Heating system

Abstract

An infrared imaging device (9) includes, within an imaging range: a person standing in front of a heating device (1); a heating unit (5); and a heated object (3). A thermal image generation unit (11) generates a thermal image from an output signal from the infrared imaging device (9). A person detection unit (12) detects whether a person is present in the thermal image. A person detection area setting unit (18) sets a person detection area (27), which is a region where a person is detected in the thermal image. A sensitivity adjustment unit (26) adjusts the sensitivity of each pixel of the infrared imaging device (9), and the sensitivity of pixels corresponding to the person detection area (27) is set to be higher than that of pixels corresponding to other regions.

Description

Heating system

[0001] The present disclosure relates to a heating system with a safety device.

[0002] A technology has been disclosed that detects the presence / absence of a person and their orientation from thermal images acquired by an infrared imaging device (see, for example, Patent Literature 1). This information is utilized for monitoring, crime prevention, autonomous driving, etc., contributing to the realization of a safe and secure society. In equipment that uses high-temperature heat sources, such as in factories or kitchens, there is a demand for improving the safety of heating devices by issuing a warning when a person approaches the heat source or by controlling the temperature of the heat source.

[0003] For example, AI-based detection methods are used to detect people on thermal images. On the other hand, safety devices using infrared imaging devices are required to operate standalone, without connecting to external PCs or servers. Therefore, using a high-performance CPU to operate AI raises product prices and increases power consumption, resulting in shorter battery life. For this reason, relatively inexpensive microcontroller units (MCUs) with limited performance are often installed. Due to the limited processing power of the MCU, the number of bits in the thermal image input to the MCU must be low. For example, images captured by an infrared camera may be converted into 8-bit, 256-level grayscale images, and AI-based human detection processing may be performed on the MCU.

[0004] Japanese Patent Publication No. 2022-35519

[0005] When a high-temperature subject is present within the imaging range of an infrared imaging device, the temperature resolution of one digit, which is the unit of digital signal, decreases in a thermal image with a reduced number of bits. As a result, the difference in brightness between the background temperature and the person becomes extremely small, making it difficult to determine whether a person is present or absent on the thermal image.

[0006] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to obtain a heating system that can accurately detect people on a thermal image even when a high-temperature subject is present within the imaging range of the infrared imaging device.

[0007] The first heating system according to the present disclosure comprises a heating device having a heating unit that heats an object to be heated, and a safety device that controls the heating device, and the safety device comprises an infrared imaging device that includes a person standing in front of the heating device, the heating unit, and the object to be heated within its imaging range, a thermal image generation unit that generates a thermal image from the output signal of the infrared imaging device, a human detection unit that detects whether a person is present in the thermal image, a human detection area setting unit that sets a human detection area that is an area in the thermal image where a person is detected, and a sensitivity adjustment unit that adjusts the sensitivity of each pixel of the infrared imaging device, and is characterized in that the sensitivity adjustment unit sets a higher sensitivity for pixels corresponding to the human detection area than for pixels corresponding to other areas.

[0008] The second heating system according to the present disclosure comprises a heating device having a heating unit that heats an object to be heated, and a safety device that controls the heating device, wherein the safety device comprises an infrared imaging device that includes a person standing in front of the heating device, the heating unit, and the object to be heated within its imaging range, a thermal image generation unit that generates a thermal image from the output signal of the infrared imaging device, a human detection unit that detects whether a person is present in the thermal image, and a protective member that is arranged in front of the infrared-transmitting lens of the infrared imaging device and is transparent to infrared rays, wherein the thickness of the protective member in an area corresponding to a human detection area, which is an area in the thermal image where a person is detected, is thinner than the thickness of the protective member in an area corresponding to the outside of the human detection area.

[0009] A third heating system according to the present disclosure comprises a heating device having a heating unit that heats an object to be heated, and a safety device that controls the heating device, wherein the safety device comprises an infrared imaging device that includes a person standing in front of the heating device, the heating unit, and the object to be heated within its imaging range, a thermal image generation unit that generates a thermal image from an output signal of the infrared imaging device, a human detection unit that detects whether a person is present in the thermal image, a human detection area setting unit that sets a human detection area, which is an area in the thermal image where a person is detected, and a sensitivity adjustment unit that switches the sensitivity of the entire pixels of the infrared imaging device for each frame of images continuously captured by the infrared imaging device, wherein the continuously captured images include a first frame and a second frame in which the sensitivity of the entire pixels is lower than that of the first frame, and the thermal image generation unit generates the thermal image using the first frame for the human detection area and the second frame for other areas.

[0010] In the first heating system according to the present disclosure, the sensitivity of pixels corresponding to the human detection area is set higher than the sensitivity of pixels corresponding to other areas, so that even if a high-temperature object is present within the imaging range of the infrared imaging device, the high-temperature object and the person can be displayed simultaneously on the thermal image using an inexpensive MCU, thereby enabling accurate detection of the person on the thermal image.

[0011] In the second heating system according to the present disclosure, the thickness of the protective member in the region corresponding to the human detection area is thinner than the thickness of the protective member in the region outside the human detection area. This reduces the infrared transmittance in the region outside the human detection area. Therefore, even if a high-temperature object is present within the imaging range of the infrared imaging device, the high-temperature object and the person can be displayed simultaneously on the thermal image using an inexpensive MCU, allowing for accurate detection of the person on the thermal image.

[0012] In the third heating system according to the present disclosure, the sensitivity of the entire pixels of the infrared imaging device is switched for each frame of continuously captured images, and a thermal image is generated using a first frame with high sensitivity for the human detection area and a second frame with low sensitivity for other areas. This allows for accurate detection of a person on a thermal image even when a high-temperature object is present within the imaging range of the infrared imaging device, as the high-temperature object and the person 2 can be displayed simultaneously on the thermal image using an inexpensive MCU.

[0013] 1 is a side view showing a heating system according to embodiment 1. FIG. 2 is a block diagram showing a heating system according to embodiment 1. FIG. 3 is a diagram showing an infrared imaging device according to embodiment 1. FIG. 4 is a diagram showing a visible image. FIG. 5 is a flowchart for setting a human detection area and sensitivity. FIG. 6 is a diagram showing an image of setting the sensitivity of an infrared imaging device. FIG. 7 is a thermal image taken without adjusting the sensitivity of the human detection area. FIG. 8 is a thermal image taken without adjusting the sensitivity of the human detection area. FIG. 9 is a thermal image taken with the sensitivity of the human detection area adjusted. FIG. 10 is a flowchart for human detection. FIG. 11 is a diagram showing an infrared imaging device according to embodiment 2. FIG. 12 is a block diagram showing a heating system according to embodiment 2. FIG. 13 is a flowchart showing the operation of a safety device according to embodiment 2. FIG. 14 is a diagram showing a thermal image before offsetting. FIG. 15 is a diagram showing a thermal image after offsetting. FIG. 16 is a flowchart showing the operation of a safety device according to embodiment 3. FIG. 17 is a diagram showing a part of a safety device according to embodiment 4. FIG. 18 is a diagram showing a first frame with high sensitivity. FIG. 19 is a diagram showing a second frame with low sensitivity. FIG. 19 is a diagram showing a thermal image generated by a thermal image generation unit according to embodiment 2.

[0014] A heating system according to an embodiment will be described with reference to the drawings. The same or corresponding components are designated by the same reference numerals, and repeated description may be omitted.

[0015] 1 is a side view showing a heating system according to embodiment 1. A heating device 1 is a cooking appliance or the like used by a person 2, and heats an object to be heated 3. A safety device 4 controls the heating device 1.

[0016] 2 is a block diagram showing the heating system according to embodiment 1. A heating unit 5 of a heating device 1 heats an object 3 to be heated. An operation unit 6 inputs operations from a person 2. A memory unit 7 of the heating device 1 stores recipe information such as a heating sequence. A control unit 8 controls the heating unit 5 in accordance with instructions from the operation unit 6 or the recipe information stored in the memory unit 7. The recipe information may include, for example, simmering the water for 100 degrees for 10 minutes, or frying the food in a frying pan at 160 degrees for 3 minutes.

[0017] The safety device 4 has an infrared imaging device 9 that captures an image of a subject. The safety device 4 is installed above the heating device 1 at a position and angle such that the imaging range of the infrared imaging device 9 includes a person 2 standing in front of the heating device 1, the heating unit 5, and the object to be heated 3. A control unit 10 controls the infrared imaging device 9.

[0018] The thermal image generating unit 11 generates a thermal image from the output signal of the infrared imaging device 9 and converts the number of bits. For example, the thermal image generating unit 11 generates an 8-bit grayscale thermal image from a 14-bit digital signal.

[0019] The human detection unit 12 detects the presence of a person 2 in the thermal image or the state of the person 2 using various detection methods such as AI. Various deep learning algorithms may be used for these detections. When performing AI processing using an inexpensive MCU, the number of bits of the input image may be limited. For example, an 8-bit grayscale thermal image is generated by extracting the maximum and minimum brightness from the 14-bit brightness data of each pixel to calculate the brightness range, dividing it into 256 gradations, and allocating the brightness of each pixel.

[0020] The temperature calculation unit 13 calculates the temperature of each pixel from the output signal of the infrared imaging device 9 using the set sensitivity and a conversion formula and coefficients set in advance in the storage unit 14. This allows for highly accurate human detection without impairing the accuracy of temperature measurement.

[0021] Light source 15 is an LED that is mounted on a typical range hood and illuminates the area around person 2. Communication unit 16 of safety device 4 and communication unit 17 of heating device 1 transmit and receive data to and from each other. Note that if recipe information is stored in memory unit 14 of safety device 4, memory unit 7 of heating device 1 may be unnecessary.

[0022] The human detection area setting unit 18 sets a human detection area, which is an area in the thermal image where a person 2 is detected. For example, the user operates the operation unit 19 while viewing the thermal image on the display to set the human detection area using the human detection area setting unit 18. Information about the set human detection area is stored in the storage unit 14.

[0023] FIG. 3 is a diagram illustrating an infrared imaging device according to the first embodiment. Infrared rays incident on an infrared-transmitting lens 20 are imaged on the light-receiving surface of the infrared imaging device 9. A plurality of detection pixels are arranged in a two-dimensional array on the light-receiving surface of the infrared imaging device 9. The detection pixels are microbolometers, thermopiles, or thermal diodes with a focal plane array (FPA) structure. Each pixel absorbs infrared rays and outputs an analog voltage corresponding to their energy. An analog-to-digital converter 21 amplifies the analog signals output from each pixel of the infrared imaging device 9 using an internal analog amplifier and converts them into, for example, a 14-bit digital signal. This digital signal is called luminance. A thermal image is created by correlating the luminance of each pixel with temperature according to a predetermined conversion formula.

[0024] The multiple pixels of the infrared imaging device 9 have different sensitivities to light intensity, output offsets, and their temperature characteristics. Therefore, a reference thermal image is acquired and saved in advance, and a thermal image is obtained by outputting the difference between the reference thermal image and the input signal from the subject. One example of a method for acquiring a reference thermal image is to capture an image for a predetermined period of time while the infrared-transmitting lens 20 is covered with a light-shielding member 22. The captured data is averaged over a preset number of frames and stored in the FPN memory 23 as a reference thermal image. The reference thermal image is FPN (fixed pattern noise) data of the light-shielding member 22. The temperature of the light-shielding member 22 is measured by a reference temperature detector 24 and stored in the FPN memory 23 as a reference temperature. The light-shielding member 22 is, for example, a mechanical shutter made of a black-painted aluminum plate. The reference temperature detector 24 is, for example, a temperature integrated circuit (IC) attached to the mechanical shutter with thermally conductive tape. Because the output from each pixel is a relative brightness based on the reference thermal image, conversion to absolute temperature requires calculation using the reference temperature. It is also possible to photograph a member of a uniform temperature during pre-shipment inspection of the infrared imaging device at the factory, and store the thermal image and the temperature of the member as a reference thermal image and reference temperature, respectively, in the FPN memory 23. In this case, the light-shielding member 22 and the reference temperature detector 24 are not required.

[0025] The frame memory 25 records the difference between the reference thermal image recorded in the FPN memory 23 and the output signal of the analog-to-digital converter 21. By outputting this to the outside, a two-dimensional thermal image can be obtained.

[0026] When the temperature of the infrared imaging device 9 changes due to self-heating of the infrared imaging device 9 or the analog-to-digital converter 21, or changes in the ambient temperature, the temperature of the photographed subject appears to change on the thermal image. To correct this, the temperature change of the infrared imaging device 9 may be read by an element temperature detection unit (not shown) installed near the element, and input and recorded in the frame memory 25, and the thermal image may be corrected.

[0027] The sensitivity adjustment unit 26 adjusts the sensitivity of the corresponding pixel by adjusting the gain of the analog amplifier based on the information from the human detection area setting unit 18. Alternatively, the sensitivity adjustment unit 26 may adjust the sensitivity of the corresponding pixel by adjusting the gain of the digital output of the analog-to-digital converter 21. Sensitivity is the amount of change in luminance when the temperature of the subject changes by 1°C. In this embodiment, the sensitivity adjustment unit 26 sets a higher sensitivity for pixels corresponding to the human detection area, which is an area in the thermal image where a person 2 is detected, than for pixels corresponding to other areas. For example, the sensitivity of the pixels in the human detection area is set to 30 digit / K, and the sensitivity of the pixels outside the human detection area is set to 10 digit / K, and these values ​​are stored in the memory unit 14.

[0028] Fig. 4 shows a visible image. An object to be heated 3 is placed on the heating device 1, and a person 2 is standing in front of the heating device 1. Fig. 5 is a flowchart showing the setting of the human detection area and sensitivity. The human detection area setting unit 18 sets the human detection area (step S1). Next, the sensitivity adjustment unit 26 changes the sensitivity of the pixels corresponding to the human detection area (step S2). Fig. 6 is a diagram showing an example of the sensitivity setting of the infrared imaging device. For example, the sensitivity of the human detection area 27 is increased to 30 digit / K, and the sensitivity of the other areas is left at 10 digit / K.

[0029] The thermal image generator 11 generates a thermal image using the brightness corrected by the sensitivity, so that the brightness of the person 2 photographed within the human detection area 27 is output relatively high, reducing the difference in brightness with the heat source outside the human detection area 27, allowing the high-temperature subject and the person to be displayed simultaneously on the thermal image.

[0030] Figures 7 and 8 are thermal images taken without adjusting the sensitivity of the human detection area. When there is no high-temperature heated object 3, it is possible to detect a person 2, as shown in Figure 7. On the other hand, when there is a high-temperature heated object 3, the difference in brightness between the person 2 and the background temperature disappears, making it difficult to detect the person 2 on the thermal image, as shown in Figure 8. Figure 9 is a thermal image taken with the sensitivity of the human detection area adjusted. The high-temperature heated object 3 and the person 2 are displayed simultaneously on the thermal image.

[0031] 10 is a flowchart of human detection. First, the infrared imaging device 9 captures an image of the subject (step S11). Next, the thermal image generation unit 11 generates and outputs a thermal image (step S12). Next, the human detection unit 12 detects whether a human 2 is present in the thermal image (step S13). If a human 2 is not detected or is not present within the human detection area 27, the process returns to step S11. If a human 2 is present within the human detection area 27, an output indicating that a human has been detected is made (step S14). Note that the presence / absence of a human 2 may be determined only within the human detection area 27.

[0032] Thereafter, the safety device 4 controls the output of the heating device 1 based on the detection result of the human detection unit 12 and the temperature information calculated by the temperature calculation unit 13. For example, the safety device 4 automatically controls the output of the heating device 1 when the person 2 is not in front of the heating device 1. Specifically, if the output of the heating device 1 is reduced or turned off when the person 2 is not in front of the heating device 1 and the heating device 1 has been on for a predetermined time, it is possible to prevent forgetting to turn it off and reduce energy consumption. Furthermore, if the person 2 is not in front of the heating device 1 and the temperature of the heating device 1 is too high, the safety device 4 reduces the output of the heating device 1 or turns it off. This makes it possible to prevent abnormal heat generation in the heated object 3, thereby improving the safety of the heating device 1.

[0033] Furthermore, when person 2 is in front of heating device 1, safety device 4 prevents automatic control of the output of heating device 1. This allows person 2 to manually control the heat output of heating device 1. Furthermore, safety device 4 will not automatically reduce the heat output even if person 2 intentionally increases the heat output. This prevents interference with person 2's operation and loss of convenience.

[0034] Next, the effects of this embodiment will be explained in comparison with the prior art. When AI-based human detection is performed using an inexpensive MCU, the number of bits of the input thermal image is limited. When attempting to display a range from high to low temperatures using a thermal image with a small number of bits, the temperature resolution decreases. When a high-temperature heated object 3 is captured, the temperature resolution per count (1 digit) of the digital signal decreases. Therefore, with the prior art, there is no difference in brightness between the human 2 and the background temperature, making it difficult to detect the human 2 on the thermal image.

[0035] In contrast, in this embodiment, the sensitivity of pixels corresponding to the human detection area 27 is set higher than the sensitivity of pixels corresponding to other areas. As a result, even if a high-temperature object is present within the imaging range of the infrared imaging device 9, the high-temperature object and the person can be displayed simultaneously on the thermal image using an inexpensive MCU, thereby enabling accurate detection of the person 2 on the thermal image. The temperature of the heat source can also be measured simultaneously. Furthermore, by presetting the human detection area 27, people who are not approaching the equipment, such as people walking in the aisle, will not be displayed on the thermal image, preventing false detection.

[0036] Embodiment 2. Fig. 11 is a diagram showing an infrared imaging device according to embodiment 2. One difference from embodiment 1 is that the sensitivity adjustment unit 26 is not present. Fig. 12 is a block diagram showing a heating system according to embodiment 2. One difference from embodiment 1 is that the safety device 4 has an offset setting unit 28. The human detection area setting unit 18 sets the upper limit temperature to be detected as the threshold value. For example, the threshold value is set to 38°C, which is slightly higher than the human body surface temperature. The other configurations are the same as those of embodiment 1.

[0037] FIG. 13 is a flowchart showing the operation of the safety device according to the second embodiment. First, the infrared imaging device 9 captures an image (step S21). Next, the temperature calculation unit 13 calculates the temperature of each pixel (step S22). Next, the offset setting unit 28 determines whether there are any pixels outside the human detection area 27 that are hotter than the threshold (step S23). If there are any, the offset setting unit 28 performs offset processing to reduce the brightness value output from the infrared imaging device 9 so that the temperature of the pixel matches the threshold, and outputs the result to the thermal image generation unit 11 (step S24). FIG. 14 shows a thermal image before offsetting. For example, the temperature of the person 2 is 35°C, and the temperature of the heated object 3 is 100°C. FIG. 15 shows a thermal image after offsetting. The temperature of the heated object 3 has been changed to the threshold of 38°C.

[0038] Next, the thermal image generator 11 generates and outputs a thermal image in which the maximum and minimum brightness of the offset-processed data are assigned to gradations according to the desired number of bits (step S25). Next, the human detector 12 detects whether a human 2 is present in the thermal image (step S26). If a human 2 is not detected or is not present within the human detection area 27, the process returns to step S21. If a human 2 is present within the human detection area 27, the process outputs that a human has been detected (step S27).

[0039] As described above, in this embodiment, if there is a pixel outside the human detection area 27 with a temperature higher than the threshold, an offset process is performed to reduce the brightness value output from the infrared imaging device 9 so that the temperature of that pixel becomes the same as the threshold. This allows a high-temperature heat source and a person to be displayed simultaneously in a thermal image without providing the infrared imaging device 9 with a mechanism for adjusting pixel sensitivity. Furthermore, because the offset is applied based on the threshold, people can be made to appear the same on the thermal image regardless of the temperature of the heated object. This allows for high detection accuracy. Furthermore, by limiting the human detection area 27, false detections can be suppressed.

[0040] Embodiment 3 In this embodiment, similar to embodiment 2, there is no sensitivity adjustment unit 26, and the safety device 4 has an offset setting unit 28. Differences from embodiment 2 include the function of the offset setting unit 28, as described below, and the human detection area setting unit 18 does not set a threshold value. Other configurations are the same as those of embodiments 1 and 2.

[0041] FIG. 16 is a flowchart showing the operation of the safety device according to the third embodiment. First, steps S21 and S22 are performed as in the second embodiment. Next, the offset setting unit 28 determines whether there is a pixel outside the human detection area 27 whose temperature is higher than the maximum temperature of the human detection area 27 (step S31). If there is a pixel outside the human detection area 27, the offset setting unit 28 performs offset processing to reduce the brightness value output from the infrared imaging device 9 so that the temperature of the pixel is the same as the maximum temperature of the human detection area 27, and outputs the result to the thermal image generating unit 11 (step S32). For example, if the temperature of the heated object 3 is 100°C and the maximum temperature of the human detection area 27 is 35.5°C, the temperature of the heated object 3 is changed to 35.5°C. Then, steps S25 to S27 are performed as in the second embodiment.

[0042] As described above, in this embodiment, if there is a pixel outside the human detection area 27 whose temperature is higher than the maximum temperature of the human detection area 27, an offset process is performed to reduce the brightness value output from the infrared imaging device 9 so that the temperature of that pixel becomes the same as the maximum temperature. This allows a high-temperature heat source and a person to be displayed simultaneously in a thermal image without providing the infrared imaging device 9 with a mechanism for adjusting pixel sensitivity. Furthermore, since there is no need to set a threshold value in advance, this embodiment is more convenient than the second embodiment. Furthermore, this embodiment can prevent changes in the appearance of the person 2 in the thermal image when the body surface temperature of the person 2 drops due to the outside air or rises due to heating by the heating device 1, thereby achieving high human detection accuracy.

[0043] The maximum temperature may be determined for each frame or at regular time intervals. Also, if a heat source other than a person is captured in the human detection area 27, the offset may not function properly. Therefore, if a heat source of a predetermined temperature or higher is detected in the human detection area 27, an abnormality may be detected and an alarm may be issued.

[0044] Embodiment 4. Figure 17 is a diagram showing a portion of a safety device according to embodiment 4. A protective member 29 is disposed in front of the infrared-transmitting lens 20 of the infrared imaging device 9 to prevent contamination of the infrared-transmitting lens 20 and to adjust the sensitivity. The protective member 29 is made of a material that transmits infrared light, such as silicon, germanium, or high-density polyethylene (HDPE). The protective member 29 must be disposed at a distance that does not affect the imaging performance on the infrared imaging device 9, so it is preferable to ensure a distance of several centimeters or more between the infrared-transmitting lens 20 and the protective member 29.

[0045] The thickness of the protective member 29 in the region corresponding to the human detection area 27 is thinner than the thickness of the protective member 29 in the region corresponding to the outside of the human detection area 27. For example, the protective member 29 in the region corresponding to the outside of the human detection area 27 is made of HDPE with a thickness of 0.5 mm, and the protective member 29 in the region corresponding to the human detection area 27 is made of HDPE with a thickness of 0.3 mm. This reduces the infrared transmittance in the region corresponding to the outside of the human detection area 27. Therefore, even if a high-temperature object is present within the imaging range of the infrared imaging device 9, the high-temperature object and the person 2 can be displayed simultaneously on the thermal image using an inexpensive MCU, thereby enabling the person 2 to be detected accurately on the thermal image.

[0046] Since the sensitivity can be changed on the hardware side between the human detection area 27 and outside the human detection area 27, it is not necessary to set the human detection area 27 and threshold values, improving convenience. The protective member 29 for adjusting the sensitivity also serves as a protective member for the module, preventing oil or water droplets from adhering to the infrared-transmitting lens 20 and preventing thermal image capture, improving product reliability.

[0047] Embodiment 5. In Embodiments 2 and 3, the brightness of the high-temperature heat source is set uniformly, which can cause the brightness of the high-temperature subject to saturate, making it impossible to see the temperature distribution inside the heat source. Therefore, in this embodiment, the sensitivity adjustment unit 26 switches the sensitivity of the entire pixels of the infrared imaging device 9 for each frame of images continuously captured by the infrared imaging device 9. The continuously captured images include a first frame and a second frame in which the sensitivity of the entire pixels is lower than that of the first frame.

[0048] Figure 18 is a diagram showing a first frame with high sensitivity. The luminance of person 2 is 200 digits. The luminance of both the outer periphery and center of the heated object 3 is saturated at 256 digits. Figure 19 is a diagram showing a second frame with low sensitivity. The luminance of person 2 is 10 digits. The luminance of the outer periphery of the heated object 3 is 240 digits, and the luminance of the center is 220 digits.

[0049] The thermal image generator 11 generates a thermal image using a first frame with high sensitivity in the human detection area 27 and a second frame with low sensitivity in other areas. This allows an inexpensive MCU to be used to simultaneously display the high-temperature subject and the person 2 on the thermal image, even if there is a high-temperature subject within the imaging range of the infrared imaging device 9, thereby enabling accurate detection of the person 2 on the thermal image.

[0050] 20 is a diagram showing a thermal image generated by the thermal image generation unit according to the fifth embodiment. It is possible to simultaneously display the high-temperature object 3 and the person 2 on the thermal image without losing information on the temperature distribution of the object 3. As a result, it is possible to obtain information on the temperature distribution of the heat source in addition to information on the presence / absence and status of the person. This improves the controllability of the heating device 1. For example, when cooking on a stove, it is possible to control the heat power according to the temperature distribution of ingredients in a frying pan.

[0051] REFERENCE SIGNS LIST 1 heating device, 2 person, 3 heated object, 4 safety device, 5 heating section, 9 infrared imaging device, 11 thermal image generation section, 12 person detection section, 13 temperature calculation section, 18 person detection area setting section, 26 sensitivity adjustment section, 27 person detection area, 28 offset setting section, 29 protective member

Claims

1. A heating device having a heating unit that heats an object to be heated; a safety device for controlling the heating device; The safety device comprises: an infrared imaging device that captures a person standing in front of the heating device, the heating unit, and the heated object within its imaging range; a thermal image generating unit that generates a thermal image from an output signal of the infrared imaging device; a human detection unit that detects whether a human is present in the thermal image; a human detection area setting unit that sets a human detection area in which a person is detected in the thermal image; a sensitivity adjustment unit that adjusts the sensitivity of each pixel of the infrared imaging device; A heating system characterized in that the sensitivity adjustment unit sets a higher sensitivity for pixels corresponding to the human detection area than for pixels corresponding to other areas.

2. The heating system described in claim 1, characterized in that the safety device further has an offset setting unit that determines whether there is a pixel outside the human detection area that is hotter than a threshold value, and if so, performs a process to reduce the brightness output from the infrared imaging device so that the temperature of the pixel becomes the same as the threshold value, and outputs the process to the thermal image generation unit.

3. The heating system described in claim 1, characterized in that the safety device further has an offset setting unit that determines whether there is a pixel outside the human detection area that is hotter than the maximum temperature of the human detection area, and if so, performs a process to reduce the brightness output from the infrared imaging device so that the temperature of the pixel becomes the same as the maximum temperature of the human detection area, and outputs the process to the thermal image generation unit.

4. A heating device having a heating unit that heats an object to be heated; a safety device for controlling the heating device; The safety device comprises: an infrared imaging device that captures a person standing in front of the heating device, the heating unit, and the heated object within its imaging range; a thermal image generating unit that generates a thermal image from an output signal of the infrared imaging device; A human detection unit that detects whether a person is present in the thermal image using AI; a protective member that is disposed in front of the infrared transmitting lens of the infrared imaging device and transmits infrared rays; A heating system characterized in that the thickness of the protective member in an area corresponding to a human detection area, which is an area in the thermal image where humans are detected, is thinner than the thickness of the protective member in an area corresponding to the outside of the human detection area.

5. A heating device having a heating unit that heats an object to be heated; a safety device for controlling the heating device; The safety device comprises: an infrared imaging device that captures a person standing in front of the heating device, the heating unit, and the heated object within its imaging range; a thermal image generating unit that generates a thermal image from an output signal of the infrared imaging device; a human detection unit that detects whether a human is present in the thermal image; a human detection area setting unit that sets a human detection area in which a person is detected in the thermal image; a sensitivity adjustment unit that switches sensitivity of all pixels of the infrared imaging device for each frame of images continuously captured by the infrared imaging device; the continuously captured images include a first frame and a second frame in which sensitivity of all pixels is lower than that of the first frame; A heating system characterized in that the thermal image generation unit generates the thermal image using the first frame for the human detection area and the second frame for other areas.

6. the safety device further includes a temperature calculation unit that calculates a temperature of each pixel from an output signal of the infrared imaging device, A heating system described in any one of claims 1 to 5, characterized in that the safety device controls the output of the heating device based on the detection result of the human detection unit and the temperature information calculated by the temperature calculation unit.