JP2015055547A - Multi wavelength radiation thermometer and multi wavelength radiation temperature measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring method that achieves both highly accurate thermometry and shape measurement, and a device thereof.SOLUTION: A multi wavelength radiation thermometer includes: a diaphragm which shields a part of thermal radiation light generated from a target; a two-dimensional diffraction element which disperses thermal radiation light transmitted through the coding diaphragm depending on a wavelength region; and a two-dimensional sensor which detects the thermal radiation light dispersed by the two-dimensional diffraction element.

Description

  The present invention relates to a multiwavelength radiation thermometer and a multiwavelength radiation thermometer measurement method.

In Patent Document 1, a multi-wavelength for measuring the temperature T of the surface of the object to be measured based on N (N is an integer of 3 or more) spectral radiance L _i of the thermal radiation emitted from the surface of the object to be measured. In the radiation temperature measurement method using the N, the N spectral emissivities corresponding to the spectral radiance L _i are converted into M states (M is an integer equal to or smaller than (N−2)), and the surface state of the object to be measured Spectral radiation obtained by preliminarily approximating on the basis of measurements as a function of the intrinsic spectral wavelength and substituting the assumed temperature T ′ and M hypothetical unknowns into the spectral emissivity formula as a function of the approximated spectral wavelength. performed and luminance L _i, the difference between the actual measurement spectral radiance L _i ^o obtained by measuring the operation by changing the unknown temperature T 'and the M hypothesis assumptions decreased below a predetermined value, the spectral emissivity When the difference between the luminance L _i and the measured spectral radiance L _i ^o is less than a predetermined value, A radiation thermometer is described in which the temperature T of the object to be measured is obtained by assuming that the temperature obtained by the calculation is the temperature T of the object to be measured.

  In addition, as a technique for managing temperature and shape with a single system, Patent Document 2 discloses a three-dimensional shape in which molten slag flowing down from a furnace outlet is simultaneously observed from different directions to measure the three-dimensional shape of the molten slag. A shape measuring means and a temperature measuring means for measuring the temperature of the molten slag, and based on input information including at least a three-dimensional shape of the molten slag, the discharge property of the molten slag is “good” or “bad” It describes about the monitoring apparatus of the molten slag flow provided with the discharge | emission quality determination means which determines either of these. The three-dimensional shape measuring means uses an optical means arranged at least at three or more positions spaced in the circumferential direction of the molten slag, and the fixed coordinate in the axial direction of the streaks of the molten slag flowing down from the discharge port An ellipse that detects the plane coordinates of a total of six or more points of contact formed on the cross section by a tangent line connecting the cross section at the point and the optical means, and includes all of the six points of contact from the value of the plane coordinates. A curve is obtained, and the data represented by the elliptic curve is hierarchically obtained with respect to the axial direction of the molten slag streak, thereby obtaining a three-dimensional surface shape for each melted slag streak, and thereby flowing down from the discharge port. The three-dimensional surface shape of all the streaks of the molten slag is obtained. The optical means is an imaging means for taking a two-dimensional image of the molten slag, and obtains a luminance distribution of the surface of the three-dimensional shape of the molten slag based on a plurality of luminance distributions of the two-dimensional images. And a temperature measurement means for obtaining a three-dimensional surface temperature distribution of the molten slag based on the correlation between the molten slag and the temperature information of the molten slag being included in the input information. An apparatus is described.

JP-A-5-231944 JP 2006-118744 A

  In Patent Document 1, although information on temperature distribution can be obtained, information on depth cannot be obtained.

  In Patent Document 2, the temperature and shape are simultaneously measured by an imaging unit that captures two-dimensional images arranged at three or more locations, but only the contour is detected, and the diameter and distortion of the cylinder are simple. Only a simple shape can be measured.

  In view of the above problems, an object of the present invention is to provide a multi-wavelength radiation thermometer and a multi-wavelength radiation temperature measurement method that achieve both high-precision temperature measurement and shape measurement.

  In order to solve the above problems, the present invention provides a two-dimensional structure in which a diaphragm that blocks part of the thermal radiation generated from the specimen, and the thermal radiation that has passed through the coded diaphragm are dispersed according to the wavelength region. Provided is a multi-wavelength radiation thermometer comprising a diffraction element and a two-dimensional sensor that detects thermal radiation dispersed by the two-dimensional diffraction element as a two-dimensional image.

  Further, in the present invention, the thermal radiation emitted from the test object is shielded by a diaphragm, and the thermal radiation transmitted through the diaphragm is dispersed by a two-dimensional diffraction element for each wavelength and dispersed by the two-dimensional diffraction element. Provided is a multi-wavelength radiation temperature measuring method characterized by detecting thermal radiation light as a two-dimensional image.

  According to the present invention, in view of the above problems, it is possible to provide a multiwavelength radiation thermometer and a multiwavelength radiation temperature measurement method that achieve both highly accurate temperature measurement and shape measurement.

It is a block diagram which shows the structure of the multiwavelength radiation thermometer which concerns on Example 1 of this invention. It is a flowchart which shows the measurement procedure by the multiwavelength radiation thermometer which concerns on Example 1 of this invention. It is a schematic diagram which shows the encoding aperture_diaphragm | restriction which concerns on Example 1 of this invention. It is a schematic diagram which shows the two-dimensional diffraction element which concerns on Example 1 of this invention. It is a schematic diagram of the image imaged with the two-dimensional sensor which concerns on Example 1 of this invention. It is a schematic diagram which shows the three-dimensional data cube which concerns on Example 1 of this invention. It is a block diagram which shows the structure of the process part of the multiwavelength thermometer which concerns on Example 1 of this invention. It is a schematic diagram explaining the calculation method of the spectral emissivity which concerns on Example 1 of this invention. It is a schematic diagram which shows GUI which concerns on Example 1 of this invention. It is a block diagram which shows the structure of the multiwavelength radiation thermometer which concerns on Example 2 of this invention. It is a block diagram which shows the structure of the management system using multiple multi-wavelength radiation thermometers concerning Example 3 of this invention. It is a flowchart which shows the measurement procedure by the management system which used multiple multiwavelength radiation thermometers concerning Example 3 of this invention.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a configuration of a multiwavelength radiation thermometer having a shape measuring function. In this multi-wavelength radiation thermometer, two-dimensional spectral elements are used to acquire wavelength information in two-dimensional space by one imaging, thereby realizing highly accurate temperature measurement that has not been possible in the past. The spectral image capturing unit 120 acquires a total of three-dimensional information of the two-dimensional space and the one-dimensional wavelength of the infrared ray 101 to be detected, which is thermal radiation emitted from the test object 100 to be inspected. The spectral image capturing unit 110 includes a wavelength cut filter 111, an objective lens 112, an encoding diaphragm 113, a collimator lens 114, and a wavelength region, which are one of the diaphragms that block a part of the thermal radiation generated from the specimen 100. The two-dimensional diffractive element 115 that disperses the thermal radiation light according to the above, an imaging lens 116 that forms an image of the dispersed thermal radiation light, and a two-dimensional sensor 117 that detects the imaged thermal radiation light. Note that the spectral image capturing unit 110 is housed in the thermostatic cover 120 so that the temperature state is constant in order to suppress changes in the characteristics of the optical element due to temperature changes and noise suppression of the two-dimensional sensor 117. The constant temperature cover 120 is provided with a measurement window 121 that transmits the test infrared ray 101 emitted from the test object 100 and guides the test infrared ray 101 to the spectral image capturing unit 110. The subsequent processing flow is shown in FIG. An image is acquired by the spectral image capturing unit 110 (S100), and the image acquired in S100 is subjected to image processing by the processing unit 130, and a depth distribution and a temperature distribution in two-dimensional space are calculated (S101). The depth distribution and temperature distribution calculated in S101 are stored in the storage unit 140 (S102), and the determination unit 150 determines whether the depth and temperature are normal (S103), and the temperature and depth information and S103 are determined. The determination result is displayed on the display unit 160 (S104).

  The role of each part will be described in detail. The test infrared light 101 passes through only a desired wavelength range by the wavelength cut filter 111, then enters the objective lens 112, and enters the coding diaphragm 113 placed on the pupil plane behind the objective lens 112. A schematic diagram of the encoding diaphragm 113 is shown in FIG. The encoding diaphragm 113 used in the present embodiment blocks the heat radiation light at an arbitrary position and transmits the heat radiation light at a position other than the shielded position. A normal stop has a circular shape, whereas an encoded stop arbitrarily places a light shielding position on the space. The diaphragm is not limited to the sign or the diaphragm 113, and any diaphragm may be used as long as it can block the heat radiation light. However, it is possible to give a strong correlation between the degree of blur and the depth of the acquired image by appropriately designing the position of light and dark using the encoding diaphragm 113 as in this embodiment, and the depth information from the degree of blur Can be estimated. This method is called Depth From Defocus (DFD). In particular, the depth information can be easily estimated from one image by using the Levin coding aperture. DFD is applied mainly to the visible range in the field of machine vision and the like. However, when used in the infrared as in this embodiment, in order to ensure the estimation accuracy of the depth information, an infrared ray is applied to the light shielding portion. It is necessary to select a medium that does not transmit light, and to suppress expansion of the coded diaphragm 113 itself by absorbing infrared rays.

  Here, the expansion of the coded diaphragm due to temperature is suppressed by the constant temperature cover 120. The test infrared light 101 that has passed through the encoding diaphragm 113 is collimated by a collimator lens 114 to obtain a primary image of the test object 100. The two-dimensional diffractive element 115 is placed at the primary image formation position, dispersed according to the wavelength region, and imaged on the two-dimensional sensor 117 by the imaging lens 116. A schematic diagram of the two-dimensional diffraction element 115 is shown in FIG. It is made of a material that transmits the test infrared ray 101, and the height differs depending on the position.

  With this structure, an image as shown in FIG. 5 is obtained on the two-dimensional sensor 117 by controlling the diffraction direction of the diffracted light. Zero-order diffracted light is obtained in the central portion (normal imaging result). In addition, 1st- and 2nd-order diffracted light is obtained in a state where dispersion is applied in a plurality of directions around the periphery. These 1st and 2nd order diffracted lights can be regarded as projections of the spatial two-dimensional (x, y) and one-dimensional wavelength (λ) three-dimensional data cubes shown in FIG. 6 from various directions. Therefore, the three-dimensional cube of FIG. 6 can be reconstructed from a plurality of 1st and 2nd order diffracted lights using CT (Computed Tomography) technology widely used in the medical field. This method is called CTIS (Computed Tomography Imaging Spectrometer). At this time, by appropriately determining the transmission wavelength range of the wavelength cut filter 111, it is possible to calculate a desired three-dimensional data cube with high accuracy without overlapping each diffracted light.

  Various CCDs, CMOSs, and the like can be used for the two-dimensional sensor 117. In particular, when the temperature of the test object 100 is 1000 ° C., the test infrared light is in the near infrared region, so a CCD sensor using InGaAs that can detect about 0.9 to 1.5 μm is used. In temperature measurement, a dynamic range of about 50 dB is required to measure about 1000 ° C. ± 300 ° C. in the wavelength band of 0.9 to 1.5 μm. If a high dynamic range sensor is not available, multiple measurements with different sensitivities are required.

  In this embodiment, it is possible to calculate the temperature at each pixel of the image with high accuracy using the two-dimensional and multi-wavelength image acquired in this way. Moreover, depth information of each pixel can be obtained by introducing the encoding diaphragm 113 into the optical system.

  Next, the processing unit 130 of the acquired data will be described. Details of the processing unit are shown in FIG. An image acquired by the two-dimensional sensor 117 of the spectral image capturing unit 110 is input to the processing unit 130. The processing unit 130 includes a depth calculation unit 131 and a temperature calculation unit 132.

  Processing contents of the depth calculation unit will be described. An image obtained by passing through the encoding aperture 113 is a greatly blurred image as it is. A restoration process using a PSF (Point Spread Function) corresponding to the shape of the encoding diaphragm 113 is performed to obtain a clear image and depth information (details are described in A. Levin, ACM Transactions on Graphics, 3, 2007.). In the image obtained by the two-dimensional sensor 117, the 0th-order light portion at the center portion shown in FIG. 5 corresponds to the image obtained by the normal optical system. This depth distribution of the 0th-order light portion is referred to as a depth distribution image.

Next, the temperature calculation unit 132 will be described. First, the three-dimensional data cube shown in FIG. 6 is reconstructed from the image including a plurality of diffracted lights shown in FIG. In CTIS, a reconstruction method using a linear model can be used. The output image g for each wavelength represented by the three-dimensional data cube is the product of the system matrix H and the input image f (image shown in FIG. 5).
(Equation 1)

It can be expressed as. From this equation, f (x, y, λ) is obtained. At this time, an Expectation Maximization (EM) Method, a Multiplicative Algebraic Reconstruction Technique (MART), or the like can be used. Here, the system matrix H is obtained in advance by calibration using light having a known two-dimensional shape and wavelength. By this pre-calibration, the transmittance of the measurement window 121, the wavelength cut filter 111, and other optical elements, the diffraction efficiency of the two-dimensional diffraction grating 115, and the detection efficiency of the two-dimensional sensor 117 are also calibrated.

Subsequently, the spectral emissivity is obtained from f (x, y, λ). Hereinafter, for simplicity, it is considered to calculate the temperature in one pixel of the image f (x, y, λ). Here, f (x _i , y _i , λ ₁ ) = I ₁ , f (x _i , y _i , λ ₂ ) = I ₂ ,..., F (x _i , y _i , λ _N ) = I _N To do. FIG. 8A shows the plot results of I ₁ , I ₂ ,..., I _N when the vertical axis represents luminance and the horizontal axis represents wavelength. When the test object 100 is a black body that absorbs 100% of light, a spectrum (black body radiation) indicated by a solid line is obtained, but the amount of radiated light is reduced depending on the material and the surface state. When the black body radiation amount is 1, the attenuation factor of I is called emissivity, and the emissivity for each wavelength is called spectral emissivity. The blackbody radiation spectrum P _j follows the Planck equation,
(Equation 2)

Can be written. Here, h is the Planck constant, c is the speed of light, k is the Boltzmann constant, and T is the temperature of the test object.

The spectrum I _j actually obtained is obtained by multiplying each wavelength of the spectrum P _j of black body radiation by the spectral emissivity ε _j .
(Equation 3)

It is expressed.

In a commercially available radiation thermometer, I _j / I _{j + 1} assuming that ε _{j and} ε _{j + 1} are equal at two wavelengths by using ε _j as an external parameter in single wavelength measurement to obtain temperature T A method for obtaining the temperature T is widely used.

  Further, in the method described in Japanese Patent Laid-Open No. 5-231944 (Patent Document 1), a spectral emissivity equation approximated as a function of the spectral wavelength is used, but the characteristic of the spectral emissivity of the object to be measured is phase transformation, alloying, Since it constantly fluctuates due to changes in oxidation, surface roughness, etc., it often deviates from the assumed function, and there is a problem that the accuracy of temperature measurement cannot be ensured.

In order to solve the above-described problem, the temperature calculation unit 132 utilizes a multi-wavelength spectrum and calculates the spectral emissivity with high accuracy. This will be described with reference to FIG. Consider derivation of emissivity ε ₂ at wavelength λ ₂ . The spectral emissivity ε _j can be described by a simple function in the local region. Here, it is assumed to be linear as follows.
(Equation 4)

Assuming that the spectral emissivity is as in (Equation 4), (Equation 3) is described by three variables: coefficient a, b, and temperature T. Therefore, the coefficients a and b can be calculated from the luminances at the minimum of three wavelengths within the range where the assumption of (Equation 4) holds. In FIG. 8 (b), it shows a case of using the intensity I _1, I _2, I ₃ in the lambda ₂ and the left and right λ _1, λ _3. Spectral emissivity ε _j (j = 2 to N−1) can be obtained by sequentially repeating the calculation for the wavelength λ _j (j = 2 to N−1). Furthermore, by repeating the calculation for all the pixels in the same manner, the spectral emissivity can be calculated with high accuracy for each pixel. When obtaining the spectral emissivity, data in the vicinity of a certain wavelength in the air absorption spectrum is excluded in advance because it causes an error.

Using the result of the spectral emissivity ε _j obtained as described above, the temperature for each pixel of f (x, y, λ) is calculated. In the method described above, the calculation of emissivity was repeated in a local range to obtain the spectral emissivity ε _j . By obtaining the temperature T using all of the spectral emissivity ε _j , measurement variations are reduced and accuracy is improved. Here, the evaluation function E is defined as follows.
(Equation 5)

T that minimizes the evaluation function E is derived by optimization calculation, and the derived T is defined as the temperature at the pixel.

  The same calculation is performed for all the pixels to obtain the temperature for each pixel of f (x, y, λ). As described above, a two-dimensional temperature distribution image of temperature can be calculated with high accuracy without giving emissivity in advance as in the existing method.

  The depth and temperature calculated by the processing unit 130 are stored in the storage unit 140. However, the user can determine the necessity of storage and select ON / OFF.

  The determination unit 150 determines normality / abnormality of the measurement target from the depth and temperature calculated by the processing unit 130. A depth distribution image pixel or a region composed of a plurality of pixels and a depth allowable range are set in advance. If the measured value does not fall within the allowable range within the set pixel or a region composed of a plurality of pixels, it is determined that there is an abnormality. Note that the average value of the region and the measured value may be compared. Similarly, regarding the temperature, a normality / abnormality is determined by setting a pixel or a region composed of a plurality of pixels and an allowable temperature range for the temperature distribution image, and comparing with a measured value. The normal / abnormal determination result is displayed on the display unit 160 together with the depth and the temperature measurement result.

  A GUI (Graphical User Interface) 170 of the display unit 160 is shown in FIG. There is a start button 171 for starting measurement and a stop button 172 for stopping measurement. When the start button 171 is pressed, measurement is performed continuously. The measurement result is displayed in the measurement result display window 173. For example, the depth and temperature are expressed simultaneously in one image by expressing the depth by hue and the temperature by brightness. Here, the temperature may be expressed by RGB and the depth may be expressed by brightness. The relationship between the displayed color, brightness, depth, and temperature is indicated by a color bar 174. Further, the measurement time is displayed on the time display window 175. When the save check box 176 is checked, all the continuously measured results are saved. In addition, it is possible to determine normality / abnormality by setting conditions in advance. A region 177 used for determination is set, and a depth or temperature that is an allowable value is set (not shown). In the judgment box 178, normal is displayed when the value is within the allowable value, and abnormal is displayed when the value is outside the allowable value.

The modification of Example 1 is shown. In the temperature calculation unit 132, several variations are conceivable for modeling the change in ε with respect to the change in λ provided for obtaining the temperature T. This modification is a method that uses only the assumption that the spectral emissivity at close wavelengths is a close value. That is, there is an effect that it is possible to flexibly cope with the conversion of the spectral emissivity depending on the material and the surface state by not providing a restriction such as applying a function to the wavelength distribution of the spectral emissivity. The spectral emissivity εj satisfying (Equation 3) is derived as follows.
(Equation 6)

However, ‖ ‖n represents the L _n norm. Here, since the appropriate conditions for the coefficients β, m ₁ , n ₁ , m ₂ , and n ₂ differ depending on the wavelength dependence of the spectral emissivity of the measurement target, select appropriate coefficients as a preliminary preparation before measurement. . Substituting the spectral emissivity obtained by (Equation 6) into (Equation 3), the temperature T is obtained as follows.
(Equation 7)

The calculation of (Equation 6) and (Equation 7) is performed for each pixel to obtain a temperature distribution image.

  As described above, according to the present embodiment, not only the temperature information of the test object 100 but also the depth information can be obtained with high accuracy by using the encoding diaphragm 113. Further, it is possible to obtain temperature information with high accuracy by repeating the calculation of the spectral emissivity for the local wavelength range.

  The block diagram of Example 2 is shown in FIG. The difference from FIG. 1, which is a configuration diagram of the first embodiment, is that the encoding diaphragm 113 is a normal circular diaphragm 118. When high-speed temperature measurement is required, image restoration processing that is necessary when the encoding diaphragm 113 is inserted becomes a problem. Therefore, by using a normal circular aperture 118 instead of the encoding aperture 113, image restoration processing can be omitted and the processing speed can be increased. For depth measurement, DFD developed by Zhuo et al. Applicable to the circular diaphragm 118 is applied. The depth calculation unit 131 is different from the first embodiment due to the difference in the aperture shape.

  The processing content of the depth calculation unit 131 in the present embodiment is as follows. The 0th order term of the image including a plurality of diffraction orders obtained in FIG. 5 is extracted and subjected to DFD processing. Edges are extracted from each of the smoothed images obtained by smoothing the 0th-order term image and the 0th-order term image with PSF simulating lens characteristics, the ratio of the respective edge images is derived, and noise removal and complement processing are performed. A depth image is obtained by applying. Zhuo et al. Used a Gaussian function assuming a thin lens model, but by applying an actual lens PSF, a more accurate depth image can be calculated.

  According to this embodiment, a circular aperture 118 is used instead of the encoding aperture 113, and restoration processing is performed by applying PSF, so that a more accurate depth image can be obtained compared to the first embodiment. it can.

  In Examples 1 and 2, the measurement method of the test object 100 using a single multi-wavelength radiation thermometer was shown. When a single sensor is used, the information regarding the shape is only the depth with respect to the observation direction. However, for use in hot forging or hot rolling, it is often necessary to manage the three-dimensional shape from various observation directions. Assuming such a case, a system using multi-wavelength radiation thermometers 201, 202, and 203 having a plurality of depth calculation functions as shown in FIG. 11 is proposed. The operations of the multi-wavelength radiation thermometers 201, 202, and 203 and the processing method in the processing unit 130 are the same as those in the first embodiment. An integration unit 210 that integrates the depth information individually processed by the multi-wavelength radiation thermometers 201, 202, and 203 calculated by the processing unit 130 is added.

  The measurement flow is shown in FIG. Images are acquired from the spectral image capturing units 110 of the three multi-wavelength radiation thermometers (S200), and the three images acquired in S200 are subjected to image processing by the processing unit 130, and the depth distribution in two-dimensional space. And a temperature distribution are calculated (S201). In S201, the depth information respectively calculated from the three multi-wavelength radiation thermometers is integrated (S202). The temperature distribution calculated in S201 and the depth information integrated in S202 are stored in the storage unit 140 (S203). The determination unit 150 determines whether the depth and temperature are normal (S204), and displays the temperature and depth information and the determination result of S204 on the display unit 160 (S205). The integration of the three depth images may be integrated on the basis of the coordinate values of each multi-wavelength radiation thermometer obtained in advance in a three-dimensional coordinate system in which the vertical and horizontal directions of the image are xy and the depth is z, You may integrate the three-dimensional point group calculated | required from the depth image using ICP (Iterative Closest Point) method.

  According to the present embodiment, by using a plurality of multi-wavelength radiation thermometers 201, 202, and 203, the depth information calculated from each of the plurality of multi-wavelength radiation thermometers is integrated, and the depth information from a plurality of observation directions is integrated.・ Temperature information can be managed.

  The embodiments described so far are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention is not limitedly interpreted by these. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

DESCRIPTION OF SYMBOLS 100 ... Test object 101 ... Test infrared 110 ... Spectral image pick-up part 111 ... Wavelength cut filter 112 ... Objective lens 113 ... Encoding aperture 114 ... Collimator lens 115- .... Two-dimensional diffraction element 116 ... Imaging lens 117 ... Two-dimensional sensor 118 ... Circular diaphragm 120 ... Constant temperature cover 121 ... Measurement window 130 ... Processing unit 131 ... Depth calculation Unit 132 ... temperature calculation unit 140 ... storage unit 150 ... determination unit 160 ... display unit 170 ... GUI
171 ... Start button 172 ... Stop button 173 ... Measurement result display window 174 ... Color bar 175 ... Time display window 176 ... Save check box 177 ... Area 178 ... Determination Box 201, 202, 203 ... Multi-wavelength thermometer 210 ... Integration unit

Claims (14)

An aperture that blocks a portion of the thermal radiation generated from the specimen;
A two-dimensional diffractive element that disperses the thermally radiated light transmitted through the coded diaphragm according to a wavelength region;
A multi-wavelength radiation thermometer comprising: a two-dimensional sensor that detects thermal radiation dispersed by the two-dimensional diffraction element.   The multi-wavelength radiation according to claim 1, wherein the stop is a coded stop that blocks the thermal radiation light at an arbitrary position and transmits the thermal radiation light at a position other than the shielded position. thermometer.   The multi-wavelength radiation thermometer according to claim 1, further comprising a temperature calculation unit that calculates a temperature distribution by repeating calculation of spectral emissivity for a wavelength range of local thermal radiation light detected by the two-dimensional sensor.   The multi-wavelength radiation thermometer according to claim 1, further comprising a depth calculation unit that performs a restoration process on the two-dimensional image detected by the two-dimensional sensor and acquires depth information of the specimen.   The multi-wavelength radiation thermometer according to claim 4, wherein the depth calculation unit estimates depth information by Depth From Defocus.   The multiwavelength radiation thermometer according to claim 4, further comprising a determination unit that compares the depth calculated by the depth calculation unit with an allowable value and determines normality or abnormality.   The multiwavelength radiation thermometer according to claim 3, further comprising a determination unit that compares the temperature calculated by the temperature calculation unit with an allowable value and determines normality or abnormality. The thermal radiation emitted from the specimen is shielded by the diaphragm,
The thermal radiation light that has passed through the diaphragm is dispersed by a two-dimensional diffraction element according to the wavelength region,
A multi-wavelength radiation temperature measuring method, wherein a two-dimensional image is obtained by detecting thermal radiation dispersed by the two-dimensional diffraction element.   The multi-wavelength radiation according to claim 8, wherein the stop is a coded stop that blocks the thermal radiation light at an arbitrary position and transmits the thermal radiation light at a position other than the shielded position. Temperature measurement method.   The multi-wavelength radiation temperature measurement method according to claim 8, wherein the temperature distribution is calculated by repeating the calculation of the spectral emissivity for the local wavelength range of the thermal radiation light detected by the two-dimensional sensor.   The multi-wavelength radiation temperature measurement method according to claim 8, wherein the two-dimensional image detected by the two-dimensional sensor is subjected to a restoration process to acquire depth information of the specimen.   The depth information is estimated by Depth From Defocus, The multiwavelength radiation temperature measuring method of Claim 11 characterized by the above-mentioned.   The multi-wavelength radiation temperature measuring method according to claim 11, wherein the calculated depth and an allowable value are compared to determine normality or abnormality.   The multi-person temperature measurement method according to claim 10, wherein the temperature is compared with an allowable value to determine normality or abnormality.

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