. [Effects of the Invention]

[0023] According to the present invention, it is possible to provide a calibration system and a calibration method for an optical non-contact speed meter that do not require a reference measurement object of a known length. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram showing a calibration system for an optical non-contact speed meter according to an embodiment. [Figure 2] FIG. 2 is a schematic perspective view of the flow velocity sensor according to the embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view of the flow velocity sensor according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an optical non-contact speed meter according to an embodiment. [Figure 5] FIG. 5 is a schematic diagram showing an optical non-contact speed meter according to an embodiment. [Figure 6] FIG. 6 is a schematic diagram showing an optical non-contact speed meter according to an embodiment. [Figure 7] FIG. 7 is a schematic graph showing the relationship between the reference speed and the measured speed according to the embodiment. [Figure 8] FIG. 8 is a schematic graph showing the relationship between the reference speed and the measured speed according to the embodiment. [Figure 9] FIG. 9 is a flowchart of a method for calibrating an optical non-contact speed meter according to the embodiment. [Figure 10] FIG. 10 is a schematic diagram showing a calibration system for an optical non-contact speed meter according to an embodiment. [Figure 11]FIG. 11 is a schematic diagram showing a calibration system for an optical non-contact speed meter according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, identical or similar parts are denoted by identical or similar reference numerals. However, the drawings are schematic. Therefore, specific dimensions and the like should be determined in light of the following description. Furthermore, it goes without saying that the dimensional relationships and ratios between the drawings may differ.

[0026] As shown in FIG. 1, the calibration system for an optical non-contact speedometer according to the embodiment includes a pipe 20 that is transparent to the inspection light emitted by the optical non-contact speedometer 10 to be calibrated, a fluid supply device 30 that supplies a fluid to the pipe 20, a flow velocity sensor 40 provided in the pipe 20 that measures the velocity of the fluid flowing through the pipe 20 as a reference velocity, and a calibration signal generation unit 301 that generates a calibration signal for calibrating the measured velocity of the optical non-contact speedometer 10 based on the measured velocity of the fluid measured by the optical non-contact speedometer 10 and the reference velocity.

[0027] The fluid may be a liquid or a gas. The fluid may have, for example, at least one of the following characteristics: scattering the inspection light, reflecting the inspection light, diffracting the inspection light, and modulating the transmission characteristics of the inspection light. The fluid may include at least one of a substance that scatters the inspection light, a substance that reflects the inspection light, a substance that diffracts the inspection light, and a substance that absorbs the inspection light. The property of the substance that scatters the inspection light, the property of the substance that reflects the inspection light, the property of the substance that diffracts the inspection light, or the property of the substance that absorbs the inspection light may be selected depending on the wavelength of the inspection light. The object may be composed of particles. Examples of liquids include, but are not limited to, water, salt water, and oil.

[0028] The fluid supply device 30 includes, for example, a container 31 that stores a fluid, a flow path 32 that connects the container 31 to the pipe 20, and a flow control device 33 provided in the flow path 32. The fluid in the container 31 can be sent unidirectionally to the pipe 20 via the flow path 32 using gravity. Alternatively, the fluid in the container 31 can be sent to the pipe 20 via the flow path 32 using a fluid machine such as a pump. Still alternatively, the fluid in the container 31 can be sent to the pipe 20 via the flow path 32 by pressure applied to the container 31. The flow control device 33 controls the flow rate of the fluid supplied to the pipe 20. A valve or a flow controller can be used as the flow control device 33. The flow rate of the fluid may be set based on the diameter of the pipe 20. The fluid supply device 30 may supply the fluid to the pipe 20 at a plurality of different supply speeds. The fluid supply device 30 may further include a damper that absorbs pressure fluctuations.

[0029] At least the portion of the pipe 20 that is irradiated with the inspection light emitted by the optical non-contact speed meter 10 is transparent to the inspection light. The pipe 20 is preferably configured to prevent turbulence in the fluid. At least one of the pipe 20 and the fluid supply device 30 is preferably configured to allow laminar flow of the fluid in the pipe 20. The pipe 20 is, for example, a straight pipe having a predetermined length. The flow velocity sensor 40 is, for example, provided on the side of the pipe 20. The flow velocity sensor 40 abuts, for example, the outer surface of the pipe 20. It is preferable that there are no irregularities near the inner surface of the pipe 20 where the flow velocity sensor 40 is provided. The flow velocity sensor 40 is not particularly limited as long as it can measure the speed of the fluid flowing through the pipe 20. Examples of the flow velocity sensor 40 include a thermal flow velocity sensor, an ultrasonic flow velocity sensor, and an electromagnetic flow velocity sensor. The type of flow velocity sensor 40 may be selected depending on the type of fluid. It is preferable that the flow velocity sensor 40 is a different type of speed meter from the optical non-contact speed meter 10. For example, the flow sensor 40 is a non-optical flow sensor.

[0030] 2 and 3, the microflow sensor includes a substrate 41 having a cavity 46, an insulating film 45 disposed on the substrate 41 so as to cover the cavity 46, a heater 42 disposed on the insulating film 45, an upstream temperature-measuring resistor 43 disposed upstream of the heater 42, and a downstream temperature-measuring resistor 44 disposed downstream of the heater 42.

[0031] The portion of insulating film 45 that covers cavity 46 forms a heat-insulating diaphragm. Heater 42 is disposed at the center of insulating film 45 that covers cavity 46, and heats the fluid flowing through pipe 20. Upstream resistance temperature element 43 is used to detect the temperature of the fluid upstream of heater 42, and downstream resistance temperature element 44 is used to detect the temperature of the fluid downstream of heater 42.

[0032] When the fluid in the pipe 20 is stationary, the heat applied by the heater 42 diffuses symmetrically in the upstream and downstream directions. Therefore, the temperatures of the upstream resistance temperature sensor 43 and the downstream resistance temperature sensor 44 become equal, and the electrical resistances of the upstream resistance temperature sensor 43 and the downstream resistance temperature sensor 44 become equal. In contrast, when the fluid in the pipe 20 flows from upstream to downstream, the heat generated by the heater 42 is carried downstream. Therefore, the temperature of the downstream resistance temperature sensor 44 becomes higher than the temperature of the upstream resistance temperature sensor 43. As a result, a difference occurs between the electrical resistance of the upstream resistance temperature sensor 43 and the electrical resistance of the downstream resistance temperature sensor 44. The difference between the electrical resistance of the downstream resistance temperature sensor 44 and the electrical resistance of the upstream resistance temperature sensor 43 is correlated with the speed and flow rate of the fluid in the pipe 20. Therefore, the velocity and flow rate of the fluid flowing through the pipe 20 can be calculated from the difference between the electrical resistance of the downstream temperature measuring resistance element 44 and the electrical resistance of the upstream temperature measuring resistance element 43 .

[0033] 1 is an ultrasonic flow velocity sensor, the ultrasonic flow velocity sensor includes, for example, an ultrasonic oscillator that contacts the side surface of the pipe 20, and measures the flow velocity of the fluid by utilizing changes in ultrasonic frequency caused by the movement of the fluid. When the flow velocity sensor 40 is an electromagnetic flow velocity sensor, the electromagnetic flow velocity sensor measures the flow velocity of the fluid by utilizing changes in electromagnetic induction caused by the movement of the fluid.

[0034] The optical non-contact velocimeter 10 irradiates the fluid in the pipe 20 with an inspection light and calculates the velocity of the fluid based on at least the light reflected from the fluid.

[0035] The optical non-contact speedometer 10 may be a laser Doppler speedometer. When the optical non-contact speedometer 10 is a laser Doppler speedometer, the optical non-contact speedometer 10 includes a light source 201 that emits laser light, as shown in FIG. 4. The laser light passes through a collimating lens 202 and is split into two beams by a half mirror 203. One of the split laser beams is reflected by a mirror 204, and the two laser beams enter the pipe 20 at an incident angle θ and interfere with each other. Scattered light or reflected light generated within the pipe 20 is collected by a collecting lens 205 and received by a light-receiving element 206.

[0036] The relationship between the frequency F of the Doppler signal obtained from the light receiving element 206, the velocity V of the fluid, the wavelength λ of the laser light, and the incident angle θ of the laser light is given by the following equation (1). F=(2V / λ)sinθ (1) The wavelength λ of the laser light and the incident angle θ of the laser light can be obtained in advance. The frequency F of the Doppler signal can be obtained by performing a Fourier transform on the time change of the light received by the light receiving element 206. Therefore, by obtaining the frequency F of the Doppler signal, the optical non-contact velocimeter 10 calculates the velocity V of the fluid.

[0037] The optical non-contact velocimeter 10 may be a self-coupling velocimeter. When the optical non-contact velocimeter 10 is a self-coupling velocimeter, the optical non-contact velocimeter 10 includes a light source 211 that emits laser light, as shown in FIG. 5 . The laser light is incident on the pipe 20. Scattered or reflected light generated within the pipe 20 travels along the same optical path as the irradiated light in the opposite direction. The returning light that re-enters the optical resonator within the light source 211 interferes with the laser light generated in the optical resonator. This interference means that a self-coupling effect occurs within the optical resonator. The interference waveform generated by the self-coupling is detected by the light-receiving element 212. Based on the period of the interference waveform, the optical non-contact velocimeter 10 calculates the velocity of the fluid.

[0038] The optical non-contact speedometer 10 may be a spatial filter speedometer. When the optical non-contact speedometer 10 is a spatial filter speedometer, the optical non-contact speedometer 10 includes a light source 221 that emits light, as shown in FIG. 6. The light source 221 may be a laser light source or an LED. The fluid in the pipe 20 is irradiated with the condensed light from an oblique direction so as to provide dark-field illumination for the light-receiving optical system of the optical non-contact speedometer 10. The scattered light or reflected light generated in the pipe 20 is condensed by a condenser lens 222, and an image of the fluid is formed on a grating 223 having a periodic transmittance distribution.

[0039] If the magnification of the light receiving optical system is M and the speed of the fluid is V, the image on the grating 223 moves at a speed MV. Light transmitted through the grating 223 is received by the light receiving element 224. The period F of the signal of the transmitted light received by the light receiving element 224 is given by the following equation (2), where p is the spacing between the gratings 223. F=MV / p (2) Since the magnification M of the light receiving optical system and the interval p of the grating 223 can be obtained in advance, the optical non-contact velocimeter 10 calculates the velocity V of the fluid by measuring the frequency F.

[0040] The response speed of at least one of the optical non-contact speed meter 10 and the flow velocity sensor 40 shown in FIG. 1 may be adjusted so that the response speed of the optical non-contact speed meter 10 and the flow velocity sensor 40 match.

[0041] The calibration system for the optical non-contact speed meter according to the embodiment may further include a holder 50 that holds the optical non-contact speed meter 10. The holder 50 holds the optical non-contact speed meter 10 so that the test light is irradiated onto a position facing the flow velocity sensor 40, for example.

[0042] The calibration signal generation unit 301 generates a calibration signal for bringing the measured speed closer to the reference speed. The optical non-contact speed meter 10 transmits the measured speed to the calibration signal generation unit 301 via a wired or wireless connection. The flow velocity sensor 40 transmits the reference speed to the calibration signal generation unit 301 via a wired or wireless connection. The calibration signal generation unit 301 receives the measured speed from the optical non-contact speed meter 10 and receives the reference speed from the flow velocity sensor 40.

[0043] The calibration signal generation unit 301 compares the measured speed with the reference speed. For example, as shown in FIG. 7, when the measured speed and the reference speed are the same, the calibration signal generation unit 301 does not generate a calibration signal. As shown in FIG. 8(a), when the measured speed is faster than the reference speed, the calibration signal generation unit 301 generates a calibration signal to calibrate the measured speed so that the measured speed becomes equal to the reference speed. As shown in FIG. 8(b), when the measured speed is slower than the reference speed, the calibration signal generation unit 301 generates a calibration signal to calibrate the measured speed so that the measured speed becomes equal to the reference speed.

[0044] The calibration signal is not particularly limited as long as it can calibrate the speed measured by the optical non-contact speedometer 10 shown in FIG. 1 . For example, the calibration signal may include a coefficient or an equation by which the measured speed calculated by the optical non-contact speedometer 10 is multiplied. The equation may be a linear equation or a polynomial equation. Alternatively, the calibration signal may be a signal that calibrates the sensitivity of the optical system or the strength and frequency of the electrical signal of the electrical circuit used by the optical non-contact speedometer 10 to calculate the measured speed.

[0045] The calibration system for a non-contact speedometer according to the embodiment further includes a calibration signal transmission unit 302 for transmitting the calibration signal generated by the calibration signal generation unit 301 to the optical non-contact speedometer 10. The optical non-contact speedometer 10 is configured to receive the calibration signal and calculate a calibrated measured speed based on the calibration signal.

[0046] The calibration system for a non-contact speed meter according to the embodiment may further include a control unit 303 for controlling at least one of the fluid supply device 30, the optical non-contact speed meter 10, and the flow velocity sensor 40 via a wired or wireless connection. The control unit 303 controls at least one of the flow rate and flow velocity of the fluid supplied by the fluid supply device 30 to the pipe 20. The control unit 303 controls the start and stop of speed measurement by the optical non-contact speed meter 10. The control unit 303 controls the start and stop of speed measurement by the flow velocity sensor 40.

[0047] The calibration signal generating unit 301, the calibration signal transmitting unit 302, and the control unit 303 are included in a central processing unit (CPU) 300, for example.

[0048] Next, a method for calibrating the optical non-contact speed meter according to the embodiment will be described with reference to FIG.

[0049] In step S101, in response to an instruction from the control unit 303, the optical non-contact velocimeter 10 starts measuring the velocity of the fluid when the fluid is not flowing in the pipe 20, and resets the measured velocity measured by the optical non-contact velocimeter 10 to zero. In step S102, in response to an instruction from the control unit 303, in response to an instruction from the flow velocity sensor 40 when the fluid is not flowing in the pipe 20, and resets the reference velocity measured by the flow velocity sensor 40 to zero.

[0050] In step S103, the control unit 303 instructs the fluid supply device 30 to supply the fluid at a predetermined flow rate to the pipe 20. After a predetermined time has elapsed during which the flow velocity of the fluid in the pipe 20 has stabilized, the control unit 303 instructs the optical non-contact velocimeter 10 to measure the velocity of the fluid and transmit the measured velocity to the calibration signal generation unit 301 in step S104. The control unit 303 instructs the flow velocity sensor 40 to measure the velocity of the fluid and transmit a reference velocity to the calibration signal generation unit 301 in step S105. Steps S103 and S104 may be performed in parallel.

[0051] In step S106, the control unit 303 instructs the fluid supply device 30 and the flow velocity sensor 40 to end measuring the velocity of the fluid. In step S107, the calibration signal generation unit 301 generates a calibration signal based on the received reference velocity and the measured velocity. In step S108, the calibration signal transmission unit 302 transmits the calibration signal generated by the calibration signal generation unit 301 to the optical non-contact velocimeter 10. The optical non-contact velocimeter 10 is configured to receive the calibration signal and thereafter calculate a calibrated measured velocity.

[0052] Steps S103 to S106 may be performed at a plurality of different fluid supply speeds. In this case, the calibration signal generator 301 generates a calibration signal so that the measured speed is equal to the reference speed at any of the plurality of different fluid supply speeds.

[0053] Although the present invention has been described above by way of the embodiments, the description and drawings forming part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art.

[0054] 10, the calibration system for an optical non-contact speedometer according to the embodiment may further include a time information providing device 400 that provides time stamps to the measured speed and the reference speed. The time information providing device 400 communicates with the optical non-contact speedometer 10 and the flow velocity sensor 40 via wire or wirelessly, and transmits time information to the optical non-contact speedometer 10 and the flow velocity sensor 40. The time information providing device 400 may be connected to an access point of the CPU 300 for wirelessly connecting with the optical non-contact speedometer 10 and the flow velocity sensor 40.

[0055] When transmitting a measured speed, the optical non-contact speed meter 10 adds a timestamp to the measured speed based on time information. When transmitting a reference speed, the flow velocity sensor 40 adds a timestamp to the reference speed based on time information. The calibration signal generator 301 compares the measured speed and the reference speed transmitted at the same time based on the timestamp. This makes it possible to generate a highly accurate calibration signal.

[0056] 11, the calibration system for the optical non-contact speed meter according to the embodiment may further include a temperature control device 21 that controls the temperature of the pipe 20. When the flow velocity of the fluid is low, convection may occur in the fluid due to a temperature gradient in the pipe 20. The temperature control device 21 controls the temperature of the pipe 20 so that the temperature of the pipe 20 is constant.

[0057] Thus, it should be understood that the present invention encompasses various embodiments that are not described herein. [Explanation of symbols]

[0058] 10... Optical non-contact speed meter, 20... Piping, 21... Temperature control device, 30... Fluid supply device, 31... Container, 32... Flow path, 33... Flow control machine, 40... Flow speed sensor, 41... Substrate, 42... Heater, 43... Upstream resistance temperature sensor, 44... Downstream resistance temperature sensor, 45... Insulating film, 46... Cavity, 50... Holding part, 201... Light source, 2 02... Collimating lens, 203... Half mirror, 204... Mirror, 205... Condenser lens, 206... Light receiving element, 211... Light source, 212... Light receiving element, 221... Light source, 222... Condenser lens, 223... Grating, 224... Light receiving element, 301... Calibration signal generating unit, 302... Calibration signal transmitting unit, 303... Control unit, 400... Time information providing device

Claims

1. A pipe that is transparent to the inspection light emitted by the optical non-contact speedometer to be calibrated; a fluid supply device for supplying a fluid to the piping; a flow velocity sensor provided in the pipe that measures the velocity of the fluid flowing through the pipe as a reference velocity; a calibration signal generating unit configured to generate a calibration signal for calibrating the measured velocity of the optical non-contact velocimeter based on the measured velocity of the fluid measured by the optical non-contact velocimeter and the reference velocity; a holder for holding the optical non-contact speed meter; Equipped with the holding unit holds the optical non-contact velocimeter so that the inspection light is irradiated at a position facing the flow velocity sensor. Optical non-contact speedometer calibration system.

2. The calibration system for an optical non-contact velocimeter according to claim 1 , wherein the fluid supply device supplies the fluid to the piping at a plurality of different supply velocities.

3. The calibration system for an optical non-contact speed meter according to claim 1 , further comprising a temperature control device that controls the temperature of the piping.

4. The calibration system for an optical non-contact speedometer according to claim 1 , further comprising a calibration signal transmitting unit for transmitting the calibration signal to the optical non-contact speedometer.

5. 2. The optical non-contact speed meter calibration system according to claim 1, wherein the calibration signal is configured to cause the measured speed to approach the reference speed.

6. 2. The calibration system for an optical non-contact velocimeter according to claim 1, wherein the piping and the fluid supply device are configured so that the flow of the fluid in the piping is a laminar flow.

7. supplying a fluid to a pipe that is transparent to an inspection light emitted by an optical non-contact speed meter to be calibrated; measuring a velocity of the fluid flowing through the pipe as a measurement velocity using the optical non-contact velocimeter; measuring a velocity of a fluid flowing through the pipe as a reference velocity with a flow velocity sensor provided in the pipe; generating a calibration signal for calibrating the measured velocity based on the measured velocity and the reference velocity; Including, The optical non-contact velocimeter is disposed so that the inspection light is irradiated at a position facing the flow velocity sensor. How to calibrate an optical non-contact speedometer.

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