JPH10185692A - Method of measuring emissivity and temperature of object, and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely determine the reflectance of an object to be measured even in the state where a pass line is fluctuated, and precisely calculate the surface tempera ture of the object to be measured. SOLUTION: A light is radiated to the surface 1 of an object to be measured from a bar-like emitting source 3, the reflecting intensity distribution is measured by a scanning optical detector 2 to determine the distance between the bar-like emitting source 3 and the object to be measured and the distance between the scanning optical detector 2 and the object to be measured, respectively. The minimum distance between the bar-like emitting source 3 and the object to be measured, the scanning point of the object to be measured and the anticipated angle of the scanning optical detector 2 are determined on the basis of these distances, the reflecting intensity of perfect diffused reflected component and the reflecting intensity of mirror diffused reflected component are obtained on the basis of these data. The total reflecting intensity is determined from the sum of the reflecting intensity of perfect diffused reflected component and the reflecting intensity of mirror diffused reflected component, the reflectance is determined from the total reflecting intensity, the emissivity is determined from the reflectance, and the temperature is also determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of measuring the reflectance, the emissivity and the temperature of a painted surface, such as a baked colored steel sheet, whose reflectance and emissivity change with paint.
The present invention relates to a method and an apparatus for measuring emissivity and temperature of an object to be measured with high accuracy, high speed, and non-contact.

[0002]

2. Description of the Related Art Generally, a radiation thermometer is used to measure the surface temperature of an object in a non-contact manner. This radiation thermometer detects radiation emitted from the surface of the measured object,
It is converted into temperature.
The emissivity needs to be set correctly. Therefore, when measuring the temperature of the surface of the measured object using the radiation thermometer, it is extremely important to correctly determine the emissivity of the surface of the measured object.

However, since it is usually difficult to directly measure the emissivity of the surface of the object to be measured, the reflectance is measured first, and the emissivity of the surface of the object to be measured is calculated using Kirchhoff's equation shown below. A method is used to determine the rate.

Reflectivity + emissivity = 1 (1)

Therefore, as a device for directly measuring the total amount of reflected light on the hemisphere with respect to the amount of incident light and obtaining the reflectance, the one described in the following document is known.

FIG. 18 shows a document "JOURNAL OF RESEARCH Vol.
89, No. 1, 1984 "(hereinafter referred to as Conventional Example 1). In this device, a plurality of detectors 23 arranged in a semicircle are rotated by 180 ° about the diameter of the semicircle, so that the detector 23 is obliquely incident on the surface 22 of the measured object from the laser light source 21, The laser beam reflected by the surface 22 of the measured object is received by the photodetector array 23 for all components on the hemisphere. However, since a large amount of measurement data is required and it is necessary to process the measurement data, measurement and calculation take time, which is not practical. In addition, there is a problem that lift-off between the measuring device and the surface 22 of the measured object cannot be performed.

FIG. 19 shows a document "OPTICAL SCATTERING Measu".
rement and Analysis by JOHN C. STOVER, P140,1990 ''
FIG. 3 is a schematic diagram of a reflectance measuring device described in (hereinafter, referred to as Conventional Example 2). This device is different from the conventional example 1 in that
Since the reflected light individually measured in all the hemispherical directions is collected and measured by using the integrating sphere 31, the total reflected light can be measured instantaneously. However, if the integrating sphere 31 is not brought into contact with the surface 32 of the object to be measured, sufficient measurement accuracy cannot be obtained, and thus it is not suitable for non-contact measurement.

[0008] Therefore, there is a radiation thermometer proposed in the following publication as a radiation thermometer which measures the reflectance of a surface of an object to be measured based on the reflectance measured online at high speed and in a non-contact manner.

FIG. 20 is a schematic diagram of a radiation type temperature measuring device described in Japanese Patent Application Laid-Open No. 4-43928 (hereinafter referred to as Conventional Example 3). In this apparatus, the distance between the hemispherical cavity 42 in which the detector is mounted and the surface 43 of the object to be measured is changed by two or more steps, and data is measured. The relationship between the emissivity and distance measured using an object with a known emissivity is calculated in advance, the emissivity of the surface of the object to be measured is obtained from the calculation result and the measured data, and the obtained emissivity is used. To measure the temperature of the surface of the object to be measured.

FIG. 21 is a schematic diagram of a radiation type temperature measuring device described in Japanese Patent Application Laid-Open No. 5-209792 (hereinafter referred to as Conventional Example 4). In this apparatus, a spot light from a light emitting source 51 is obliquely incident on a surface 52 of an object to be measured, and a one-dimensional distribution of the reflected light is measured by a one-dimensional CCD 53 to obtain a reflectance. Is used to determine the temperature of the surface of the measured object.

[0011]

However, when the above-mentioned prior art 3 or 4 is applied to a coating material, there are the following problems. Before showing the problems, the reflection characteristics on the surface of the coating material and its mechanism will be described first. FIG. 22 shows a one-dimensional reflection pattern measured by irradiating the surface of the coating material with a laser beam and measuring the surface perpendicular to the surface to be measured including the irradiation direction.
(A). As shown in the figure, the reflection pattern is a composite reflection pattern in which specular diffuse reflection and perfect diffuse reflection are combined. FIG. 22B is an enlarged view of a portion B in FIG. Here, the specular diffuse reflection refers to light that is incident on the surface of the painted object to be measured, as shown in FIG. 23, where a part of the incident light is reflected on the painted surface. Specular diffuse reflection indicates an ellipsoidal reflection pattern having directivity about the regular reflection direction. In addition, the complete diffuse reflection means that, as shown in FIG. 24, the light incident on the surface of the painted object to be measured does not reflect part of the irradiated light on the painted surface but enters the interior of the paint. , Are emitted to the outside by multiple reflection and Rayleigh scattering. Perfect diffuse reflection shows a spherical reflection pattern (Lambertian) without directivity. Synthetic reflection is reflection in which such specular diffuse reflection and perfect diffuse reflection are added.

The light component of perfect diffuse reflection per unit solid angle is very weak compared to the component of specular diffuse reflection.
In a measurement using a narrow-angle reflection pattern centered on the specular reflection direction, it is difficult to confirm even the presence of the component, rather than measuring the perfect diffuse reflection component. However, since the perfect diffuse reflection has reflection components in all hemispherical directions, they are integrated and the calculated perfect diffuse reflection component may be larger than the specular diffuse reflection, and cannot be ignored. Therefore, fully diffuse reflection is evaluated separately from composite reflection,
Unless the total reflection light amount is accurately obtained, an accurate reflectance cannot be obtained.

Considering the above characteristics, the problem of measuring the amount of reflected light of the coating material in Conventional Example 3 or 4 will be described. The technique of Conventional Example 3 (Japanese Patent Application Laid-Open No. 4-43928) is based on the premise that the relationship between the change in the multiple reflection intensity within the cavity 41 due to the distance and the emissivity obtained in advance is always constant. However, this relationship holds when the reflection characteristics are only specular diffuse reflection or only complete diffuse reflection, but the combination of both characteristics varies in various combinations depending on the object to be measured in the combined reflection where both are combined. Does not hold. Therefore, the measurement accuracy is reduced accordingly.

The technique of Conventional Example 4 (JP-A-5-209792) is based on the technique of measuring a one-dimensional reflection pattern having a narrow angle centered on the regular reflection direction on the surface of a measurement object by using a point light source to perform total reflection. We are looking for the amount of light. However, in such a narrow-angle one-dimensional reflection pattern measurement, it is impossible to calculate a perfect diffuse reflection component that diffuses in a hemispherical shape. Also, the measurement direction of the reflection pattern is centered on the regular reflection direction,
In addition, because of the narrow angle, it is also difficult to separate and evaluate a composite reflection pattern in which specular reflection and perfect diffuse reflection overlap.

Further, there is a problem that if the pass line fluctuates during the measurement, an error is included in the calculation result.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has been made in consideration of the problem of reflection of an object to be measured having a reflection characteristic in which a specular reflection component and a perfect diffuse reflection component are combined, such as a coating material. The emissivity and the method for measuring the emissivity and temperature of the object that enable the surface temperature of the object to be measured to be calculated with high accuracy, while enabling the rate to be obtained with high accuracy even in a state where the path line varies. The purpose is to obtain the device.

[0017]

[Means for Solving the Problems]

(1) The emissivity measuring method for an object according to the present invention (described in claim 1) includes the following processing steps. (A) a step of irradiating the surface of the object to be measured with a rod-shaped radiation source arranged parallel to the object to be measured; (B) a step of measuring a reflection intensity distribution of the object to be measured in a plane orthogonal to the rod-shaped radiation source by a scanning photodetector arranged so as to include the specular reflection direction of the reflected light within a scanning angle range. (C) determining a distance between the rod-shaped radiation source and the object to be measured and a distance between the scanning photodetector and the object to be measured, respectively. (D) determining a minimum distance between the rod-shaped radiation source and the object to be measured, a scanning point of the object to be measured, and a prospective angle of the scanning photodetector based on the distance. (E) determining a relative illuminance of each scanning point of the measured object based on the total length of the rod-shaped radiation source and the minimum distance. (F) performing a correction for calculating a perfect diffuse reflection pattern on the measured value of the scanning photodetector based on the relative illuminance of each scanning point and the expected angle of the scanning photodetector. (G) a step of obtaining the reflection intensity of the perfect diffuse reflection component from the perfect diffuse reflection pattern obtained by the correction; (H) applying a reverse correction to the correction for calculating the perfect diffuse reflection pattern to the perfect diffuse reflection pattern, subtracting the reverse diffused perfect diffuse reflection pattern from the reflection intensity distribution to obtain a mirror surface Obtaining a measurement value of the scanning photodetector corresponding to the diffuse reflection component. (I) correcting the measurement value of the scanning photodetector corresponding to the specular diffuse reflection component to obtain a specular diffuse reflection pattern based on the minimum distance and the scan point of the measured object. . (J) a step of calculating the reflection intensity of the specular diffuse reflection component from the specular diffuse reflection pattern obtained by the correction; (K) determining the total reflection intensity from the sum of the reflection intensity of the perfect diffuse reflection component and the reflection intensity of the specular diffuse reflection component, determining the reflectance from the total reflection intensity and the luminance of the rod-shaped radiation source, and A step of obtaining emissivity from the reflectance using Kirchhoff's law. (2) Emissivity measuring method according to the present invention (claim 2)
Has the following processing steps in the emissivity measuring method of the above (1). (N) a step of determining the inclination of the rod-shaped radiation source in the object to be measured in the longitudinal direction. (O) issuing an alarm when the inclination exceeds a predetermined angle. (3) The temperature measuring method according to the present invention (described in claim 3)
The method comprises the steps of obtaining the emissivity of the object to be measured by the emissivity measurement method of (1) or (2) above, and measuring the intensity of light emitted from the object to be measured. The surface temperature of the measured object is determined from the intensity of the emitted light.

(4) An emissivity measuring apparatus according to the present invention (described in claim 4) is arranged in parallel with an object to be measured, and irradiates a surface of the object to be measured with a rod-shaped radiation source; Scanning photodetector arranged to include the specular reflection direction in the range of the scanning angle, and measuring the reflection intensity distribution of the measured object in a plane orthogonal to the rod-shaped radiation source, and the rod-shaped radiation source and the measured object A first distance meter for determining the distance between the scanning photodetector and the object to be measured.
And a calculation means for performing the calculation processes (d) to (k). (5) Emissivity measuring apparatus according to the present invention (claim 5)
Is a third device arranged in the longitudinal direction of the rod-shaped radiation source with respect to the first distance meter or the second distance meter in the apparatus according to the above (4), for determining a distance from the object to be measured. A distance meter, wherein the calculating means is configured to determine a length of the rod-shaped radiation source in the measured object based on an output of the first distance meter or the second distance meter and an output of the third distance meter. The inclination of the direction is determined, and an alarm is generated when the inclination exceeds a predetermined angle. (6) The temperature measuring device according to the present invention (claim 6)
The apparatus has the emissivity measuring device according to (4) or (5) above, and obtains the surface temperature of the measured object from the emissivity and the intensity of light emitted from the measured object.

In the present invention, the measured reflection intensity distribution is separated into a perfect diffuse reflection component and a specular diffuse reflection component, and each of them is separately corrected and calculated. It is possible to measure the reflectance, emissivity, and temperature of the surface of the object to be measured, which includes a perfect diffuse reflection component and a specular diffuse reflection component, with high accuracy, at high speed, and without contact. Furthermore, in the present invention, the distance between the rod-shaped radiation source and the object to be measured is measured based on the distance between the rod-shaped radiation source / scanning photodetector meter and the surface of the object to be measured. When determining the scanning point of the object to be measured and the expected angle of the scanning type photodetector, and determining the reflection intensity of the perfect diffuse reflection component and the reflection intensity of the specular diffuse reflection component, the illuminance is calculated based on the obtained data. Since the correction is performed, even when there is a variation in the pass line, an error caused by the fluctuation can be eliminated, and from this point, a highly accurate measurement is possible.

[0020]

FIG. 1 is a block diagram of an apparatus for measuring the emissivity and temperature of an object according to an embodiment of the present invention, and FIG. 2 is a plan view of the apparatus. In the figure, the surface 1 of the object to be measured is painted with a painting material. The rod-shaped radiation source 3 is connected to a power supply 5 and is disposed in parallel with the surface 1 of the measured object. In order to directly measure the intensity of irradiation light from the rod-shaped radiation source 3, a photodetector 9 is provided in parallel with the radiation direction of the rod-shaped radiation source 3, and a signal of the irradiation intensity is sent to a relay switch 14. In addition, between the rod-shaped radiation source 3 and the surface 1 of the measured object,
The blocking device 4 is provided so as to block the irradiation light applied to the upper reflected light measurement range. The operation of the shut-off device 4 is controlled by the controller 13, and the control data is sent to the calculator 8 as a shutter signal. The scanning type photodetector 2 has a rod-shaped radiation source 3 as a normal line, and on a plane including the center of the rod-shaped radiation source 3, and further, irradiates the irradiation light obliquely from the rod-shaped radiation source 3 to the surface 1 of the measured object. It is arranged so that the regular reflection direction is near the center of the scanning angle. An angle trigger signal is output from the scanning photodetector 2 to the calculator 8.

A reflected light signal from the scanning type photodetector 2 is output to a relay switch 14. Relay switch 1
In 4, the data signal input from the photodetector 9 and the reflected light signal input from the scanning type photodetector 2 are switched and output to the amplifier 7, which amplifies the input signal and computes 8 is output. The relay switch 14 sends a switching signal to the computing unit 8 so that the computing unit 8 can know which signal has been sent. The rod-shaped radiation source 3
It is not always necessary to use the photodetector 9 for the measurement of the intensity of the irradiation light of the bar-shaped radiation source 3 in the scanning range of the scanning photodetector 2.
And the scanning photodetector 2 may directly measure the intensity of the irradiation light from the rod-shaped radiation source 3.

Further, as shown in the figure, laser rangefinders 15 and 16 are arranged in a direction orthogonal to the longitudinal direction of the rod-shaped radiation source 3 to determine the distance from the surface 1 of the measured object. As described later, the rod-shaped radiation source 3
The minimum distance between the object and the object to be measured, the scanning point of the object to be measured, and the expected angle of the scanning photodetector are obtained. Further, a laser distance meter 17 is arranged at a position apart from the laser distance meter 15 in the longitudinal direction of the rod-shaped radiation source 3.
With the laser distance meter 17 and the laser distance meter 15,
The inclination in the longitudinal direction of the rod-shaped radiation source 3 on the surface 1 of the measured object is obtained. The outputs of these laser rangefinders 15, 16 and 17 are all input to the calculator 8.

This embodiment measures the intensity of the reflected light having a wider angle than the range including the specular diffuse reflection by using the scanning type photodetector 2, so that the light amount of the complete diffuse reflection from a part of the reflection pattern is measured. Is calculated, and the total amount of reflected light on the hemisphere is calculated together with the specular diffuse reflection component. When the surface 1 of the measured object changes in the vertical direction due to the change of the pass line, an error occurs. However, a correction operation described later is performed so that such an error does not occur.

FIG. 3 is a block diagram showing an example of the configuration of the arithmetic unit 8 of FIG. In the figure, the timing switch 9
1 samples the input reflected light signal or the data signal of the intensity of the irradiation light based on the angle trigger signal. The light intensity data sampled and output from the timing switch 91 is converted from analog data to digital data by the A / D converter 92 and sent to the memory changeover switch 93. The memory changeover switch 93 outputs the input data to the corresponding memory of the memory 94, the memory 95, or the memory 96 according to the shutter signal sent from the controller 13 and the changeover signal sent from the relay switch 14. Memory 94
In the example, the signal of the intensity of the reflected light + the emitted light measured with the blocking device 4 opened is stored as data for each sampling. In the memory 95, a signal of the intensity of only the emitted light measured with the blocking device 4 closed is stored as data for each sampling. The memory 96 stores a signal of the intensity of the emitted light of the rod-shaped radiation source 3 measured by the photodetector 9 as data. At this time, the memories 97, 98, and 99 are also provided to the laser distance meters 15, 1 via the timing switch 91, the A / D converter 92, and the memory changeover switch 93.
The measured values from 6 and 17 are input and stored. Memory 9
The data stored in 4-99 are read out by the arithmetic unit 100 as necessary and subjected to arithmetic processing described later.

FIG. 4 is a diagram showing a calculation procedure of the calculation unit 100. FIG. 5 is a diagram showing a calculation process for obtaining the total reflected light amount. Here, the reflectance of the surface 1 of the measured object is obtained,
A method for obtaining the emissivity and the temperature of the surface 1 of the measured object from the reflectance will be described. The arithmetic unit 100 receives data from the memories 94 and 95, and calculates a difference between the value of the memory 95 and the value of the memory 94 (S1). As a result, the intensity of only the reflected light is determined. By calculating this for each scanning angle, the reflection intensity distribution is obtained. In order to synthesize a reflection pattern at one point from the reflection intensity distribution corresponding to the scanning angle, the positional relationship among the surface 1, the radiation thermometer 2, and the rod-shaped radiation source 3 of the object to be measured is taken into consideration, and the surface of the object to be measured is taken into account. It is necessary to perform reflection intensity correction in accordance with each position on S1 (S2).

Therefore, correction is performed to obtain a perfect diffuse reflection pattern from the reflection intensity distribution obtained previously. FIG. 6 shows a surface 1, a scanning photodetector 2, and a rod-shaped radiation source 3 of an object to be measured.
FIG. 7 is a diagram showing the positional relationship between
FIG. 3 is a diagram showing a positional relationship between a bar and a rod-shaped radiation source 3. The surface 1 of the measured object is defined as an xz plane, and the perpendicular of the xz plane passing through the center of the rod-shaped radiation source 3 is defined as a y-axis. The intensity correction items for perfect diffuse reflection are the following four items. (1) rod-like radiation source 3 and the distance correction between the surface 1 of the object to be measured ... l ² (2) incidence angle correction of a rod-shaped radiation source 3 to the target ... COS .theta ₂
(X _O ) (3) Correction of the length of the rod-shaped radiation source 3 ... 2 · z ₀ (4) Correction of the expected angle of the scanning photodetector 2 ... COSθ
(X _O )

First, the correction in consideration of the requirements (1) to (3) will be described. The scanning photodetector 2 scans on the X-axis. The length of the rod-shaped radiation source 3 is 2 · Z ₀ , and the position of the object to be measured is determined from a certain point (0, h ₁ , z) on the rod-shaped radiation source 3. Let l be the distance to the point (X ₀ , 0,0) on the surface 1 and h _{1 be} the minimum distance between the rod-shaped radiation source 3 and the surface 1 of the measured object, and define θ ₁ and θ ₂ as shown in the figure I do. When the brightness per unit length of the rod-shaped radiation source 3 and _{k, (X 0, 0,} 0) brightness in the direction is expressed by the following equation.

[0028]

(Equation 1)

Therefore, the illuminance ΔE of the unit length of the rod-shaped radiation source 3 at (X ₀ , 0,0) is as follows.

[0030]

(Equation 2)

[0031] Thus (X _{0, 0, 0)} illuminance E from the entire rod-shaped radiation source 3 in is expressed by the following equation as a function of Z.

[0032]

(Equation 3)

The result of this calculation is as follows.

[0034]

(Equation 4)

Furthermore final intensity correction expression including the requirement (4), the normal direction of the viewing angle of the scanning optical detector 2 theta (target pixel scanning photodetector 2 as a function of X ₀ To 0
When the object is expected at (degree), it is corrected by the following equation. Here, point X ₀ by a rod radiation source 3 corresponding thereto when the visual angle θ of the scanning optical detector 2 is changed even changed, it means that also changes the illuminance of the point, the point X ₀
By correcting the raw data of each pixel by the theoretical illuminance E (X ₀ ), correction data of each pixel is generated.

[0036]

(Equation 5)

The above calculation is an example in the case where there is no change in the pass line. However, when there is a change in the pass line, the correction coefficients (θ, X ₀ ) in the above equations (5) and (6) are used. , H ₁ ) must be obtained from the measured values of the distance measuring devices 15 and 16.

FIG. 8 is an explanatory diagram showing the relative positional relationship between the scanning photodetector 2 and the distance measuring devices 15 and 16 when obtaining the correction coefficient. (A) Reference line: a straight line AB passing through the rod-shaped light source and a straight line CD passing perpendicularly through the rod-shaped light source. (B) Position of the scanning photodetector 2: distance R from the rod-shaped light source
(C) Steel plate position: distance h1 from rod-shaped radiation source and angle α with straight line AB (d) Position of laser rangefinder: distance ha from straight line AB,
hb and distance ka from the rod-shaped light sources perpendicular foot drawn down to a straight line AB, kb (e) Distance correction _{parameters: h1, X 0 (θ '} ), θ
(Θ ') θ': Scan angle (f) Intermediate parameter used for calculation: LS ': Distance from bar-shaped light source perpendicular to straight line AB to steel plate LD': Scanning light detection perpendicular to straight line AB Distance from detector to steel plate h2: Distance from scanning photodetector measured perpendicular to steel plate to steel plate

FIG. 9 is a flow chart showing a process for obtaining a correction coefficient based on the positional relationship of FIG.
Here, the measured values la and lb and the known constants R _DS , β,
ha, hb, ka, parameters of the steel plate position based on kb alpha, seeking h1, then correction parameters h1, X ₀ based on these parameters to determine the theta. Step S2a: From the measured values la and lb, intermediate parameters LS 'and LD' are obtained by the following equations.

[0040]

(Equation 6)

Step S2b: Intermediate parameter LS ',
From LD ′, the steel sheet position α, h1 (, h2) based on the following equation:
Ask for.

[0042]

(Equation 7)

Step S2c: Distance correction parameters θ, X based on the following equation based on the steel plate positions α, h1 and the scanning angle θ ′.
_{Find 0} .

[0044]

(Equation 8)

The illuminance E and correction data of each pixel are obtained by substituting the correction coefficients (θ, X ₀ , h ₁ ) obtained as described above into the above equations (5) and (6). At this time, it is possible to eliminate the influence of the fluctuation of the pass line.

FIG. 10 is a diagram showing angle conversion of perfect diffuse reflection on the surface 1 of the measured object. In the perfect diffuse reflection, since the reflection pattern is Lambertian, at each reflection point on the surface 1 of the measured object corresponding to the scanning angle, the angle between the vertical direction of the surface 1 of the measured object and the measuring direction. the calculated respectively, by combining them, and calculates the reflection pattern at one point on the surface 1 of the object to be measured _{(X 0, 0, 0)} . This reflection pattern includes a reflection pattern by specular diffuse reflection. Since the perfect diffuse reflection pattern is synthesized as a circle, a portion of the reflection pattern corresponding to the circle is a reflection pattern by perfect diffuse reflection. Therefore, the part corresponding to this circle is grasped as a perfect diffuse reflection pattern, and this perfect diffuse reflection pattern is represented by θ.
And the reflection intensity of the perfect diffuse reflection component is calculated (S3). Here, a portion corresponding to the circle of the reflection pattern (a portion that clearly does not include the specular diffuse reflection portion) is selected, the diameter of the circle is determined from the portion, and a circle specified by the diameter is obtained. That is, the integral (-π / 2 to + π / 2) is calculated as described above to calculate the complete diffuse reflection component reflection intensity.

After the complete diffuse reflection component intensity is derived as described above, a reflection intensity correction for obtaining a specular diffuse reflection pattern is performed. A portion corresponding to a circle which is a perfect diffuse reflection pattern is separated from the reflection intensity distribution obtained previously (the reflection intensity distribution obtained in S1). Here, since the perfect diffuse reflection pattern is corrected for perfect diffuse reflection, the perfect diffuse reflection pattern is
In the above equation (6), reverse correction of perfect diffuse reflection is performed to generate raw data of each pixel corresponding to perfect diffuse reflection, and the reflection intensity distribution measured by the scanning photodetector 2 (FIG. 5).
(See the hatched portion in S4), and the above separation processing is performed (S4).

In the case of specular diffuse reflection, most of the reflected light detected by the scanning type photodetector 2 is contributed by light emitted from the center of the rod-shaped radiation source 3, so that the radiation source is a point. The intensity is corrected by treating it as a radiation source (S5). Illuminance at the point (X _{0, 0, 0)} is expressed by the following formula a radiation source intensity as k.

[0049]

(Equation 9)

The correction items here are (1) distance correction between the rod-shaped radiation source 3 and the surface 1 of the measured object ... L ² (2) correction of the incident angle from the rod-shaped radiation source 3 to the surface 1 of the measured object ... COSθ _2a (X _O ). Further, the following correction is made. (3) Outgoing angle correction from the surface 1 of the measured object to the scanning photodetector 2... COSθ (X _O ) The correction formula taking into account the above requirements (1) to (3) is as follows. In the following equation, the raw light amount data of each pixel is obtained by separating a portion corresponding to a circle which is a perfect diffuse reflection pattern from the reflection intensity distribution previously obtained (: reflection intensity distribution obtained in S1). In addition, pixel data corresponding to specular diffuse reflection is shown.

[0051]

(Equation 10)

FIG. 11 is a diagram showing the angle conversion of the specular diffuse reflection on the surface 1 of the measured object. An angle between the specular reflection direction and the measurement direction at each reflection point on the measured object corresponding to the scanning angle is obtained and combined, and one point on the surface 1 of the measured object is calculated based on the raw light amount data of each pixel. (X ₀ , 0,
Calculate the specular diffuse reflection pattern at 0).

When a specular diffuse reflection pattern is required,
This is integrated as a function of θ (S6). Thereby, the reflection intensity of the specular diffuse reflection component is derived. The sum of the reflection intensity of the perfect diffuse reflection component and the reflection intensity of the specular diffuse reflection component obtained above becomes the total reflection light amount (total reflection intensity) (S
7).

The radiation intensity of the rod-shaped radiation source 3 stored in the memory 96 is calculated (S8), and the reflectance is obtained from the ratio of this to the total reflected light amount. Further, the emissivity can be obtained from the obtained emissivity and the Kirchhoff equation described above (S
9). The temperature of the surface 1 of the measured object is determined based on the intensity and emissivity of only the emitted light input to the memory 95 (S10).

When the surface 1 of the object to be measured is inclined in the longitudinal direction of the rod-shaped radiation source 3, there is no change in the correspondence between the scanning pixel and the composite angle, and there is no change in the illuminance and the expected angle. Not required. However, if the inclination is large, the length of the rod-shaped radiation source is finite, and as shown in FIG. 12, the specular reflection direction viewed from the scanning photodetector 2 deviates from the rod-shaped radiation source 3 and the measurement is performed. Becomes impossible. Therefore, the inclination θc of the measured object is obtained from the outputs of the laser rangefinders 15 and 17, and when the inclination θc satisfies Z ₀ <h1 × tan (2θc) (12), a warning of the deviation of the inclination is generated. .

FIG. 13 is a view showing a result when a one-dimensional reflection pattern of a color steel plate is measured by the measuring apparatus of FIG. The same sample as that measured in FIG. 22 is used. It can be seen that perfect diffuse reflection appears in a part of the reflection pattern. In addition, since the rod-shaped radiation source 3 is used,
Since there is an integration effect in the longitudinal direction of the rod-shaped light source represented by the above equation (4), perfect diffuse reflection is emphasized as compared with FIG. As a result, the measurement accuracy of perfect diffuse reflection is improved, and the reflectance measurement accuracy is improved.

FIG. 14 is a view showing the result of off-line measurement of the temperature of a color steel plate by the measuring apparatus of FIG. For the comparison of the measured temperature values, the indicated values of the thermocouples welded to the color steel plates were used. The measured temperature value is a value obtained by using the measured reflectance value and emissivity value. As a result of the measurement, the temperature accuracy is ± 1 ° C., and a highly accurate temperature measurement is possible.

FIG. 15 is a view showing an example of an experimental result when the pass line is varied by the measuring apparatus of FIG. A change in the emissivity measurement result when the color steel sheet sample was varied in the range of a distance of 200 to 400 mm was evaluated based on the measured value at a distance of 300 mm.
The error when applied to temperature measurement of a steel sheet at 00 ° C. was evaluated. Correction worked well and sufficient accuracy was obtained in each case.

FIG. 16 is a diagram showing errors evaluated in the same manner as in FIG. 15 when the inclination is changed in a direction perpendicular to the longitudinal direction of the rod-shaped radiation source while the distance is fixed at 300 mm. .

Further, FIG. 17 is a diagram showing errors evaluated similarly when the inclination is changed in the longitudinal direction of the rod-shaped radiation source. It can be seen that the error does not increase at all until the inclination is about 6 degrees, but the error increases rapidly when it is larger than 6 degrees. At this time, the effective length of the rod-shaped radiation source is about 160 mm, which substantially corresponds to Expression (12), and an alarm is generated in this state.

The present invention is applicable not only to painted objects but also to objects before painting.

[0062]

As described above, according to the present invention, the reflection intensity distribution is separated into a perfect diffuse reflection pattern and a specular diffuse reflection pattern, and each correction and calculation are performed separately. It is possible to measure the emissivity and temperature of the surface of the object to be measured, which contains the perfect diffuse reflection component and the specular diffuse reflection component, with high accuracy, at high speed, and without contact. Further, in the present invention, the distance between the rod-shaped radiation source / scanning photodetector meter and the surface of the object to be measured is measured, and based on the distance, the reflection intensity of the perfect diffuse reflection component and the specular diffuse reflection When calculating the reflection intensity of the component, the minimum distance between the rod-shaped radiation source and the object to be measured, the scanning point of the object to be measured, and the expected angle of the scanning photodetector are corrected, so that the path line has fluctuations. Even in such a case, an error caused by the error can be eliminated, and this also enables highly accurate measurement.
For this reason, it is possible to apply the method to a surface-treated steel sheet line in which the fluctuation of the pass line is large, and an improvement in yield and an improvement in quality can be expected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus for measuring emissivity and temperature of an object according to an embodiment of the present invention.

FIG. 2 is a plan layout view of the measuring device of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration example of a computing unit in FIG. 1;

FIG. 4 is a diagram illustrating a calculation procedure of a calculation unit in FIG. 3;

FIG. 5 is a diagram illustrating a calculation process of obtaining a total reflection light amount.

FIG. 6 is a diagram showing a positional relationship between a point on the surface 1 of the measured object, a scanning photodetector, and a rod-shaped radiation source.

FIG. 7 is a diagram showing a positional relationship between a point on the surface 1 of the measured object and a rod-shaped radiation source.

FIG. 8 is a diagram showing a relationship between a path distance and a correction value of a minimum distance between a rod-shaped radiation source and an object to be measured, a scanning point of the object to be measured, and a correction value of an expected angle of a scanning photodetector. It is.

FIG. 9 is a block diagram showing a process of obtaining a correction value in FIG. 8;

FIG. 10 is a diagram illustrating angle conversion of perfect diffuse reflection.

FIG. 11 is a diagram showing angle conversion of specular diffuse reflection.

FIG. 12 is a diagram showing the influence of a visual field deviation due to the inclination of the measured object in the longitudinal direction of the rod-shaped radiation source.

FIG. 13 is a one-dimensional reflection pattern diagram obtained by measuring a color steel plate.

FIG. 14 is a diagram showing the results of off-line measurement of the temperature of a color steel plate.

FIG. 15 is a diagram illustrating an example of a result obtained when measurement is performed by the measurement device of FIG. 1 when a pass line is varied.

FIG. 16 is a diagram showing errors similarly evaluated when the inclination is changed in a direction perpendicular to the longitudinal direction of the rod-shaped radiation source while the distance is fixed to 300 mm as in FIG.

FIG. 17 is a diagram showing errors similarly evaluated when the inclination is changed in the longitudinal direction of the rod-shaped radiation source.

FIG. 18 is a schematic view of a reflectance measuring apparatus according to Conventional Example 1.

FIG. 19 is a schematic diagram of a reflectance measuring apparatus according to Conventional Example 2.

FIG. 20 is a schematic diagram of a radiation temperature measuring device according to Conventional Example 3.

FIG. 21 is a schematic diagram of a radiation temperature measuring device according to Conventional Example 4.

FIG. 22 is a one-dimensional reflection pattern diagram and an enlarged diagram when a coating surface is irradiated with laser light.

FIG. 23 is a diagram showing specular diffuse reflection.

FIG. 24 is a diagram showing perfect diffuse reflection.

[Description of Signs] 1 Surface of object to be measured 2 Scanning photodetector 3 Bar-shaped radiation source 4 Shading device 5 Power supply 7 Amplifier 8 Computing unit 9 Photodetector 13 Controller

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshiki Manabe 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd.

Claims (6)

[Claims] 1. A step of irradiating a surface of an object to be measured with light by a rod-shaped radiation source arranged in parallel with the object to be measured, and arranged so as to include a regular reflection direction of the reflected light within a scanning angle range. A step of measuring a reflection intensity distribution of the object to be measured in a plane orthogonal to the rod-shaped radiation source by a scanning light detector; anda distance between the rod-shaped radiation source and the object to be measured and the scanning light detector and the measured light. A step of obtaining a distance to the object, and a step of obtaining a minimum distance between the rod-shaped radiation source and the object to be measured, a scanning point of the object to be measured, and a prospective angle of the scanning photodetector, based on the distance. Determining the relative illuminance of each scanning point of the measured object based on the total length of the rod-shaped radiation source and the minimum distance, based on the relative illuminance of each scanning point and the expected angle of the scanning photodetector, The scanning photodetector Performing a correction for calculating a perfect diffuse reflection pattern on the measured value; and obtaining a reflection intensity of a perfect diffuse reflection component from the perfect diffuse reflection pattern obtained by the correction; and The scanning type light detection corresponding to the specular diffuse reflection component is performed by performing an inverse correction to the correction for calculating the perfect diffuse reflection pattern, and subtracting the reverse diffused perfect diffuse reflection pattern from the reflection intensity distribution. Obtaining a specular diffuse reflection pattern, based on the minimum distance and the scanning point of the object to be measured, based on the measurement value of the scanning photodetector corresponding to the specular diffuse reflection component. Correcting the reflection intensity of the specular diffuse reflection pattern from the specular diffuse reflection pattern obtained by the correction, and reflecting the perfect diffuse reflection component. The total reflection intensity is determined from the sum of the intensity and the reflection intensity of the specular diffuse reflection component, the reflectance is determined from the total reflection intensity and the luminance of the rod-shaped radiation source, and Kirchhoff's law is used from the reflectance. Determining the emissivity of the object. 2. The method according to claim 1, further comprising the steps of: determining a longitudinal inclination of the rod-shaped radiation source in the measured object; and generating an alarm when the inclination exceeds a predetermined angle. Emissivity measurement method for objects. 3. A step of obtaining an emissivity of an object to be measured by the method of measuring an emissivity of an object according to claim 1 or 2, and a step of measuring intensity of emitted light from the object to be measured. A method for measuring the temperature of an object, comprising determining a surface temperature of the object to be measured from the emissivity and the intensity of the emitted light. 4. A rod-shaped radiation source arranged in parallel to an object to be measured and irradiating light to the surface of the object to be measured, and a rod-shaped radiation source arranged so as to include a regular reflection direction of the reflected light within a scanning angle range. A scanning light detector for measuring a reflection intensity distribution of the object to be measured in a plane orthogonal to the source; a first distance meter for determining a distance between the rod-shaped radiation source and the object to be measured; A second distance meter for determining a distance between the detector and the object to be measured; and a minimum distance between the rod-shaped radiation source and the object to be measured based on outputs of the first distance meter and the second distance meter. The distance, the scanning point of the object to be measured and the prospective angle of the scanning photodetector are respectively obtained, and the relative illuminance of each scanning point of the object to be measured is obtained based on the total length of the rod-shaped radiation source and the minimum distance. The relative illuminance of the scanning point and the expected angle of the scanning photodetector Based on the measured values of the scanning photodetector, perform a correction for calculating a perfect diffuse reflection pattern, determine a reflection intensity of a perfect diffuse reflection component from the perfect diffuse reflection pattern obtained by the correction, The reflection pattern is subjected to inverse correction to the correction for calculating the perfect diffuse reflection pattern, and the perfect diffuse reflection pattern subjected to the reverse correction is subtracted from the reflection intensity distribution to correspond to the specular diffuse reflection component. Calculating the measurement value of the scanning photodetector, based on the minimum distance and the scanning point of the measured object, the measurement value of the scanning photodetector corresponding to the specular diffuse reflection component, the specular diffusion A correction for obtaining a reflection pattern is performed, a reflection intensity of a specular diffusion component is obtained from the specular diffusion reflection pattern, and a reflection intensity of the perfect diffusion reflection component and the specular diffusion reflection component are determined. Calculation of the total reflection intensity from the sum of the reflection intensity and the luminance of the rod-shaped radiation source, and calculating the emissivity from the reflectance using Kirchhoff's law. An emissivity measuring apparatus for an object, comprising: an arithmetic unit for performing a process. 5. A third distance meter which is disposed in the longitudinal direction of the rod-shaped radiation source with respect to the first distance meter or the second distance meter, and obtains a distance to an object to be measured. Calculating the longitudinal inclination of the rod-shaped radiation source in the measured object based on the output of the first or second distance meter and the output of the third distance meter, 5. The apparatus according to claim 4, wherein an alarm is issued when the inclination exceeds a predetermined angle. 6. An object having the emissivity measuring apparatus according to claim 4 or 5, wherein a surface temperature of the object to be measured is obtained from the emissivity and the intensity of light emitted from the object to be measured. Temperature measuring device.