JPH03175326A - Method and apparatus for measuring emissivity and surface temperature - Google Patents

Abstract

PURPOSE:To accurately measure the surface temp. of an object to be measured by calculating emissivity on the basis of the reflectivity corrected on the basis of the measured value of the distance between the photoelectric conversion element of a quantity-of-light measuring radiometer and the object to be measured. CONSTITUTION:When wide parallel luminous flux is emitted to the surface of an object 2 to be measured from a light emitted source 15, the quantity I0 of the parallel luminous flux is measured by a photodetector 21 and the quantity I1 of the light from the surface of the object 2 to be measured is measured by a radiometer 13. Next, when the surface of the object 2 to be measured is not irradiated with the luminous flux, the quantity I2 of the light from the object 2 to be measured is measured by a radiometer 23. Further, approximate semisphere reflectivity is calculated from a predetermined formula using the measured value of the distance (l) between the photoelectric conversion element of the radiometer 18 and the object 2 to be measured and the emissivity epsilon of the object 2 to be measured is obtained. Furthermore, the accurate surface temp. of the object 2 to be measured is calculated on the basis of the outputs V0 of a thermometer calculated based on the quantity I0 of light only of emitted light and the emissivity epsilon.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for simultaneously measuring the emissivity and surface temperature of an object to be measured without contacting the object, and an apparatus therefor. .

<Prior art and its problems> The radiation temperature measurement method, which measures the temperature of an object based on the emitted light from the object and the emissivity of the object, can quickly measure temperature without touching the object. Because of its ability to
It is one.

However, when measuring temperature using this radiation temperature measurement method, it is extremely important to remove disturbances from ambient heat sources (noise light) and to accurately determine the emissivity of the object to be measured. However, the emissivity of an object, which is desired to be accurately determined for temperature measurement, not only fluctuates greatly depending on temperature and material, but also reflects light when the object is a relatively specular cold-rolled plate. It has the characteristic that it exhibits an extremely small value compared to the rate of measurement, so even when light is detected from a non-measurable object, most of it is rarely reflected light. Therefore, it is extremely difficult to directly measure the emissivity of an object from synchrotron radiation, and therefore, improving measurement accuracy has been a major challenge in the "radiant temperature measurement method."

Therefore, in order to solve the above-mentioned problems pointed out in the radiation temperature measurement method, the following proposal was made.

In other words, the temperature measurement means shown in Fig. 4 was published in the Proceedings of the Society of Instrument and Control Engineers, Vol. 16, No. 2 (1982), and uses specular reflection to improve temperature measurement accuracy. That is what it says.

In this method, a blackbody radiation source (3) and a radiometer (4) are mirror-symmetrically arranged at an angle θ with respect to the normal to the surface of a mirror-surfaced object (2) placed in a container (1). At the same time, a water-cooled rotating sector (6) (fan-shaped shielding plate) rotated by a motor (5) is placed in front of the blackbody radiation source (3) to measure temperature. This means that when measuring temperature, the rotating sector (
6) is at an angular position that does not block the blackbody radiation source (3), the radiometer (4) detects the light (reflected light) from the blackbody radiation 8 (3) reflected from the surface of the object to be measured (2). It receives both the radiation light emitted from the object to be measured (2) itself, and detects the light intensity as the combined value. On the other hand, rotating sector (6
) is at an angular position that blocks the blackbody radiation source (3), the radiometer (4) receives only the radiation emitted from the object to be measured (2) itself, and this value is detected as the light intensity. .

Therefore, by first determining the amount of reflected light from the difference between these two light intensities and calculating the reflectance based on this, the law that says "the sum of reflectance and emissivity is constant" indicates that the object to be measured (2) Emissivity is derived. Furthermore, the surface temperature of the object to be measured (2) is determined from this emissivity and the above-mentioned "light intensity detected by receiving only the emitted light".

Further, as a radiation temperature measurement method that similarly utilizes specular reflection, a means as shown in FIG. 5 is disclosed in Japanese Patent Application Laid-Open No. 6186621.

The means shown in FIG. 5 emits light from a light emitting source (Ma) by a mirror (8) in the normal direction to the object to be measured (2), the reflected light, and the object to be measured (2) itself. A condensing lens (9) installed above the mirror (8)
The temperature is measured by collecting it in a radiometer (4). When measuring the temperature, first, a reference reflector having a reflectance ρ of 1 is set in place of the object to be measured (2), and in this state, the amount of light L0 from the light emitting source (7) is measured in advance. Also, from an object whose reflectance ρ and emissivity ε are already known, ρ
Find the sum K of and ε. Next, the object to be measured (2) is irradiated with light from the light emitting source (7), and the scene L1 from the surface of the object at this time is measured by the radiometer (4). Furthermore, the radiation meter (4) also measures the light lLz emitted from the surface of the object to be measured in a state where the irradiation light power (object to be measured 2) does not hit the surface. Then, in the first step, the reflectance ρ of the surface of the object to be measured in the normal direction is determined from these measured values using the formula 1, and then the formula ε = 1 ρ (where 7, for a mirror surface, ρ = 1 ) to determine the emissivity ε of the surface of the object to be measured. Next, in the second step, the equation Ts = A εT (where A is a constant of proportionality) is obtained from the luminance T obtained from the "light amount L!"', which is a scene of only synchrotron radiation, and the emissivity ε. Based on this, the accurate temperature T of the surface of the object to be measured (2) is determined.

However, with any of these methods, if the surface of the object to be measured is specularly reflective, noise light from the surroundings (for example, the wall of the container, etc.) will not enter the radiometer, making it difficult to measure emissivity and temperature with high precision. This is possible, but if the surface of the object to be measured is diffusely reflective, thermal radiation from the surroundings will be diffusely reflected on the surface of the object and enter the radiometer, increasing measurement errors in emissivity and temperature. There was an inconvenience. In addition, if the surface of the object to be measured is other than a mirror surface, the relationship "ε + ρ = 1" does not hold between the emissivity ε and the reflectance ρ in a specific direction, so the parameter P that represents the diffuse reflection characteristics of the material is The reflectance of the measured object is corrected by introducing [ρ-P(1-ε)], but this P is the material 1 surface roughness of the measured object,
Since it varies depending on the degree of oxidation, etc., there has been a problem that accurate measurement is difficult from this point of view as well.

On the other hand, apart from these, ["Tetsu to Hagane", Vol. 65, No. 1 (1979)] and "Special Publication No. 7954 of 1979"
published a proposal to improve temperature measurement accuracy using a highly reflective cylinder.

FIG. 6 is a schematic explanatory diagram of the means, and for temperature measurement, an apparatus as shown in FIG. 6 (Ta) is used. That is,
Object to be measured (2) between the object to be measured (2) and the radiometer (4)
A cylinder (10) with a highly reflective inner surface is installed at a position close to the radiometer (4), and a sixth
This is a device in which a rotating sector (12) having two openings (11) as shown in Figure (bl) is arranged.

The rotating sector (12) is rotated by the motor (13), but the opening (11) is located at the cylinder (10).
The entrance of the radiometer (4) is also placed on the central axis (14).

In the above device, the rotating sector (12) is a cylinder (10).
When the angular position is such that it does not come between the object to be measured (2) and the radiometer (4), only the light emitted from the object to be measured (2) that follows the optical path on the central axis (14) enters the radiometer (4).

That is, at this time, the same state as if the cylinder (10) did not exist can be realized, but the surface temperature, emissivity, and radiant energy of the object to be measured at that time are T, respectively.

Let ε and E be, the radiant energy E detected by the radiometer (4) is expressed by the formula %. On the other hand, the rotating sector (12) is a cylinder (10
) and the radiometer (4), the emitted light from the object to be measured (2) is emitted from the inner surface of the cylinder (10).

Radiant light other than the radiant light that is variously reflected on the lower surface of the rotating sector (12) and the surface of the object to be measured (2) and follows the optical path on the central axis (14) also passes through the opening (11) of the rotating sector (12). )
and enters the radiometer (4). Therefore, the radiant energy E2 detected by the radiometer (4) at this time has an increased emissivity, and is expressed by the formula %. Here, since the relationship between g(ε) and ε can be known in advance, the emissivity ε and surface temperature T of the object to be measured can be determined by solving the above two equations as simultaneous equations. be.

This means also uses a cylinder (10) to direct ambient light to a radiometer (4).
), noise light is prevented from entering the radiometer (4).
), it was possible to measure with high accuracy, but it was difficult to place the cylinder (10) with high internal reflection as close to the object to be measured (2) as possible. This method has the problem that it is difficult to regularly apply it to online manufacturing processes because it is necessary to take precautionary measures, and a decrease in reflectance due to contamination on the inner surface of the cylinder is unavoidable.

Therefore, the present inventor first discovered that there is no need for an auxiliary member such as the cylindrical member, which is difficult to properly install, and that accurate measurement is possible even if the surface of the object to be measured is diffusely reflective. The following method was proposed (Japanese Patent Application No. 75,670/1982) that allows simultaneous measurement of emissivity and surface temperature without requiring correction each time the emissivity changes due to changes in the object.

That is, as shown in FIG. 7, the previous proposal by the present inventor was to first convert the light from the light emitting fi (15) of a semiconductor laser or the like into a lens (16) with a predetermined spread and uniform intensity distribution. Parallel light flux” and convert it into a half mirror (1
7) to the surface of the object to be measured (2) from its normal direction, and a radiometer (18) measures the sum of the approximate amount of reflected light from the irradiated surface and the amount of radiation emitted by the object to be measured itself. The amount of parallel light flux at that time is detected by a photodetector (21) via a mirror (19) and a condensing lens (20), while the light emitted m (15) is blocked by a shutter or the light source ( 15) when the light output is set to zero so that the irradiated light does not hit the surface of the object to be measured (the amount of radiation emitted by the object to be measured itself) is measured by the radiometer (22) via the half mirror (22). 23).Then, “Radiometer (18)
The approximate reflectance of the object to be measured is determined from the approximate amount of reflected light calculated as the difference between the measured value of and the measured value of the radiometer (23) and the amount of parallel light detected by the photodetector (21). , Furthermore, after calculating the emissivity of the object to be measured from the relational expression that holds between reflectance and emissivity, the calculated emissivity and radiometer (
23) The surface temperature of the object to be measured is determined based on the "radiant energy of the object to be measured" obtained based on the measured value.

According to such means, even if the surface of the object to be measured (2) is diffusely reflective and noise light from the ambient light source is incident on the radiometer (18), the noise light is transmitted to the light emitting source (15). Since the amount of light emitted by the irradiated light is extremely small compared to the irradiated light from the irradiated light source, the emissivity and reflectance can be measured accurately, and therefore the temperature can be measured with high precision.

However, as a result of the inventor's continued studies,
The method for measuring emissivity and temperature proposed above (Japanese Patent Application No. 63-75670) also uses reflections that emit light in proportion to the distance between the thermometer (radiometer) and the object to be measured. It is necessary to widen the luminous flux of the reference light for rate measurement, and this requires the inconvenience of increasing the size of the equipment, so in practice it is not possible to place the object to be measured and the thermometer very far apart. It became clear that there was a problem.

Therefore, an object of the present invention is to solve the above-mentioned problems observed in the emissivity and temperature measuring means proposed earlier (Japanese Patent Application No. 63-75670), and to eliminate the need for larger devices. The aim was to provide a means to accurately measure the emissivity and surface temperature of an object without contact, by installing a thermometer (radiometer) at a position at a flexible distance.

Means for Solving the Problems> Therefore, the inventor of the present invention aimed to achieve the above object (he conducted extensive research and obtained the following findings).

In other words, the emissivity and temperature measuring means proposed earlier (Japanese Patent Application No. 63-75670) requires a uniform intensity distribution with a "predetermined spread determined by the distance between the object to be measured and the thermometer (radiometer)". In this case, the object to be measured and the thermometer (
Once the distance to the projector (radiometer) is determined, the minimum necessary spread of the projected luminous flux is determined, and it becomes necessary to project light with a luminous flux diameter larger than that. However, the emissivity is reduced by the means proposed above.

When measuring temperature, instead of spreading the luminous flux, the distance between the object to be measured and the thermometer (radiation needle) is measured, and based on this, the "integral efficiency of reflectance f (0 < f ≦ 1)"
, and correct the reflectance based on the assumption that the surface to be measured is a completely diffusive surface.
We have discovered that it is possible to properly measure emissivity without having to adjust the distance to a radiometer.

The present invention has been made based on the above-mentioned findings and the like. The amount of emitted light and the amount of reflected light from the surface of the object to be measured in the same direction are measured, the reflectance of the object to be measured is determined based on the measured values, and the reflectance of the object to be measured is determined from the relationship between the reflectance and emissivity. In this method, the temperature of the surface of the measured object is calculated based on the calculated emissivity and the radiant energy from the measured object. By performing the correction based on the reflectance corrected based on the measured value of the distance to the object to be measured, it is possible to obtain the appropriate emissivity and surface temperature of the object to be measured without having to adjust the distance between the object to be measured and the radiometer. It is characterized by the fact that it is capable of measuring the emissivity and surface temperature of an object to be measured. a lens system that converts the parallel light beam into a parallel light beam having a distribution, a half mirror that reflects the parallel light beam and guides it to the surface of the object to be measured from the normal direction thereof but transmits light from the surface of the object to be measured, and the predetermined spread. a means for measuring the light intensity of a parallel light beam having a uniform intensity distribution; a radiometer for receiving light in the normal direction from the surface of the object to be measured; and a means for measuring the intensity of the emitted light from the surface of the object to be measured. The present invention is also characterized in that it is configured to include means for measuring the distance between the charge conversion element of the radiometer and the surface of the object to be measured.

Here, it is preferable that the parallel light beam having a predetermined spread and uniform intensity be light of a single wavelength, and it is also desirable to use a radiometer that has light reception sensitivity for the same wavelength.

In addition, the light from the light source should not be constantly irradiated as a parallel light beam with a predetermined spread and uniform intensity distribution, but should preferably be output intermittently by a shutter, etc. As a method, the light emitted by the light source may be intensity-modulated.

Next, the reason why the emissivity and surface temperature of the object to be measured can be measured by means of the present invention will be explained.

Effect〉 Incident light when light is incident on the surface of an object.

The law of conservation of energy holds true between reflected light and absorbed light, where the energy of the incident light is IO + the reflectance is ρ, and the absorption rate is α.

If the transmittance is β, then according to the law of conservation of energy, Equation 1 % (1
) holds true.

Furthermore, from Kirchhoff's law, the following equation holds true, where ε is the emissivity.

ε=α (2) By the way, FIG. 1 fal explains the directions of incident light and reflected light on plane A. Now, the light is BO at the 0 point on the plane A
The incident angle of light is (θ, φ) with respect to the straight line OX and normal ON on the plane A when the light is incident from the force direction and reflected in the OC direction.

Let the reflection angle be (θ', φ'), and light of wavelength λ is incident on the surface of an opaque plane object with an incident angle (θ, φ) and is reflected with a reflection angle (θ', φ'). Assuming that, since the object is opaque, β = OJ, and since the surface of the object is flat, if the hemispherical reflectance is ρt, then [ρ = ρzrCJ, and emissivity 1 reflectance Considering that is a function of the wavelength λ and the incident angle (θ, φ), (from equations 11 and (2) )...(
3) holds true.

Here, episode 2 (λ: θ, φ) means that light with wavelength λ is (θ,
It is the total reflectance (hemispherical reflectance) reflected in the 2π space in front of the object when it is incident from the direction of becomes as follows.

That is, as shown in FIG. 1(b), when light with intensity I0 and beam diameter D is perpendicularly incident on the surface of the object (24), it is detected at a position P at a distance l from the object surface and suggestion(
In the emissivity and temperature measuring means (Japanese Patent Application No. 63-75670), the approximate hemispherical reflectance 1 determined by equation (5) becomes a value close to the hemispherical reflectance ρ2 calculated by equation (4). It was assumed that the "luminous flux diameter D" and "distance l between the photoelectric conversion element of the radiometer and the object to be measured" were adjusted as shown in the figure, but if the luminous flux diameter is large to some extent, this luminous flux can be applied. The approximate hemispherical reflectance γ21 is calculated using the following formula using the reflectance 1 measured at It can be found by

If) 2j (λ: 0.0) 10-(1-'i5"(λ: 0.O)) ... (7
) The above equation (7) shows that the approximate hemispherical reflectance Tzn is a function of the distance l and the apparent reflectance 1 measured by the reflection method, and the approximate hemispherical reflectance in equation (7) is For a perfectly diffuse reflective surface and a mirror surface, the hemispherical reflectance is determined by equation (4). That is, this fact is the gist of the present invention.

On the other hand, in the emissivity and temperature measuring means proposed earlier (Japanese Patent Application No. 63-75670), when l is large, that is, f≧
In the case of 0.1, it is clear that an error will occur if the reflectance 1 is low.

Next, the present invention will be explained more specifically based on Examples.

<Example> Fig. 2 shows the “emissivity 1 surface temperature measuring device” according to the present invention.
It is a schematic diagram showing an example.

In Fig. 2, reference numeral (2) is the object to be measured, and above it there is a hole so that the light from the light emitting source (15) is irradiated onto the surface of the object to be measured (2) from the normal direction. A ＼-humirar (17) is provided. A radiometer (18) is placed above the nof mirror (1, 7) in order to detect the reflected light from the irradiated light reflected on the surface of the object to be measured (2) and the emitted light from the object to be measured itself. ) are placed. Note that this radiometer (18) is arranged coaxially with the central axis (center optical axis) of the light beam irradiated onto the surface of the object to be measured via the half mirror (17) (therefore, it is aligned with the normal to the surface of the object to be measured). The incident light path to the radiometer is in the same direction).

Also, between the half mirror (17) and the radiometer (18), there is a radiometer (23) that transmits the emitted light from the surface of the object in the vicinity of the central optical axis (the part indicated by the broken line in Fig. 2). A half mirror (22) is arranged to guide the direction.

However, the role of the radiometer (23) can be replaced by the radiometer (18), so the half mirror (22) and the radiometer (23) are not essential.

By the way, the above-mentioned light emitting source (15) is a source of parallel light flux having a predetermined width and intensity, and the radiation thermometer (18)
It is necessary to emit light that includes an emission spectrum at the measurement wavelength (for example, 0.65stm or O09 for a Si radiometer) or a wavelength similar to this, and usually a semiconductor laser that emits laser light is used. However, it does not necessarily have to be a single wavelength light source (,)\Rogen lamp etc. can also be used.

Reference numeral (16) is an aspherical lens that converts the light from the light emitting source (15) into a parallel beam of predetermined width (diameter). The parallel light flux converted and formed by this lens (16) is transmitted to the object to be measured (
2) When measuring its own emitted light, it is not necessary to irradiate the surface of the object to be measured (2), so the light emitting source (15) must be operated intermittently, the emitted light intensity can be modulated, or the light emitted A chopper, shutter (25) optical switch, etc. should be provided in front of the mouth so that the irradiation light is intermittently irradiated onto the object to be measured (2). Note that the reference numeral (26) is a motor for driving the shutter (25).

The photodetector (21) detects the amount of irradiated light. The mirror (19) is installed at one end of the wide (large diameter) parallel beam formed by the lens (16).
It is placed coaxially with the optical path of the reflected light.

Further, a condensing lens (20) is placed in front of the photodetector (21). Note that this reference photodetector (21) is
There is no problem even if the half mirror (17) is placed on the back side so as to face the light source.

Reference numeral (27) is a distance meter (here, an optical trigonometric method is adopted), which is used to measure the distance between the photoelectric conversion element of the radiometer (18) and the object to be measured (2).

Measurement of emissivity and surface temperature using the above device is carried out as follows.

First, the object to be measured (2) is brought to the position shown in Fig. 2, and the light emission [(15) when a wide parallel beam of light is irradiated onto the surface of the object to be measured, ``the amount of parallel light beam 1'' is emitted. Detector (21
), and also measure the amount of light emitted from the surface of the object to be measured using a radiometer (18). This amount of light (1) is the majority of the amount of reflected light on the surface of the object to be measured (approximate value of the amount of reflected light described above).
i I o ) and the amount of emitted light I2 from the object to be measured itself.

Next, when the irradiation light is not hitting the surface of the object to be measured, for example by "shielding the front part of the light emitting source (15) with a shutter" or "setting the light output of the light emitting source (15) to zero", The amount of light (2) from the surface of the object to be measured is measured with a radiometer (23).

Of course, instead of using the radiometer (23), the measurement of the light intensity 1z may also be performed using the radiometer (18). Note that this light amount I2
is only the emitted light from the object to be measured itself. Therefore, the approximate amount of reflected light 71o is ρ■. = It Iz , and the approximate reflectance ρ can be determined by 0. Furthermore, the photoelectric conversion element of the radiometer (18) and the object to be measured (2) by the distance meter (27)
The approximate hemispherical reflectance ρZlt is obtained from equation (7) using the measured value of the distance l'' from Thermometer output V0 determined by Io indicating the amount of radiation only,
The accurate temperature T of the surface of the object to be measured (2) is determined based on the above-mentioned emissivity ε and the above-mentioned formula V0-A·ε·T″ (where A and n are constants).

By the way, in such a measurement, since the surface of the object to be measured (2) is diffusely reflective, noise light from an ambient light source enters the radiometer (18). However, the radiometer (18
) There will be no problem if a cylindrical radiation shield is installed between the object to be measured and this thermometer so that the noise light incident on the thermometer is far less than the light emitted from the light source (15). .

Therefore, according to the method of the present invention, it is possible to measure the emissivity and reflectance only in the normal direction of the surface of the object to be measured with high accuracy.

Furthermore, if the ambient temperature is sufficiently high compared to the object to be measured (2), the noise light can be reduced to a negligible level by installing a shielding plate having a cooling structure as necessary.

In addition, according to the method of the present invention using the apparatus shown in Fig. 2, the emissivity and surface temperature of a high-temperature object were actually measured at a measurement wavelength of 0.9 u, resulting in the previous proposal (Japanese Patent Application No. 75,670/1982). When compared with the measurement results obtained by applying this method, the following results were obtained. That is, when the measurement temperature is 1000℃, the conventional method had a measurement temperature error of ±17℃ for a change in emissivity of about 0.6±0.1, whereas the method of the present invention The emissivity is 0.60±0.03 for the change in
It was confirmed that temperature can be measured with a high accuracy of approximately ±6°C.

Figure 3 shows an example of data obtained by measuring the surface temperature of a galvanized steel sheet undergoing alloying heat treatment according to the method of the present invention. The emissivity of the material to be measured changes greatly in the process of forming layers, but the data shown in Figure 3 clearly shows that highly accurate temperature measurements are being made despite the large changes in emissivity. It shows.

<Summary of Effects> As explained above, according to the present invention, it is possible to accurately measure emissivity and surface temperature without being greatly affected by the distance between the measurement position and the object to be measured, and furthermore, Industrially useful effects are brought about, such as making it possible to measure with high precision even materials whose emissivity varies in various ways.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the emissivity and temperature measurement method according to the present invention. Fig. 2 is a schematic configuration diagram showing an example of the measuring device according to the present invention. Fig. 3 shows the surface temperature of a galvanized copper plate undergoing alloying heat treatment according to the method of the present invention. Fig. 4 is an explanatory diagram of the conventional radiation thermometry method. Fig. 5 is an explanatory diagram of the conventional radiation thermometry method. Fig. 6 is an explanatory diagram of the conventional radiation thermometry method. FIG. 6(a) is an explanatory diagram regarding yet another example of the radiation thermometry method, and FIG. 6(a) shows the overall configuration of the device used.
Figure (BL shows the detailed structure of each. Figure 7 is an explanatory diagram of the emissivity and temperature measuring means proposed earlier. In the drawing, 1... Container, 2... Measured object Object. 3... Blackbody radiation source. 4, 18.23... Radiometer, 5, 13.26.
··motor. 6.12... Rotating sector, 7.15... Light emitting source. 8.19...Mirror, 9.20...Condensing lens. 10... Cylinder, 11... Opening. 14... Central axis of cylinder, 16... Lens. 17, 22... Half mirror 221... Photodetector. 24...Object, 25...Shasota 27...Distance meter.

Claims (2)

[Claims] (1) A parallel beam of light with a predetermined spread and uniform intensity distribution is irradiated onto the surface of the object to be measured from the normal direction, and the amount of emitted light and reflected light from the surface of the object to be measured in approximately the same direction as the normal line. , calculate the reflectance of the object to be measured based on this measured value, calculate the emissivity of the object to be measured from the relationship between the reflectance and emissivity, and then calculate the emissivity of the object to be measured based on the measured value. In a method for determining the temperature of the surface of a measured object based on the radiant energy from the measured object, the calculation of emissivity is corrected based on the measured value of the distance between the photoelectric conversion element of the light intensity measuring radiometer and the measured object. It is characterized by being carried out based on reflectance,
How to measure emissivity and surface temperature. (2) A light emitting source, a lens system that converts the light from the light source into a parallel light beam with a predetermined spread and uniform intensity distribution, and a lens system that reflects the parallel light beam and guides it to the surface of the object to be measured from its normal direction. A half mirror that transmits the light from the surface of the object to be measured, a means for measuring the light intensity of the parallel light beam having the predetermined spread and uniform intensity distribution, and a means for measuring the light intensity of the parallel light beam having the predetermined spread and uniform intensity distribution, and a means for measuring the light intensity of the parallel light beam having the predetermined spread and uniform intensity distribution, and emissivity, characterized by comprising a radiometer that receives the emissivity, a means for measuring the intensity of emitted light from the surface of the object to be measured, and a means for measuring the distance between the photoelectric conversion element of the radiometer and the surface of the object to be measured. and surface temperature measuring device.