Temperature measurement system and method

Abstract

To reduce flickering of a thermal image by automatically adjusting a color scale without removing noise.SOLUTION: A temperature measurement system comprises: an image processing unit 200 for generating a thermal image by converting the temperature corresponding to each pixel of temperature distribution data measured by an infrared array sensor 1 into each color; a display unit 201 for displaying the thermal image; and a scale adjustment unit 202 for adjusting the maximum value and minimum value of a color scale by acquiring the maximum value and minimum value of temperature in the temperature distribution data measured by the sensor 1. The scale adjustment unit 202 includes: updating the maximum value of the color scale to the maximum value of temperature when the amount of variation of the maximum value of temperature to the maximum value of the color scale exceeds a threshold level; and updating the minimum value of the color scale to the minimum value of temperature when the amount of variation of the minimum value of temperature to the minimum value of the color scale exceeds a threshold level.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a temperature measurement system and method for measuring a temperature distribution of a measurement object and displaying the temperature distribution using color gradation. [Background technology]

[0002] Conventionally, infrared array sensors that detect infrared rays emitted from objects have been put to practical use (see Patent Documents 1 to 3). Infrared array sensors can measure human body temperature and estimate the location and number of people in a room.

[0003] Temperature measurement systems using infrared array sensors are equipped with a function called a thermoviewer that visualizes the temperature of the object being measured. In order to keep the thermoviewer easy to see even when the temperature in the measurement range changes significantly (for example, by a few degrees Celsius to a few tens of degrees Celsius), it is desirable to have an automatic color scale adjustment function. One possible method of automatic adjustment is to set the maximum and minimum temperature values ​​as the maximum and minimum values ​​of the color scale every time temperature data is received.

[0004] However, inexpensive infrared array sensors have the problem of large noise (measurement error). Because of this noise, the maximum and minimum temperature values ​​change frequently, so if an automatic color scale adjustment function like the one described above is introduced, the maximum and minimum values ​​of the color scale will change frequently, causing the thermo viewer to flicker and making it difficult to view.

[0005] Therefore, it is conceivable to remove noise as in the techniques disclosed in Patent Documents 1 to 3. If the color scale is automatically adjusted after removing noise, flickering of the thermo viewer can be suppressed. However, there is a problem in that if the color scale is automatically adjusted after removing temporal and spatial noise, it becomes impossible to confirm the spatial locality of the noise.

[0006] The spatial locality of noise means that there is a difference in the magnitude of noise, for example, between the center and the periphery in a temperature distribution display image. The spatial locality of noise may differ depending on the material, manufacturing method, and design method of the lens used in the infrared array sensor. Since the use of the infrared array sensor may change depending on the difference in the spatial locality of noise, it is necessary to check the spatial locality of noise at the prototype and development stage of the infrared array sensor. Therefore, it is desirable to be able to automatically adjust the color scale without removing noise. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2022-181356 A [Patent Document 2] Patent Publication No. 2021-179404 [Patent Document 3] Special Publication No. 2022-540161 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a temperature measurement system and method that can automatically adjust the color scale to suppress flickering in thermal images without performing noise removal. [Means for solving the problem]

[0009] The temperature measurement system of the present invention comprises a sensor configured to measure the temperature distribution of a measurement object, an image processing unit configured to convert the temperature indicated by each pixel of the temperature distribution data measured by the sensor into a color to generate a thermal image, a display unit configured to display the thermal image, and a scale adjustment unit configured to acquire maximum and minimum temperature values ​​in the temperature distribution data measured by the sensor and adjust maximum and minimum values ​​of a color scale indicating a temperature range to be displayed in the thermal image, wherein the scale adjustment unit updates the maximum value of the color scale to the maximum temperature when an amount of change in the maximum temperature value relative to the maximum value of the color scale exceeds a threshold value, and updates the minimum value of the color scale to the minimum temperature when an amount of change in the minimum temperature value relative to the minimum value of the color scale exceeds the threshold value, and the image processing unit converts the temperature indicated by each pixel of the temperature distribution data into a color based on the maximum and minimum values ​​of the color scale.

[0010] Furthermore, one configuration example of the temperature measurement system of the present invention is characterized in that it further includes a threshold setting unit configured to increase the threshold by a predetermined change amount when at least one of the maximum and minimum values ​​of the color scale is updated. Furthermore, one configuration example of the temperature measurement system of the present invention is characterized in that it further includes a noise measurement unit configured to measure noise contained in the temperature distribution data measured by the sensor, and a threshold setting unit configured to refer to the measurement result of the noise measurement unit when at least one of the maximum and minimum values ​​of the color scale is updated, and to raise the threshold by a predetermined change amount when it is determined that the cause of the update is a change in the temperature data due to noise. In addition, in one configuration example of the temperature measurement system of the present invention, the threshold setting unit is characterized in that when neither the maximum nor minimum value of the color scale is updated and it is determined that the threshold should be changed, the threshold setting unit lowers the threshold by a predetermined change amount. In addition, in one configuration example of the temperature measurement system of the present invention, the threshold setting unit is characterized in that it determines that the threshold should be changed when the threshold has not been changed for a specified time or longer since the threshold was last changed.

[0011] In addition, in one configuration example of the temperature measurement system of the present invention, the threshold setting unit is characterized in that when at least one of the maximum and minimum values ​​of the color scale is updated and it is determined that the threshold should be changed, the threshold setting unit raises the threshold by a predetermined change amount, and when neither the maximum nor minimum values ​​of the color scale is updated and it is determined that the threshold should be changed, the threshold setting unit lowers the threshold by the predetermined change amount. In addition, in one configuration example of the temperature measurement system of the present invention, the threshold setting unit is characterized in that it determines that the threshold should be changed when the threshold has not been changed for a specified time or longer since the threshold was last changed. Moreover, one configuration example of the temperature measurement system of the present invention is characterized in that it further includes a noise measurement unit configured to measure noise contained in the temperature distribution data measured by the sensor, and a threshold setting unit configured to refer to the measurement result of the noise measurement unit and set the threshold value larger than the maximum value of the difference between the noise and the temperature.

[0012] Further, the temperature measurement method of the present invention includes a first step of measuring the temperature distribution of the object to be measured, a second step of acquiring maximum and minimum temperature values ​​in the temperature distribution data measured in the first step and adjusting maximum and minimum values ​​of a color scale indicating the temperature range to be displayed in a thermal image, a third step of converting the temperature indicated by each pixel of the temperature distribution data measured in the first step into a color to generate a thermal image, and a fourth step of displaying the thermal image, wherein the second step includes a step of updating the maximum value of the color scale to the maximum value of the temperature when a change amount of the maximum value of the temperature relative to the maximum value of the color scale exceeds a threshold value, and updating the minimum value of the color scale to the minimum value of the temperature when a change amount of the minimum value of the temperature relative to the minimum value of the color scale exceeds the threshold value, and the third step includes a step of converting the temperature indicated by each pixel of the temperature distribution data into a color based on the maximum and minimum values ​​of the color scale. Effect of the Invention

[0013] According to the present invention, by providing a scale adjustment unit, the color scale can be automatically adjusted without removing noise. In the present invention, the color scale is changed only when the amount of change in the maximum or minimum measured temperature exceeds a threshold value, so that even when an inexpensive, low-resolution sensor is used, the color scale is not changed frequently and flickering of the thermal image can be suppressed. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram showing a configuration of a temperature measuring system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a flowchart illustrating the operation of the temperature measurement system according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a block diagram showing a configuration of a temperature measuring system according to a second embodiment of the present invention. [Figure 4]FIG. 4 is a flowchart illustrating the operation of the temperature measuring system according to the second embodiment of the present invention. [Diagram 5] FIG. 5 is a block diagram showing a configuration of a temperature measuring system according to a third embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart illustrating the operation of the temperature measuring system according to the third embodiment of the present invention. [Figure 7] FIG. 7 is a block diagram showing a configuration of a temperature measuring system according to a fourth embodiment of the present invention. [Figure 8] FIG. 8 is a flowchart illustrating the operation of the temperature measuring system according to the fourth embodiment of the present invention. [Figure 9] FIG. 9 is a block diagram showing a configuration of a temperature measuring system according to a fifth embodiment of the present invention. [Figure 10] FIG. 10 is a flowchart illustrating the operation of the threshold setting unit according to the fifth embodiment of the present invention. [Figure 11] FIG. 11 is a diagram for explaining a method of setting a threshold in a threshold setting unit according to the fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [First Example] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of a temperature measurement system according to a first embodiment of the present invention. The temperature measurement system includes an infrared array sensor 1, a computer 2, and a display device 3.

[0016] The computer 2 includes a CPU (Central Processing Unit) 20 and a memory 21. The CPU 20 executes the following processes in accordance with a program stored in the memory 21, and functions as an image processing unit 200, a display unit 201, and a scale adjustment unit 202.

[0017] The infrared array sensor 1 has a structure in which multiple infrared sensor chips are arranged in a plane. Each infrared sensor chip measures infrared rays emitted from an object at a distant point, thereby determining the temperature.

[0018] 2 is a flow chart for explaining the operation of the temperature measurement system of this embodiment. The temperature distribution data output from the infrared array sensor 1 is stored in the memory 21 of the computer 2 (step S100 in FIG. 2). The scale adjustment unit 202 adjusts the maximum temperature value T max and the minimum value T min (Step S101 in FIG. 2).

[0019] The scale adjustment unit 202 adjusts the maximum temperature T max the current maximum value ST of the color scale that indicates the temperature range to be displayed in the thermal image max Compare with the minimum temperature T min the current minimum value ST of the color scale min Compare with the current maximum value of the color scale ST max and the minimum value ST min is stored in the memory 21.

[0020] The scale adjustment unit 202 adjusts the maximum value ST of the color scale. max The maximum temperature T max If the change in exceeds the threshold value α (YES in step S102), the maximum value ST of the color scale max The maximum temperature T max (Step S103). The maximum value of the color scale ST max Maximum temperature T max The change in temperature exceeds the threshold value α when the maximum temperature T max and the maximum value of the color scale ST max This means that the absolute value of the difference between the two is greater than the threshold value α. α<|T max -ST max | ···(1)

[0021] In addition, the scale adjustment unit 202 adjusts the minimum value ST of the color scale. min The minimum temperature T min If the amount of change in exceeds the threshold value α (YES in step S104), the minimum value ST of the color scale is min The minimum temperature T min (Step S105). The minimum value of the color scale ST min The minimum temperature T min The change in temperature exceeds the threshold value α when the minimum temperature T min and the minimum value of the color scale ST min This means that the absolute value of the difference between the two is greater than the threshold value α. α<|T min -ST min | ···(2)

[0022] In this embodiment, the threshold value α is set based on the noise level (maximum value T max , minimum value T min It is a positive real value that is set in advance taking into account the degree of change in For example, the current maximum value of the color scale ST max is 30°C, the current minimum value of the color scale is ST min If the temperature is 20°C and the threshold value α is 2°C, the maximum value of the temperature T max If the temperature is higher than 32°C or lower than 28°C, the maximum temperature T max and the maximum value of the color scale ST max = 30°C, the absolute value of the difference is greater than the threshold value α = 2°C, so the maximum value ST of the color scale max = 30℃ is the maximum temperature T max will be updated.

[0023] Also, the minimum temperature T min If is higher than 22°C or lower than 18°C, the minimum temperature T min and the minimum value of the color scale ST min = 20°C, the absolute value of the difference is greater than the threshold value α = 2°C, so the minimum value ST of the color scale min = 20℃ is the minimum temperature T minwill be updated.

[0024] The scale adjustment unit 202 adjusts the current maximum value ST of the color scale after the processing of steps S102 to S105. max and the minimum value ST min and a color range with a predetermined number of gradations (for example, 256 gradations), the maximum value ST max to minimum value ST min A color is assigned to each temperature in the temperature range from 0 to 100° C., that is, a color scale is determined for converting the temperature distribution data into thermal imaging data (step S106).

[0025] The image processing unit 200 converts the temperature indicated by each pixel of the two-dimensional temperature distribution data measured by the infrared array sensor 1 into color based on the color scale determined by the scale adjustment unit 202, and generates a thermal image (step S107). The display unit 201 causes the display device 3 to display the thermal image generated by the image processing unit 200 (step S108). In this way, a thermal image showing the temperature distribution of the measurement object is displayed on the screen of the display device 3. The temperature measurement system repeatedly executes the processes of steps S100 to S108.

[0026] As described above, in this embodiment, the color scale can be automatically adjusted without removing noise. max The minimum change in temperature T min Since the color scale is changed only when the amount of change in exceeds the threshold value α, the color scale is not changed frequently even when an inexpensive, low-resolution infrared array sensor is used, and flickering of the thermal image can be suppressed.

[0027] [Second Example] Next, a second embodiment of the present invention will be described. Fig. 3 is a block diagram showing the configuration of a temperature measurement system according to the second embodiment of the present invention. The temperature measurement system of this embodiment includes an infrared array sensor 1, a computer 2a, and a display device 3.

[0028] The computer 2a includes a CPU 20a and a memory 21. The CPU 20a executes the following processes in accordance with a program stored in the memory 21, and functions as an image processing unit 200, a display unit 201, a scale adjustment unit 202, and a threshold setting unit 203.

[0029] Fig. 4 is a flow chart for explaining the operation of the temperature measuring system of this embodiment. The processing of steps S200 to S205 in Fig. 4 is the same as the processing of steps S100 to S105 in the first embodiment.

[0030] The threshold setting unit 203 sets the maximum value ST of the color scale. max and the minimum value ST min If at least one of them has been updated (YES in step S206), the threshold value α is increased by a predetermined change amount Δα as shown in equation (3) (step S207). α←α+Δα (3)

[0031] The change width Δα is a preset positive real value, for example, 0.1° C. Furthermore, the threshold setting unit 203 changes the maximum value ST max and the minimum value ST min If neither of them has been updated (NO in step S206), it is determined whether the threshold value α should be lowered (step S208). The threshold value setting unit 203 measures the elapsed time since the threshold value α was last changed, for example, and if the threshold value α has not been changed for a period of time equal to or longer than the specified time T since the threshold value α was last changed, it determines that the threshold value α has risen excessively and should be lowered (YES in step S208), and lowers the threshold value α by a predetermined change amount Δα as shown in equation (4) (step S209). α←α-Δα (4)

[0032] The threshold setting unit 203c determines that the threshold α should not be lowered if the time elapsed since the previous change of the threshold α is less than the specified time T (NO in step S208). The specified time T is a measure of the degree of responsiveness with which the threshold change is performed.

[0033] 4 are the same as the processes of steps S106 to S108 in the first embodiment. The temperature measurement system repeatedly executes the processes of steps S200 to S212.

[0034] As described above, in this embodiment, the maximum value ST of the color scale max and the minimum value ST min The threshold value α is automatically changed each time at least one of the threshold values ​​α and α is updated. However, the threshold value α does not only need to be increased, but also needs to be appropriately decreased. If the threshold value α is set too high, it will not be possible to express the values ​​near the maximum and minimum temperature values ​​in different colors, and the color expression range will become narrower, making it difficult to see. Therefore, in this embodiment, if it is determined that the threshold value α has risen too high and should be lowered, the threshold value α is lowered. This makes it possible to prevent the threshold value α from rising too high.

[0035] [Third Example] Next, a third embodiment of the present invention will be described. Fig. 5 is a block diagram showing the configuration of a temperature measurement system according to the third embodiment of the present invention. The temperature measurement system of this embodiment includes an infrared array sensor 1, a computer 2b, and a display device 3.

[0036] The computer 2b includes a CPU 20b and a memory 21. The CPU 20b executes the following processes in accordance with a program stored in the memory 21, and functions as an image processing unit 200, a display unit 201, a scale adjustment unit 202, a threshold setting unit 203b, and a noise measurement unit 204.

[0037] Fig. 6 is a flow chart for explaining the operation of the temperature measuring system of this embodiment. The processing of steps S300 to S305 in Fig. 6 is the same as the processing of steps S100 to S105 and S200 to S205 in the first and second embodiments.

[0038] The threshold setting unit 203b sets the maximum value ST of the color scale. max and the minimum value ST minIf at least one of them has been updated (YES in step S306), it is determined whether the update is due to a change in temperature data caused by noise (step S307).

[0039] The noise measurement unit 204 constantly measures noise contained in the temperature distribution data measured by the infrared array sensor 1. For example, the noise measurement unit 204 records as noise a temperature whose absolute value of the change width per certain time exceeds a predetermined change width threshold. The measurement results of the noise measurement unit 204 are stored in the memory 21.

[0040] The threshold setting unit 203b determines the maximum value ST of the color scale by the process of step S303. max When the temperature is updated, the noise measurement unit 204 measures the time series data of the noise, and the maximum temperature T max If the noise is recorded at the time when is measured, the maximum value T max The noise value at the time when is measured and the maximum value ST before updating the color scale max The threshold setting unit 203b compares the noise value with the maximum value ST before the update of the color scale. max If the absolute value of the difference between is greater than the threshold value α, the maximum value ST max It is determined that the cause of the update is a change in temperature data due to noise (YES in step S307).

[0041] In addition, the threshold setting unit 203b sets the minimum value ST of the color scale by the process of step S305. min When the temperature is updated, the noise measurement unit 204 measures the time series data of the noise, and the minimum temperature T min If the noise is recorded at the time when is measured, the minimum value T min The noise value at the time when is measured and the minimum value ST before updating the color scale min The threshold setting unit 203b compares the noise value with the minimum value ST before the update of the color scale. min If the absolute value of the difference between is greater than the threshold value α, the minimum value ST minIt is determined that the cause of the update is a change in temperature data due to noise (YES in step S307).

[0042] The threshold setting unit 203b sets the maximum value ST max and the minimum value ST min If it is determined that the update is caused by a change in temperature data due to noise, the threshold value α is increased by a predetermined change amount (step S308). If it is determined that the update is not caused by a change in temperature data due to noise (NO in step S307), the threshold value setting unit 203b does not change the threshold value α.

[0043] The temperature data measured by the infrared array sensor 1 changes due to temperature changes in the object to be measured or noise. The threshold value α needs to be changed only when the temperature data changes due to noise. The reason why the threshold value α is not changed in response to temperature changes in the object to be measured is that the threshold value α may increase more than necessary when the temperature changes in the object to be measured occur continuously.

[0044] 6 are the same as the processes of steps S208 to S212 in the second embodiment. The temperature measurement system repeatedly executes the processes of steps S300 to S313.

[0045] As described above, in this embodiment, the threshold value α can be automatically changed in the same manner as in the second embodiment. max and the minimum value ST min By determining whether the update is caused by a change in temperature data due to noise, an excessive increase in the threshold value α can be prevented.

[0046] [Fourth Example] Next, a fourth embodiment of the present invention will be described. Fig. 7 is a block diagram showing the configuration of a temperature measurement system according to the fourth embodiment of the present invention. The temperature measurement system of this embodiment includes an infrared array sensor 1, a computer 2c, and a display device 3.

[0047] The computer 2c includes a CPU 20c and a memory 21. The CPU 20c executes the following processes in accordance with the programs stored in the memory 21, and functions as an image processing unit 200, a display unit 201, a scale adjustment unit 202, and a threshold setting unit 203c.

[0048] Fig. 8 is a flowchart for explaining the operation of the temperature measuring system of this embodiment. The processing in steps S400 to S405 in Fig. 8 is the same as the processing in steps S100 to S105, S200 to S205, and S300 to S305 in the first to third embodiments.

[0049] The threshold setting unit 203c sets the maximum value ST of the color scale max and the minimum value ST min When at least one of them is updated (YES in step S406), it is determined whether the threshold value α should be increased (step S407). For example, the threshold value setting unit 203c measures the elapsed time since the threshold value α was last changed, and when the threshold value α has not been changed for a period of time equal to or longer than the specified time T since the threshold value α was last changed, it determines that the threshold value α should be increased (YES in step S407) and increases the threshold value α by a predetermined change width Δα as shown in equation (3) (step S408). In addition, when the elapsed time since the threshold value α was last changed is less than the specified time T, the threshold value setting unit 203c determines that the threshold value α should not be increased (NO in step S407).

[0050] The processing of steps S409 to S413 in Fig. 8 is the same as the processing of steps S208 to S212 and S309 to S313 in the second and third embodiments. The temperature measurement system repeatedly executes the processing of steps S400 to S413.

[0051] As described above, in this embodiment, in addition to determining whether or not to lower the threshold value α as in the second embodiment, it is also determined whether or not to raise the threshold value α, which makes it possible to prevent the threshold value α from increasing excessively.

[0052] [Fifth Example] Next, a fifth embodiment of the present invention will be described. Fig. 9 is a block diagram showing the configuration of a temperature measurement system according to the fifth embodiment of the present invention. The temperature measurement system of this embodiment includes an infrared array sensor 1, a computer 2d, and a display device 3.

[0053] The computer 2d includes a CPU 20d and a memory 21. The CPU 20d executes the following processes in accordance with a program stored in the memory 21, and functions as an image processing unit 200, a display unit 201, a scale adjustment unit 202, a threshold setting unit 203d, and a noise measurement unit 204.

[0054] The operations of the image processing unit 200, the display unit 201, and the scale adjustment unit 202 are the same as those in the first embodiment, and therefore a description thereof will be omitted. 10 is a flowchart for explaining the operation of the threshold setting unit 203d of this embodiment. As in the third embodiment, the noise measurement unit 204 constantly measures noise contained in the temperature distribution data measured by the infrared array sensor 1.

[0055] The threshold setting unit 203d refers to the noise time series data measured by the noise measuring unit 204 and stored in the memory 21. For example, if the noise time series data as shown in Fig. 11 is stored in the memory 21, the threshold setting unit 203d sets a new threshold α to a value obtained by adding a predetermined value β to a value A having the largest absolute value of the temperature change range among the temperatures recorded as the noise time series data (the absolute value of the temperature range of the noise data having the largest change range from the average temperature value of the noise time series data as the reference).

[0056] α ← A + β (5) The range of the noise time series data to be referenced may be a part of the image, may be the entire image, or may be the maximum or minimum value of the temperature distribution data.

[0057] The predetermined value β is a positive real value that is set in advance. In this way, the threshold value α is set to be larger than the maximum value of the temperature change range recorded as noise. The threshold value setting unit 203d executes the process of FIG. 10 at regular intervals. In this manner, in this embodiment, by setting the threshold value α based on the magnitude of the noise, flickering on the screen can be suppressed. [Industrial Applicability]

[0058] The present invention can be applied to a temperature measurement system that displays a temperature distribution by color tones. [Explanation of symbols]

[0059] 1...infrared array sensor, 2, 2a to 2d...computer, 3...display device, 20, 20a to 20d...CPU, 21...memory, 200...image processing unit, 201...display unit, 202...scale adjustment unit, 203, 203b to 203d...threshold setting unit, 204...noise measurement unit.

Claims

1. A sensor configured to measure a temperature distribution of a measurement object; an image processing unit configured to convert a temperature indicated by each pixel of the temperature distribution data measured by the sensor into a color to generate a thermal image; a display configured to display the thermal image; a scale adjustment unit configured to acquire maximum and minimum temperature values ​​in the temperature distribution data measured by the sensor and adjust maximum and minimum values ​​of a color scale indicating a temperature range to be displayed in the thermal image, the scale adjustment unit updates the maximum value of the color scale to the maximum value of the temperature when a change amount of the maximum value of the temperature relative to the maximum value of the color scale exceeds a threshold value, and updates the minimum value of the color scale to the minimum value of the temperature when a change amount of the minimum value of the temperature relative to the minimum value of the color scale exceeds the threshold value; The temperature measuring system according to claim 1, wherein the image processing unit converts the temperature indicated by each pixel of the temperature distribution data into a color based on a maximum value and a minimum value of the color scale.

2. 2. The temperature measurement system of claim 1, A temperature measurement system further comprising a threshold setting unit configured to increase the threshold by a predetermined change amount when at least one of a maximum value and a minimum value of the color scale is updated.

3. 2. The temperature measurement system of claim 1, a noise measurement unit configured to measure noise included in the temperature distribution data measured by the sensor; a threshold setting unit configured to, when at least one of the maximum and minimum values ​​of the color scale is updated, refer to the measurement results of the noise measuring unit, and when it is determined that the cause of the update is a change in temperature data due to noise, raise the threshold by a predetermined change amount.

4. 4. The temperature measurement system according to claim 2, The temperature measurement system is characterized in that the threshold setting unit lowers the threshold by a predetermined change amount when neither the maximum nor minimum values ​​of the color scale are updated and it is determined that the threshold should be changed.

5. 5. The temperature measurement system according to claim 4, The temperature measurement system, wherein the threshold setting unit determines that the threshold should be changed if the threshold has not been changed for a specified time or longer since the threshold was last changed.

6. 3. The temperature measurement system according to claim 2, The temperature measurement system is characterized in that the threshold setting unit raises the threshold by a predetermined change amount when at least one of the maximum and minimum values ​​of the color scale is updated and it is determined that the threshold should be changed, and lowers the threshold by the predetermined change amount when neither the maximum nor minimum values ​​of the color scale is updated and it is determined that the threshold should be changed.

7. 7. The temperature measurement system according to claim 6, The temperature measurement system, wherein the threshold setting unit determines that the threshold should be changed if the threshold has not been changed for a specified time or longer since the threshold was last changed.

8. 2. The temperature measurement system of claim 1, a noise measurement unit configured to measure noise included in the temperature distribution data measured by the sensor; and a threshold setting unit configured to refer to a measurement result of the noise measuring unit and set the threshold value greater than a maximum value of a difference between the noise and the temperature.

9. A first step of measuring a temperature distribution of a measurement object; a second step of acquiring maximum and minimum values ​​of temperature in the temperature distribution data measured in the first step and adjusting maximum and minimum values ​​of a color scale indicating a temperature range to be displayed in a thermal image; a third step of converting the temperature indicated by each pixel of the temperature distribution data measured in the first step into a color to generate a thermal image; and a fourth step of displaying the thermal image. the second step includes a step of updating the maximum value of the color scale to the maximum value of the temperature when an amount of change of the maximum value of the temperature relative to the maximum value of the color scale exceeds a threshold value, and updating the minimum value of the color scale to the minimum value of the temperature when an amount of change of the minimum value of the temperature relative to the minimum value of the color scale exceeds the threshold value; The temperature measuring method according to the present invention, wherein the third step includes a step of converting the temperature indicated by each pixel of the temperature distribution data into a color based on a maximum value and a minimum value of the color scale.

Images