Measuring device and measuring method

Abstract

To improve a temperature measurement result obtained by a thermography device.SOLUTION: A thermography device (100) includes: an acquisition unit (41) that acquires a measurement result obtained using an imaging element (51) for measuring electromagnetic waves emitted from a measurement target, during a measurement period (t) shorter than a thermal time constant (τ) of the imaging element (51); and a calculation unit (43) that calculates the temperature of the measurement target (IT) using a plurality of measurement results measured by the imaging element (51) during different measurement periods (t).SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a measuring device and a measuring method for measuring the temperature of a measurement object, such as a thermography device.

Background Art

[0002] Conventionally, techniques for imaging a thermal image showing the thermal distribution of an imaging object, such as a thermography device, are known. As an example of such a technique, when taking a thermal image using an infrared sensor, based on the difference between the imaging result of a predetermined pixel and the imaging result of a pixel adjacent to the predetermined pixel, the imaging result of the predetermined pixel is corrected, thereby preventing image blur, that is, image flow, which occurs when the imaging object or the thermography device moves.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional technology, it cannot be said that the temperature of the imaging object is appropriately measured.

[0005] For example, in the above-described conventional technology, based on the response characteristics of the infrared sensor, the measurement result of a predetermined pixel is corrected based on the difference between the measurement result of the predetermined pixel and the measurement result of a pixel adjacent to the predetermined pixel. Therefore, in the above-described conventional technology, although image blur, that is, image flow, which occurs when the imaging object or the imaging device moves, can be prevented, it cannot be said that the temperature of the imaging object is appropriately measured.

[0006] On the one hand, a thermographic device may be used for various inspections based on the temperature of the object to be photographed. For example, based on a thermal image captured using a thermographic device, the temperature, amount, position, splashing or elongation of hot melt is determined, and based on the determination result, the adhesion state of the hot melt is determined. However, in the above-described conventional technology, since the temperature of the hot melt cannot be measured appropriately, there is a risk that the inspection cannot be performed appropriately.

[0007] In addition, not only when the object to be photographed or the thermographic device moves, but also a desire such as searching for an object to be photographed whose temperature changes rapidly may be considered. However, in the above-described conventional technology, since only the image flow is prevented by using the information of adjacent pixels, when the infrared response characteristics cannot follow the temperature change, the temperature cannot be measured appropriately.

[0008] The present application is for solving such problems and aims to improve the measurement result of temperature by a thermographic device.

Means for Solving the Problems

[0009] The measuring device according to the present application is a measurement result using an imaging element that measures electromagnetic waves radiated from a measurement object, and an acquisition unit that acquires a measurement result measured in a measurement period shorter than the thermal time constant of the imaging element, and a calculation unit that calculates the temperature of the measurement object using a plurality of measurement results measured by the imaging element in different measurement periods.

[0010] Further, in the above-described measuring device, the calculation unit may calculate the temperature of the measurement object based on the amount of change in a plurality of measurement results.

[0011] Further, in the above-described measuring device, the calculation unit may calculate the temperature of the measurement object using a first measurement result measured in a first measurement period and a second measurement result measured in a second measurement period before the first measurement period.

[0012] Further, in the measurement device described above, the calculation unit may use the measurement result measured immediately before the first measurement result as the second measurement result.

[0013] Further, in the measurement device described above, the calculation unit may calculate the temperature of the measurement target based on a value obtained by dividing a value obtained by subtracting a value obtained by integrating the first measurement result with a predetermined coefficient having a negative value of the natural logarithm as the base and dividing the measurement period by the thermal time constant from the second measurement result, and dividing the result by a value obtained by subtracting the predetermined coefficient from 1.

[0014] Further, in the measurement device described above, the calculation unit may calculate the temperature of the measurement target using the first measurement result and a plurality of measurement results measured before the first measurement period.

[0015] Further, in the measurement device described above, the acquisition unit may acquire a measurement result for each pixel of the imaging element, and the calculation unit may calculate the temperature of the region that is the emission source of the electromagnetic wave measured by the pixel for each pixel of the measurement target.

[0016] Further, in the measurement device described above, the acquisition unit may acquire, as a measurement result, the temperature of the imaging target measured based on the measurement result of the electromagnetic wave by the imaging element, and the calculation unit may calculate the temperature of the measurement target based on a plurality of temperatures based on the measurement results of different measurement periods.

[0017] Further, in the measurement device described above, the acquisition unit may acquire a measurement result using a non-cooled imaging element.

[0018] Further, in the measurement device described above, the acquisition unit may acquire a measurement result using an imaging element that measures infrared rays radiated from the measurement target.

[0019] Further, in the measurement device described above, the acquisition unit may acquire a measurement result using an imaging element that measures the radiation luminance of infrared rays radiated from the measurement target.

[0020] Further, in the measurement device described above, the acquisition unit may acquire a measurement result from an imaging device having an imaging element.

[0021] Further, the measurement device described above may have an imaging unit having an imaging element.

Advantages of the Invention

[0022] The measurement device described above acquires a plurality of measurement results measured in a measurement period shorter than the thermal time constant, which is the time interval at which the imaging element can appropriately measure the temperature of the imaging target, that is, a plurality of measurement results measured at different timings in time series. Then, the measurement device calculates the temperature of the measurement target using the plurality of acquired measurement results. That is, the measurement device calculates the temperature of the measurement target using the measurement results measured at different timings, rather than using the information of adjacent pixels measured at the same timing.

[0023] For example, when the imaging element is a non-cooled imaging element that measures the radiant intensity of infrared rays, the temperature based on the measurement result of the imaging element may change rapidly at the start of imaging and then gradually approach the temperature of the measurement target as an exponential function. Therefore, if the measurement device performs measurements at time intervals shorter than the period during which the temperature based on the measurement result sufficiently approaches the temperature of the measurement target (i.e., the thermal time constant), it cannot measure an appropriate temperature.

[0024] Therefore, the measurement device acquires a plurality of measurement results obtained by measuring the measurement target at time intervals shorter than the thermal time constant. Then, the measurement device estimates, for example, for each pixel of the imaging element, what the actual temperature of the measurement target was based on the amount of change between the imaging result at timing T1 and the imaging result at timing T2 taken next to timing T1. That is, the measurement device estimates the temperature that would finally be measured from the amount of change in the temperature based on the measurement results at at least any two points in the function showing the relationship between the temperature based on the measurement result of the imaging element and the imaging period.

[0025] As a result of such processing, even when the measuring device captures an object to be measured at time intervals shorter than the thermal time constant, the measuring device can appropriately measure the temperature of the object to be captured. As a result, the measuring device can appropriately measure the temperature of the object to be measured even when, for example, the object to be measured or the measuring device moves, or when the temperature of the object to be measured changes rapidly.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0027] Next, embodiments will be described with reference to the drawings. In the following description, the same reference numerals are given to the common components in each embodiment, and repeated descriptions are omitted.

[0028] [Regarding the Overview of the Thermography Device] First, the outline of the thermography device will be described with reference to FIG. 1. FIG. 1 is a diagram showing the outline of the thermography device in the embodiment. In the example shown in FIG. 1, the thermography device 100 includes a controller 10 and an infrared camera 50. The controller 10 is also connected to a terminal device 200.

[0029] Such a thermography device 100 measures the radiant luminance of infrared rays generated from the measurement target using the imaging element included in the infrared camera 50, and measures the temperature of the measurement target according to the measured radiant luminance. For example, the thermography device 100 calibrates calibration information indicating the correspondence between the radiant luminance and the temperature by measuring the radiant luminance of infrared rays generated from a blackbody furnace while changing the temperature of the blackbody furnace. Then, the thermography device calculates the temperature of the measurement target from the radiant luminance generated from the measurement target based on the calibrated calibration information (hereinafter referred to as "calibration information").

[0030] Also, when measuring the temperature of a workpiece or the like in a factory or the like, the thermography device 100 adjusts the distance from the measurement target to match the measurement distance during calibration. Then, the thermography device 100 calculates the temperature of the measurement target from the measured radiant luminance of the infrared rays using the calibration information.

[0031] For example, the infrared camera 50 uses, as an imaging element, an FPA (Focal Plane Array) such as a thermopile array sensor composed of a plurality of thermopiles to measure the radiant luminance of infrared rays emitted from the measurement target IT flowing through the inspection line IL1, and transmits the measurement result to the controller 10. Note that the infrared camera 50 may use various thermal infrared sensors such as a microbolometer or a pyroelectric sensor, or may use various quantum infrared sensors.

[0032] In such a case, the controller 10 measures the temperature of the IT under measurement based on the measurement results. More specifically, the controller 10 measures the temperature distribution on the surface of the IT under measurement by measuring the temperature of each region on the surface of the IT under measurement. Then, the controller 10 generates a thermal image indicating the measured temperature distribution. For example, the controller 10 generates, as a thermal image, data associating signal values indicating the amount of infrared rays and temperature measured for each pixel. Then, the controller 10 provides the generated thermal image to the terminal device 200.

[0033] Note that the controller 10 may provide, for example, an inspection result of the IT under measurement based on the measured temperature distribution. For example, the controller 10 calculates the area of the range in which the temperature of the IT under measurement is equal to or higher than a predetermined temperature based on the thermal image. Then, when the calculated area exceeds a predetermined threshold value, the controller 10 may output that the inspection result of the IT under measurement is appropriate. In addition to this, for example, the controller 10 may output various inspection results according to whether the shape, temperature distribution, etc. of the range in which the temperature is equal to or higher than a predetermined temperature satisfy predetermined conditions.

[0034] Here, in order to perform inspections while flowing inspection targets such as workpieces on inspection lines in factories and the like, highly responsive sensors such as quantum infrared sensors are required. However, thermal cameras using cooled detectors are expensive and cannot be easily adopted. For example, quantum infrared sensors tend to be more expensive than thermal infrared sensors because the imaging device needs to be cooled, and maintenance can also be time-consuming. Also, when a shutter is attached to the infrared camera 50, the measurement results when the shutter is open can be corrected from the measurement results when the shutter is closed, so the accuracy of the measurement results can be improved. However, since the number of components increases, the cost and the labor for maintenance increase. Furthermore, when the infrared camera 50 has the shutter closed, it becomes impossible to capture an image of the imaging target, so it is considered inappropriate for in-line inspections that perform inspections while flowing the inspection target. For this reason, considering cost, maintainability, and the mode of in-line inspection, an infrared camera 50 that does not have a shutter and uses a thermal infrared sensor is considered desirable.

[0035] However, when the temperature is measured using such a thermal infrared sensor, the relationship between the temperature measurement result and the measurement time has the characteristic that the temperature changes exponentially with the passage of time and then gradually approaches the temperature of the measurement target. For this reason, in order to appropriately measure the temperature of the measurement target IT using a thermal infrared sensor, it is necessary to capture the measurement target IT for a period longer than a predetermined measurement period (i.e., the thermal time constant).

[0036] For example, FIG. 2 is a diagram showing an example of the relationship between the temperature measured by the thermography apparatus according to the embodiment and the imaging time. In the example shown in FIG. 2, a graph showing an example of the relationship between temperature and elapsed time is shown, with the horizontal axis representing the time elapsed since each pixel of the infrared sensor started capturing the measurement target IT and the vertical axis representing the temperature based on the output of each pixel at each timing.

[0037] For example, when a certain pixel starts capturing the measurement target IT from timing T0, the temperature output as the measurement result at that pixel rises exponentially with the passage of time. Then, the temperature output as the measurement result becomes the same as the temperature of the measurement target at timing TX according to the characteristics of the infrared sensor which is the imaging device. After that, when the measurement target IT moves out of the imaging range at timing TY, the temperature output as the measurement result decreases exponentially to the room temperature.

[0038] Thus, the temperature that the thermography device 100 uses as the measurement result changes depending on the time elapsed since the start of the measurement. Therefore, in order to appropriately measure the temperature of the measurement target, it is necessary to measure the temperature of the measurement target for a period longer than the thermal time constant corresponding to the specification of the infrared sensor (for example, the period from timing T0 to TX).

[0039] However, when the measurement target IT is moving at high speed, the measurement target IT moves within a period shorter than the thermal time constant of the infrared sensor, and the area measured by each pixel in the measurement target IT changes. As a result, when the measurement target IT is moving at high speed, it becomes impossible to appropriately measure the temperature in each area of the measurement target IT.

[0040] For example, FIG. 3 is a first diagram showing an example of a thermal image of the measurement target. In the example shown in FIG. 3, an example of a thermal image showing the temperature of the measurement target IT is shown such that it changes from black to white as the temperature increases. Also, in the example shown in FIG. 3, an example of a thermal image showing the measurement result when the temperature of the measurement target IT is measured for a period longer than the thermal time constant of the infrared sensor with the measurement target IT stopped is shown.

[0041] As shown in FIG. 3, when the IT to be measured is photographed for a period longer than the thermal time constant of the infrared sensor, a clear thermal image without image flow can be obtained in the outer edge region EA including the outer extension of the IT to be measured. Also, as shown in FIG. 3, when the IT to be measured is photographed for a period longer than the thermal time constant of the infrared sensor, a thermal image showing an appropriate temperature can be obtained in the inner edge region EA including the central portion of the IT to be measured.

[0042] On the other hand, FIG. 4 is a second diagram showing an example of a thermal image of the object to be measured. The example shown in FIG. 4 shows an example of a thermal image of the measurement result when the temperature of the moving IT to be measured is measured in a measurement period shorter than the thermal time constant of the infrared sensor. In the example shown in FIG. 4, an example of a thermal image showing the measurement result when the IT to be measured is moved from the left side to the right side of the drawing is shown. In the example shown in FIG. 4, as a result of the IT to be measured moving at high speed, the radiant intensity of the infrared rays measured by each pixel of the infrared sensor changes in a period shorter than the thermal time constant of the infrared sensor, and image flow occurs.

[0043] More specifically, in the front outer edge region FEA1 including the outer extension in the moving direction of the IT to be measured, since the IT to be measured changes from a state without the IT to be measured to a state with the IT to be measured during a period shorter than the thermal time constant, a region where the temperature changes stepwise together with image flow has occurred. Also, in the rear outer edge region BEA1 including the outer extension opposite to the moving direction of the IT to be measured, since the IT to be measured changes from a state with the IT to be measured to a state without the IT to be measured during a period shorter than the thermal time constant, a region where the temperature changes stepwise together with image flow has occurred. Furthermore, in the inner edge region IA1 including the central portion of the IT to be measured, since regions with different temperatures of the IT to be measured pass through the regions corresponding to each pixel during a period shorter than the thermal time constant, a temperature lower than the actual temperature is output as the measurement result.

[0044] Such problems can occur not only when the IT to be measured is moving at high speed, but also, for example, when the infrared camera 50 is changing its orientation at high speed. Further, when the surface temperature of the IT to be measured changes rapidly, the temperature of the IT to be measured changes before the measurement results of each pixel of the infrared sensor reach the temperature of the IT to be measured, and an appropriate thermal image cannot be obtained.

[0045] Therefore, the thermography device 100 acquires the measurement results measured by the infrared camera 50 in a measurement period shorter than the thermal time constant, and calculates the temperature of the IT to be measured using a plurality of measurement results measured at different timings. Hereinafter, an outline of the processing executed by the thermography device 100 will be described.

[0046] [Outline of the principle] For example, as shown in FIG. 2, the thermal time constant, which is the period from timing T0 to timing TX, depends on the characteristics of the infrared sensor of the infrared camera 50. Therefore, the thermography device 100 measures the thermal time constant τ of the infrared sensor in advance. Note that such a thermal time constant τ may be a value calculated according to, for example, the design or material of the infrared sensor, or may be an actually measured value. Further, such a thermal time constant τ may be registered in advance at the time of shipment of the thermography device 100.

[0047] Subsequently, the thermography device 100 measures the temperature of the IT to be measured a plurality of times in a period shorter than the thermal time constant τ. For example, the thermography device 100 measures the temperature of the IT to be measured at timings T1 and T2 shown in FIG. 2. Then, the thermography device 100 estimates the temperature (the temperature of the solid line portion in FIG. 2) that would have been measured if the measurement had been performed for the thermal time constant τ based on the amount of change in the measurement results at timings T1 and T2.

[0048] For example, assuming that the measurement result at timing T1 is I1, the measurement result at timing T2 is I2, and the difference between timing T1 and timing T2 (i.e., the period of one frame for operating the infrared camera 50) is t, the thermography device 100 calculates, for each pixel, the measurement result I that would have been measured if the measurement had been performed for the thermal time constant τ using the following equation (1).

[0049]

Equation

[0050] As a result, even when the thermography device 100 measures the temperature of the measurement target IT in a period shorter than the thermal time constant, it can appropriately measure the temperature. For example, FIG. 5 is a third diagram showing an example of a thermal image of the measurement target. In the example shown in FIG. 5, an example of a thermal image obtained when calculating the temperature of the measurement target IT using the above-described equation (1) is shown.

[0051] More specifically, in the example shown in FIG. 5, in the front extension region FEA2 including the extension in the moving direction and the rear extension region BEA2 including the extension opposite to the traveling direction of the measurement target IT, although the temperature changes stepwise to some extent, compared with the front extension region FEA1 and the rear extension region BEA2 shown in FIG. 4, the region where the temperature changes is narrower. Also, in the example shown in FIG. 5, in the inner edge region IA1 including the central portion of the measurement target IT, a more appropriate temperature (i.e., a temperature closer to the temperature shown in FIG. 3) is measured than in FIG. 4.

[0052] In this way, the thermography device 100 measures the temperature of the measurement target IT at time intervals shorter than the thermal time constant τ, and calculates the temperature of the measurement target IT based on the amount of change in the measurement results measured at different timings. As a result of such processing, the thermography device 100 can appropriately measure the temperature of the measurement target. In other words, since the thermography device 100 corresponds to the moving speed of the measurement target IT, it can appropriately measure the temperature of the measurement target IT even when the frame rate is improved.

[0053] [Embodiment] Hereinafter, an example of an embodiment will be described. First, with reference to FIG. 6, an example of the functional configuration of the controller 10 and the infrared camera 50 of the thermography apparatus 100 will be described. FIG. 6 is a diagram showing an example of the functional configuration of the thermography apparatus according to the embodiment. In the following description, the functional configuration of the infrared camera 50 will be described first, and then the functional configuration of the controller 10 will be described.

[0054] The infrared camera 50 of the thermography apparatus 100 has an image pickup element 51 and a lens 52 in the housing. The image pickup element 51 is, for example, an element that measures the radiation luminance of infrared rays emitted from the measurement target, and provides a value indicating the radiation luminance measured by each pixel to the controller 10. The lens 52 is a lens that condenses infrared rays from the measurement target onto the image pickup element 51.

[0055] Here, the infrared camera 50 identifies the temperature of the measurement target IT by a non-cooled image pickup element 51 such as a bolometer, and generates a thermal image indicating the identified temperature. In addition, the infrared camera 50 desirably does not have a shutter in terms of maintainability, cost, and the mode of in-line inspection.

[0056] On the other hand, the controller 10 of the thermography apparatus 100 has a communication unit 20, a storage unit 30, and a control unit 40.

[0057] The communication unit 20 controls communication between the infrared camera 50 that obtains a thermal image indicating the thermal distribution of the imaging target and the terminal device 200. For example, the communication unit 20 is realized by a NIC (Network Interface Card), a USB (Universal Serial Bus) port, or the like, and controls communication between the infrared camera 50 and the terminal device 200.

[0058] The memory unit 30 is a storage device that stores various types of information, and is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, or a storage device such as a hard disk or an optical disk. For example, calibration data 31, a correction formula 32, and frame data 33 are registered in the memory unit 30.

[0059] The calibration data 31 is information for calculating the temperature of the measurement target IT from the radiant intensity of the infrared rays emitted from the measurement target IT. For example, it is a temperature calculation formula for calculating the temperature with the radiant intensity of the infrared rays as a variable. In the following description, it is assumed that the calibration data 31 is a temperature calculation formula in which each coefficient is set so as to calculate the temperature of the blackbody furnace from the radiant intensity of the infrared rays emitted from the blackbody furnace during a period longer than the thermal time constant.

[0060] The correction formula 32 is a correction formula for calculating the temperature from a plurality of measurement targets measured at different timings, and is, for example, formula (1). For example, in the memory unit 30, there is a correction formula 32 that reflects the thermal time constant corresponding to the specific characteristics of the imaging element 51, which is registered in advance. Such a correction formula 32 may be set and registered, for example, at the time of factory shipment of the thermographic device 100, or may be set and registered at any timing.

[0061] The frame data 33 is a thermal image captured by the infrared camera 50 at each timing. For example, the frame data 33 is a thermal image of the measurement target IT captured by the infrared camera 50 at time intervals shorter than the thermal time constant of the imaging element 51.

[0062] The control unit 40 is realized by various programs stored in the storage device inside the thermography device 100 being executed with a RAM or the like as a work area by a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Further, the control unit 40 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0063] As shown in FIG. 6, the control unit 40 includes an acquisition unit 41, a generation unit 42, a calculation unit 43, a correction unit 44, and a provision unit 45.

[0064] The acquisition unit 41 acquires a measurement result obtained using an imaging element that measures electromagnetic waves radiated from the IT under measurement, and the measurement result is measured in a measurement period shorter than the thermal time constant of the imaging element. For example, the acquisition unit 41 controls the infrared camera 50 to measure the radiation luminance of infrared rays radiated from the IT under measurement at time intervals shorter than the thermal time constant of the imaging element 51. More specifically, the acquisition unit 41 causes the radiation luminance of infrared rays to be measured for each pixel of the imaging element 51 during a measurement period t shorter than the thermal time constant. Then, the acquisition unit 41 acquires the value of the radiation luminance measured by each pixel of the imaging element 51 at each timing.

[0065] The generation unit 42 generates a thermal image at each timing using the value of the radiation luminance acquired by the acquisition unit 41. For example, the generation unit 42 receives from the acquisition unit 41 the value of the radiation luminance of infrared rays measured by each pixel of the imaging element 51 at a certain timing. In this case, the generation unit 42 uses the calibration data 31 to calculate the temperature measured by each pixel from the received radiation luminance value, and generates a thermal image with a color corresponding to the temperature measured by each pixel assigned to the position corresponding to each pixel. Then, the generation unit 42 registers the generated thermal image in the storage unit 30 as frame data 33.

[0066] Here, the frame data 33 generated by the generation unit 42 is information based on the radiance measured at time intervals shorter than the thermal time constant of the imaging device 51, that is, information using so-called raw data. Therefore, the thermal image registered as the frame data 33 is likely not a thermal image indicating an appropriate temperature. Thus, the calculation unit 43 calculates the temperature of the measurement target IT using a plurality of measurement results measured by the imaging device 51 at different measurement periods. For example, the calculation unit 43 calculates the temperature of the measurement target IT based on the amount of change in the plurality of measurement results.

[0067] For example, the calculation unit 43 reads a plurality of frame data 33 from the storage unit 30. More specifically, the calculation unit 43 reads a plurality of frame data 33 based on the radiance measured at consecutive timings. For example, the calculation unit 43 reads the frame data FD1 based on the radiance captured at the timing T1 and the frame data FD2 based on the radiance captured at the timing T2, which is the imaging timing after the timing T1.

[0068] Then, the calculation unit 43 uses the frame data FD1 and the frame data FD2 to calculate, for each pixel, the temperature of the measurement target IT at the timing T2 based on the amount of change in temperature. For example, the calculation unit 43 specifies the temperature I1 based on the radiance measured by the pixel to be processed at the timing T1 from the frame data FD1, and specifies the temperature I2 based on the radiance measured by the pixel to be processed at the timing T1 from the frame data FD2. Then, the calculation unit 43 subtracts the value obtained by integrating the temperature I1 with a predetermined coefficient having a negative value of the value obtained by dividing the measurement period t by the thermal time constant τ with the base of the Napier number as the power exponent from the temperature I2, and divides the result by the value obtained by subtracting the predetermined coefficient from 1. Based on this value, the temperature at the position corresponding to the pixel to be processed in the measurement target IT at the timing T2 is calculated. That is, the calculation unit 43 calculates the temperature at the timing T2 for each pixel using the formula (1) using the measurement result at the timing T1 and the measurement result at the timing T2.

[0069] The correction unit 44 generates a thermal image with temperature correction. For example, the correction unit 44 acquires the temperature calculated by the calculation unit 43 for each pixel. Then, the correction unit 44 generates a thermal image indicating the temperature of each acquired pixel.

[0070] The providing unit 45 provides the thermal image generated by the correction unit 44 to the operator OP. For example, the providing unit 45 provides a thermal image with colors corresponding to the calculated temperatures assigned to the pixels on the image at each pixel in the imaging region to the terminal device 200 for display.

[0071] [An example of the operation in the embodiment] Next, with reference to the drawings, an example of the operation timing of the controller 10 according to the embodiment will be described. FIG. 7 is a flowchart showing an example of the measurement process executed by the controller according to the embodiment.

[0072] For example, the controller 10 determines whether it has acquired the measurement result measured by the infrared camera 50 in a measurement time shorter than the thermal time constant τ (step S101). If not (step S101: No), it waits. And when the controller 10 has acquired the measurement result (step S101: Yes), it calculates the temperature of the measurement target based on the amount of change between the temperature at the previous measurement and the temperature at the current measurement (step S102). Then, the controller 10 generates a thermal image indicating the calculated temperature (step S103), provides the generated thermal image (step S104), and ends the process.

[0073] [Expansion of the embodiment] In the above, an example of the measurement process executed by the thermography device 100 has been described. However, the embodiment is not limited to this. Hereinafter, variations of the processes executed by the thermography device 100 and variations of the measurement process and the generation process will be described.

[0074] (1. Regarding the information used for calculation) In the above example, the thermography device 100 calculated the temperature of the measurement target IT at timing T2 using the measurement result at timing T1 and the measurement result at timing T2 following timing T1. However, the embodiment is not limited to this.

[0075] For example, the thermography device 100 may calculate the temperature of the measurement target IT using three or more measurement results. For example, the thermography device 100 uses each pixel of the imaging element 51 to obtain the temperature measured in a measurement period t shorter than the thermal time constant τ at each of timings T1, T2, and T3. Then, the thermography device 100 may calculate the temperature of the measurement target IT at timing T3 from the temperature measured at timing T1, the temperature measured at timing T2, and the temperature measured at timing T3 for each pixel. That is, the thermography device 100 may calculate the temperature of the measurement target IT at timing T3 using the measurement results measured at a plurality of timings before timing T3.

[0076] For example, the thermography device 100 may estimate the temperature of the measurement target IT based on three consecutive timings among the curves shown in FIG. 2. Further, the thermography device 100 may use the average value of the temperature calculated from timing T1 and timing T2, the temperature calculated from timing T1 and timing T3, and the temperature calculated from timing T2 and timing T3 as the temperature to be determined. In addition to such processing, if the thermography device 100 uses a plurality of measurement results measured at different timings, the temperature of the measurement target IT may be calculated by an arbitrary calculation method based on an arbitrary number of measurement results.

[0077] Further, the thermography device 100 may or may not use the measurement results measured at consecutive timings. For example, the thermography device 100 may calculate the temperature of the measurement target IT from the measurement result at timing T1 and the measurement result at timing T3. Further, the thermography device 100 may calculate the temperature of the determination target IT at timing T2, for example, using the measurement results measured at timings T1, T2, and T3. That is, the thermography device 100 may calculate the temperature of the determination target IT at a certain timing from the measurement results at past timings and the measurement results at future timings.

[0078] (2. Regarding mathematical formulas) Also, in the above-described example, the thermography device 100 measured the temperature of the measurement target IT using Equation (1). However, the embodiment is not limited to this. For example, the thermography device 100 may calculate the temperature of the measurement target IT using any equation other than Equation (1).

[0079] Also, when the characteristic between the temperature of the measurement result in the imaging element 51 and the measurement period t is approximated by an n-th order mathematical formula, the thermography device 100 may calculate the temperature of the measurement target IT based on the measurement results measured at n or more different timings. That is, the thermography device 100 may calculate the temperature of the measurement target IT based on the number of measurement targets corresponding to the characteristics of the imaging element 51.

[0080] (3. Regarding the flow of temperature calculation) In the above-described example, the thermography device 100 calculated the temperature of the measurement target IT using the temperature I1 at timing T1 and the temperature I2 at timing T2. However, the embodiment is not limited to this.

[0081] For example, the thermography device 100 may calculate the temperature of the measurement target IT from the infrared radiation luminance measured by each pixel of the imaging device 51 and the amount of change in the values of the radiation luminance measured at different timings. For example, instead of the relationship between the temperature and the measurement period t as shown in FIG. 2, the thermography device 100 may calculate the value of the radiation luminance estimated to be measured when shooting at a time interval longer than the thermal time constant τ from the relationship between the measured radiation luminance and the measurement period t, and measure the temperature of the measurement target IT from the calculated value of the radiation luminance.

[0082] (4. Regarding the imaging device) In the above description, the thermography device 100 measures the temperature of the measurement target IT using the imaging device 51 which is a thermal infrared sensor. However, the embodiment is not limited to this. For example, the thermography device 100 may use the imaging device 51 which is a cooled infrared sensor, and may also have a shutter. Even for such a thermography device 100, there exists a thermal time constant τ for the imaging device 51 to appropriately measure the temperature of the determination target. Therefore, the thermography device 100 may perform the measurement of the determination target IT during a measurement period t shorter than the thermal time constant τ using a cooled infrared sensor or the like, and calculate the temperature of the determination target IT from a plurality of measurement results.

[0083] (5. Regarding other corrections) In addition, the thermography device 100 may further correct the temperature calculated from a plurality of measurement results by using various techniques. For example, the thermography device 100 may calculate the temperature for each pixel from a plurality of measurement results and further correct the temperature based on the temperature difference between adjacent pixels. For example, the thermography device 100 may reduce variations by averaging the temperatures in surrounding pixels. Also, the thermography device 100 may perform temperature correction on all pixels or a part of the pixels that the imaging device 51 has. Further, the thermography device 100 may perform temperature correction according to the thermal time constant τ and the measurement period t. For example, the thermography device 100 may apply a larger correction as the difference between the thermal time constant τ and the measurement period t is larger.

[0084] (6. Regarding infrared rays) In the example described above, the thermography device 100 calculated the calculated temperature based on the radiation luminance of the infrared rays emitted from the measurement target. However, the embodiment is not limited to this. For example, the thermography device 100 may calculate the temperature of the measurement target based on the radiation luminance etc. of electromagnetic waves having various arbitrary wavelengths. For example, when the measurement target is a substance that becomes red-hot etc. and the visible light emitted by the temperature changes, the measurement device (for example, a camera etc.) corresponding to the thermography device 100 may calculate the temperature of the measurement target based on the measured color.

[0085] (7. Regarding the execution entity) In the example described above, the controller 10 included in the thermography device 100 performed the above-described measurement process from the measurement results of the imaging device that operates as a measurement unit, that is, the infrared camera 50. However, the embodiment is not limited to this. For example, the thermography device 100 may have an infrared camera 50 that can exhibit the same functions as the above-described controller 10. For example, such an infrared camera 50 will calculate the temperature using the calibration information generated in advance for each of a plurality of calibration regions.

[0086] Further, for example, the above-described measurement process may be realized by various information processing devices such as the terminal device 200.

[0087] [Effects in the Embodiment] As described above, the thermography device 100 measures the electromagnetic wave radiated from the measurement target in a measurement period t shorter than the thermal time constant τ. Then, the thermography device 100 calculates the temperature of the measurement target IT using a plurality of measurement results. For example, the thermography device 100 calculates the temperature of the measurement target IT using the measurement result at timing T1 and the measurement result at timing T2 measured next to timing T1. More specifically, the thermography device 100 estimates the actual temperature of the determination target IT from the measurement result at timing T1 and the measurement result at timing T2 based on the characteristic of the imaging element 51 that the temperature as the measurement result approaches the actual temperature of the measurement target IT exponentially over time.

[0088] As a result of such processing, the thermography device 100 can measure the measurement target IT in a measurement period t shorter than the thermal time constant τ of the imaging element 51. As a result, even when the thermography device 100 moves the measurement target IT at high speed to improve the tact time, it can appropriately measure the temperature of the measurement target IT while preventing image blur. For this reason, the thermography device 100 can appropriately measure the temperature of the workpiece even when, for example, the moving speed of the workpiece in a factory or the like is increased, so that it is possible to prevent the accuracy of the inspection based on the temperature from decreasing. For example, the thermography device 100 can prevent the accuracy of an inspection such as whether a range above a predetermined temperature is equal to or greater than a predetermined area from decreasing.

[0089] Further, even when the thermography device 100 moves or the temperature of the measurement target IT changes rapidly, the thermography device 100 can appropriately measure the temperature of the measurement target IT. Therefore, for example, it is possible to prevent the accuracy of an inspection based on the temperature from decreasing.

[0090] Moreover, even without a shutter or a relatively ineffective cooling-type infrared sensor, the thermography device 100 can appropriately measure the temperature of the IT under measurement. Therefore, the thermography device 100 can improve cost and maintainability, and for example, reduce the introduction barrier for inspections based on temperature.

[0091] As described above, an example of the embodiment has been explained, but these are merely examples, and the present embodiment is not limited to the above description. Based on the knowledge of those skilled in the art, the configuration and details of the embodiment can be implemented in other forms with various modifications and improvements, starting from the aspects described in the column of the disclosure of the invention. Also, each embodiment can be arbitrarily combined and implemented within a non-contradictory range.

Explanation of Reference Numerals

[0092] 10 Controller 20 Communication Unit 30 Storage Unit 31 Calibration Data 32 Correction Formula 33 Frame Data 40 Control Unit 41 Acquisition Unit 42 Generation Unit 43 Calculation Unit 44 Correction Unit 45 Provision Unit 50 Infrared Camera 51 Imaging Element 52 Lens 100 Thermography Device 200 Terminal Device IT Object Under Measurement IL1 Inspection Line τ Thermal Time Constant t Measurement Period

Claims

1. A measurement result obtained using an imaging device that measures electromagnetic waves emitted from a measurement target, the acquisition unit acquiring a measurement result measured in a measurement period shorter than the thermal time constant of the imaging device, using the first measurement result measured at the first measurement timing within the first measurement period in which the imaging device is within the range of the measurement period and the second measurement result measured at the second measurement timing within the second measurement period in which the imaging device is within the range of the measurement period after the first measurement period, subtracting the value obtained by integrating the first measurement result with a predetermined coefficient having a negative value of the period from the first measurement timing of the first measurement period to the second measurement timing of the second measurement period divided by the thermal time constant as the exponent to Napier's number from the second measurement result, and calculating the temperature of the measurement target based on the value obtained by dividing by the value obtained by subtracting the predetermined coefficient from 1. A calculation unit A measuring device characterized by comprising:

2. In addition to the first measurement result and the second measurement result, the calculation unit uses a third measurement result measured at a third measurement timing within the range of the measurement period, and calculates the temperature calculated from the first measurement result and the second measurement result, and the temperature calculated from the first measurement result and the third measurement result, and the temperature calculated from the second measurement result and the third measurement result, and calculates the temperature of the measurement target based on the above The measuring device according to claim 1, characterized in that:

3. The acquisition unit acquires the measurement result for each pixel included in the imaging device, The calculation unit calculates, for each pixel, the temperature of the region that is the emission source of the electromagnetic wave measured by the pixel in the measurement target The measuring device according to claim 1 or 2, characterized in that:

4. The acquisition unit acquires a measurement result obtained using a non-cooled imaging device The measuring device according to any one of claims 1 to 3, characterized in that:

5. The acquisition unit acquires a measurement result obtained using an imaging device that measures infrared rays emitted from the measurement target The measuring device according to any one of claims 1 to 4, characterized in that:

6. The acquisition unit acquires a measurement result obtained using an imaging device that measures the radiant intensity of infrared rays emitted from the measurement target The measuring device according to claim 5, characterized in that:

7. The acquisition unit acquires the measurement result from an imaging device having the imaging device The measuring device according to any one of claims 1 to 6, characterized in that:

8. An imaging unit having the imaging device The measuring device according to any one of claims 1 to 7, characterized by having

9. A measuring method executed by a measuring device, An acquisition step of acquiring a measurement result obtained by using an imaging element that measures electromagnetic waves radiated from a measurement target, the measurement result being measured in a measurement period shorter than the thermal time constant of the imaging element; Using the first measurement result measured by the imaging element at the first measurement timing within the first measurement period within the range of the measurement period and the second measurement result measured at the second measurement timing within the second measurement period within the range of the measurement period after the first measurement period, subtracting the value obtained by integrating the first measurement result with a predetermined coefficient having a negative value of the period from the first measurement timing of the first measurement period to the second measurement timing of the second measurement period divided by the thermal time constant as the power exponent with the Napier number as the base from the second measurement result, and calculating the temperature of the measurement target based on the value obtained by dividing by the value obtained by subtracting the predetermined coefficient from 1. A measuring method characterized by including

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