Temperature Measuring Device, Temperature Measuring Method, and Program

Abstract

Provided are a temperature measurement device, a temperature measurement method, and a program, which can measure a two-dimensional temperature distribution of a measurement target at low cost, increase sensor output for a low-temperature object with a small amount of radiation, and increase temperature measurement accuracy for a high-temperature object with a large amount of radiation. 【Solution means】A single image sensor having pixels two-dimensionally and adopting a global shutter method, a rotating filter in which a plurality of sets of a first filter region and a second filter region through which first light and second light having different wavelengths respectively pass are provided in sequence, a light guide means for guiding light from a measurement target to the image sensor, and an output addition unit that adds outputs of the first light that has passed through a plurality of first filter regions in units of each pixel and adds outputs of the second light that has passed through a plurality of second filter regions in units of each pixel. Based on the output of the output addition unit or the addition average of the outputs of the output addition unit, the temperature of the measurement target is measured.

Description

Technical Field

[0001] The present invention relates to a temperature measurement device, a temperature measurement method, and a program that can measure a two-dimensional temperature distribution of a measurement object at low cost without requiring a complicated optical system or image sensor, can increase the sensor output for a low-temperature object with a small radiation amount, and can increase the temperature measurement accuracy for a high-temperature object with a large radiation amount.

Background Art

[0002] As a temperature measurement device for measuring the temperature of a measurement object, a device using a two-color temperature method that converts temperature from the ratio of radiance using two different wavelengths close to each other is known. Among various specific methods using the two-color temperature method, a method of rotating filters with different transmission wavelength ranges provided in the optical path from the measurement object to the sensor to measure temperature at low cost is known from Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, not only can the two-dimensional temperature distribution of the measurement object not be measured, but also the convenience of increasing the sensor output for a low-temperature object with a small radiation amount and increasing the temperature measurement accuracy for a high-temperature object with a large radiation amount is not considered.

[0005] An object of the present invention is to provide a temperature measurement device, a temperature measurement method, and a program that can measure a two-dimensional temperature distribution of a measurement object at low cost, can increase the sensor output for a low-temperature object with a small radiation amount, and can increase the temperature measurement accuracy for a high-temperature object with a large radiation amount.

Means for Solving the Problems

[0006] To achieve the above object, a temperature measuring device according to the present invention is a temperature measuring device using a two-color temperature method for converting temperature from the ratio of radiance using two different wavelengths close to each other, and has a single image sensor in a global shutter method that two-dimensionally provides pixels and each pixel is simultaneously exposed to output a digital signal, a rotating filter in which a plurality of sets of a first filter region and a second filter region through which first light and second light having different wavelengths respectively pass are provided in order, a light guiding means for guiding the first light and the second light from a measurement object to the image sensor through the rotating filter in a time series manner, an output addition unit for adding the outputs of the first light passing through a plurality of the first filter regions in units of each pixel and adding the outputs of the second light passing through a plurality of the second filter regions in units of each pixel, light and has, a measurement unit that measures the temperature of the object to be measured using at least the output of the output addition unit; based on the output addition unit, when it is determined that the object to be measured imaged by the image sensor is a low-temperature object not exceeding 500°C, the measurement unit uses, as the number of additions, which is the number of outputs to be added in the output addition unit, only the number of additions selected based on the number of rotations per unit time of the rotary filter and the number of filter divisions of the rotary filter measures the temperature of the measurement object. output This is the gist of the present invention. On the other hand, when it is determined that the object to be measured imaged by the image sensor is a high-temperature object exceeding 500°C, the measurement unit measures the temperature of the object to be measured based on the addition average of the outputs of the output addition unit

[0007] Further, a temperature measuring method according to the present invention is A temperature measurement device using a two-color temperature method for converting temperature from the ratio of radiance using light of two different wavelengths close to each other, comprising a single image sensor of a global shutter method that has pixels two-dimensionally and each pixel is simultaneously exposed to output a digital signal, a rotary filter in which a plurality of sets of a first filter region and a second filter region through which first light and second light having different wavelengths respectively pass are provided in order, a light guiding means for guiding the first light and the second light from the object to be measured to the image sensor through the rotary filter in a time series manner, an output addition unit that adds the outputs of the first light that has passed through a plurality of the first filter regions in units of each pixel and adds the outputs of the second light that has passed through a plurality of the second filter regions in units of each pixel, and a measurement unit that measures the temperature of the object to be measured using at least the output of the output addition unit, in a temperature measurement device a temperature measuring method, when it is determined that the object to be measured imaged by the image sensor is a low-temperature object not exceeding 500°C, the measurement unit uses, as the number of additions, which is the number of outputs to be added in the output addition unit, only the number of additions selected based on the number of rotations per unit time of the rotary filter and the number of filter divisions of the rotary filter and has a step of measuring the temperature of the measurement object based on the output addition unit, output which is the gist of the present invention. when it is determined that the object to be measured imaged by the image sensor is a high-temperature object exceeding 500°C, the step of the measurement unit measuring the temperature of the object to be measured based on the addition average of the outputs of the output addition unit;

[0008] Further, the present invention is also configured as a computer to execute each of the above steps program.

Advantages of the Invention

[0009] According to the present invention, a two-dimensional temperature distribution of a measurement object can be measured at low cost, the sensor output can be increased for a low-temperature object with a small radiation amount, and the temperature measurement accuracy can be increased for a high-temperature object with a large radiation amount.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] (First Embodiment) Prior to the specific description of this embodiment, first, the two-color temperature measurement method will be described.

[0013] (Two-Color Temperature Measurement Method) The concept of two-color thermometer measurement will be described below. In order to measure the temperature of a high-temperature processed object of 300 °C or higher non-contact, the electromagnetic radiation emitted from the measurement target is measured, and the temperature is calculated from its intensity. As products based on this principle, there are radiation thermometers that obtain temperature from visible light or infrared light, and thermography for measuring temperature distribution. Since a general measurement target is a non-blackbody, to know the true temperature from a radiation thermometer or thermography, correction must be made using the emissivity, which is the ratio of the radiation amount to that of a blackbody. However, since the emissivity of a non-blackbody generally varies depending on its material, shape, and temperature, it is difficult to obtain an accurate temperature.

[0014] Therefore, the two-color thermometer measurement method is used. The two-color thermometer measurement method focuses on the fact that the emissivities of radiation at two adjacent wavelengths are the same, and since the ratio of the radiation amounts at the two wavelengths has a functional relationship with the true temperature, the radiation amounts at the two wavelengths are measured and the true temperature is calculated. Explaining using mathematical formulas, it is as follows.

[0015] Wien's radiation formula for the radiation amount Mλ at wavelength λ is as follows.

[0016]

Equation

[0017] Here, c1: First radiation constant = 2πc2h = 3.741844X10-16 [Wm2] λ: Wavelength μm c2: Second radiation constant = 1.438769X10-2 [m K] T: Absolute temperature (Kelvin) For the two wavelengths λ1 and λ2 to be measured, with emissivities ε1 and ε2 respectively, and radiation amounts M1 and M2 for both, and with the ratio of the radiation amounts at both wavelengths (output ratio in the image sensor) being R, R is expressed by Equation (2).

[0018]

Equation

[0019] When the condition ε1 = ε2 is satisfied, equation (2) becomes equation (3).

[0020]

Number

[0021] When both sides are arranged, the temperature T is obtained by equation (4).

[0022]

Number

[0023] Here, C3 and C4 are constants calculated from both wavelengths and are represented by the following equations.

[0024]

Number

[0025] Even when the emissivities and the transmittances of the inclusions are different at two wavelengths, if the ratio does not change with temperature, the true temperature of an object with a changing temperature can be known by correcting the ratio to a blackbody.

[0026] (Temperature measurement by the rotating filter method) Fig. 1 shows the overall configuration diagram of the temperature measurement device according to the embodiment of the present invention, which is composed of a measurement head and a computer. The measurement head is provided with an objective lens 1, a rotating filter 2, an image sensor unit 3, a wavelength-specific image distribution circuit 4, an image addition / non-addition processing circuit 5, a memory bank 6, a trigger light source 8, a trigger sensor 9, and a motor 10 for rotating the rotating filter 2 at a constant speed. At least the computer 7 that performs exposure time indication and two-color temperature processing is provided with computer hardware / software. The image sensor unit 3 is provided with an image sensor 3a, an analog amplifier 3b, and an A / D conversion element 3c.

[0027] For these members, those with the same reference numerals are shown in the block diagram of FIG. 2.

[0028] In this embodiment, in order to reduce costs, a rotating filter 2 is provided between the objective lens 1 and the image sensor 3a. The rotating filter 2 is provided with a first filter region and a second filter region through which first light and second light having different wavelengths respectively pass as a band-pass filter, and the two regions are adjacent to each other in the rotation direction, and a plurality of such sets are provided in the rotation direction.

[0029] In FIG. 3(a), the filter is divided into four parts, and two sets of a first filter 12 and a second filter 13 are provided. In FIG. 3(b), the filter is divided into 20 parts, and ten sets of a first filter 22 and a second filter 23 are provided.

[0030] In the conventional two-color thermometer, the measurement target is one-dimensional point measurement of one point or one area, whereas in this embodiment, an image sensor is used and the measurement targets a large number such as 300,000 points (640x480).

[0031] Furthermore, while the conventional two-color thermometer depends on analog signal processing with floating elements for temperature measurement from the radiation ratios of two wavelengths, in this embodiment, temperature calculation processing for each of about 300,000 pixels can perform accurate numerical processing based on Wien's radiation law.

[0032] In such an embodiment, the image sensor 3a has pixels two-dimensionally, and each pixel is simultaneously exposed and serves as a single image sensor with a global shutter that outputs a digital signal. The global shutter method is adopted because when performing dynamic imaging with the rotating filter 2 intervening, it is preferable that each pixel is simultaneously exposed and outputs a digital signal.

[0033] The objective lens 1 guides the image of the measurement object to the image sensor 3a through the band-pass filter formed on the disk of the rotary filter 2. In this way, the objective lens 1 functions as a light guiding means for guiding the first light and the second light from the measurement object to the image sensor 3a in time series via the rotary filter 2. As the light guiding means, a glass fiber image transmission tube (image guide fiber) is provided on the focal plane of the objective lens, and a lens is arranged at the tip of the transmission tube again to construct a system for transmitting to the image sensor through the filter disk, thereby avoiding stray light around the measurement object and performing temperature measurement.

[0034] Here, prior to temperature measurement, the computer 7 instructs the image sensor unit 3 to set the exposure time, and the image sensor 3a can set the exposure time to the global shutter function (for example, when step S1 in FIG. 6 described later is YES).

[0035] In the image sensor unit 3, after the output of each pixel of the image sensor 3a is amplified by the analog amplifier 3b, it is sent as digital data such as 12 to 16 bits to the wavelength-specific image distribution circuit 4 by the A / D converter 3c. Then, it is accumulated in each wavelength region of the memory bank 6 as an image of the wavelength identified by the trigger signal which is the output of the trigger light-receiving sensor 9 (FIG. 2).

[0036] Regarding data reading, the image addition / non-addition processing circuit 5 reads the data of two pairs of wavelengths required from the memory bank 6, and according to the command from the computer 7, after adding or not adding the data of each pixel, it outputs to the computer 7. Then, the computer 7 performs two-color temperature processing on the non-added or added image data, and then outputs a signal for display or control.

[0037] Regarding the image addition in the image addition / non-addition processing circuit 5, when the rotation speed of the disk of the rotary filter 2 is P revolutions per second (RPS) and the number of filter divisions is Q, if the required exposure time is longer than 1 / (P×Q) seconds, two pairs of memory values read from the memory bank 6 are added (Fig. 7). For example, when the rotation speed of the disk of the rotary filter 2 is 2400 RPM (40 revolutions per second) and the number of filter divisions is 4 (the disk is divided into 4 parts), the exposure time per wavelength is 1 / 40×1 / 4×1000 = 6.25 milliseconds (msec). However, when adding two images for each wavelength, the exposure time per wavelength can be extended to 12.5 milliseconds (msec).

[0038] (Synchronization signal detection) In the rotary filter, a synchronization signal with the filter position is required so that the image sensor can perform shooting when the filter area transmitting a predetermined wavelength is in front of the image sensor.

[0039] In this embodiment, as shown in Figs. 1 and 4, the light from the trigger light source 8 is received by the trigger light receiving sensor (photodiode) 9 through the trigger filter 50 (Fig. 4), and its output is used.

[0040] That is, since the trigger filter 50 has the same filter (the same spectral transmission characteristics) as one of the different filters of the rotary filter 2, when the filter on the optical path of the rotary filter 2 is the same as the trigger filter 50, the output of the trigger light receiving sensor 9 becomes on. On the other hand, when the filter on the optical path of the rotary filter 2 is different from the trigger filter 50, the output of the trigger light receiving sensor 9 becomes off.

[0041] In this embodiment, the synchronization signal can be detected in this way, and the image signal can be sorted by wavelength by the wavelength-by-wavelength image distribution circuit 4 and stored in a predetermined memory area (Fig. 2) of the memory bank 6.

[0042] In this embodiment, regardless of the number of divisions (even when the number of filter divisions is increased), it is not necessary to allocate the trigger detection area to the rotating filter 2, and a wider filter area can be adopted.

[0043] The output of the trigger sensor in this case is shown in FIG. 5. In the image sensor 14a, from the time point of the output state where the light of the first wavelength λ1 is received (on) and the light of the second wavelength λ2 is not received (off), it shifts to the time point of the output state where the light of the first wavelength λ1 is not received (off) and the light of the second wavelength λ2 is received (on).

[0044] In this embodiment, the above-described synchronization signal (trigger signal) is obtained, and the image signal is selected by wavelength according to the signal and stored in the predetermined memory area (memory bank 6) shown in FIG. 2. For λ1 Regarding the light of the wavelength λ1 that passes through the filter, it is sequentially stored in the memory areas 1-1, 1-2, ··· 1-n as the rotating filter 2 rotates. Also, regarding the light of the wavelength λ2 that passes through the λ2 filter, it is sequentially stored in the memory areas 2-1, 2-2, ··· 2-n as the rotating filter 2 rotates.

[0045] (One-image input time to the image sensor and time delay between two-wavelength images according to the number of filter divisions and rotation speed) In this embodiment, the light reception time (exposure time) of the radiant light from the measurement target can be precisely set in the image sensor. For example, if a disk is divided into 4 parts and each of the two wavelengths is assigned to the two-wavelength filter, and the disk is rotated at 1500 RPM (25 rotations per second), the one-image input time (exposure time) to the image sensor and the time delay between the two-wavelength images are each 1 / 25 × 1 / 4 × 1000 = 10 milliseconds (msec).

[0046] 1) When the temperature is high and the radiation amount is strong (when step S1 or S2 in FIG. 6 is YES) When the temperature of the measurement target is high and the radiation dose is strong, if the motor speed is changed from the initially set reference value of 750 RPM (12.5 revolutions per second) to 3000 RPM (50 revolutions per second), the exposure time and the time delay between the two-wavelength images (λ1~λ2 time difference) can each be set to 1 / 50×1 / 4×1000 = 5 milliseconds. Regarding the exposure time, it becomes half of the initially set predetermined value of 10 milliseconds.

[0047] Furthermore, the motor speed can be increased further to shorten the exposure time. However, according to this embodiment that employs a sensor with a global shutter function as the image sensor, the exposure time can be shortened to about 1 microsecond. However, in this case, the time delay between the two-wavelength images (λ1~λ2 time difference) cannot be eliminated (see Table 1 below). To shorten this radiation capture time, increasing the motor speed per minute will cause noise and vibration, and further consideration for durability is required.

[0048] Therefore, as a method of shortening the time delay between the two-wavelength images without increasing the motor speed, it can be addressed by increasing the number of divisions of the rotating disk filter. For example, when the filter is divided into 20, that is, 20 divisions (Fig. 3(b)), the exposure time and the time delay of the two-wavelength images at 3000 RPM will each be 1 / 50×1 / 20×1000 = 1 millisecond (see Table 2 below).

[0049] Here, the time delay between the two-wavelength images cannot be determined only by the motor speed per minute of the rotating filter and is restricted by the FPS (number of images captured per second, i.e., the shooting speed) of the image sensor. At 30 FPS used in normal shooting, the time delay of the two-wavelength images is 30.3 milliseconds, but to make the time delay 1 millisecond, high-speed shooting at 1000 FPS is required.

[0050] 2) When the temperature is low and the radiation dose is weak (when steps S1 and S2 in Fig. 6 are NO) When the temperature of the measurement target is low and the radiation intensity is weak, it corresponds to the case where long-time incidence (exposure) is required, and the motor rotation speed is decreased. For example, when a four-segment filter disk is rotated at 750 RPM (12.5 rotations per second), the exposure time of one image and the time delay between two-wavelength images are 1 / 12.5×1 / 4×1000 = 20 milliseconds (msec). Here, if the motor rotation speed is further decreased to 150 RPM (2.5 rotations per second), it becomes 1 / 2.5×1 / 4×1000 = 100 milliseconds (msec). This is acceptable for a measurement target without changes such as flow, but it is not suitable for a measurement target with changes such as flow.

[0051] As a countermeasure in this case, while keeping the motor rotation speed constant (1500 RPM as the reference value), to increase the exposure time, the data of the same address of each pixel of the image captured in the memory bank 6 (Figure 2) for each wavelength is added (image addition). For example, when a rotating filter divided into four segments and assigning two wavelengths to each of the two-wavelength filters is rotated at 1500 RPM (25 rotations per second), the input time of one image to the image sensor and the time delay between two-wavelength images are 1 / 25×1 / 4×1000 = 10 milliseconds (msec). When the images of each wavelength are added 10 times each, the exposure time becomes 100 milliseconds (refer to Table 3 below). The time delay between the two wavelengths in this case is the same 100 milliseconds as when the motor rotation speed was set to 150 RPM (2.5 rotations per second) as described above, but there is an advantage that the exposure time can be changed while the motor rotation speed is 10 times (1500 RPM) and the rotation unevenness is small.

[0052] Also, when a rotating filter divided into 20 segments and assigning 10 wavelengths to each of the two-wavelength filters is rotated at 750 RPM (12.5 rotations per second), the input time of one image to the image sensor and the time delay between two-wavelength images are 1 / 12.5×1 / 20×1000 = 4 milliseconds. When the images of each wavelength are added 16 times each, the exposure time becomes 64 milliseconds (refer to Table 4 below).

[0053] Also, regarding this image addition, when it is desired to reduce noise components such as dust floating between the measurement target and the objective lens and the dynamic noise of the sensor, it can be addressed by increasing the number of divisions of the rotating filter and adding (image addition) the data of each pixel. In this case, for example, if a 4-division filter disk is replaced with an 8-division filter disk and rotated at 1500 RPM (25 rotations per second), the time delay between the input time of one image to the image sensor and between the two-wavelength images is 1 / 25 × 1 / 8 × 1000 = 5 milliseconds (msec). When 10 images of each wavelength are added, the exposure time becomes 50 msec.

[0054]

Table 1

[0055] Various values when the filter is divided into 4 (changing the rotation speed) RPM = Rotations per minute, RPS = Rotations per second, FPS = Number of captured images per second

[0056]

Table 2

[0057] Various values when the filter is divided into 20 (changing the rotation speed) RPM = Rotations per minute, RPS = Rotations per second, FPS = Number of captured images per second

[0058]

Table 3

[0059] Various values when the filter is divided into 4 (changing the number of addition at 1500 RPM)

[0060]

Table 4

[0061] Various values when the filter is divided into 20 (changing the number of addition at 750 RPM)

[0062] (Flowchart related to temperature measurement) Next, a flowchart related to temperature measurement will be described with reference to FIG. 6.

[0063] 1) Initial settings and flowchart overview As initial settings, assume that the motor speed is set to 750 RPM and the exposure time of the image sensor is set to 10 milliseconds. In this state, the measurement head is directed towards the measurement target (initial setting).

[0064] If the image displayed on the monitor in the initial setting is judged to be visible but unsatisfactory (when step S1 in FIG. 6 is YES), the objective lens is adjusted to focus. Then, the initial setting value of 10 milliseconds is used for the exposure time of the image sensor. In step S4, the addition average of image addition in FIG. 7 described later is used to improve the temperature measurement accuracy.

[0065] If the image is overexposed and whitewashed in the initial setting (when step S2 in FIG. 6 is YES), the exposure time of the image sensor is adjusted. When measurement is instructed in this state, the image signal from the sensor unit is accumulated in the image memory of λ1 or λ2, skipping the addition process. The two-color temperature processing unit reads the image data of both wavelengths adjacent in time, performs two-color temperature processing, and then displays the temperature or transmits a control signal to an external device.

[0066] If the limit of exposure time shortening control is exceeded in the shutter setting of the sensor, the rotation speed (RPM) of the motor is set high, and then the exposure time of the sensor is set.

[0067] Then, in step S4, the addition average of image addition in FIG. 7 described later is used to improve the temperature measurement accuracy.

[0068] If the image displayed on the monitor during the initial setup is underexposed and dark (when step S2 in FIG. 6 is NO), a plurality of time-series images of the same wavelength are added pixel by pixel (image addition) to synthesize an image density that enables two-color temperature measurement. In this case, instead of adding a single image, images that are temporally continuous are added to reduce dynamic noise. The required number of addition images is calculated from the initial image, and after instructing the image addition / non-addition processing circuit from the computer to perform image addition, it is stored in the image memory. The two-color temperature processing unit reads the image data of both wavelengths that are temporally adjacent, performs two-color temperature processing, and then displays the temperature or transmits a control signal to an external device.

[0069] 2) Specific Flow First, in step S1, it is determined whether the measurement target is visible (the thermal radiation from the measurement target is light in the visible region).

[0070] 1) If it is YES in step S1, for high-temperature measurement of about 700 °C or higher, as the image sensor, a commercially available photodiode array, CCD, CMOS, etc. are used, and the exposure time in a single image sensor with a global shutter method is set, and the process proceeds to the addition average (temperature measurement accuracy improvement) process of image addition in step S4. Regarding step S4, for convenience, it will be described in 2-2) described later.

[0071] After the addition average (temperature measurement accuracy improvement) process of image addition in step S4, the output of the image sensor 2 is image-stored at the memory address determined corresponding to the trigger signal via step S5.

[0072] 2) If it is NO in step S1 (the target is not visible in the initial setup), for temperature measurement of 700 °C or lower, since the radiation amount is small due to thermal radiation and the central wavelength range of the radiation is in the near-infrared region with a longer wavelength than visible light, a silicon-based commercially available C-MOS color image sensor, etc. cannot receive light, and an image sensor made of a material such as InGaAs that has photosensitive characteristics in the near-infrared region must be used.

[0073] If the answer is NO in step S1, it is determined in step S2 whether to increase the RPM (whether the rotary filter 2 can rotate at high speed). If the answer is YES in step S2, the measurement is for medium to high temperatures below 700°C and above 500°C. If the answer is NO in step S2, the measurement is for low temperatures below 500°C.

[0074] 2-1) If the answer is NO in step S2, for low-temperature measurement below 500°C and above 300°C, the RPM of the rotary filter 2 is set to be low, and the process proceeds to the image addition (sensor output increase) process in step S3 to calculate the number of image addition sheets. Regarding the image addition process, as shown in FIG. 7, the same pixel outputs (outputs of the same coordinate values) S1, S2,... S n of the sensor that receives the light transmitted through the λ1 filter are added (image addition). Similarly, the same pixel outputs (outputs of the same coordinate values) T1, T2,... T n of the sensor that receives the light transmitted through the λ2 filter are added (image addition). Then, temperature measurement is performed based on the ratio of the outputs of the two image additions.

[0075] Generally, for temperature measurement of low-temperature objects with low radiation, such an image addition process is used to increase the sensor output.

[0076] 2-2) If the answer is YES in step S2, for medium to high-temperature measurement above 500°C and below 700°C, the RPM of the rotary filter 2 is set to be high, and a short exposure time is set as the sensor exposure time. Then, in step S4, as shown in FIG. 7, the same pixel outputs (outputs of the same coordinate values) S1, S2,... S n of the sensor that receives the light transmitted through the λ1 filter are added and the addition average divided by n is calculated. Similarly, the same pixel outputs (outputs of the same coordinate values) T1, T2,... T n of the sensor that receives the light transmitted through the λ2 filter are added and the addition average divided by n is calculated. Then, temperature measurement is performed based on the ratio of the addition averages of the two.

[0077] Generally, for measuring the temperature of a high-temperature (medium-high temperature) object with a large radiation dose, by using such addition-average processing of image addition, it is possible to compensate for the decrease in temperature measurement accuracy caused by floating substances such as dust existing between the optical paths and the dynamic noise of the sensor and analog electronic components (improve the temperature measurement accuracy).

[0078] In the above-described embodiment, as a temperature measurement device used when the measurement target is a low-temperature object not exceeding 500 °C, the temperature of the measurement target can be measured based on the output of the output addition unit used for increasing the output of the image sensor.

[0079] Also, as a temperature measurement device used when the measurement target is a high-temperature object exceeding 500 °C, the temperature of the measurement target can be measured based on the addition average of the output of the output addition unit used for improving the temperature measurement accuracy.

[0080] Also, as a temperature measurement device used from the case where the measurement target is a low-temperature object not exceeding 500 °C to the case where the measurement target is a high-temperature object exceeding 500 °C, when the measurement target is a low-temperature object not exceeding 500 °C, the temperature of the measurement target is measured based on the output of the output addition unit used for increasing the output of the image sensor, and when the measurement target is a high-temperature object exceeding 500 °C, the temperature of the measurement target can be measured based on the addition average of the output of the output addition unit used for improving the temperature measurement accuracy.

[0081] Also, when the measurement target is a low-temperature object not exceeding 500 °C, the rotation speed of the rotary filter can be made slower than the reference value (for example, 750 RPM or 2000 RPM) by the control unit, and when the measurement target is a high-temperature object exceeding 500 °C, the rotation speed of the rotary filter can be made faster than the above reference value.

[0082] Also, when the measurement target is a high-temperature object exceeding 500 °C, the exposure time in the image sensor can be made shorter than the predetermined value (for example, 10 milliseconds) by the control unit.

[0083] (Second Embodiment) The rotating filter in the second embodiment of the present invention is shown in FIG. 8 together with the image sensor 14b. The rotating filter of this embodiment has the filter divided into four parts, and two sets of a first filter 32 and a second filter 33 are provided. Synchronization detection marks 16 to 19 are provided on this rotating filter. A light source and a sensor for reading this synchronization detection mark are provided with the disk of the rotating filter interposed therebetween. The trigger light source 8 and the trigger detection sensor 9 in the state excluding the trigger filter 50 in FIG. 4 described in the first embodiment can be used.

[0084] In this embodiment, except for the rotating filter and the synchronization detection system, it is the same as the first embodiment.

[0085] (Temperature measurement method) The present invention is also represented as a temperature measurement method in addition to the temperature measurement device described in the embodiment. That is, as a temperature measurement method, a step of providing a single image sensor in an optical path from a measurement target, which is a global shutter method in which pixels are two-dimensionally provided and each pixel is simultaneously exposed to output a digital signal; a step of providing a rotating filter in which a plurality of sets of a first filter region and a second filter region through which first light and second light having different wavelengths pass are provided in order, corresponding to the image sensor; a step of guiding the first light and the second light from the measurement target to the image sensor through the rotating filter in a time series; a step of adding the outputs of the first light that has passed through a plurality of the first filter regions for each pixel, and adding the outputs of the second light that has passed through a plurality of the second filter regions for each pixel; and a step of measuring the temperature of the measurement target based on the output of the output addition unit or the addition average of the output of the output addition unit.

[0086] (Modification example) As described above, the preferred embodiments of the present invention have been explained. However, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof. For example, as shown in FIG. 9, the measurement terminal 41 (one or more) may be connected to the server 42 (functioning as the computer 7 in FIG. 1) via the Internet.

[0087] In addition to the temperature measuring device and the temperature measuring method, the present invention can also be configured as a program for causing a computer to function as each means of the temperature measuring device described above.

Explanation of Reference Numerals

[0088] 1... objective lens, 2... rotary filter, 3... image sensor unit, 3a... image sensor, 3b... analog amplifier, 3c... A / D conversion element, 4... wavelength-specific image distribution circuit, 5... image addition / non-addition processing circuit, 6... memory bank, 7... computer, 8... trigger light source, 9... trigger light receiving sensor, 10... motor, 41... measurement head, 42... server

Claims

1. A temperature measuring device using a two-color temperature method that converts temperature from the ratio of radiance using light of two different wavelengths that are close to each other, A single image sensor having two-dimensional pixels, each pixel being simultaneously exposed to light and outputting a digital signal, a rotary filter including a plurality of first filter regions and a plurality of second filter regions arranged in order, through which a first light and a second light having different wavelengths pass, respectively; a light guiding unit that guides the first light and the second light from the measurement target to the image sensor via the rotary filter in a time-series manner; an output summing unit that sums outputs of first light that has passed through a plurality of the first filter regions in units of each pixel, and that sums outputs of second light that has passed through a plurality of the second filter regions in units of each pixel; a measurement unit that measures a temperature of the measurement object using at least an output of the output adder unit; having When the measurement object imaged by the image sensor is determined to be a low-temperature object not exceeding 500° C., the measurement unit measures the temperature of the measurement object based on the output of the output adder, which is added by an addition number that is selected based on the number of rotations per unit time of the rotary filter and the number of filter divisions of the rotary filter as an addition number that is the number of outputs to be added in the output adder, and A temperature measuring device characterized in that when the measurement object imaged by the image sensor is determined to be a high-temperature object exceeding 500°C, the measurement unit measures the temperature of the measurement object based on the average of the outputs of the output addition unit.

2. The temperature measuring device described in claim 1, characterized in that it has a control unit that makes the rotation speed of the rotating filter slower than a reference value when the object to be measured is a low-temperature object not exceeding 500°C, and makes the rotation speed of the rotating filter faster than the reference value when the object to be measured is a high-temperature object exceeding 500°C.

3. 3. The temperature measuring device according to claim 2, wherein the control unit further sets an exposure time of the image sensor to be shorter than a predetermined value when the measurement target is a high-temperature object exceeding 500°C.

4. A temperature measuring device using a two-color temperature method in which temperature is calculated from the ratio of radiance using light of two different wavelengths that are close to each other, A single image sensor having two-dimensional pixels, each pixel being simultaneously exposed to light and outputting a digital signal, a rotary filter including a plurality of first filter regions and a plurality of second filter regions arranged in order, through which a first light and a second light having different wavelengths pass, respectively; a light guiding unit that guides the first light and the second light from the measurement target to the image sensor via the rotary filter in a time-series manner; an output summing unit that sums outputs of first light that has passed through a plurality of the first filter regions in units of each pixel, and that sums outputs of second light that has passed through a plurality of the second filter regions in units of each pixel; a measurement unit that measures a temperature of the measurement object using at least an output of the output adder unit; A method for measuring temperature in a temperature measuring device having When the measurement object imaged by the image sensor is determined to be a low-temperature object not exceeding 500° C., the measurement unit measures the temperature of the measurement object based on the output of the output adder, which is added by an addition number that is the number of outputs to be added in the output adder and is selected based on the number of rotations per unit time of the rotary filter and the number of filter divisions of the rotary filter; When the measurement object imaged by the image sensor is determined to be a high-temperature object having a temperature exceeding 500° C., the measurement unit measures a temperature of the measurement object based on an arithmetic average of outputs from the output adder; A temperature measuring method comprising the steps of:

5. A program for causing a computer to execute each of the steps recited in claim 4.

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