Infrared imaging device and output value correction method for infrared imaging device

Abstract

Provided is an infrared imaging device capable of uniformly correcting signals obtained from an infrared imaging element to accurately measure absolute temperature. [Solution] The device includes an internal temperature correction unit 23 and an environmental temperature correction unit 24 which estimate and correct the convergence value of the sensor internal temperature from the temporal changes in the sensor internal temperature and the environmental temperature, an offset correction table acquisition unit 25 which acquires an offset correction table for each temperature based on the estimated value of the sensor internal temperature, a sensor output value acquisition unit 22 which acquires the output value output from the infrared image sensor unit 3, an offset / gain correction unit 26 which performs offset correction for each of the imaging elements based on the output value based on the offset correction table and corrects the gain variation of each of the imaging elements, and a thermal image data acquisition unit 28 which acquires two-dimensional thermal image data representing the absolute temperature of the heat source measurement object 14.

Description

[Technical field]

[0001] The present disclosure relates to an infrared imaging device and an output value correction method for an infrared imaging device. [Background technology]

[0002] An infrared imaging device is a device that has an infrared sensor in which imaging elements that detect infrared rays are arranged in a high-density two-dimensional array as pixels, and obtains thermal video data by focusing an image using a lens placed in front of the infrared sensor and detecting infrared rays emitted from the subject.

[0003] The output of an infrared sensor changes temperature over time due to changes in the environmental temperature or increases in temperature inside the sensor. Therefore, in order to accurately correspond the pixel values ​​constituting each pixel of an infrared image to the absolute temperature of the subject, it was necessary to calibrate the signal output by the infrared sensor by converting it into an absolute temperature using an offset value for each pixel.

[0004] Conventional infrared imaging devices required a thermometer to be placed on the surface of the shutter to accurately measure the temperature of the shutter surface, convert the value of each pixel captured when the shutter was closed to the temperature of the shutter, and then accurately convert the difference in the thermal image when the shutter was open into an absolute temperature value of the thermal image (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-201807 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, even if a high-speed shutter correction method is adopted, it is not possible to sufficiently correct the offset or gain variation for each pixel of the infrared imaging element. Also, even if shutter correction is performed, it is not possible to accurately measure temperatures that are significantly different on the negative or positive side from the temperature at which the offset is corrected, and there is a problem that the image becomes uneven due to the gain variation.

[0007] The present disclosure discloses techniques for solving the problems described above, and aims to provide an infrared imaging device and an output value correction method for an infrared imaging device that can uniformly correct signals obtained from an infrared imaging element to accurately measure absolute temperature. [Means for solving the problem]

[0008] The infrared imaging device of the present disclosure is On the infrared sensor base board, an infrared image sensor unit in which imaging elements are arranged in a two-dimensional array; a lens that projects radiant energy of a heat source object onto the infrared image sensor; an internal temperature sensor for measuring the temperature inside the infrared image sensor unit; On the main base board, the infrared sensor base substrate; A data processing unit is provided. The data calculation processing unit includes: an internal temperature acquisition unit that acquires a sensor internal temperature from the internal temperature sensor; an environmental temperature acquisition unit that acquires an environmental temperature, which is an outside air temperature; an internal temperature correction unit and an environmental temperature correction unit that estimate and correct a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired by the internal temperature acquisition unit and the environmental temperature acquired by the environmental temperature acquisition unit, respectively; an offset correction table acquisition unit that acquires an offset correction table for each temperature that is pre-stored in a memory unit based on the estimated value of the sensor internal temperature from the internal temperature correction unit and the environmental temperature correction unit; a sensor output value acquisition unit that acquires an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction unit that performs offset correction for each of the image pickup elements on the output value acquired by the sensor output value acquisition unit based on the offset correction table acquired by the offset correction table acquisition unit, and corrects variations in gain of each of the image pickup elements; and a thermal image data acquisition unit that acquires two-dimensional thermal image data representing the absolute temperature of the heat source measurement object based on the correction by the offset / gain correction unit.

[0009] The output value correction method for the infrared imaging device disclosed herein includes the steps of: An output value correction method for an infrared imaging device having an infrared image sensor unit in which imaging elements are arranged in a two-dimensional array, comprising: an internal temperature acquisition step of acquiring an internal temperature of the infrared image sensor unit; An environmental temperature acquisition step of acquiring an environmental temperature, which is an outside air temperature; an internal temperature correction step and an environmental temperature correction step of estimating and correcting a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired in the internal temperature acquisition step and the environmental temperature acquired in the environmental temperature acquisition step; a correction table acquisition step of acquiring an offset correction table for each temperature that has been stored in advance, based on the estimated value of the sensor internal temperature in the internal temperature correction step and the environmental temperature correction step; a sensor output value acquisition step of acquiring an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction step of performing offset correction for each of the image pickup elements on the output values ​​acquired in the sensor output value acquisition step based on the offset correction table acquired in the correction table acquisition step, and correcting variations in gain of each of the image pickup elements; and a thermal image data acquisition step of acquiring two-dimensional thermal image data representing the absolute temperature of the heat source measurement object based on the correction in the offset / gain correction step. Effect of the Invention

[0010] According to the infrared imaging device and the output value correction method for the infrared imaging device of the present disclosure, the signals obtained from the infrared imaging elements can be uniformly corrected to measure the absolute temperature accurately. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a configuration diagram for explaining an infrared imaging device according to a first embodiment. [Diagram 2] 4 is a graph for explaining the infrared imaging device according to the first embodiment. [Diagram 3] 4 is a graph for explaining the infrared imaging device according to the first embodiment. [Figure 4] 4 is a graph for explaining the infrared imaging device according to the first embodiment. [Diagram 5] FIG. 4 is a diagram for explaining the internal temperature of a sensor unit of the infrared imaging device according to the first embodiment. [Figure 6] FIG. 4 is a diagram showing an offset correction table of the infrared imaging device in accordance with the first embodiment. [Figure 7] FIG. 1 is a functional block diagram and a flow diagram for explaining an infrared imaging device according to a first embodiment. [Figure 8] FIG. 11 is a configuration diagram for explaining an infrared imaging device according to a second embodiment. [Figure 9] 10 is a graph for explaining an infrared imaging device according to the second embodiment. [Figure 10] 11 is a functional block diagram and a flow diagram for explaining an infrared imaging device according to a second embodiment. FIG. [Figure 11] FIG. 11 is a configuration diagram for explaining an infrared imaging device according to a third embodiment. [Figure 12] 13 is a graph for explaining an infrared imaging device according to the third embodiment. [Figure 13] 13A and 13B are diagrams showing thermal images for explaining the infrared imaging device according to the third embodiment. [Figure 14] 13 is a graph for explaining an infrared imaging device according to the third embodiment. [Figure 15] FIG. 11 is a diagram showing a gain calibration table of the infrared imaging device according to the third embodiment. [Figure 16] 11 is a functional block diagram and a flow diagram for explaining an infrared imaging device according to a third embodiment. FIG. [Figure 17] FIG. 13 is a configuration diagram for explaining an infrared imaging device according to a fourth embodiment. [Figure 18] FIG. 13 is a functional block diagram and a flow diagram for explaining an infrared imaging device according to a fourth embodiment. [Figure 19] 13 is a graph for explaining an infrared imaging device according to the fourth embodiment. [Figure 20] 13 is a graph for explaining an infrared imaging device according to the fifth embodiment. [Figure 21] 13 is a graph for explaining an infrared imaging device according to the fifth embodiment. [Figure 22] 13 is a graph for explaining an infrared imaging device according to the fifth embodiment. [Diagram 23] FIG. 23 is a diagram showing a table for explaining the infrared imaging device according to the sixth embodiment. [Figure 24] 13 is a graph for explaining an infrared imaging device according to the sixth embodiment. [Diagram 25] FIG. 13 is a configuration diagram for explaining an infrared imaging device according to a seventh embodiment. [Figure 26] FIG. 13 is a functional block diagram and a flow diagram for explaining an infrared imaging device according to a seventh embodiment. [Figure 27] FIG. 13 is a thermal image diagram for explaining the infrared imaging device according to the seventh embodiment. [Figure 28] FIG. 13 is a functional block diagram and a flow diagram for explaining an infrared imaging device according to an eighth embodiment. [Figure 29] FIG. 23 is a thermal image diagram for explaining the infrared imaging device according to the eighth embodiment. [Diagram 30] 30A and 30B are configuration diagrams for explaining an infrared imaging device according to the ninth embodiment. [Diagram 31] FIG. 13 is a configuration diagram for explaining an infrared imaging device according to a ninth embodiment. [Diagram 32] 32A and 32B are configuration diagrams for explaining an infrared imaging device according to the tenth embodiment. [Diagram 33] FIG. 23 is a functional block diagram and a flow diagram for explaining an infrared imaging device according to a tenth embodiment. [Diagram 34] FIG. 2 is a block diagram showing an example of hardware of a data processing unit according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Each embodiment will be described below with reference to the drawings.

[0013] Embodiment 1 FIG. 1 is a configuration diagram for explaining an infrared imaging device according to the first embodiment.

[0014] 1, the infrared imaging device 1 includes an infrared sensor base substrate 2, an infrared image sensor unit 3 in which a plurality of imaging elements such as thermal diodes, thermopiles, bolometers, or current collector sensors are arranged in a two-dimensional array on the infrared sensor base substrate 2, a housing 4 for the infrared image sensor unit 3, and a lens 5 that is attached to a hole in the upper part of the housing 4 and forms an image of a heat source measurement object 14 to be measured on the infrared image sensor unit 3. Each of the imaging elements arranged in a two-dimensional array on the infrared image sensor unit 3 constitutes each pixel of the infrared image sensor unit 3.

[0015] A high-speed processing microcomputer 6 using, for example, a DSP (Digital Signal Processor) is arranged on the infrared sensor base board 2. The high-speed processing microcomputer 6 is equipped with an A / D converter, and the voltage value (analog signal) for each pixel measured by the infrared image sensor unit 3 is converted into a digital signal by the AD converter of the high-speed processing microcomputer 6. Furthermore, on the infrared sensor base board 2, an internal temperature sensor 7 for measuring the internal temperature of the infrared image sensor unit 3 is disposed.

[0016] The infrared sensor base substrate 2 is disposed on a main body base substrate 8. On the main body base substrate 8, there are mounted a data processing microcomputer 9, a volatile memory 10 (e.g., RAM (Random Access Memory)), and a non-volatile memory 11 (e.g., E2PRM (Electrically Erasable and Programmable Read Only Memory) or a flash memory) for processing data of the infrared imaging device 1, and the non-volatile memory 11 pre-stores data of a correction table described later. In this disclosure, the data processing microcomputer 9 corresponds to a data processing calculation unit in the claims.

[0017] Furthermore, an environmental temperature sensor 13 for measuring the outside air temperature is disposed on the main body base substrate 8. The environmental temperature sensor 13 is insulated by a heat insulating material 12 for blocking the heat generated by the main body base substrate 8, and is configured so as to be able to accurately measure only the outside air temperature.

[0018] The high-speed processing microcomputer 6 mounted on the infrared sensor base board 2 and the data processing microcomputer 9 mounted on the main body base board 8 are connected by an interface such as SPI (Serial Peripheral Interface), enabling high-speed data transmission. The data processing microcomputer 9 is also connected to an external device via an interface connector 15 and a wiring 16, enabling high-speed data transmission. The data processing microcomputer 9 may transmit data at high speed to an external device by wireless communication 18 via a wireless transmission module 17.

[0019] FIG. 2 is a diagram for explaining the offset of the infrared imaging device according to the first embodiment. 2, the vertical axis represents the output value (digital value) converted by the AD converter of the high-speed processing microcomputer 6, and the horizontal axis represents the temperature. Here, the output value from the AD converter of the high-speed processing microcomputer 6 is shown to be 14 bits, and the vertical axis represents output values ​​from 0 to 16383.

[0020] 2, the image pickup elements a, b, c, d, e, ... of the pixels of the infrared image sensor unit 3 have different offset values ​​in the initial state. In this state, it is not possible to measure the absolute temperature of the heat-source measurement object 14 based on the output value output from the infrared image sensor unit 3 in response to the infrared energy radiation emitted from the heat-source measurement object 14.

[0021] In principle, imaging elements such as thermal diodes, thermopiles, bolometers, or current collection sensors can measure temperature differences, but in order to measure absolute temperatures, it is necessary to calibrate the reference temperature in advance.

[0022] If the offset values ​​of the various imaging elements as shown in Figure 2 are aligned by calibrating the temperature using a temperature calibration plate that is the same as room temperature of 23°C, for example, it is possible to make the offset values ​​the same at 23°C, as shown in Figure 3. Note that in Figure 3, as in Figure 2, the vertical axis indicates 14-bit digital values, and the offset values ​​are calibrated with 8192, which is the median value of the output data values ​​from 0 to 16383, set to 23°C.

[0023] On the other hand, the internal temperature of the infrared image sensor unit 3 (hereinafter referred to as the sensor internal temperature) rises over time due to heat generation from the infrared sensor base board 2, as shown in Fig. 4, for example, as shown by curve A when the environmental temperature (room temperature) is 10°C, as shown by curve B when the environmental temperature (room temperature) is 23°C, and as shown by curve C when the environmental temperature (room temperature) is 30°C, and becomes constant at a predetermined temperature value. In this case, since the offset value changes during the temperature rise, it is necessary to perform offset value correction many times.

[0024] FIG. 5 is a graph showing how the offset value changes with changes in the internal temperature of the sensor. In FIG. 5, for example, when sensing a thermal image of the heat-source measurement object 14 at around 27°C, the line segment of the graph of the output value from the infrared image sensor unit 3 against the horizontal axis representing the absolute temperature of each part of the heat-source measurement object 14 shows how the offset value shifts downward as the temperature rises.

[0025] In the state shown in FIG. 5, if the temperature inside the infrared image sensor unit 3 changes drastically, it becomes impossible to measure the absolute temperature accurately, and with the existing method, it is necessary to repeatedly correct the offset value every time the temperature changes by placing a mechanical shutter, the temperature of which is known, in front of the lens.

[0026] Therefore, in the first embodiment, an offset correction table 105 for each pixel to be corrected in accordance with an increase in the sensor internal temperature is stored in advance in the non-volatile memory 11. Then, a correction table close to the output value of the internal temperature sensor 7 that measures the sensor internal temperature is selected from the non-volatile memory 11, and offset correction is performed, thereby making it possible to obtain thermal image data that represents accurate absolute temperature.

[0027] FIG. 6 shows offset correction table 105 for each pixel pre-stored in non-volatile memory 11 according to the first embodiment, which stores a data table for correcting the offset value in accordance with an increase in the temperature inside the sensor. In FIG. 6, XXX represents the offset value of each pixel for each temperature (15° C., 20° C., 25° C.). Also, while FIG. 6 shows an example of a two-dimensional sensor (infrared image sensor unit 3) having 10×8 pixels, in the case of, for example, 80×60 pixels, a data table corresponding to that number of pixels is stored.

[0028] FIG. 7 is a functional block diagram and a flow diagram of a data calculation processing section which is processed as software by the high speed processing microcomputer (DSP microcomputer) 6 and the data processing microcomputer 9.

[0029] In FIG. 7, an internal temperature acquisition unit 20 acquires an output value from an internal temperature sensor 7 that measures the internal temperature of the infrared image sensor unit 3 . The environmental temperature acquisition unit 21 acquires an output value from the environmental temperature sensor 13 that measures the environmental temperature, which is the outside air temperature. The internal temperature correction unit 23 and the environmental temperature correction unit 24 estimate and correct the convergence value of the sensor internal temperature that follows the change in the environmental temperature from the temporal changes of the sensor internal temperature and the environmental temperature, for example based on the graph in Figure 4.

[0030] The offset correction table acquisition unit 25 acquires an offset correction table 105 for each temperature shown in FIG. 6, which is pre-stored in the non-volatile memory 11, based on the estimated values ​​of the sensor internal temperature from the internal temperature correction unit 23 and the environmental temperature correction unit 24.

[0031] The sensor output value acquisition unit 22 acquires an output value output from the infrared image sensor unit 3 in response to infrared energy radiation emitted from the heat-source measurement object 14 . The offset / gain correction unit 26 performs offset correction for each pixel on the output value acquired by the sensor output value acquisition unit 22 based on the offset correction table 105 acquired by the offset correction table acquisition unit 25 . Further, the offset / gain correction unit 26 corrects the variation in gain of each pixel for the output value acquired by the sensor output value acquisition unit 22, based on the offset correction table 105 acquired by the offset correction table acquisition unit 25. That is, the offset / gain correction unit 26 corrects the variation in gain by making the gain, which is the slope of a graph connecting the offset values ​​for each temperature for each pixel, the same value, based on the offset correction table 105.

[0032] The thermal image data acquisition unit 28 acquires two-dimensional thermal image data representing the accurate and consistent absolute temperature of the heat-source measurement object 14 based on the correction by the offset / gain correction unit 26 .

[0033] As described above, the infrared imaging device of the first embodiment On the infrared sensor base board, an infrared image sensor unit in which imaging elements are arranged in a two-dimensional array; a lens that projects radiant energy of a heat source object onto the infrared image sensor; an internal temperature sensor for measuring the temperature inside the infrared image sensor unit; On the main base board, the infrared sensor base substrate; A data processing unit is provided. The data calculation processing unit includes: an internal temperature acquisition unit that acquires a sensor internal temperature from the internal temperature sensor; an environmental temperature acquisition unit that acquires an environmental temperature, which is an outside air temperature; an internal temperature correction unit and an environmental temperature correction unit that estimate and correct a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired by the internal temperature acquisition unit and the environmental temperature acquired by the environmental temperature acquisition unit, respectively; an offset correction table acquisition unit that acquires an offset correction table for each temperature that is pre-stored in a memory unit based on the estimated value of the sensor internal temperature from the internal temperature correction unit and the environmental temperature correction unit; a sensor output value acquisition unit that acquires an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction unit that performs offset correction for each of the image pickup elements on the output value acquired by the sensor output value acquisition unit based on the offset correction table acquired by the offset correction table acquisition unit, and corrects variations in gain of each of the image pickup elements; and a thermal image data acquisition unit that acquires two-dimensional thermal image data representing the absolute temperature of the heat source measurement object based on the correction by the offset / gain correction unit. The signal obtained from the infrared imaging element can be uniformly corrected to measure the absolute temperature accurately.

[0034] In addition, the output value correction method of the infrared imaging device according to the first embodiment is as follows: An output value correction method for an infrared imaging device having an infrared image sensor unit in which imaging elements are arranged in a two-dimensional array, comprising: an internal temperature acquisition step of acquiring an internal temperature of the infrared image sensor unit; An environmental temperature acquisition step of acquiring an environmental temperature, which is an outside air temperature; an internal temperature correction step and an environmental temperature correction step of estimating and correcting a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired in the internal temperature acquisition step and the environmental temperature acquired in the environmental temperature acquisition step; a correction table acquisition step of acquiring an offset correction table for each temperature that has been stored in advance, based on the estimated value of the sensor internal temperature in the internal temperature correction step and the environmental temperature correction step; a sensor output value acquisition step of acquiring an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction step of performing offset correction for each of the image pickup elements on the output values ​​acquired in the sensor output value acquisition step based on the offset correction table acquired in the correction table acquisition step, and correcting variations in gain of each of the image pickup elements; and a thermal image data acquisition step of acquiring two-dimensional thermal image data representing the absolute temperature of the heat source measurement object based on the correction in the offset / gain correction step. The signal obtained from the infrared imaging element can be uniformly corrected to measure the absolute temperature accurately.

[0035] Embodiment 2 FIG. 8 is a configuration diagram for explaining an infrared imaging device according to the second embodiment. The configuration diagram of the second embodiment in Fig. 8 differs from the configuration diagram of the first embodiment in Fig. 1 in that the heat insulating material 12 and the environmental temperature sensor 13 are not necessary in the second embodiment. Note that the other components of the infrared imaging device are the same as those in Fig. 1, and therefore the description thereof will be omitted.

[0036] The temperature that can be measured by the internal temperature sensor 7 can be considered to be approximately the same as the ambient temperature (room temperature) when the infrared imaging device 1 is not powered on.

[0037] That is, the internal temperature sensor 7 measures the temperature at the moment when the infrared imaging device 1 is turned on from a powered-off state, and the temperature is stored in the non-volatile memory 11. Then, by reading out the temperature and setting it as room temperature, virtual shutter correction is performed as if a mechanical shutter with the same temperature as room temperature exists, and the offset value can be calibrated at that room temperature.

[0038] FIG. 9 is a graph for explaining the infrared imaging device according to the second embodiment. 9, if the internal temperature of the infrared imaging device 1 rises from when it is turned on as shown by curve A1, it can be estimated that the temperature at the starting point, 10°C, is room temperature. In addition, in the case of curve B1, it can be estimated that room temperature is 23°C. Furthermore, in the case of curve C1, it can be estimated that room temperature is 30°C.

[0039] The value measured instantaneously when the infrared imaging device 1 is turned on is stored in the non-volatile memory 11 as the environmental temperature (room temperature), and if the convergence value of the sensor internal temperature does not change thereafter, that value is used as the environmental temperature (room temperature) for the correction described below.

[0040] If the convergence value of the sensor internal temperature changes over time, it is assumed that the environmental temperature (room temperature) has changed, and the environmental temperature (room temperature) is estimated from the internal temperature rise graph data in Figure 9 and the table of convergence temperature values ​​that were measured in advance under each environmental temperature (room temperature).

[0041] A table of the internal temperature rise graph values ​​and the convergence temperature values ​​is stored in advance in the non-volatile memory 11, and the change over time of the environmental temperature (room temperature) is estimated.

[0042] FIG. 10 is a functional block diagram and a flow diagram of the data calculation processing section which is processed as software by the data processing microcomputer 9. The method of estimating the change over time of the environmental temperature (room temperature) is as follows: data is read from a table of internal temperature rise graph values ​​and convergence temperature values, for example, as shown in FIG. 9, which has been stored in advance in non-volatile memory 11 by table acquisition unit 30 of internal temperature rise graph values ​​and convergence temperature values; subtle changes in the sensor's internal temperature are detected by sensor internal temperature change detection unit 31; internal temperature rise graph data that corresponds to this is selected by internal temperature rise graph value selection unit 32; and estimation processing is performed by environmental temperature estimation unit 33, with the starting point of the graph being the environmental temperature (room temperature).

[0043] As described above, according to the infrared imaging device of the second embodiment, The environmental temperature acquisition unit includes a table acquisition unit for acquiring the table of internal temperature rise graph data and convergence temperature values ​​stored in advance in the memory unit, a sensor internal temperature change detection unit for detecting a change in the sensor internal temperature, an internal temperature rise graph value selection unit for selecting internal temperature rise graph data corresponding to the change in the sensor internal temperature detected by the sensor internal temperature change detection unit, and an environmental temperature estimation unit for performing estimation processing with the starting point of the graph of the internal temperature rise graph data selected by the internal temperature rise graph value selection unit being room temperature. It is possible to obtain an infrared imaging device that can estimate subtle changes in the environmental temperature without mounting an environmental temperature sensor.

[0044] Moreover, according to the output value correction method for the infrared imaging device of the second embodiment, The environmental temperature acquisition step includes a step of acquiring a table of prestored internal temperature rise graph data and convergence temperature values, a step of detecting a change in the sensor internal temperature, a step of selecting an internal temperature rise graph value that matches the change in the sensor internal temperature detected in the step of detecting a change in the sensor internal temperature, and a step of performing an estimation process in which the starting point of the graph of the internal temperature rise graph data selected in the step of selecting a value of the internal temperature rise graph is set to room temperature. Subtle changes in the environmental temperature can be estimated without implementing an environmental temperature sensor.

[0045] Embodiment 3 FIG. 11 is a configuration diagram for explaining an infrared imaging device according to the third embodiment. The configuration of the third embodiment shown in FIG. 11 is similar to that of the second embodiment shown in FIG. 8, except that the gain correction is realized by software implemented in the non-volatile memory 11 and the data processing microcomputer 9.

[0046] Since each imaging element of the infrared image sensor unit 3 has a slightly different gain, represented by the slope of the graph shown in Figure 12, even if the offset value is calibrated to the median of the output value 8192 at, for example, an environmental temperature (room temperature) of 30°C, subtle errors will occur between each pixel at temperatures significantly lower than that, for example 10°C, or at temperatures significantly higher than that, for example 50°C.

[0047] Therefore, for example, a thermal image of a background that has a temperature significantly different from room temperature may be displayed as a fixed pattern of horizontal stripes as shown in FIG. 13A, or vertical stripes as shown in FIG. 13B, or a cross-hatch pattern that includes both horizontal and vertical stripes.

[0048] In order to eliminate the problems shown in FIGS. 13A and 13B, it is necessary to accurately calibrate not only the offset of each pixel but also the gain.

[0049] In Figure 14, for example, when offset calibration is performed at 7°C with an output value of 4096, the output value of the heat source measurement object 14 at 43°C is slightly different as indicated by the circles at each imaging element a, b, c, and d, although they should actually show the same value.

[0050] Therefore, the gradient θ of the output value of each image sensor (each pixel) is calculated and calibrated so that they are the same.

[0051] A calibration table (hereinafter referred to as gain calibration table 110) indicating the gradient of the output value of each imaging element (each pixel) shown in FIG. 15 is stored in advance for each infrared image sensor unit 3, and this is used to make the gain of the pixels uniform. The gradient (gain variation) of the output value of each image sensor (each pixel) in the gain calibration table 110 shown in FIG. 15 is represented as yyy.

[0052] In the third embodiment, the calibration of the gain variation is realized by software of the data processing microcomputer 9, as shown in FIG. In FIG. 16, a gain calibration table 110 indicating the variation in gain of each of the image pickup devices is read out by a gain calibration table reading unit 34. Next, the offset / gain correction unit 26 corrects the gain of the output value of the AD converter of the high-speed processing microcomputer 6 using a gain calibration table. Then, the thermal image display unit 36 ​​displays a thermal image of the output value, the gain of which has been corrected by the offset / gain correction unit 26 . The thermal image displayed by the thermal image display unit 36 ​​does not have a fixed pattern of horizontal or vertical stripes or crosshatch patterns that are a combination of these, and a very clean and sharp thermal image is obtained. The correction of the offset value by the offset / gain correction unit 26 is similar to that described in the first embodiment.

[0053] As described above, according to the third embodiment, the offset / gain correction unit reads out the gain calibration table indicating the gain variations of each of the imaging elements using the gain calibration table reading unit, and performs gain correction using the gain calibration table, so that a very clear and sharp thermal image can be obtained.

[0054] Embodiment 4 FIG. 17 is a configuration diagram for explaining an infrared imaging device according to the fourth embodiment.

[0055] In the fourth embodiment, a method for accurately measuring the internal body temperature of a human being 40 using the infrared imaging device 1 described in the first to third embodiments will be described.

[0056] When the face of a human 40 is measured by the infrared imaging device 1, the surface skin temperature of the face can be accurately measured. However, the surface skin temperature of the face is different from the human core temperature.

[0057] Here, it is known that the relationship between the environmental temperature (room temperature), the surface skin temperature, and the actual internal body temperature is as shown in FIG. Therefore, the graph of FIG. 19 is stored in advance in the non-volatile memory 11 as a surface skin temperature-internal body temperature correction table.

[0058] In the fourth embodiment, in order to measure the human body's internal temperature accurately, this is realized by the software functional blocks and flow of the data processing microcomputer 9 (data calculation processing unit) as shown in FIG. In FIG. 18, the output of the thermal image data acquisition section 28 is input to a surface temperature acquisition section 38, which acquires the surface skin temperature. The environmental temperature acquisition unit 21 acquires the environmental temperature (room temperature). The internal body temperature estimation unit 39 estimates the internal body temperature based on the environmental temperature (room temperature) acquired by the environmental temperature acquisition unit 21, the surface skin temperature acquired by the surface temperature acquisition unit 38, and the surface temperature-internal body temperature correction table shown in FIG. 19. That is, in the internal body temperature estimation unit 39, based on the surface temperature-internal body temperature correction table shown in FIG. 19, an accurate internal body temperature can be obtained from the difference between the surface skin temperature and the actual internal body temperature for each room temperature, which is the environmental temperature. In FIG. 19, the actual surface skin temperature and core body temperature data can be approximated to a straight line to simply calculate the difference between the average surface skin temperature and the average core body temperature in advance.

[0059] As described above, according to the fourth embodiment, a surface temperature acquisition unit that acquires an output of the thermal image data acquisition unit as a surface skin temperature; The present invention further includes an internal body temperature estimation unit that estimates an internal body temperature based on the environmental temperature acquired by the environmental temperature acquisition unit, the surface skin temperature acquired by the surface temperature acquisition unit, and a surface temperature-internal body temperature correction table. It is possible to measure the exact internal body temperature of a human being.

[0060] Embodiment 5. In the first to third embodiments, the relationship between the pixel-by-pixel data obtained by the infrared imaging device and the absolute temperature is assumed to represent a linear line. However, in reality, due to the characteristics of the imaging element, for example the characteristics of a thermodiode, the data often exhibits nonlinearity, as shown in FIG. In the example of Fig. 20, for example, from 40°C to 180°C can be regarded as an approximate straight line V. Similarly, from 220°C to 340°C can be regarded as an approximate straight line W.

[0061] However, when measuring temperature distribution over a wide temperature range from -50°C to 500°C, this nonlinearity becomes a drawback and makes it impossible to measure the absolute temperature distribution accurately.

[0062] Therefore, since the nonlinear characteristic curve described above can be expressed as a quadratic curve as shown in Figure 21, the value obtained by the image sensor is measured in advance, the object surface temperature is stored, and an equation is obtained by fitting each coefficient of the quadratic curve to this using the least squares method, and the absolute temperature of the heat source measurement object can be accurately calculated from the value corresponding to the radiant energy emitted from the image sensor.

[0063] In addition, the nonlinear curve in Figure 22 can be considered as a line graph that shows multiple straight lines connected together. In this case, the absolute temperature of the heat source measurement object can be accurately calculated by linear approximation from the equation of the straight line in a certain section.

[0064] As described above, according to embodiment 5, the offset / gain correction unit approximates the nonlinear curve of the output values ​​acquired by the sensor output value acquisition unit with a quadratic curve or a straight line graph to perform offset correction for each of the imaging elements and correct the variation in gain of each of the imaging elements, thereby making it possible to accurately calculate the absolute temperature of the heat source measurement object.

[0065] Embodiment 6 In the first to third embodiments, the offset correction table or the gain calibration table is stored in a non-volatile memory, and a table close to the environmental temperature or the internal temperature of the sensor is selected to perform correction based on the environmental temperature or the internal temperature of the sensor. However, the capacity of the non-volatile memory is limited, and it is not possible to store the environmental temperature or the internal temperature of the sensor in a table at fine intervals.

[0066] In the sixth embodiment, as shown in FIG. 23, for example, an offset correction table or a gain calibration table for any temperature between 10° C. and 20° C. is derived from an offset correction table or a gain calibration table for 10° C. and 20° C.

[0067] Specifically, as shown in FIG. 24, a graph of the output value data of the amount of radiant energy, which varies among the imaging elements, and the temperature is calculated from the quadratic curve approximation described in the fifth embodiment above to obtain a correction table data string (a 14.8°C correction table and a 17.5°C correction table) between two correction tables (a 10°C correction table and a 20°C correction table), and this is used for correction, thereby making it possible to know the accurate absolute temperature.

[0068] As described above, according to the sixth embodiment, The offset / gain correction unit approximates a nonlinear curve of the output values ​​acquired by the sensor output value acquisition unit with a quadratic curve or a straight line graph, and calculates an offset correction table or a gain calibration table between at least two temperature points from an offset correction table or a gain calibration table for the two temperature points, thereby performing offset correction for each of the imaging elements and correcting variations in gain of each of the imaging elements. An offset correction table or gain calibration table for an intermediate temperature between the fewer offset correction tables or gain calibration tables can be derived.

[0069] Embodiment 7 In the seventh embodiment, the infrared imaging device 1 according to any one of the first to sixth embodiments is connected to a personal computer or a high-speed board-type computer equipped with a high-speed, large-capacity microcomputer, and the obtained thermal image is sharpened, converted into pseudo-color, and the absolute temperature for each of the imaging elements is displayed.

[0070] In the seventh embodiment, as shown in Fig. 25, the infrared imaging device 1 according to any one of the first to sixth embodiments is connected to a high-speed board-type computer 40 having a personal computer or a high-speed, large-capacity microcomputer mounted thereon by a wired cable 42 or wirelessly to transfer data at high speed. The high-speed board-type computer 40 has a keyboard 43 and a display device 44 such as an LCD.

[0071] In the inexpensive infrared image sensor unit 3, each pixel is coarse, for example, the number of pixels is only about 80×60. When displaying the output of a low-cost infrared image sensor unit 3 on a display device 44 such as a high-resolution LCD, it is necessary to double the number of pixels. However, simply doubling the number of pixels can result in noticeable block noise. Also, if the doubled pixels are linearly derived to produce intermediate pixels or corrected with a correction curve, the image will be smooth but will appear blurry.

[0072] In the seventh embodiment, as shown in FIG. 26, even if the data obtained by the thermal image data acquisition unit 50 with a low resolution of about 80×60 pixels is doubled tenfold to 800×600 by the pixel doubling unit 51 and the super-resolution unit 52, the thermal image displayed on the thermal image display unit 53 is sharp and not blurred.

[0073] To achieve this, a well-known method using frame correlation of moving images or, more recently, a super-resolution technique using AI (Artificial Intelligence) can be used to learn high-resolution thermal images and obtain high resolution from the low-resolution thermal image data acquired by the low-resolution thermal image data acquisition unit 50.

[0074] This makes it possible to obtain a sharp thermal image on the display device 44 such as an LCD (Liquid Crystal Display) which is the thermal image display unit 53 in FIG.

[0075] As shown in FIG. 27, when the head portion of a low-resolution thermal image 58 is enlarged, pixel-by-pixel block noise 59 becomes noticeable.

[0076] In embodiment 7, by using a low-resolution thermal image data acquisition unit 50, a pixel doubling unit 51, a super-resolution unit 52, and a thermal image display unit 53, it is possible to obtain a high-resolution, sharp thermal image 60 with inconspicuous block noise, as shown in the thermal image data in Figure 27.

[0077] As described above, according to the seventh embodiment, The thermal image data acquisition unit includes a pixel doubling unit and a super-resolution unit for doubling the number of pixels of the thermal image data acquired by the thermal image data acquisition unit and for super-resolution, and the outputs of the pixel doubling unit and the super-resolution unit are displayed by the thermal image display unit. High resolution means no noticeable block noise, allowing you to obtain sharp thermal images.

[0078] Embodiment 8 In the eighth embodiment, a method will be described in which a processing device such as a personal computer connected to the infrared imaging device 1 used in the seventh embodiment converts the absolute temperature of each pixel into a color table and displays a thermal image using the color values ​​of that temperature, rather than a black and white thermal image.

[0079] FIG. 28 is a functional block diagram showing data processing in the infrared imaging device according to the eighth embodiment. As shown in FIG. 28, the eighth embodiment is realized by a thermal image data acquisition unit 28 that acquires thermal image data, a pseudo-colorization unit 55 that replaces the thermal image data acquired by the thermal image data acquisition unit 28 with a predetermined color table, a temperature point display unit 56 that displays the temperature at the required local area by aligning a marker with the pixel to be measured, and a thermal image display unit 57.

[0080] An image displayed on the thermal image display unit 57 of Fig. 28 is shown in Fig. 29. In Fig. 29, 61 is a thermal image displayed in color, and 62 is a color table showing absolute temperature. Also, 63 is a marker for the pixel to be measured, and the absolute temperature of the pixel at the center can be displayed.

[0081] As described above, according to the eighth embodiment, the present invention includes a pseudo-coloring unit that replaces the thermal image data acquired by the thermal image data acquisition unit with a predetermined color table, a temperature point display unit that displays the temperature at a localized location by aligning a marker with a pixel to be measured, and a thermal image display unit that displays the output of the pseudo-coloring unit and the temperature point display unit. It is possible to display a marker for the pixel to be measured and to display the absolute temperature of the pixel at its center.

[0082] Embodiment 9 Figures 30A and 30B are configuration diagrams for explaining an infrared imaging device according to embodiment 9. In Figures 30A and 30B, an infrared imaging device 1 has the same configuration as the infrared imaging device 1 in Figure 1, and a description of its components will be omitted.

[0083] 30A shows a case where the heat-source measurement object 41 is located far away from the infrared imaging device 1. In this case, the energy radiated from the heat-source measurement object 41 is located far away from the infrared image sensor unit 3, so that the temperature of the heat-source measurement object 41 can be accurately measured without heating the housing 4 or the lens 5 by the radiant energy.

[0084] However, as shown in FIG. 30B, when the heat-source measurement object 41 is located very close to the sensor of the infrared imaging device 1, the housing 4 or the lens 5, etc. are heated by the radiant energy from the heat-source measurement object 41, and the infrared image sensor unit 3 detects the energy radiated from the housing 4 or the lens 5, etc., making it impossible to accurately measure the surface temperature of the heat-source measurement object 41.

[0085] FIG. 31 is a configuration diagram for explaining an infrared imaging device according to the ninth embodiment. In FIG. In addition to the components in embodiments 1 to 3, a filter 70 that transmits only infrared light is placed on the front side of the infrared image sensor unit 3, so that the housing 4 or lens 5, etc. are not affected by the radiant energy of the heat source measurement object 41 due to the filter 70.

[0086] The filter 70 is heated by radiant energy from the heat source measurement object 41. To eliminate this effect, the filter 70 is provided with cooling fins 71, which dissipate heat to the surroundings to prevent a rise in temperature.

[0087] As described above, according to the ninth embodiment, a filter that transmits only infrared light is disposed in front of the infrared image sensor unit, and a cooling fin is provided on the filter. Even if the heat source is located nearby, the surface temperature of the heat source can be accurately measured.

[0088] Embodiment 10 32A and 32B are configuration diagrams for explaining an infrared imaging device according to the tenth embodiment. 32A and 32B, the infrared imaging device 1 has the same configuration as the infrared imaging device 1 in FIG. 1, and the description of the components will be omitted.

[0089] 32A shows a case where the heat-source measurement object 41 is located far away from the infrared imaging device 1. In this case, the energy radiated from the heat-source measurement object 41 is far away from the infrared imaging device 1, so that the radiant energy from the heat-source measurement object 41 does not heat the housing 4 or the lens 5 of the infrared imaging device 1, and the temperature of the heat-source measurement object 41 can be accurately measured.

[0090] As shown in FIG. 32B, when the heat-source measurement object 41 is located very close to the infrared imaging device 1, the radiant energy from the heat-source measurement object 41 heats the housing 4 or the lens 5 of the infrared imaging device 1, and the infrared image sensor unit 3 detects the energy radiated from the housing 4 or the lens 5, etc., making it impossible to accurately measure the surface temperature of the heat-source measurement object 41.

[0091] As shown in FIG. 32A, when the heat-source measurement object 41 is located far away, the thermal image displayed on the thermal image display unit 57 has a small area of ​​the heat-source measurement object 41 relative to the entire image, like a subject (far) image 85. Also, as shown in FIG. 32B, when the heat-source measurement object 41 is nearby, the thermal image displayed on the thermal image display unit 57 has a large area of ​​the heat-source measurement object 41 relative to the entire image, as in a subject (nearby) image 86.

[0092] FIG. 33 is a functional block diagram and a flow diagram for explaining the infrared imaging device according to the tenth embodiment. In Figure 33, when the area of ​​the target heat source measurement object 41 (subject (main subject)) is determined in advance, the main image area extraction unit 82 extracts the main image area of ​​the predetermined subject (main image), such as a human face, based on the data acquired by the thermal image data acquisition unit 28. The distance calculation and correction unit 83 calculates the distance of the subject (main image) according to the image area extracted by the main image area extraction unit 82, and corrects the data acquired by the thermal image data acquisition unit 28 according to the calculated distance. The thermal image display unit 84 realizes display of a highly accurate thermal image of the subject (main image) based on the data corrected by the distance calculation and correction unit 83 .

[0093] As described above, according to the tenth embodiment, The device includes a main image area extraction unit that extracts an image area of ​​the object based on the data acquired by the thermal image data acquisition unit when the area of ​​the object, which is the target heat source measurement object, is determined in advance, a distance calculation and correction unit that calculates the distance of the object according to the image area extracted by the main image area extraction unit and corrects the data acquired by the thermal image data acquisition unit according to the distance, and a thermal image display unit that displays a thermal image of the object based on the data corrected by the distance calculation and correction unit, It is possible to display absolute temperature with high accuracy regardless of the distance of the subject.

[0094] The data processing microcomputer 9 (data processing calculation unit) described in the above embodiment is configured with a processor 1000 and a storage device 1010, as shown in an example of hardware in Fig. 34. The storage device 1010 includes a volatile memory 10 such as the random access memory described above, and a non-volatile memory 11 such as a flash memory. Also, an auxiliary storage device such as a hard disk may be provided instead of the flash memory. The processor 1000 executes a program input from the storage device 1010. In this case, the program is input from the auxiliary storage device to the processor 1000 via the volatile memory 10. Also, the processor 1000 may output data such as a calculation result to the volatile memory 10 of the storage device 1010, or may store the data in the auxiliary storage device via the volatile memory 10.

[0095] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not exemplified are assumed within the scope of the technology disclosed in this specification, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

[0096] Various aspects of the present disclosure are summarized below as appendices.

[0097] (Appendix 1) On the infrared sensor base board, an infrared image sensor unit in which imaging elements are arranged in a two-dimensional array; a lens that projects radiant energy of a heat source object onto the infrared image sensor; an internal temperature sensor for measuring the temperature inside the infrared image sensor unit; On the main base board, the infrared sensor base substrate; A data processing unit is provided. The data calculation processing unit includes: an internal temperature acquisition unit that acquires a sensor internal temperature from the internal temperature sensor; an environmental temperature acquisition unit that acquires an environmental temperature, which is an outside air temperature; an internal temperature correction unit and an environmental temperature correction unit that estimate and correct a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired by the internal temperature acquisition unit and the environmental temperature acquired by the environmental temperature acquisition unit, respectively; an offset correction table acquisition unit that acquires an offset correction table for each temperature that is pre-stored in a memory unit based on the estimated value of the sensor internal temperature from the internal temperature correction unit and the environmental temperature correction unit; a sensor output value acquisition unit that acquires an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction unit that performs offset correction for each of the image pickup elements on the output value acquired by the sensor output value acquisition unit based on the offset correction table acquired by the offset correction table acquisition unit, and corrects variations in gain of each of the image pickup elements; and a thermal image data acquisition unit that acquires two-dimensional thermal image data representing the absolute temperature of the heat source measurement object based on the correction by the offset / gain correction unit. (Appendix 2) 2. The infrared imaging device according to claim 1, wherein the environmental temperature acquisition unit acquires the environmental temperature using an environmental temperature sensor arranged on the infrared sensor base board via a thermal insulating material. (Appendix 3) The environmental temperature acquisition unit is a table acquisition unit for acquiring the internal temperature rise graph data and the convergence temperature value stored in advance in the memory unit; a sensor internal temperature change detection unit for detecting a change in the sensor internal temperature; an internal temperature rise graph value selection unit that selects internal temperature rise graph data corresponding to the change in the internal temperature of the sensor detected by the sensor internal temperature change detection unit; The infrared imaging device according to claim 1, further comprising an environmental temperature estimation unit that performs estimation processing in which a starting point of the graph of the internal temperature rise graph data selected by the internal temperature rise graph value selection unit is set to room temperature. (Appendix 4) The offset / gain correction unit reads out a gain calibration table representing the gain variations of each of the imaging elements using a gain calibration table reading unit, and corrects the gain using the gain calibration table. (Appendix 5) a surface temperature acquisition unit that acquires an output of the thermal image data acquisition unit as a surface skin temperature; An infrared imaging device as described in any one of Supplementary Note 1 to Supplementary Note 4, comprising an internal body temperature estimation unit that estimates internal body temperature based on the environmental temperature acquired by the environmental temperature acquisition unit, the surface skin temperature acquired by the surface temperature acquisition unit, and a surface temperature-internal body temperature correction table. (Appendix 6) The infrared imaging device described in Appendix 4, wherein the offset / gain correction unit performs offset correction for each of the imaging elements by approximating a nonlinear curve of the output values ​​acquired by the sensor output value acquisition unit with a quadratic curve or a straight line graph, thereby correcting variations in gain of each of the imaging elements. (Appendix 7) The infrared imaging device described in Appendix 6, wherein the offset / gain correction unit approximates a nonlinear curve of the output values ​​acquired by the sensor output value acquisition unit with a quadratic curve or a straight line graph, and calculates an offset correction table or a gain calibration table between the two temperature points from an offset correction table or a gain calibration table for at least two temperature points, thereby performing offset correction for each of the imaging elements and correcting variations in gain of each of the imaging elements. (Appendix 8) 8. An infrared imaging device according to any one of claims 1 to 7, further comprising a pixel doubling unit and a super-resolution unit for doubling and super-resolution the number of pixels of the thermal image data acquired by the thermal image data acquisition unit, and displaying the outputs of the pixel doubling unit and the super-resolution unit on a thermal image display unit. (Appendix 9) An infrared imaging device according to any one of appendices 1 to 8, comprising a pseudo-coloring unit which replaces the thermal image data acquired by the thermal image data acquisition unit with a predetermined color table, a temperature point display unit which displays the temperature at a localized location by aligning a marker with a pixel to be measured, and a thermal image display unit which displays the output of the pseudo-coloring unit and the temperature point display unit. (Appendix 10) 10. The infrared imaging device according to claim 1, further comprising a filter that transmits only infrared light and is disposed in front of the infrared image sensor, the filter being provided with a cooling fin. (Appendix 11) a main image area extraction unit that extracts an image area of ​​the object based on the data acquired by the thermal image data acquisition unit when the area of ​​the object, which is the heat source measurement object, is determined in advance; a distance calculation and correction unit that calculates a distance to the subject according to the image area extracted by the main image area extraction unit, and corrects the data acquired by the thermal image data acquisition unit according to the calculated distance; and a thermal image display unit that displays a thermal image of the subject based on the data corrected by the distance calculation and correction unit. (Appendix 12) An output value correction method for an infrared imaging device having an infrared image sensor unit in which imaging elements are arranged in a two-dimensional array, comprising: an internal temperature acquisition step of acquiring an internal temperature of the infrared image sensor unit; An environmental temperature acquisition step of acquiring an environmental temperature, which is an outside air temperature; an internal temperature correction step and an environmental temperature correction step of estimating and correcting a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired in the internal temperature acquisition step and the environmental temperature acquired in the environmental temperature acquisition step; a correction table acquisition step of acquiring an offset correction table for each temperature that has been stored in advance, based on the estimated value of the sensor internal temperature in the internal temperature correction step and the environmental temperature correction step; a sensor output value acquisition step of acquiring an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction step of performing offset correction for each of the image pickup elements on the output values ​​acquired in the sensor output value acquisition step based on the offset correction table acquired in the correction table acquisition step, and correcting variations in gain of each of the image pickup elements; and a thermal image data acquisition process for acquiring two-dimensional thermal image data representing the absolute temperature of the heat source measurement object based on the correction in the offset / gain correction process. (Appendix 13) The output value correction method for an infrared imaging device described in Appendix 12, wherein the environmental temperature acquisition process includes a table acquisition process of pre-stored internal temperature rise graph data and convergence temperature values, a sensor internal temperature change detection process of detecting a change in the sensor internal temperature, an internal temperature rise graph value selection process of selecting internal temperature rise graph data corresponding to the change in the sensor internal temperature detected in the sensor internal temperature change detection process, and an environmental temperature estimation process of performing estimation processing in which the starting point of the graph of the internal temperature rise graph data selected in the internal temperature rise graph value selection process is room temperature. (Appendix 14) The output value correction method for an infrared imaging device according to claim 12 or 13, wherein the offset / gain correction step reads out a pre-stored gain calibration table representing the gain variations of each of the imaging elements, and corrects the gain using the gain calibration table. [Explanation of symbols]

[0098] 1 infrared imaging device, 2 infrared sensor base board, 3 infrared image sensor unit, 4 housing, 5 lens, 6 high-speed processing microcomputer, 7 internal temperature sensor, 8 main body base board, 9 data processing microcomputer, 10 volatile memory, 11 non-volatile memory, 12 heat insulating material, 13 environmental temperature sensor, 14 heat source measurement object, 20 internal temperature acquisition unit, 21 environmental temperature acquisition unit, 22 sensor output value acquisition unit, 23 internal temperature correction unit, 24 environmental temperature correction unit, 25 offset correction table acquisition unit, 26 offset / gain correction unit, 28 thermal image data acquisition unit, 30 A section for acquiring a table of internal temperature rise graph values ​​and convergence temperature values; 31 sensor internal temperature change detection unit; 32 internal temperature rise graph value selection unit; 33 environmental temperature estimation unit, 34 gain calibration table readout unit, 36 thermal image display unit, 38 surface temperature acquisition unit, 39 internal body temperature estimation unit, 40 high-speed board-type computer, 41 heat source measurement object, 44 display device, 50 low-resolution thermal image data acquisition unit, 51 pixel doubling unit, 52 super-resolution unit, 53 thermal image display unit, 55 pseudo-color unit, 56 temperature point display unit, 57 thermal image display unit, 58 low resolution thermal image, 59 Block noise per pixel, 60 Sharp thermal image, 61 Thermal image in color, 62 Color table representing absolute temperature, 63 Marker of pixel to be measured, 70 filter, 71 cooling fin, 82 main image area extraction unit, 83 distance calculation and correction unit, 84 thermal image display unit, 85 subject (distant) image, 86 Object (nearby) image, 105 Offset correction table, 110 gain calibration table, 1000 processor, 1010 storage device.

Claims

1. On the infrared sensor base board, an infrared image sensor unit in which image pickup elements are arranged in a two-dimensional array; a lens that projects radiant energy of a heat source object onto the infrared image sensor; an internal temperature sensor for measuring the temperature inside the infrared image sensor unit; On the main base board, the infrared sensor base substrate; A data processing unit is provided. The data calculation processing unit includes: an internal temperature acquisition unit that acquires a sensor internal temperature from the internal temperature sensor; an environmental temperature acquisition unit that acquires an environmental temperature, which is an outside air temperature; an internal temperature correction unit and an environmental temperature correction unit that estimate and correct a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired by the internal temperature acquisition unit and the environmental temperature acquired by the environmental temperature acquisition unit, respectively; an offset correction table acquisition unit that acquires an offset correction table for each temperature that is pre-stored in a memory unit based on the estimated value of the sensor internal temperature from the internal temperature correction unit and the environmental temperature correction unit; a sensor output value acquisition unit that acquires an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction unit that performs offset correction for each of the image pickup elements based on the output value acquired by the sensor output value acquisition unit and the offset correction table acquired by the offset correction table acquisition unit, and corrects variations in gain of each of the image pickup elements; and a thermal image data acquisition unit that acquires two-dimensional thermal image data representing an absolute temperature of the heat source measurement object based on the correction by the offset / gain correction unit.

2. The infrared imaging device according to claim 1 , wherein the environmental temperature acquisition unit acquires the environmental temperature using an environmental temperature sensor disposed on the infrared sensor base board via a thermal insulating material.

3. The environmental temperature acquisition unit is a table acquisition unit for acquiring the internal temperature rise graph data and the convergence temperature value stored in advance in the memory unit; a sensor internal temperature change detection unit for detecting a change in the sensor internal temperature; an internal temperature rise graph value selection unit that selects internal temperature rise graph data corresponding to the change in the internal temperature of the sensor detected by the sensor internal temperature change detection unit; The infrared imaging device according to claim 1 , further comprising an environmental temperature estimation unit that performs estimation processing to set a starting point of the graph of the internal temperature rise graph data selected by the internal temperature rise graph value selection unit as room temperature.

4. 4. The infrared imaging device according to claim 1, wherein the offset / gain correction unit reads out a gain calibration table representing gain variations of the imaging elements by a gain calibration table reading unit, and performs gain correction using the gain calibration table.

5. a surface temperature acquisition unit that acquires an output of the thermal image data acquisition unit as a surface skin temperature; An infrared imaging device as described in any one of claims 1 to 3, comprising an internal body temperature estimation unit that estimates internal body temperature based on the environmental temperature acquired by the environmental temperature acquisition unit, the surface skin temperature acquired by the surface temperature acquisition unit, and a surface temperature-internal body temperature correction table.

6. 5. The infrared imaging device according to claim 4, wherein the offset / gain correction unit performs offset correction for each of the imaging elements by approximating a nonlinear curve of the output values ​​acquired by the sensor output value acquisition unit with a quadratic curve or a straight line graph, thereby correcting variations in gain of each of the imaging elements.

7. 7. The infrared imaging device according to claim 6, wherein the offset / gain correction unit approximates a nonlinear curve of the output values ​​acquired by the sensor output value acquisition unit with a quadratic curve or a straight line graph, and calculates an offset correction table or a gain calibration table between the two temperature points from an offset correction table or a gain calibration table for at least two temperature points, thereby performing offset correction for each of the imaging elements and correcting variations in gain of each of the imaging elements.

8. 4. An infrared imaging device as described in any one of claims 1 to 3, further comprising a pixel doubling unit and a super-resolution unit which double and super-resolution the number of pixels of the thermal image data acquired by the thermal image data acquisition unit, and the outputs of the pixel doubling unit and the super-resolution unit are displayed by a thermal image display unit.

9. 4. An infrared imaging device as described in any one of claims 1 to 3, comprising a pseudo-color conversion unit that replaces the thermal image data acquired by the thermal image data acquisition unit with a predetermined color table, a temperature point display unit that displays the temperature at a local area by aligning a marker with a pixel to be measured, and a thermal image display unit that displays the output of the pseudo-color conversion unit and the temperature point display unit.

10. 4. The infrared imaging device according to claim 1, further comprising a filter that transmits only infrared light and is disposed in front of the infrared image sensor, the filter being provided with a cooling fin.

11. a main image area extraction unit that extracts an image area of ​​the object based on the data acquired by the thermal image data acquisition unit when the area of ​​the object, which is the heat source measurement object, is determined in advance; a distance calculation and correction unit that calculates a distance to the subject according to the image area extracted by the main image area extraction unit, and corrects the data acquired by the thermal image data acquisition unit according to the calculated distance; 4. The infrared imaging device according to claim 1, further comprising a thermal image display unit that displays a thermal image of the subject based on the data corrected by the distance calculation and correction unit.

12. An output value correction method for an infrared imaging device having an infrared image sensor unit in which imaging elements are arranged in a two-dimensional array, comprising the steps of: an internal temperature acquisition step of acquiring an internal temperature of the infrared image sensor unit; An environmental temperature acquisition step of acquiring an environmental temperature, which is an outside air temperature; an internal temperature correction step and an environmental temperature correction step of estimating and correcting a convergence value of the sensor internal temperature that follows a change in the environmental temperature from changes over time of the sensor internal temperature acquired in the internal temperature acquisition step and the environmental temperature acquired in the environmental temperature acquisition step; a correction table acquisition step of acquiring an offset correction table for each temperature stored in advance based on the estimated value of the sensor internal temperature in the internal temperature correction step and the environmental temperature correction step; a sensor output value acquisition step of acquiring an output value output from the infrared image sensor unit in response to energy radiation emitted from the heat source measurement object; an offset / gain correction step of performing offset correction for each of the image pickup elements on the output values ​​acquired in the sensor output value acquisition step based on the offset correction table acquired in the correction table acquisition step, and correcting variations in gain of each of the image pickup elements; and acquiring two-dimensional thermal image data representing the absolute temperature of the heat source measurement object based on the correction in the offset / gain correction step.

13. The output value correction method for an infrared imaging device described in claim 12, wherein the environmental temperature acquisition process includes a table acquisition process of pre-stored internal temperature rise graph data and convergence temperature values, a sensor internal temperature change detection process of detecting a change in the sensor internal temperature, an internal temperature rise graph value selection process of selecting internal temperature rise graph data that corresponds to the change in the sensor internal temperature detected in the sensor internal temperature change detection process, and an environmental temperature estimation process of performing estimation processing in which the starting point of the graph of the internal temperature rise graph data selected in the internal temperature rise graph value selection process is room temperature.

14. 14. The output value correction method for an infrared imaging device according to claim 12, wherein the offset / gain correction step reads out a pre-stored gain calibration table representing gain variations of each of the imaging elements, and corrects the gain using the gain calibration table.

Images