JP2008191107A - Surface temperature measuring instrument and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface temperature measuring instrument and a surface temperature measuring method, capable of measuring precisely a surface temperature of an object, even when detecting intensity distributions of a plurality of infrared rays having different wavebands in respective different detection times. <P>SOLUTION: This surface temperature measuring instrument 101 includes an infrared ray distribution detector 110 for detecting the intensity distributions of the three kinds of infrared rays different in the wavebands, in respective different detection times, out of the infrared rays emitted from a cavity face 102a of a forging die 102, and for detecting those twice or more in each waveband, a correction part 121b for finding a relation (linear expression) between intensities of the three kinds of infrared rays different in the wavebands, or measured temperatures calculated based on the intensities, and respective detection times, and for correcting the intensities of the infrared rays, or the measured temperatures to corrected values in a detection time of a short wavelength of infrared ray, and a surface temperature distribution calculating part 121c for calculating a temperature distribution of the cavity face 102a in the forging die 102, based on the corrected values. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for measuring a surface temperature distribution of an object.

Conventionally, a non-contact type surface temperature measuring method is known as a method for measuring the surface temperature of an object. A typical example of the non-contact type surface temperature measurement method is an infrared thermography that measures the surface temperature of an object by detecting infrared rays emitted from the object.
Infrared thermography not only has the advantage that the surface temperature of the object can be measured in a non-contact manner, but also has the advantage that the temperature (temperature distribution) of a predetermined region on the surface of the object can be measured in real time.

  However, the temperature distribution measured by infrared thermography greatly varies depending on the emissivity and reflectance of the object and the ambient temperature, and even if the object is the same, Since the emissivity and reflectivity can vary greatly depending on the surface condition, etc., it is necessary to ensure the accuracy of temperature distribution measurement on the object surface by infrared thermography for objects whose surface condition changes from moment to moment. It was difficult.

  As a method for solving such a problem, infrared thermography using a three-color radiation thermometer has been proposed. For example, as described in Patent Document 1, Patent Document 2, and Non-Patent Document 1.

Infrared thermography using a three-color radiation thermometer is an infrared camera that can detect three types of infrared rays with different wavelength bands (for example, an infrared camera that detects infrared rays with different wavelength bands by exchanging filters, or each wavelength). The distribution of the surface temperature of the object is measured by three infrared cameras that detect infrared rays with different bands, and the measured values are used to (1) the black body temperature (true surface temperature) of the object ( 2) Obtain three equations (equations based on the law of conservation of energy) with three as variables: the emissivity of the object (reflectance = 1-emissivity), and (3) the ambient temperature. The distribution of the black body temperature (true surface temperature) of the object is calculated by solving the equation.
Infrared thermography using a three-color radiation thermometer can measure the distribution of the surface temperature of an object without requiring emissivity, reflectance, or ambient temperature, which is difficult to measure accurately. Excellent workability.

  In particular, the surface temperature measuring device of the type that detects the intensity distribution of infrared rays of different wavelengths with the same infrared camera by switching three or more types of filters that can transmit infrared rays of different wavelength bands, has different wavelength bands. Compared with a surface temperature measuring device using three infrared cameras for detecting infrared rays, (A) the number of infrared cameras is small and the equipment cost is low, and (B) basically one fixed infrared camera is used. In addition, it is possible to relatively reduce the number of steps involved in calibration of the infrared camera, and the relative positional relationship between the infrared camera and the object does not change and the measurement accuracy is improved.

However, the surface temperature measurement device that detects the intensity distribution of infrared rays of different wavelengths with the same infrared camera by switching three or more types of filters that can transmit infrared rays of different wavelength bands is the infrared ray of each wavelength band. Since the detection of the intensity distribution and the replacement of the filter are alternately performed, the time (detection time) at which the infrared light intensity distribution in each wavelength band is acquired is different.
When the temperature of the object changes with time, the surface temperature of the object at the time (detection time) at which the infrared light intensity distribution in each wavelength band is acquired also changes. This is contrary to the precondition of the infrared thermography using the three-color radiation thermometer that the black body temperature (true surface temperature) of the object is the same in each equation, and causes a decrease in measurement accuracy of the surface temperature.
JP 2004-219114 A JP 7-146179 A Nondestructive Inspection Vol. 48, No. 10 (1999), p. 673

  In view of the situation as described above, the present invention provides a surface temperature inspection apparatus and surface capable of accurately measuring the surface temperature of an object even when detecting the intensity distribution of infrared rays in different wavelength bands at different detection times. A temperature inspection method is provided.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in claim 1,
Among infrared rays radiated from the surface of the object, infrared distribution detection means for detecting the intensity distribution of three or more types of infrared rays having different wavelength bands at different detection times and detecting at least twice for each wavelength band;
Obtain the intensity of three or more types of infrared rays having different wavelength bands detected by the infrared distribution detection means or the relationship between the measurement temperature calculated from the intensity and the detection time thereof, and determine the intensity or measurement temperature of the infrared rays. Correction means for correcting to a correction value in the detection time of any of three or more types of infrared rays having different wavelength bands;
Surface temperature distribution calculating means for calculating the temperature distribution of the surface of the object based on the correction value;
It comprises.

In claim 2,
The infrared distribution detection means includes
An infrared camera for detecting infrared intensity distribution;
Three or more types of filters that can transmit infrared rays in different wavelength bands,
A switching device for switching which of the three or more types of filters covers the field of view of the infrared camera;
It comprises.

In claim 3,
Among infrared rays radiated from the surface of the object, an infrared distribution detection step of detecting the intensity distribution of three or more types of infrared rays having different wavelength bands at different detection times and detecting at least twice for each wavelength band;
Obtain the intensity of three or more types of infrared rays with different wavelength bands detected in the infrared distribution detection step or the relationship between the measurement temperature calculated from the intensity and the respective detection times, and determine the intensity or measurement temperature of the infrared rays A correction process for correcting to a correction value in any detection time of three or more types of infrared rays having different wavelength bands,
A surface temperature distribution calculating step of calculating a temperature distribution of the surface of the object based on the correction value;
It comprises.

In claim 4,
In the infrared distribution detection step,
An infrared camera for detecting infrared intensity distribution;
Three or more types of filters that can transmit infrared rays in different wavelength bands,
A switching device for switching which of the three or more types of filters covers the field of view of the infrared camera;
The intensity distribution of three or more types of infrared rays having different wavelength bands is detected using an infrared distribution detecting means comprising:

  The present invention has an effect that it is possible to accurately measure the surface temperature of an object even when detecting intensity distributions of infrared rays in different wavelength bands at different detection times.

  Hereinafter, a surface temperature measuring apparatus 101 which is an embodiment of the surface temperature measuring apparatus according to the present invention will be described with reference to FIGS. 1 to 3.

  As shown in FIG. 1, the surface temperature measuring device 101 measures the temperature distribution of the surface of the forging die 102, particularly the cavity surface 102a. The surface temperature measurement device 101 mainly includes an infrared distribution detection device 110 and a control device 120.

  The forging die 102 is an embodiment of the object according to the present invention, and the mating surface of the forging die 102 is a cavity surface having a shape corresponding to the forging (forged into a predetermined shape by the forging die 102). 102a is formed.

A release agent is applied to the cavity surface 102 a of the forging die 102 in advance so that the forged product can be easily taken out from the forging die 102.
If the temperature of the cavity surface 102a when the mold release agent is applied is too high, the mold release agent may firmly adhere to the cavity surface 102a and the forged product may not be easily removed. In addition, if the temperature of the cavity surface 102a when applying the release agent is too low, moisture may remain in the applied release agent, which may evaporate during forging, leading to a reduction in quality of the forged product.
Therefore, when the release agent is applied, the temperature of the cavity surface 102a is set so that the release agent does not firmly adhere to the cavity surface 102a and moisture is sufficiently evaporated from the applied release agent. It is necessary to confirm that it is in the temperature range.
The surface temperature measuring apparatus 101 of the present embodiment determines whether or not the temperature distribution of the cavity surface 102a when the mold release agent is applied to the cavity surface 102a of the forging die 102 is within a predetermined temperature range. Used.

  In addition, the use of the surface temperature measuring apparatus according to the present invention is not limited to the present embodiment, and can be widely applied to the use of measuring the temperature distribution on the surface of various objects.

The infrared distribution detection device 110 is an embodiment of the infrared distribution detection means according to the present invention, and among the infrared rays radiated from the cavity surface 102a of the forging die 102, the intensity of three types of infrared rays having different wavelength bands. The distribution is detected at different detection times and at least twice for each wavelength band.
The infrared distribution detection device 110 mainly includes an infrared camera 111, a short wavelength filter 112a, a medium wavelength filter 112b, a long wavelength filter 112c, a switching device 113, and the like.

  The infrared camera 111 detects an infrared intensity distribution. Here, the “intensity distribution” refers to an intensity distribution on the surface of the object.

The infrared camera 111 includes a detection element 111a and a lens 111b.
The detection element 111a of the present embodiment is a two-dimensional array type semiconductor element made of HgCdTe that can detect infrared rays having a wavelength of about 5 μm to 15 μm, that is, infrared rays in all wavelength bands from a short wavelength band to a long wavelength band, It is possible to detect an infrared intensity distribution in a predetermined region within the field of view of the infrared camera 111.
The detection element 111a in the infrared camera 111 of the present embodiment is a two-dimensional array type semiconductor element made of HgCdTe, but the present invention is not limited to this, and other detection elements may be used.
The lens 111b converges infrared rays emitted from a predetermined region (field of view) onto the detection element 111a. In the case of the present embodiment, the infrared rays emitted from the cavity surface 102a of the forging die 102 are converged on the detection element 111a by arranging the cavity surface 102a of the forging die 102 within a predetermined region (field of view). .

The short wavelength filter 112a, the medium wavelength filter 112b, and the long wavelength filter 112c are embodiments of the filter according to the present invention, and are filters that can transmit infrared rays having different wavelength bands.
In this embodiment, the short wavelength filter 112a has an infrared wavelength of 7.4 μm to 9.0 μm, the medium wavelength filter 112b has an infrared wavelength of 9.3 μm to 11.3 μm, and the long wavelength filter 112c has a wavelength of 10.9 μm. Transmits infrared light of ˜14.3 μm. In the following description, infrared light with a wavelength of 7.4 μm to 9.0 μm is “short-wavelength infrared light”, infrared light with a wavelength of 9.3 μm to 11.3 μm is “medium-wavelength infrared light”, and wavelength is 10.9 μm The infrared of 14.3 μm is referred to as “long-wavelength infrared”.

In addition, the wavelength band which each filter permeate | transmits is not limited to a present Example, It is good also as a structure which permeate | transmits another wavelength band. Moreover, a part of wavelength band which each filter permeate | transmits may overlap.
In addition, the infrared distribution detection device 110 of this embodiment is configured to include filters (short wavelength filter 112a, medium wavelength filter 112b, and long wavelength filter 112c) that transmit infrared rays in three different wavelength bands. However, the present invention is not limited to this, and a configuration including a filter capable of transmitting infrared rays in four or more different wavelength bands may be employed.

The switching device 113 switches which of the short wavelength filter 112a, the medium wavelength filter 112b, and the long wavelength filter 112c covers the field of view of the infrared camera 111.
The switching device 113 mainly includes a disk 113a, a motor 113b, and the like.
The disk 113a is a substantially disk-shaped member, and holes for fitting the short wavelength filter 112a, the medium wavelength filter 112b, and the long wavelength filter 112c are formed. These holes are formed at positions where the distances from the center of the disk 113a are substantially the same.
The motor 113b is an actuator that is driven to rotate, and its rotation shaft is fixed at the center of the disk 113a.

The disk 113a is disposed at a position where any of the short wavelength filter 112a, medium wavelength filter 112b, and long wavelength filter 112c fitted therein faces the lens 111b, that is, a position covering the field of view of the infrared camera 111.
When the motor 113b is driven, the disk 113a rotates, and one of the three filters, the short wavelength filter 112a, the medium wavelength filter 112b, and the long wavelength filter 112c, that is arranged at a position that covers the field of view of the infrared camera 111 is switched.

  In this embodiment, three filters (short wavelength filter 112a, medium wavelength filter 112b, and long wavelength filter 112c) that can transmit infrared rays of different wavelength bands are fitted into the disk 113a, and the disk 113a is rotated by a motor 113b. However, the present invention is not limited to this, and other methods (for example, a member in which three or more filters are fitted side by side are arranged). The same effect can be achieved by switching the filter that covers the field of view of the infrared camera by sliding or the like.

The infrared camera 111 is blackbody calibrated in a state where none of the short wavelength filter 112a, medium wavelength filter 112b, and long wavelength filter 112c covers the field of view.
The measurement temperature range of the infrared camera 111 is set in accordance with the apparent temperature fluctuation by the short wavelength filter 112a, the medium wavelength filter 112b, and the long wavelength filter 112c with respect to the temperature fluctuation range of the cavity surface 102a of the forging die 102 as the object. The In the case of the present embodiment, the upper limit of the temperature of the forging die 102 is about 450 ° C., but the apparent temperature variation due to the short wavelength filter 112a, the medium wavelength filter 112b, and the long wavelength filter 112c is taken into consideration. The upper limit of the measurement temperature range (upper limit of black body calibration temperature) is set to about 250 ° C.

  The control device 120 mainly includes a control unit 121, an input unit 122, a display unit 123, and the like.

The control unit 121 controls a series of operations of the surface temperature measuring device 101.
The control unit 121 is substantially various programs and the like (for example, a detection operation control program, a correction program, a surface temperature distribution calculation program to be described later, and an apparent measurement temperature (measurement value) when each filter is used. A storage means for storing a data table showing a relationship with infrared intensity, a developing means for developing these programs, a calculating means for performing a predetermined calculation in accordance with these programs, a storage means for storing calculation results, etc. It has.

More specifically, the control unit 121 may have a configuration in which a CPU, a ROM, a RAM, an HDD, and the like are connected by a bus, or may be configured by a one-chip LSI or the like.
Although the control unit 121 of this embodiment is a dedicated product, it can also be achieved by storing the above program group in a commercially available personal computer or workstation.

The control unit 121 is connected to the infrared camera 111 of the infrared distribution detection device 110, can transmit a signal for operating the infrared camera 111, and from the cavity surface 102a of the forging die 102 detected by the infrared camera 111. It is possible to receive (acquire) information related to the distribution of the intensity of infrared rays in each radiated wavelength band.
The control unit 121 is connected to the motor 113b of the switching device 113, and controls the operation of the motor 113b by transmitting signals related to driving and stopping of the motor 113b, that is, the short wavelength filter 112a, the medium wavelength filter 112b, It is possible to select which of the long wavelength filters 112c covers the field of view of the infrared camera 111.

The input unit 122 is connected to the control unit 121 and inputs various information / instructions related to the operation of the surface temperature measuring apparatus 101 to the control unit 121.
Although the input unit 122 of the present embodiment is a dedicated product, the same effect can be achieved even if a commercially available keyboard, mouse, pointing device, button, switch, or the like is used.

The display unit 123 displays the operation status of the surface temperature measuring device 101, the input content from the input unit 122 to the control unit 121, the measurement result by the surface temperature measuring device 101, and the like.
Although the display unit 123 of this embodiment is a dedicated product, the same effect can be achieved even if a commercially available monitor, liquid crystal display, or the like is used.

  Moreover, it is possible to achieve what integrated the function as the input part 122 and the function as the display part 123 using a commercially available touch panel etc. FIG.

Below, the detailed structure of the control part 121 is demonstrated.
Functionally, the control unit 121 includes a detection operation control unit 121a, a correction unit 121b, a surface temperature distribution calculation unit 121c, and the like.

The detection operation control unit 121a controls operations of the infrared distribution detection device 110, more specifically, the infrared camera 111 and the switching device 113.
Substantially, the control unit 121 functions as the detection operation control unit 121a by performing a predetermined calculation or the like according to the detection operation control program stored in the storage unit.

As shown in FIG. 2, the detection operation control unit 121 a drives the motor 113 b of the switching device 113 so that the short wavelength filter 112 a covers the field of view of the infrared camera 111.
Then, at time t ₍₁ , ₁₎ , the intensity Q of infrared rays radiated from the cavity surface 102a of the forging die 102 detected by the infrared camera 111 with the short wavelength filter 112a covering the field of view of the infrared camera 111. The distribution of _(1,1) (the first infrared intensity distribution in the short wavelength band) is acquired.
Here, the subscript i in Q _{(i, m)} and T _{(i, m)} represents the filter number, and the subscript m represents the number of measurements in the same filter (infrared wavelength band). In this embodiment, i = 1 corresponds to the short wavelength filter 112a, i = 2 corresponds to the medium wavelength filter 112b, and i = 3 corresponds to the long wavelength filter 112c.

Next, the detection operation control unit 121a drives the motor 113b of the switching device 113 so that the medium wavelength filter 112b covers the field of view of the infrared camera 111.
Then, at time t ₍₂ , ₁₎ , the intensity Q of the infrared ray radiated from the cavity surface 102a of the forging die 102 detected by the infrared camera 111 with the medium wavelength filter 112b covering the field of view of the infrared camera 111. The distribution _{(2, 1)} (the first infrared intensity distribution in the middle wavelength band) is acquired.

Subsequently, the detection operation control unit 121a drives the motor 113b of the switching device 113 so that the long wavelength filter 112c covers the field of view of the infrared camera 111.
Then, at time t ₍₃ , ₁₎ , the intensity Q of infrared rays radiated from the cavity surface 102a of the forging die 102 detected by the infrared camera 111 with the long wavelength filter 112c covering the field of view of the infrared camera 111. The distribution of _{(3, 1)} (the first infrared wavelength distribution in the long wavelength band) is acquired.

Similarly, the detection operation control unit 121a drives the motor 113b of the switching device 113 to switch the filter covering the field of view of the infrared camera 111 in the order of the short wavelength filter 112a → the medium wavelength filter 112b → the long wavelength filter 112c, and the time t _{( 1} , 2 ₎ distribution of the second short-wavelength infrared intensity Q _(1,2) , time t _(2,2) distribution of the second medium-wavelength infrared intensity Q _(2,2) , time At t ₍₃ , 2 ₎ , the distribution of infrared intensity Q ₍₃ , 2 ₎ in the second long wavelength band is acquired.

  In this embodiment, the short wavelength filter 112a (first time) → the medium wavelength filter 112b (first time) → the long wavelength filter 112c (first time) → the short wavelength filter 112a (second time) → the medium wavelength filter 112b (second time) → long Although the configuration is such that the field of view of the infrared camera 111 is covered in the order of the wavelength filter 112c (second time), the present invention is not limited to this, and it is possible to arbitrarily select the order of wavelength bands for detecting the infrared intensity distribution. It is.

The correction unit 121b is an embodiment of the correction means according to the present invention, and obtains the relationship between the intensity of three types of infrared rays having different wavelength bands and the respective detection times, and the intensity or measurement temperature of the infrared rays is determined by the wavelength band. The correction value is corrected to a correction value at any detection time of three or more different types of infrared rays.
Substantially, the control unit 121 functions as the correction unit 121b by performing a predetermined calculation or the like according to the correction program stored in the storage unit.

First, the correction unit 121b includes the infrared intensity (Q _(1,1) , Q _{(2,1 ) at} a predetermined measurement point 102b on the cavity surface 102a of the forging die 102 among the acquired infrared intensity distribution. ₎ , Q _(3,1) , Q _(1,2) , Q _(2,2) , Q _(3,2) ) based on the measurement temperature Trs _{(i, m)} by the infrared camera 111 at the measurement point. Is calculated.
Here, the measurement temperature Trs _{(i, m)} is the same as Q _{(i, m)} , the subscript i represents the filter number, and the subscript m represents the number of times of measurement (how many times).
In the case of the present embodiment, the measurement is performed by referring to a data table showing the relationship between the apparent measurement temperature (measurement value) and the infrared intensity when each filter stored in advance in the storage means of the control unit 121 is used. The temperature Trs _{(i, m)} is obtained.

Next, the correction unit 121b determines the measured temperature Trs _{(i, m)} (specifically, Trs _(1,1) , Trs _(2,1) , Trs _{(3,1 ) at} the calculated predetermined measurement point 102b. ₎ , Trs _(1,2) , Trs _(2,2) , Trs _(3,2) ), the measured temperature Trs _{(i, m)} and the detection time t _{(i, m} ) for the medium wavelength band and the long wavelength band. ₎ .
In this embodiment, as shown in FIG. 2, an equation of a straight line passing through the coordinates (t _(2,1) , Trs _(2,1) ) and the coordinates (t _(2,2) , Trs _(2,2) ), And finding an equation of a straight line passing through the coordinates (t _(3,1) , Trs _(3,1) ) and the coordinates (t _(3,2) , Trs _(3,2) ) This corresponds to obtaining the relationship between the measurement temperature Trs _{(i, m)} and the detection time t _{(i, m)} for the wavelength band.

Here, linearly approximating the relationship between the measurement temperature Trs _{(i, m)} and the detection time t _{(i, m)} for the medium wavelength band and the long wavelength band is based on the experimental result of the test piece.
That is, a thermocouple was embedded in five different locations in the vicinity of the cavity surface (position at a depth of 0.5 mm from the cavity surface) of the test piece of the casting mold, casting was performed using the test piece, and the cast was taken out. The temperature change of the later test piece was measured. The material constituting the test piece is SKD61 (JIS standard), which is a general mold material, and experiments were conducted both when a commercially available release agent was applied to the cavity surface and when it was not applied.
As a result, as shown in FIG. 3, the temperature change of the test piece can be linearly approximated at about 0.2 ° C./sec regardless of whether or not the release agent is applied. In addition, the experimental result of FIG. 3 shows the case where it does not apply | coat.

Subsequently, the correction unit 121b determines the medium wavelength band for each measurement point on the cavity surface 102a of the forging die 102 (the entire measurement region in the field of view of the infrared camera 111) based on the obtained two linear equations. calculating a correction value _{Trs (3, 0)} in the correction value _Trs in the measurement temperature of the detection time _{t (1,1) (2,0),} and a long wavelength band of the measured temperature of the detection time _{t (1, 1)} .
The correction value Trs _{(2, 0)} of the measured temperature is calculated from a predetermined measurement point that would have been detected if the medium wavelength filter 112b covered the field of view of the infrared camera 111 at the detection time t _{(1, 1).} This represents the intensity of the emitted infrared light in the medium wavelength band. The correction value Trs _{(3, 0)} of the measured temperature is assumed to be obtained when the long wavelength filter 112c sets the field of view of the infrared camera 111 at the detection time t _{(1, 1).} It represents the intensity of long-wavelength infrared rays radiated from a predetermined measurement point that would have been detected if covered.

The predetermined measurement point 102b on the cavity surface 102a of the forging die 102 for calculating the correction values (Trs _{(2, 0)} and Trs _{(3, 0)} ) of the measurement temperature is the same as that of the forging die 102. It can be set at an arbitrary position on the cavity surface 102a.
However, from the viewpoint of improving the measurement accuracy, the cavity surface 102a forms a surface that is substantially orthogonal to the line (optical path) connecting the infrared camera 111 and the measurement point, and its surface properties are unlikely to change. It is desirable to set it at a position (which is less likely to be worn out by repeated casting).

In the present embodiment, the correction value is calculated based on the infrared intensity at the predetermined measurement point 102b of the cavity surface 102a of the forging die 102, but the present invention is not limited to this.
For example, a relational expression between the intensity of infrared rays in each wavelength band and a detection time is obtained for each of a plurality of measurement points, and an average value of correction values calculated for each of the obtained relational expressions is a representative value of the correction value. The measurement temperature Trs _{(i, m)} and the detection time t _{(i, m} ) for each of the measurement points (pixels) in the field of view measured by the infrared camera for the medium wavelength band and the long wavelength band may be used. _The correction value may be calculated after obtaining the relationship (linear equation).

  In this embodiment, the infrared intensity Q of each wavelength band at a predetermined measurement point is converted into the measurement temperature Trs (calculation of the measurement temperature Trs), the relationship between the measurement temperature Trs and the detection time t is obtained, and based on the relationship. Thus, the correction value of the measurement temperature Trs is calculated, but the present invention is not limited to this, and the relationship between the infrared intensity Q of each wavelength band at a predetermined measurement point and the detection time t is obtained. The same effect can be obtained by calculating a correction value of the intensity Q of infrared rays based on the relationship and converting the correction value of the intensity Q into a correction value of the measurement temperature Trs (calculating the correction value of the measurement temperature Trs). Play.

The surface temperature distribution calculation unit 121c is an embodiment of the surface temperature distribution calculation unit according to the present invention, and the measurement temperature Trs ₍₁ , ₁₎ in the short wavelength band at the detection time t _{(1, 1)} correction value _Trs in the detection time of the measured temperature _{t (1,1) (2,0),} and on the basis of the correction value _{Trs (3, 0)} in the detection time _{t (1, 1)} of the measured temperature of the long wavelength band, The surface temperature distribution of the cavity surface 102a of the forging die 102 is calculated.
Substantially, the control unit 121 functions as the surface temperature distribution calculation unit 121c by performing a predetermined calculation or the like according to the surface temperature distribution calculation program stored in the storage unit.

The calculation method of the black body temperature (true surface temperature) Ts of an object in infrared thermography using a general three-color radiation thermometer is a multiplier n1, from the following equations 1 to 3 and equations 4 to 6, respectively. Select one by one so that n2 and n3 are not the same, and apply a bisection method, Newton method, Newton-Phson method or the like to obtain a convergent solution (find Ts where F (Ts) = F (Ta) = 0) Thus, Ts is determined (see Non-Patent Document 1).
There are a total of 6 patterns for selecting the above formulas (Equation 1 and Equation 5, Equation 1 and Equation 6, Equation 2 and Equation 4, Equation 2 and Equation 6, Equation 3 and Equation 4, Equation 3 and Equation 5).
Here, Trs is the (apparent) measurement temperature, Ta is the ambient temperature, and multipliers n1, n2, and n3 are values determined by the infrared wavelength band and the type of detection element of the infrared camera, respectively.

In the case of the present embodiment, the surface temperature distribution calculation unit 121c uses the measurement temperatures Trs _{1 to} Trs ₃ in Equations _{1 to} 6 as the measurement temperatures Trs ₍₁ , _{1) for} the short wavelength band for each pixel (measurement point ₎ , correction value in the detection time of the measured temperature of the wavelength band _{t (1,1) Trs (2,0)} , and the _{Trs (3, 0)} correction values in the detection time _{t (1, 1)} of the measured temperature of the long wavelength band By substituting and calculating, the distribution of the surface temperature Ts of the cavity surface 102a of the forging die 102 is calculated.

When obtaining the convergence solution of the surface temperature of the cavity surface 102a of the forging die 102, (a) when the surface temperature Ts and the ambient temperature Ta converge together with the number of repetitions of the calculation, (b) When the surface temperature Ts converges at the number of repetitions (for example, 10 times) but the ambient temperature Ta diverges, it is determined that the calculated surface temperature Ts is normal, and (c) a predetermined number of repetitions of calculation When the ambient temperature Ta converges (for example, 10 times) but the surface temperature Ts diverges, it is determined that the calculated surface temperature Ts is abnormal.
In the case of the present embodiment, calculation is performed for all of the above six patterns, and Ts is determined based on the calculation result of the remaining surface temperature Ts except when it is determined to be abnormal (for example, normal) The average value or median value of Ts determined to be the final calculated value of Ts).

As described above, the surface temperature measuring apparatus 101 is
Among the infrared rays radiated from the cavity surface 102a of the forging die 102, the intensity distribution of three types of infrared rays (short wavelength, medium wavelength and long wavelength infrared rays) having different wavelength bands is detected at different detection times. An infrared distribution detection device 110 that detects two or more times for each wavelength band;
The intensity (measurement) calculated from the intensity of three types of infrared rays with different wavelength bands detected by the infrared distribution detection device 110 or the measurement temperature calculated from the intensity and the respective detection times (linear equation) are obtained, and the intensity or measurement of the infrared rays is obtained. A correction unit 121b for correcting the temperature to a correction value in the detection time of the short-wavelength infrared light;
A surface temperature distribution calculating unit 121c for calculating the temperature distribution of the cavity surface 102a of the forging die 102 based on the correction value;
It comprises.
With this configuration, it is possible to accurately measure the temperature of the cavity surface 102a of the forging die 102 even when detecting the intensity distributions of infrared rays in different wavelength bands at different detection times. .

The infrared temperature distribution detection device 110 of the surface temperature measurement device 101 is
An infrared camera 111 for detecting an infrared intensity distribution;
Three types of filters (short wavelength filter 112a, medium wavelength filter 112b, and long wavelength filter 112c) that can transmit infrared rays in different wavelength bands,
A switching device 113 for switching which of the three or more types of filters covers the field of view of the infrared camera 111;
It comprises.
With this configuration, it is possible to easily achieve the surface temperature measuring device according to the present invention using an existing infrared camera.

Below, one Embodiment of the surface temperature measuring method which concerns on this invention is described using FIG.
One embodiment of the surface temperature measuring method according to the present invention is a method of measuring the temperature distribution of the surface of the forging die 102, particularly the cavity surface 102a, using the surface temperature measuring device 101, as shown in FIG. The process mainly includes an infrared distribution detection step S1100, a correction step S1200, and a surface temperature distribution calculation step S1300.

  The infrared distribution detection step S1100 detects the intensity distributions of three types of infrared rays having different wavelength bands among the infrared rays emitted from the cavity surface 102a of the forging die 102 at different detection times and twice for each wavelength band. This is the detecting step.

In the infrared distribution detection step S1100, the detection operation control unit 121a drives the motor 113b of the switching device 113 and sets a filter covering the field of view of the infrared camera 111 as a short wavelength filter 112a → a medium wavelength filter 112b → a long wavelength filter 112c → a short wavelength. switch to the order of the filter 112a → medium wavelength filter 112b → long-wavelength filter 112c, the distribution of the infrared intensity _{Q (1,1)} for the first time in the short wavelength band at time _{t (1,1),} at time _{t (2,1)} first distribution of infrared intensity _{Q (2,1)} in the wavelength band in the distribution of the infrared intensity _{Q (3, 1)} of the first long wavelength band at time _{t (3, 1),} the time _{t (1, 2} distribution of the infrared intensity _{Q (1, 2)} of the second short wavelength band _in), infrared intensity of the wavelength band in the second at time _{t (2, 2) (2,2)} distribution of, respectively obtains the distribution of the infrared intensity _{Q (3,2)} of the second long wavelength band at time _{t (3,2).}
When the infrared distribution detection step S1100 is completed, the process proceeds to the correction step S1200.

  The correction step S1200 obtains the relationship between the intensity of three types of infrared rays having different wavelength bands and the respective detection times, and corrects the intensity or measurement temperature of the infrared rays at the detection time of any of three or more types of infrared rays having different wavelength bands. This is a step of correcting the value.

In the correction step S1200, the correction unit 121b includes the infrared intensity (Q ₍₁ , ₁₎ , Q ₍ Q _{) at} a predetermined measurement point 102b on the cavity surface 102a of the forging die 102 among the acquired infrared intensity distribution. _2,1) , Q _(3,1) , Q _(1,2) , Q _(2,2) , Q _(3,2) ) based on the measurement temperature Trs _{(i ,} M ₎ , a relationship (linear expression) between the measurement temperature Trs _{(i, m)} and the detection time t _{(i, m)} is obtained for the medium wavelength band and the long wavelength band, and forging gold is calculated based on the relationship. For each measurement point on the cavity surface 102a of the mold 102 (entire measurement region in the field of view of the infrared camera 111 _), the correction value Trs ₍₂ , _{0) at} the detection time t _{(1, 1)} of the measurement temperature in the middle wavelength band, and Measurement temperature in long wavelength band Calculating a correction value _{Trs (3, 0)} in the detection time _{t (1, 1).}
When the correction step S1200 is completed, the process proceeds to the surface temperature distribution calculation step S1300.

Surface temperature distribution calculating step S1300 is corrected value Trs in the measurement temperature _Trs short wavelength band in the detection time _{t (1,1) (1,1),} detection time measured temperature of the medium wavelength band _{t (1,1) (2 , 0)} and the correction value Trs _{(3 , 0)} in the detection time t _{(1, 1)} of the measurement temperature in the long wavelength band, the surface temperature distribution of the cavity surface 102a of the forging die 102 is calculated. It is a process.

In the surface temperature distribution calculation step S1300, the surface temperature distribution calculation unit 121c applies the measurement temperatures Trs _{1 to} Trs ₃ in Equations _{1 to} 6 to the measurement temperatures Trs _{(1, 1) in the} short wavelength band for each pixel (measurement point _). The correction value Trs ₍₂ , _{0) at} the detection time t _{(1, 1)} of the measurement temperature in the medium wavelength band, and the correction value Trs _{(3, 0 ) at} the detection time t _{(1, 1)} of the measurement temperature in the long wavelength band ₎ Is substituted, and the distribution of the surface temperature Ts of the cavity surface 102a of the forging die 102 is calculated.

As described above, one embodiment of the surface temperature measurement method according to the present invention is as follows.
Among the infrared rays radiated from the cavity surface 102a of the forging die 102, the intensity distribution of three types of infrared rays (short wavelength, medium wavelength and long wavelength infrared rays) having different wavelength bands is detected at different detection times. Infrared distribution detection step S1100 for detecting twice or more for each wavelength band;
Infrared distribution detection step S1100 detects the intensities of three types of infrared rays having different wavelength bands or the relationship between the measurement temperatures calculated from the intensities and the respective detection times (linear equations), and the infrared intensity or measurement temperature. Correction step S1200 for correcting the correction value to the correction value in the detection time of the short wavelength infrared ray,
A surface temperature distribution calculating step S1300 for calculating a temperature distribution of the cavity surface 102a of the forging die 102 based on the correction value;
It comprises.
With this configuration, it is possible to accurately measure the temperature of the cavity surface 102a of the forging die 102 even when detecting the intensity distributions of infrared rays in different wavelength bands at different detection times. .

One embodiment of the surface temperature measurement method according to the present invention is as follows:
In infrared distribution detection step S1100,
An infrared camera 111 for detecting an infrared intensity distribution;
Three types of filters (short wavelength filter 112a, medium wavelength filter 112b, and long wavelength filter 112c) that can transmit infrared rays in different wavelength bands,
A switching device 113 for switching which of the three or more types of filters covers the field of view of the infrared camera 111;
Is used to detect the intensity distribution of three types of infrared rays having different wavelength bands.
With this configuration, it is possible to easily achieve the surface temperature measurement method according to the present invention using an existing infrared camera.

The figure which shows one Embodiment of the surface temperature measuring apparatus which concerns on this invention. The figure which shows the relationship between the measurement temperature and detection time in one Embodiment of the surface temperature measuring apparatus which concerns on this invention. The figure which shows the temperature change of a test piece. The flowchart which shows one Embodiment of the surface temperature measuring method which concerns on this invention.

Explanation of symbols

101 Surface temperature measuring device 102 Casting mold (object)
102a Cavity surface (surface of the object)
110 Infrared distribution detector (Infrared distribution detector)
DESCRIPTION OF SYMBOLS 111 Infrared camera 112a Short wavelength filter 112b Medium wavelength filter 112c Long wavelength filter 113 Switching apparatus 121b Correction | amendment part (correction means)
121c Surface temperature distribution calculation unit (surface temperature distribution calculation means)

Claims (4)

Among infrared rays radiated from the surface of the object, infrared distribution detection means for detecting the intensity distribution of three or more types of infrared rays having different wavelength bands at different detection times and detecting at least twice for each wavelength band;
Obtain the intensity of three or more types of infrared rays having different wavelength bands detected by the infrared distribution detection means or the relationship between the measurement temperature calculated from the intensity and the detection time thereof, and determine the intensity or measurement temperature of the infrared rays. Correction means for correcting to a correction value in the detection time of any of three or more types of infrared rays having different wavelength bands;
Surface temperature distribution calculating means for calculating the temperature distribution of the surface of the object based on the correction value;
A surface temperature measuring device comprising: The infrared distribution detection means includes
An infrared camera for detecting infrared intensity distribution;
Three or more types of filters that can transmit infrared rays in different wavelength bands,
A switching device for switching which of the three or more types of filters covers the field of view of the infrared camera;
The surface temperature measuring device according to claim 1 comprising: Among infrared rays radiated from the surface of the object, an infrared distribution detection step of detecting the intensity distribution of three or more types of infrared rays having different wavelength bands at different detection times and detecting at least twice for each wavelength band;
Obtain the intensity of three or more types of infrared rays with different wavelength bands detected in the infrared distribution detection step or the relationship between the measurement temperature calculated from the intensity and the respective detection times, and determine the intensity or measurement temperature of the infrared rays A correction process for correcting to a correction value in any detection time of three or more types of infrared rays having different wavelength bands,
A surface temperature distribution calculating step of calculating a temperature distribution of the surface of the object based on the correction value;
A surface temperature measuring method comprising: In the infrared distribution detection step,
An infrared camera for detecting infrared intensity distribution;
Three or more types of filters that can transmit infrared rays in different wavelength bands,
A switching device for switching which of the three or more types of filters covers the field of view of the infrared camera;
The surface temperature measurement method according to claim 3, wherein the distribution of the intensity of three or more types of infrared rays having different wavelength bands is detected using an infrared distribution detection means comprising:

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