Thermal imaging device and method for calibrating thermal imaging device

Abstract

To provide a thermal image processing device capable of appropriately calibrating a far-infrared camera.SOLUTION: A thermal image processing device 10 includes: an imaging unit 100 having an imaging element 102 that captures an infrared image through a lens 101; a thermal uniform body 103 that emits infrared light of constant intensity and wavelength; a reflecting element 104 that is provided on an optical path from the lens 101 to the imaging element 102, and is switchable between a first angle at which the infrared light incident from the lens 101 is reflected and made incident on the imaging element 102 and a second angle at which the infrared light incident from the thermal uniform body 103 is reflected and made incident on the imaging element 102, for each section corresponding to the imaging element 102; and a calibration control unit 310 that switches the reflecting element 104 from the first angle to the second angle for each section while capturing an infrared image, and performs calibration based on the infrared light emitted from the thermal uniform body 103 for each switched section.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a thermal imaging device and a method for calibrating a thermal imaging device. [Background technology]

[0002] A far-infrared camera requires periodic calibration. Generally, calibration is performed by periodically capturing images of a shutter, which is a thermally uniform body, with a far-infrared sensor. When a far-infrared camera is used for safety support of a moving object, such calibration does not allow capturing images while the shutter is closed, making it impossible to detect vehicles and people, which may lead to dangerous situations. Patent Document 1 discloses a technique for performing calibration based on the positional relationship between a vehicle and an object when a far-infrared camera is used in a vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-125639 Summary of the Invention [Problem to be solved by the invention]

[0004] The method of Patent Document 1 is intended to be used on moving objects such as vehicles, and the same determination cannot be made on surveillance cameras, etc., where the camera position is fixed. Therefore, the object of the present disclosure is to provide a thermal image processing device etc. that can appropriately calibrate a far-infrared camera. [Means for solving the problem]

[0005] The thermal image processing device of the present disclosure includes: an imaging unit including an imaging element that captures an infrared image through a lens; a thermal homogeneous body that emits infrared light of constant intensity and wavelength; a reflecting element that is provided on an optical path from the lens to the image sensor, and that is switchable between a first angle at which infrared light incident from the lens is reflected and made incident on the image sensor, and a second angle at which infrared light incident from the thermal uniform body is reflected and made incident on the image sensor, for each section corresponding to the image sensor; a calibration control unit that switches the reflecting element from the first angle to the second angle for each of the sections while capturing the infrared image, and performs calibration based on infrared light radiation from the thermal uniform body for each of the switched sections; The thermal image processing device includes:

[0006] The calibration method for a thermal imaging device of the present disclosure includes: During imaging by an imaging element that captures infrared images through a lens, a reflecting element that is provided on the optical path from the lens to the image sensor, and that can switch between a first angle at which infrared light incident from the lens is reflected and made incident on the image sensor, and a second angle at which infrared light of a constant intensity and wavelength incident from a thermal homogeneous body is reflected and made incident on the image sensor, for each section corresponding to the image sensor; performing a calibration based on infrared light from the thermal uniform body for each of the sections; A method for calibrating a thermal imaging device. [Effects of the Invention]

[0007] The present disclosure provides a thermal image processing device and the like that can perform calibration while capturing infrared images. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a configuration of a thermal image processing device according to an embodiment; [Figure 2] FIG. 2 is a block diagram showing a configuration of an image processing unit in the thermal image processing device according to the embodiment; [Figure 3] 1 is a schematic diagram of a far-infrared camera according to an embodiment; [Figure 4] 1 is a schematic diagram showing sections of an imaging element according to an embodiment; [Figure 5] 3 is a schematic diagram showing the correspondence between the divisions of the imaging element and the divisions of the reflective element according to the embodiment; FIG. [Figure 6] 3 is a flowchart of a calibration method for the thermal image processing device according to the first embodiment. [Figure 7] 3 is a flowchart of a calibration method for the thermal image processing device according to the first embodiment. [Figure 8] FIG. 4 is a diagram illustrating an example of a range in which a moving object is detected according to the first embodiment. [Figure 9] 10 is a flowchart of a calibration method for a thermal image processing device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the invention according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential means for solving the problems. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. Furthermore, in the following, the terms "calibration" and "calibration" are used interchangeably.

[0010] (Description of a thermal image processing device according to an embodiment) FIG. 1 is a block diagram showing the configuration of a thermal image processing device according to an embodiment. FIG. 2 is a block diagram showing the configuration of the image processing unit shown in FIG. 1. FIG. 3 is a schematic diagram of a far-infrared camera according to an embodiment. FIG. 4 is a schematic diagram showing the divisions of an image pickup element according to an embodiment. FIG. 5 is a schematic diagram showing the correspondence between the divisions of an image pickup element and the divisions of a reflecting element according to an embodiment. The thermal image processing device according to an embodiment will be described with reference to FIGS. 1 to 5. The thermal image processing device 10 is a device that captures and processes infrared images using a far-infrared camera. The thermal image processing device 10 is mounted on a smart pole or the like and detects people, bicycles, motorcycles, automobiles, and other vehicles.

[0011] A smart pole is a multi-function pole equipped with various sensors including a camera and a communication device, which is installed near a road or the like, and is used for traffic monitoring, safety support, crime prevention, etc. A thermal image processing device according to an embodiment is mounted on such a smart pole, detects target objects such as people and vehicles from thermal images captured by a far-infrared camera, and outputs information such as the type, coordinates, and movement speed of the detected target objects. The information output from the smart pole is used to issue warnings to vehicles traveling near the smart pole. The thermal image processing device according to an embodiment is not limited to being mounted on a smart pole, and can also be used for other purposes.

[0012] 1, the thermal image processing device 10 includes an imaging unit 100 and a control unit 300. The imaging unit 100 is a far-infrared camera, and includes a lens 101, an imaging element 102, a thermal uniform body 103, and a reflecting element 104.

[0013] The lens 101 is an objective lens that forms an image of far-infrared light within the range imaged by the thermal image processing device 10 on the image sensor 102. The lens 101 is a lens that can transmit and refract far-infrared light.

[0014] The image sensor 102 is an image sensor that captures far-infrared images, and is, for example, a microbolometer. The image sensor 102 is composed of thermal elements arranged in an array, and captures far-infrared images by detecting changes in the resistance value of each thermal element when it receives far-infrared light with a wavelength of 3 μm to 1000 μm. Far-infrared rays are emitted from a heated object. Under the control of the image processor 308, the image sensor 102 captures and outputs moving images at, for example, 24 frames per second.

[0015] The thermally uniform body 103 is an object in which heat is uniformly distributed. Therefore, the thermally uniform body 103 emits far-infrared light with a constant intensity and wavelength. By capturing an image of the thermally uniform body 103, pixel values ​​representing an image of a thermally uniform surface can be obtained, allowing calibration of the image sensor 102.

[0016] The reflecting element 104 is provided on the optical path from the lens 101 to the image sensor 102. The reflecting element 104 is switchable between a first angle at which far-infrared light incident from the lens 101 is reflected and made incident on the image sensor 102 for each section corresponding to the image sensor 102, and a second angle at which far-infrared light incident from the thermal uniform body 103 is reflected and made incident on the image sensor 102. The reflecting element 104 can be, for example, an element such as a digital micromirror device. The sections corresponding to the image sensor 102 will be described later.

[0017] The infrared light incident from the lens 101 is due to infrared light incident from the imaging range of the thermal image processing device 10. The infrared light incident from the thermal uniform body 103 has a constant wavelength and intensity, shows a constant signal, and is used for calibration.

[0018] 3 is a schematic diagram of the imaging unit 100 shown in FIG. 1, conceptually illustrating the arrangement of the lens 101, imaging element 102, thermal uniform body 103, and reflecting element 104. As shown in FIG. 3, the imaging unit 100 is configured and arranged such that far-infrared light incident from the lens 101 and far-infrared light incident from the thermal uniform body 103 are selectively incident on the imaging element 102 by the reflecting element 104. FIG. 3 illustrates a state in which the far-infrared light incident from the thermal uniform body 103 is incident on the section of the imaging element 102 corresponding to section 1042 because the micromirror of section 1042 in the reflecting element 104 is at a second angle.

[0019] The control unit 300 controls the imaging unit 100 and processes the far-infrared image captured by the imaging unit 100. The control unit 300 is composed of an arithmetic unit such as a CPU (Central Processing Unit) or an MCU (Micro Controller Unit), a non-volatile or volatile memory such as a flash memory or a DRAM (Dynamic Random Access Memory), and various interfaces. These arithmetic units execute programs stored in the memory, thereby realizing various functions of the control unit 300, including the functional blocks shown below.

[0020] The control unit 300 includes a temperature measurement unit 306 , a reflection control unit 307 , an image processing unit 308 , an output unit 309 , and a calibration control unit 310 .

[0021] The temperature measurement unit 306 acquires information from a temperature sensor (not shown) installed in the thermal uniformity body 103 and outputs the information to the calibration control unit 310. Calibration processing is performed using parameters based on the temperature of the thermal uniformity body 103 acquired by the temperature measurement unit 306.

[0022] The reflection control unit 307 controls the driving of the micromirrors that constitute the reflection element 104 under the control of the calibration control unit 310. Specifically, under the control of the calibration control unit 310, control is performed so that each section of the reflection element 104 that corresponds to the section set in the image sensor 102 is set to either the first angle or the second angle.

[0023] The divisions set in the image sensor 102 and the divisions set in the reflecting element 104 will be described using Figures 4 and 5. As shown in Figure 4, the image sensor 102 is set with divisions including a plurality of thermal elements. The image sensor 102 has, for example, thermal elements measuring 640 horizontally and 480 vertically, and as shown in Figure 4, 7 horizontally and 6 vertically divided divisions are set. The divisions set in the image sensor 102 are not limited to the configuration shown in the figure and can take various forms. In Figure 4, division 1022 indicates a division set in the image sensor 102.

[0024] As shown in FIG. 5, the sections of the reflective element 104 correspond to the sections of the image sensor 102. For example, the micromirrors of the reflective element 104 that correspond to section 1022 of the image sensor 102 are micromirrors included in section 1042 shown in FIG. 5. Therefore, when the micromirrors included in section 1042 of the reflective element 104 are at a first angle, far-infrared light incident from the lens 101 and reflected by section 1042 of the reflective element 104 is incident on section 1022 of the image sensor 102. Similarly, when the micromirrors included in section 1042 of the reflective element 104 are at a second angle, far-infrared light incident from the thermal uniform body 103 and reflected by section 1042 of the reflective element 104 is incident on section 1022 of the image sensor 102. In this way, it is possible to calibrate the corresponding section of the image sensor 102 by switching some of the micromirrors of the reflective element 104. The divisions set in the reflective element 104 may be such that the peripheries of the divisions overlap at the boundaries of the divisions, taking into consideration the influence of light leakage or the influence of correspondence with the pixels of the sensor.

[0025] Returning to the explanation of Fig. 1, the image processing unit 308 acquires the far-infrared image captured by the image sensor 102 and performs various processes. The image processing unit 308 performs known processes on the far-infrared image captured by the image sensor 102 to make the far-infrared image an appropriate image, such as interpolation of defective pixels and correction of pixel values. The image processing unit 308 also includes an object detection unit 3081 and a moving object detection unit 3082, as shown in Fig. 2.

[0026] The object detection unit 3081 detects a preset detection target object from the far-infrared image acquired by the image processing unit 308. When the thermal image processing device 10 is mounted on a smart pole, the detection target object detected by the object detection unit 3081 is a person or a vehicle, as described above.

[0027] The object detection unit 3081 detects a detection target object included in the far-infrared image acquired by the image processing unit 308, using a detection model that has been machine-learned on detection target objects such as people and vehicles captured as far-infrared images. Specifically, the object detection unit 308 detects people and vehicles for each frame of the far-infrared image acquired by the image processing unit 308, using a person detection model that has been machine-learned on far-infrared images of people, and a vehicle detection model that has been machine-learned on far-infrared images of vehicles. The detection of the detection target object may be performed using AI (Artificial Intelligence). Furthermore, the object detection unit 3081 determines information such as the type, coordinates, and movement speed of the detected detection target object using a known method.

[0028] The moving object detection unit 3082 detects a moving object included in the far-infrared image acquired by the image processing unit 308. A moving object detected by the moving object detection unit 3082 is an object whose position moves for each consecutive frame of the far-infrared image acquired by the image processing unit 308. The moving object detection unit 3082 detects a moving object based on detecting that the position of an edge portion, which is formed by a difference in pixel values ​​in the far-infrared image acquired by the image processing unit 308, changes for each consecutive frame. AI may be used to detect the moving object.

[0029] The output unit 309 outputs information about the detection target object detected by the object detection unit 3081 to another device, etc. Specifically, it outputs information such as the type, coordinates, and moving speed of the detected detection target object to a device that transmits the information to vehicles traveling around the smart pole, etc. The output unit 309 may output to another device an image in which information indicating the position and range of the detection target object detected by the object detection unit 3081 has been added to the far-infrared image acquired by the image processing unit 308.

[0030] The calibration control unit 310 switches the reflecting element 104 from the first angle to the second angle for each section while capturing a far-infrared image, and performs calibration for each switched section based on the infrared light emitted from the thermal uniform body 103. By changing the reflecting element 104 from the first angle to the second angle for each section of the imaging element 102, the range of the corresponding section of the imaging element 102 captures far-infrared light from the thermal uniform body 103. Therefore, calibration can be performed for the section of the imaging element 102 to which the reflecting element 104 has been switched so that the thermal uniform body 103 can be captured. The above configuration provides a thermal image processing device that can perform calibration during imaging.

[0031] (Description of the calibration method for the thermal image processing device according to the first embodiment) 6 is a flowchart of the calibration method for the thermal image processing device according to the embodiment 1. The calibration method for the thermal image processing device according to the embodiment will be described with reference to FIG.

[0032] 6 is a process for determining whether to perform calibration on the image sensor 102, assuming that the thermal image processing device 10 is capturing an image. First, the calibration control unit 310 determines whether calibration is required for the image sensor 102 (step S101). The determination in step S101 determines that calibration is required when a change occurs in the temperature of the image sensor 102 or the ambient temperature, or when a condition is met, such as when image capturing begins or when a predetermined time has elapsed since the start of image capturing.

[0033] If the calibration control unit 310 determines that calibration is required (YES in step S101), it executes calibration (step S102). If the calibration control unit 310 does not determine that calibration is required (NO in step S101), it determines whether to end the process (step S103). The process in step S103 will be described later. Also, except during the period when calibration is being performed, all micromirrors in the reflecting element 104 or micromirrors corresponding to all sections of the image sensor 102 are at the first angle.

[0034] The control unit 300 determines whether or not to end the process (step S103). End of the process means end of imaging by the imaging unit 100. End of the process is based on an operation to stop imaging by the thermal image processing device 10, etc. When the thermal image processing device 10 is installed in a smart pole, it continues to operate except during maintenance of the smart pole, so the processes of steps S101 and S102 continue while the operation continues. When it is determined to end the process (YES in step S103), the process of FIG. 6 ends. When it is determined not to end the process (NO in step S103), proceed to step S101.

[0035] Fig. 7 is a flowchart illustrating the process of step S102 in Fig. 6. The process of Fig. 7 is executed when it is determined in step S101 in Fig. 6 that calibration is required.

[0036] When calibration starts, the calibration control unit 310 acquires a moving object detection result from the moving object detection unit 3082 and determines whether a moving object is detected in the far-infrared image (step S201). More specifically, the calibration control unit 310 determines whether a moving object is detected and also identifies the position where the moving object is detected. The position where the moving object is detected is identified, for example, by identifying the section of the image sensor 102 (see FIG. 4) corresponding to the pixel range where the moving object is detected. The detection of the moving object is continued until the calibration process of step S102 is completed, in other words, until the calibration of all sections of the image sensor 102 is completed.

[0037] If the calibration control unit 310 determines that a moving object has been detected (YES in step S201), the process proceeds to step S202, and if it does not determine that a moving object has been detected (NO in step S201), the process proceeds to step S206.

[0038] In step S206, the calibration control unit 310 performs calibration of the entire image sensor 102, and ends the process shown in Fig. 7. Specifically, the calibration control unit 310 controls the reflection control unit 307 so that all micromirrors in the reflection element 104 that were at the first angle before the start of calibration, or the micromirrors corresponding to all sections of the image sensor 102, are set to the second angle.

[0039] Furthermore, when all the micromirrors or the micromirrors corresponding to all sections of the image sensor 102 reach the second angle, the calibration control unit 310 controls the image processing unit 308 to cause the image sensor 102 to capture an image. At this time, the object captured by the image sensor 102 is the thermal uniform body 103. At this time, the calibration control unit 310 acquires information on the temperature of the thermal uniform body 103 from the temperature measurement unit 306.

[0040] The calibration control unit 310 sets an offset value for the output value based on the image of the thermally uniform body 103 and the temperature information of the thermally uniform body 103 so that the output value of each thermal element of the imaging element 102 becomes uniform, and reflects this in the output value of each thermal element.

[0041] In step S202, the calibration control unit 310 performs calibration preferentially on sections of the image sensor 102 in which no moving object is detected. In other words, the calibration control unit 310 performs calibration on sections (moving object non-detection sections) in which no moving object is detected among the sections set in the image sensor 102. Specifically, the calibration control unit 310 controls the reflection control unit 307 to set all micromirrors in the reflection element 104 that are at the first angle before the start of calibration, or to set micromirrors corresponding to sections in which no moving object is detected, out of the micromirrors corresponding to all sections of the image sensor 102, to the second angle.

[0042] Furthermore, when the micromirror corresponding to the section where no moving object is detected reaches the second angle, the calibration control unit 310 controls the image processing unit 308 to cause the image sensor 102 to capture an image. At this time, the calibration control unit 310 acquires information about the temperature of the thermal uniformity medium 103 from the temperature measurement unit 306.

[0043] Based on the image of the thermally uniform body 103 and the temperature information of the thermally uniform body 103, the calibration control unit 310 sets an offset value for the output value so that the output value of each thermal sensor corresponding to the section of the imaging element 102 where no moving object is detected becomes uniform, and reflects this in the output value of each thermal sensor.

[0044] Next, the calibration control unit 310 determines whether or not a moving object has been detected in a section that has not been calibrated in the process of step S202 (non-calibration section) (step S203). When the thermal image processing device 10 is mounted on a smart pole, pedestrians, moving vehicles, etc. are detected as moving objects, and as they move, even in a section where a moving object was detected in the process of step S201, the moving object may not be detected in the image one to several frames later.

[0045] If the calibration control unit 310 determines that a moving object has been detected in a non-calibration section (YES in step S203), it performs the process of step S203 again, and if it does not determine that a moving object has been detected (NO in step S203), it proceeds to step S204. In the process of step S203, if it is determined that a moving object has been detected in some of the sections that were not calibrated in step S202, the process of determining whether a moving object has been detected in those sections is performed again on the video one to several frames later (YES in step S203). Also, if it is determined that a moving object has not been detected in some of the sections that were not calibrated in step S202, NO is determined in step S203 for those sections.

[0046] In step S204, the calibration control unit 310 performs calibration on the sections (remaining sections) for which no moving object was detected in step S203, among the sections for which calibration was not performed in step S202. The calibration is performed in such a way that the section to be calibrated is the section for which the result of step S203 is NO, and other processing is the same as in step S202 or step S206.

[0047] Next, the calibration control unit 310 determines whether the calibration of all sections has been completed (step S205). If it is determined that the calibration of all sections has been completed (YES in step S205), the process of FIG. 7 ends, and the process proceeds to step S103 in FIG. 6. If it is not determined that the calibration of all sections has been completed (NO in step S205), the process proceeds to step S203. In step S205, if the calibration of all sections is not completed within a period of, for example, 3 to 5 seconds in a state where moving objects such as pedestrians and vehicles are passing by continuously without interruption, the process of FIG. 7 may be terminated.

[0048] By performing this process, calibration is performed preferentially on sections where no moving object is detected, and even in sections where a moving object is detected, calibration is performed only after the moving object is no longer detected. This allows calibration to be performed without interrupting imaging and detection of target objects.

[0049] (Description of a Modified Example of the Calibration Method for the Thermal Image Processing Device According to the First Embodiment) A modified example of the calibration method for the thermal image processing device according to the first embodiment will be described with reference to Fig. 8. In this embodiment, the divisions of the image capturing element 102 corresponding to the range in which a moving object to be detected is detected within the imaging range of the imaging unit 100 are stored in advance. When the thermal image processing device 10 is mounted on a smart pole, the object to be detected is a person or a vehicle, and there is no problem in performing calibration for the divisions in which a moving object other than the object to be detected is detected, which is used as information to warn vehicles traveling around the smart pole.

[0050] Fig. 8 illustrates an example of the range in which a moving object is detected in a section set in the image sensor 102. In the example of Fig. 8, the sections with diagonal lines are pre-stored as sections in which a moving object is detected. The road and vehicles in the example of Fig. 8 mimic the range captured by the image sensor 100 of the thermal image processing device 10 installed on a smart pole, and are the roadway and vehicles traveling on the roadway. Since the orientation of the image sensor 100 is fixed when used on a smart pole, the image sensor 102's image capture range corresponding to each section does not change.

[0051] As shown in the example of Figure 8, the section corresponding to the range in which a moving object that is a detection target can be detected is the range in which it is necessary to detect a vehicle or person that is a detection target object for which a warning is issued, such as the roadway and its surroundings.

[0052] In a modified example of the calibration method for the thermal image processing device according to the first embodiment, in step S202 of FIG. 7, calibration is performed on sections that are not within the range in which a moving object to be detected is detected, in addition to the non-moving object detection section in the section corresponding to the range in which a moving object to be detected is detected.

[0053] By performing such processing, even if a moving object is detected in a section other than the section corresponding to the range in which the moving object to be detected is detected, calibration can be performed simultaneously with the section in which the moving object is not detected, thereby enabling efficient calibration.

[0054] (Explanation of the calibration method of the thermal image processing device according to the second embodiment) Fig. 9 is a flowchart of a calibration method for a thermal image processing device according to the second embodiment. The calibration method for a thermal image processing device according to the embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart illustrating the process of step S102 in Fig. 6, similar to Fig. 7. Steps S301, S309, and S310 shown in Fig. 9 perform the same processes as steps S201, S205, and S206 shown in Fig. 7.

[0055] If it is determined in step S301 that a moving object has been detected, the calibration control unit 310 determines whether the detected moving object is a detection target object (step S302). Specifically, the calibration control unit 310 determines that the detected moving object is a detection target object when the range of the moving object detected by the moving object detection unit 3082 is included in or matches the range of the detection target object detected by the object detection unit 3081. In other words, it determines whether the moving object detected by the moving object detection unit 3082 is a person or a vehicle, which is a detection target object.

[0056] If it is determined that the detected moving object is a detection target object (YES in step S302), the process proceeds to step S303, and if it is not determined that the detected moving object is a detection target object (NO in step S302), the process proceeds to step S310. The process of step S310 is the same as the process of step S206 shown in Fig. 7, but if it is NO in step S301, calibration of the entire image sensor 102 is performed in a state where no moving object is detected, and if it is NO in step S302, calibration of the entire image sensor 102 is performed in a state where a moving object is detected, and the process of Fig. 9 ends.

[0057] In step S303, the calibration control unit 310 performs calibration preferentially on sections of the image sensor 102 in which no moving object, which is a detection target object, has been detected as a moving object non-detection section. In other words, the calibration control unit 310 performs calibration on sections set in the image sensor 102 in which no moving object has been detected and sections in which a moving object has been detected but is not a detection target object.

[0058] Next, the calibration control unit 310 determines whether a moving object has been detected in a section that has not been calibrated in the process of step S303 (a non-calibration section) (step S304). If the calibration control unit 310 determines that a moving object has been detected in a non-calibration section (YES in step S304), the process proceeds to step S305, and if it does not determine that a moving object has been detected (NO in step S304), the process proceeds to step S308. In the process of step S304, if it is determined that a moving object has been detected in some of the sections that have not been calibrated in step S303, the process proceeds to step S305 for those sections, and if it is determined that a moving object has not been detected in some of the sections, NO is determined in step S304 for those sections.

[0059] In step S308, the calibration control unit 310 performs calibration on the sections in which no moving object was detected in step S304, among the sections (remaining sections) that were not calibrated in step S303, and then the process proceeds to step S309.

[0060] In step S305, the calibration control unit 310 determines whether the moving object detected in step S305 is a detection target object (step S305). If it is determined that the detected moving object is a detection target object (YES in step S305), the process proceeds to step S306, and if it is not determined that the detected moving object is a detection target object (NO in step S305), the process proceeds to step S307.

[0061] In step S306, the calibration control unit 310 performs calibration preferentially on the section of the image sensor 102 in which no moving object, which is a detection target object, is detected as the moving object non-detection section, and proceeds to step S309.

[0062] In step S307, the calibration control unit 310 performs calibration on the sections (remaining sections) that were not calibrated in step S303, and the process proceeds to step S309.

[0063] By performing such processing, calibration of sections in which moving objects other than the object to be detected are detected can be performed simultaneously with calibration of sections in which moving objects are not detected, thereby enabling efficient calibration.

[0064] The above configuration provides a thermal image processing device that can appropriately calibrate a far-infrared camera.

[0065] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0066] 10 Thermal image processing device, 100 Imaging unit, 101 Lens, 102 Imaging element, 103 Thermal uniform body, 104 Reflection element, 300 Control unit, 306 Temperature measurement unit, 307 Reflection control unit, 308 Image processing unit, 309 Output unit, 310 Calibration control unit, 3081 Object detection unit, 3082 Moving object detection unit

Claims

1. an imaging unit including an imaging element that captures an infrared image through a lens; a thermal homogeneous body that emits infrared light of constant intensity and wavelength; a reflecting element that is provided on an optical path from the lens to the image sensor, and that is switchable between a first angle at which infrared light incident from the lens is reflected and made incident on the image sensor, and a second angle at which infrared light incident from the thermal uniform body is reflected and made incident on the image sensor, for each section corresponding to the image sensor; a calibration control unit that switches the reflecting element from the first angle to the second angle for each of the sections while capturing the infrared image, and performs calibration based on infrared light radiation from the thermal uniform body for each of the switched sections; A thermal image processing device comprising:

2. a moving object detection unit that detects a moving object included in the infrared image, the calibration control unit performs calibration preferentially on a section in which the moving object is not detected; The thermal imaging device according to claim 1 .

3. A division of the imaging element corresponding to a range in which a detection target object is to be detected within an imaging range is stored in advance, the moving object detection unit detects a moving object in a section of the imaging element corresponding to a range in which the detection target object is to be detected; the calibration control unit performs calibration preferentially on a section of the imaging element corresponding to a range in which the detection target object is to be detected and in which the moving object is not detected; The thermal image processing device according to claim 2 .

4. an object detection unit that detects a detection target object from the infrared image captured by the imaging unit, The thermal image processing device according to claim 2 , wherein the calibration control unit performs calibration preferentially on a section in which no moving object determined by the object detection unit to be the detection target object is detected.

5. During imaging by an imaging element that captures infrared images through a lens, a reflecting element that is provided on the optical path from the lens to the image sensor, and that can switch between a first angle at which infrared light incident from the lens is reflected and made incident on the image sensor, and a second angle at which infrared light of a constant intensity and wavelength incident from a thermal homogeneous body is reflected and made incident on the image sensor, for each section corresponding to the image sensor; performing a calibration based on infrared light from the thermal uniform body for each of the sections; A method for calibrating a thermal imaging device.

Images