Body temperature measuring device and body temperature measuring method

Abstract

To provide a body temperature measuring device and a body temperature measuring method capable of measuring a body temperature accurately.SOLUTION: A body temperature measuring device 100 includes: an infrared camera 1 for taking an infrared image including a measurement object person; an exposed part temperature measuring part 2 for measuring a temperature of an exposed part in which the skin of the measurement object person is exposed on the basis of the infrared image; a non-exposed part temperature measuring part 3 for measuring a temperature of a non-exposed part in which the skin of the measurement object person is not exposed on the basis of the infrared image; an environmental temperature measuring part 4 for measuring an environmental temperature of an environment where the measurement object person is; and a body temperature calculation part 6 for calculating a body temperature of the measurement object person on the basis of the exposed part temperature, the non-exposed part temperature, and the environmental temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a body temperature measuring device and a body temperature measuring method. [Background technology]

[0002] In recent years, there has been a problem that patients with infectious diseases such as the new coronavirus push themselves to do things when they are not feeling well, and unknowingly spread the infection. If a sudden increase in the number of infectious disease patients places a heavy burden on hospitals and other facilities, there is a concern that it could lead to a collapse of the medical system. Therefore, systems for measuring biological conditions are installed in facilities used by an unspecified number of people, such as offices, sports gyms, and commercial facilities. For example, a body surface temperature measuring device using an infrared camera is installed at the entrance of the facility.

[0003] Patent Document 1 discloses an infrared monitoring system equipped with an infrared camera that captures an image of a monitoring area. The system of Patent Document 1 includes a means for detecting a temperature change area that is different from the background area in an infrared image. The temperature measurement range is determined by the minimum and maximum temperatures in the background area. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-38217 Summary of the Invention [Problem to be solved by the invention]

[0005] Infrared cameras such as FIR (Far Infrared Rays) cameras measure temperature distribution by detecting infrared rays emitted from the surface of the subject, but when using such infrared cameras, it may not be possible to measure body temperature accurately. For example, if there is a large difference between the indoor temperature inside a facility and the outdoor temperature outside the facility, the difference between the body surface temperature and the body temperature will be large. Since FIR cameras detect infrared rays emitted from the body surface, there is variation in measurement accuracy.

[0006] In particular, when the outdoor temperature is very low compared to the indoor temperature, the temperature difference between the body surface temperature and the body core temperature becomes large, and when an infrared camera is used to measure the body surface temperature, the measurement error becomes large.

[0007] The present disclosure has been made in consideration of the above-mentioned points, and has an object to provide a body temperature measuring device and a body temperature measuring method that can measure body temperature with high accuracy. [Means for solving the problem]

[0008] The body temperature measuring device of this embodiment includes an infrared camera that captures an infrared image of the subject, an exposed part temperature measuring unit that measures the exposed part temperature of the exposed part where the skin of the subject is exposed based on the infrared image, a non-exposed part temperature measuring unit that measures the non-exposed part temperature of the non-exposed part where the skin of the subject is not exposed based on the infrared image, an environmental temperature measuring unit that measures the environmental temperature of the environment in which the subject is present, and a body temperature calculation unit that calculates the body temperature of the subject based on the exposed part temperature, the non-exposed part temperature, and the environmental temperature.

[0009] The body temperature measurement method of this embodiment includes the steps of capturing an infrared image of the subject using an infrared camera, measuring the exposed part temperature of the exposed part where the skin of the subject is exposed based on the infrared image, measuring the non-exposed part temperature of the non-exposed part where the skin of the subject is not exposed based on the infrared image, measuring the environmental temperature of the measurement environment in which the subject is present based on the infrared image, and calculating the body temperature of the subject based on the exposed part temperature, the non-exposed part temperature, and the environmental temperature. Effect of the Invention

[0010] According to the present disclosure, an object of the present invention is to provide a body temperature measuring device and a body temperature measuring method capable of measuring body temperature with high accuracy. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a block diagram showing the configuration of the body temperature measuring device. [Diagram 2] FIG. 2 is a schematic diagram showing an infrared image captured by an infrared camera. [Diagram 3] FIG. 1 shows an example of an acclimatization curve. [Figure 4] FIG. 1 shows an example of an acclimatization curve. [Diagram 5] FIG. 1 shows an example of an acclimatization curve. [Figure 6] 10 is a flowchart showing the process of a body temperature measuring method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings are appropriately simplified for clarity of explanation.

[0013] A body temperature measuring device and a body temperature measuring method according to this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a block diagram showing the configuration of the body temperature measuring device 100. Fig. 2 is a diagram showing an example of an infrared image captured by an infrared camera 1. For example, the body temperature measuring device 100 is installed in a body temperature measuring area such as the entrance of a facility.

[0014] The body temperature measuring device 100 includes an input unit 10, a data storage unit 5, a body temperature calculation unit 6, and an output unit 7. The input unit 10 includes an infrared camera 1, an exposed part temperature measurement unit 2, a non-exposed part temperature measurement unit 3, and an environmental temperature measurement unit 4.

[0015] The infrared camera 1 captures an infrared image F of a subject P. For example, the infrared camera 1 installed at the entrance of a facility captures an image of a person entering the facility. The infrared camera 1 is equipped with a microbolometer that detects infrared rays emitted from a subject within the camera frame. The output of the microbolometer is converted into an electrical signal and visualized to generate an infrared image F. The infrared image F is input to a body temperature calculation unit 6.

[0016] The infrared camera 1 is a thermography such as an FIR camera, and can measure the temperature distribution of a subject without contact. Here, the infrared camera 1 captures an image of a subject P from the front. The infrared image F includes the head and upper body of the subject P.

[0017] The exposed part temperature measuring unit 2 measures the exposed part temperature of the exposed part A1 where the skin of the subject P is exposed. Here, the exposed part A1 may include a non-exposed part. The exposed part temperature measuring unit 2 transmits the measured exposed part temperature to the body temperature calculating unit 6. Particularly suitable locations on the skin surface are facial parts such as the forehead, inner corners of the eyes, and ears. As shown in FIG. 2, the exposed part A1 includes facial parts such as the forehead, inner corners of the eyes, and ears of the subject P. Alternatively, the exposed part A1 may include the neck of the subject P. Also, in FIG. 2, the exposed part A1 is rectangular including the facial part, but it may be in the shape of a face.

[0018] For example, the exposed part temperature measuring unit 2 performs image processing such as face recognition on the infrared image F. Then, the exposed part temperature measuring unit 2 captures the peak of the microbolometer in the face recognition area and determines it as the exposed part temperature. The exposed part temperature indicates the temperature of the skin surface of the measurement subject P (also called the body surface temperature). Here, the exposed part temperature measuring unit 2 measures the temperature of the hottest part in the exposed part A1 as the exposed part temperature. The part of the exposed part A1 with the highest body surface temperature varies from person to person, but may be, for example, the forehead, inner corners of the eyes, mouth, or ears.

[0019] The non-exposed part temperature measuring unit 3 measures the temperature of the non-exposed part A2 where the skin of the measurement subject P is not exposed, based on the infrared image F. The non-exposed part temperature measuring unit 3 transmits the measured non-exposed part temperature to the body temperature calculating unit 6.

[0020] The non-exposed part A2 is, for example, the hair or clothes of the measurement subject P. The non-exposed part temperature measuring unit 3 assumes that the upper 1 / 4 area of ​​the face recognition area is the hair part and sets it as the non-exposed part A2U. Furthermore, the non-exposed part temperature measuring unit 3 assumes that the lower part of the face recognition area is the clothes and sets it as the non-exposed part A2D. The non-exposed part temperature measuring unit 3 compares the output values ​​of the non-exposed part A2U and the non-exposed part A2D and sets the part with the lowest temperature as the non-exposed part temperature. The non-exposed part temperature corresponds to the outside air temperature. In other words, the temperature of the non-exposed part A2 of a person immediately after entering the facility corresponds to the outside air temperature. The non-exposed part A2 is a part other than the skin. For example, it is desirable that the non-exposed part A2 is a part or thing that as many people as possible have in common, such as hair, clothes, or shoes.

[0021] The environmental temperature measuring unit 4 measures the environmental temperature of the environment where the subject P is present. The environmental temperature measuring unit 4 transmits the measured environmental temperature to the body temperature calculating unit 6. For example, a temperature sensor mounted on the infrared camera 1 detects the temperature of the temperature measurement area. Alternatively, the environmental temperature measuring unit 4 may have a temperature sensor provided separately from the infrared camera 1. The temperature sensor measures the room temperature of the temperature measurement area as the environmental temperature. Of course, the environmental temperature may be measured based on the infrared image F. That is, the environmental temperature measuring unit 4 may measure the temperature of a part of the infrared image F other than the person such as the subject P as the environmental temperature. Alternatively, the environmental temperature measuring unit 4 may acquire temperature data of a temperature sensor provided in an air conditioner or the like by data communication.

[0022] The data storage unit 5 stores data on the acclimation curve. The data on the acclimation curve is data that quantifies the degree of acclimation of the body surface temperature. FIG. 3 is a graph showing an example of an acclimation curve. In FIG. 3, the horizontal axis represents elapsed time, and the vertical axis represents temperature. FIG. 3 shows the changes over time of exposed part temperature T1 and non-exposed part temperature T2 as they acclimate to the measurement environment. The time at which the subject enters the room is set to 0 minutes, and as time passes, exposed part temperature T1 and non-exposed part temperature T2 gradually increase.

[0023] The body temperature calculation unit 6 calculates the body temperature of the subject P based on the exposed part temperature, the unexposed part temperature, and the environmental temperature. When the subject P moves to the measurement space from another space with a temperature difference from the measurement space, a difference occurs between the body surface temperature and the body temperature. For example, when the heating is on in the facility, the outside air temperature outside the facility becomes extremely lower than the room temperature of the measurement space in the facility. In this case, the temperature difference between the body surface temperature and the body temperature becomes large. The body temperature calculation unit 6 calculates the body temperature by using the characteristic that the body surface temperature of the subject P acclimates from the outside air temperature to the room temperature of the measurement environment. The calculation method in the body temperature calculation unit 6 will be described later.

[0024] The body temperature calculation unit 6 outputs the calculated body temperature to the output unit 7. The output unit 7 outputs the body temperature of the subject P to an external device. The external device is, for example, a monitor capable of displaying the body temperature. Alternatively, the external device may be a speaker that outputs the body temperature as sound. If the body temperature is equal to or higher than the upper limit of the reference range, the external device may output an alarm or warning message.

[0025] Hereinafter, a description will be given of an example of the processing of the body temperature calculation unit 6. Here, the body temperature calculation unit 6 refers to the data of the acclimation curve stored in the data storage unit 5 to calculate the body temperature of the subject P.

[0026] As shown in Figure 3, the acclimation curve is data on the time change when exposed part temperature T1 and unexposed part temperature T2 become acclimated to the temperature of the measurement environment. Consider the case where a person enters a room with an environmental temperature of 25°C from a room with an outside temperature of 10°C. The time immediately after entering the room is elapsed time 0 in Figure 3. Since unexposed part A2 is a part exposed to the outside air, such as clothing, immediately after entering the room, unexposed part temperature T2 is almost the same temperature as the outside air temperature. Unexposed part temperature T2 at elapsed time 0 in Figure 3 corresponds to the outside air temperature. Infrared camera 1 captures infrared image F immediately after entering the room. The exposed part temperature measured by exposed part temperature measurement unit 2 corresponds to exposed part temperature T1 at elapsed time 0. The exposed part temperature measured by unexposed part temperature measurement unit 3 corresponds to unexposed part temperature T2 at elapsed time 0

[0027] The non-exposed part temperature T2 takes a certain amount of time to adapt to the environmental temperature. In FIG. 3, after about 10 minutes, the non-exposed part temperature T2 rises from the outside air temperature of 10°C to the room temperature of 25°C. On the other hand, the exposed part temperature T1 does not match the outside air temperature even immediately after entering the room due to human body temperature (heat generation), and has a certain offset value. In other words, the exposed part temperature T1 is higher than the non-exposed part temperature T2. Here, the exposed part temperature T1 immediately after entering the room is about 24°C. Over time, the exposed part temperature T1 adapts to the body temperature to be measured.

[0028] The acclimation time of the exposed part temperature T1 becomes longer as the difference between the outside air temperature and the environmental temperature becomes larger. Using this characteristic, the body temperature calculation unit 6 estimates the body temperature from the measured exposed part temperature, the non-exposed part temperature, and the environmental temperature. For example, the temperature difference between the measured non-exposed part temperature and the environmental temperature is obtained. Then, the body temperature calculation unit 6 estimates the acclimation time from an acclimation curve corresponding to this temperature difference. The body temperature calculation unit 6 determines the temperature to which the measured exposed part temperature rises after the acclimation time has passed as the body temperature. In other words, the body temperature calculation unit 6 estimates the temperature reached when the measured exposed part temperature is acclimated to the measurement environment as the body temperature. After the acclimation time has passed, the exposed part temperature T1 and the non-exposed part temperature T2 become almost constant. In other words, the temperature rise of the exposed part temperature T1 and the non-exposed part temperature T2 after the acclimation time has passed is saturated.

[0029] When the temperature difference between the outside air temperature and the environmental temperature is equal to or greater than a certain predetermined value S, the body temperature calculation unit 6 calculates the body temperature by referring to the acclimation curve. That is, the body temperature calculation unit 6 calculates the body temperature by correcting the exposed part temperature to the temperature after acclimation to the measurement environment. In this way, it is possible to realize more accurate body temperature measurement. Note that when the temperature difference between the outside air temperature and the environmental temperature is small, the exposed part temperature may be used as the body temperature.

[0030] In this way, the body temperature calculation unit 6 estimates the body temperature from the exposed part temperature by referring to the data of the acclimation curve. The body temperature calculation unit 6 calculates the body temperature by referring to the acclimation curve and correcting the body surface temperature to the temperature after acclimation. In this way, the body temperature can be measured with high accuracy.

[0031] Furthermore, if the temperature difference between the environmental temperature and the outside air temperature estimated from the temperature of the unexposed part is greater than a predetermined threshold, it becomes difficult to calculate the body temperature with high accuracy. Here, the predetermined threshold is greater than the above-mentioned predetermined value S. In such a case, the output unit 7 may prompt the subject P to perform remeasurement after a predetermined time has elapsed. For example, the output unit 7 outputs, via an external device, that a measurement error has occurred.

[0032] Then, after a predetermined time has elapsed, the infrared camera 1 captures an infrared image again. Then, based on the infrared image captured again, the exposed part temperature measuring unit 2 and the non-exposed part temperature measuring unit 3 measure the exposed part temperature and the non-exposed part temperature. The body temperature calculating unit 6 calculates the body temperature based on the remeasured exposed part temperature and non-exposed part temperature. In this way, the body temperature can be measured with higher accuracy.

[0033] Specifically, if the temperature difference between the outside air temperature and the environmental temperature is 15°C or more, the body temperature measuring device 100 may perform remeasurement. In this case, the output unit 7 presents the measurement subject P with a one-minute waiting time through the monitor of the external device. Then, the body temperature measuring device 100 measures the body temperature based on the infrared image captured after one minute has elapsed. In addition, the body temperature calculation unit 6 may select an appropriate acclimatization curve according to the time difference between the first infrared image captured and the second infrared image captured. Of course, the temperature difference threshold is not limited to 15°C. In addition, the waiting time is not limited to one minute.

[0034] The body temperature measuring device 100 shown in Fig. 1 does not have to be a single device. For example, the infrared camera 1 and the body temperature calculation unit 6 that performs arithmetic processing may be physically separated into different devices. Furthermore, the body temperature calculation unit 6 may access the data storage unit 5 via a network.

[0035] In the above explanation, the measured values ​​of the exposed portion temperature and the unexposed portion temperature correspond to the temperature at elapsed time 0 on the acclimation curve in Fig. 3, but they may correspond to temperatures at times other than elapsed time 0. For example, if the measurement location is far from the facility entrance, the measurement times of the exposed portion temperature and the unexposed portion temperature may be times other than elapsed time 0 on the acclimation curve.

[0036] At this time, the elapsed time can be estimated by reading which elapsed time on the acclimation curve corresponds to the temperature difference between the exposed and unexposed parts. For example, if the temperature difference between the exposed and unexposed parts is 10°C, the estimated elapsed time is the elapsed time at which the difference between T1 and T2 in Figure 3 becomes 10°C.

[0037] In this embodiment, it is preferable that acclimation curves corresponding to various situations are measured in advance. For example, the temperature difference between the environmental temperature of the measurement environment and the outside air temperature is changed and the acclimation curve is measured. The temperature of the acclimation curve may be measured based on an infrared image or may be measured by another temperature sensor. The data storage unit 5 stores a plurality of acclimation curves. The body temperature calculation unit 6 selects an acclimation curve suitable for the temperature difference between the measured values ​​of the non-exposed part temperature and the environmental temperature from the plurality of acclimation curves. Alternatively, the body temperature calculation unit 6 may obtain the acclimation curve by data interpolation. Also, a calculation formula for calculating the body temperature may be obtained based on the measured values ​​of the environmental temperature, the exposed part temperature, and the non-exposed part temperature. The calculation formula can be obtained by approximation using a polynomial or the like.

[0038] 4 and 5 are graphs showing other examples of the acclimation curve. FIG. 4 shows an acclimation curve when the environmental temperature of the measurement environment is 25° C. and the outside air temperature is 0° C. As shown in FIG. 4, even if the outside air temperature is extremely lower than the environmental temperature, the non-exposed part temperature T2 rises rapidly. Therefore, by using an infrared image captured again about one minute after the first measurement by the body temperature measuring device 100, the body temperature can be measured with high accuracy. In addition, it is possible to determine whether the outside air temperature (non-exposed part temperature) is extremely lower than the environmental temperature, and if the determination is true, not to perform the measurement immediately, but to perform the first measurement after one minute has passed.

[0039] Figure 5 shows the acclimation curve when the measurement environment temperature is 25°C and the outside air temperature is 35°C. Even when the outside air temperature is higher than the environmental temperature, the non-exposed part temperature T2 will acclimate to the environmental temperature over time. In other words, the non-exposed part temperature T2 will gradually decrease to the environmental temperature. In addition, the exposed part temperature T1 will also decrease over time and will acclimate to a temperature equivalent to body temperature.

[0040] By preparing an acclimation curve when the outside temperature is higher than the ambient temperature, as shown in Figure 5, it is possible to improve the measurement accuracy in various situations. In other words, even if the air conditioner is operating in the measurement environment, the body temperature can be measured accurately.

[0041] A body temperature measuring method according to this embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the body temperature measuring method. The body temperature measuring device 100 uses the infrared camera 1 to capture an infrared image F of the subject P (S101). Next, based on the infrared image F, the exposed part temperature measuring unit 2 measures the exposed part temperature of the exposed part where the skin of the subject is exposed (S102). In other words, based on the infrared image F of the infrared camera 1, the exposed part temperature measuring unit 2 measures the exposed part temperature, which is the body surface temperature of the person.

[0042] Based on the infrared image F, the non-exposed part temperature measuring unit 3 measures the non-exposed part temperature of the non-exposed part of the subject P where the skin is not exposed (S103). The non-exposed part temperature measuring unit 3 measures the non-exposed part temperature by treating the parts other than the skin as the non-exposed part in the infrared image F. The outside air temperature can be estimated from the non-exposed part temperature measured by the non-exposed part temperature measuring unit 3.

[0043] The environmental temperature measurement unit 4 measures the environmental temperature of the environment in which the measurement subject P is present (S104). The body temperature calculation unit 6 determines whether the temperature difference between the environmental temperature and the unexposed part temperature is equal to or greater than a threshold value (S105). The unexposed part temperature corresponds to the outside air temperature as described above. If the temperature difference is equal to or greater than the threshold value (YES in S105), the infrared camera 1 captures an infrared image again. For example, as described above, the output unit 7 prompts for remeasurement, and an infrared image F is captured after a predetermined time has passed. This causes the exposed part temperature, unexposed part temperature, and environmental temperature to be measured again.

[0044] If the temperature difference is not equal to or greater than the threshold (NO in S105), the body temperature calculation unit 6 calculates the body temperature of the subject P based on the exposed part temperature, the unexposed part temperature, and the environmental temperature (S106). Here, as described above, the body temperature calculation unit 6 calculates the body temperature by referring to the data of the acclimation curve stored in the data storage unit 5.

[0045] In this way, the body temperature can be measured with high accuracy. The order of measurements in steps S102 to S104 is not particularly limited. For example, the environmental temperature may be measured, followed by the non-exposed portion temperature and the exposed portion temperature. Furthermore, the environmental temperature, non-exposed portion temperature, and exposed portion temperature may be measured substantially simultaneously. Furthermore, step S105 may be omitted.

[0046] Although the present invention has been specifically described based on the embodiments, it goes without saying that the present invention is not limited to the above-mentioned embodiments and can be modified in various ways without departing from the spirit of the invention. Two or more of the above-mentioned embodiments can also be appropriately combined. [Explanation of symbols]

[0047] 100 Body temperature measuring device 10 Input section 1. Infrared camera 2 Exposed temperature measurement part 3 Non-exposed temperature measuring section 4 Environmental temperature measurement section 5 Data storage section 6 Body temperature calculation unit 7 Output section 8 External device F Infrared image P Measurement subject A1 Exposed part A2 Non-exposed part

Claims

1. An infrared camera that captures an infrared image of a subject; an exposed part temperature measuring unit that measures a temperature of an exposed part of the subject's skin based on the infrared image; a non-exposed part temperature measuring unit that measures a temperature of a non-exposed part of the measurement subject's skin that is not exposed based on the infrared image; and an environmental temperature measurement unit for measuring an environmental temperature of a measurement environment in which the measurement subject is present; a body temperature calculation unit that calculates a body temperature of the measurement subject based on the exposed portion temperature, the non-exposed portion temperature, and the environmental temperature, The body temperature calculation unit calculates the body temperature by referring to data of an acclimation curve measured in advance, the acclimatization curve includes data on changes in temperature of the exposed portion and the temperature of the unexposed portion over time, The body temperature calculation unit calculates the body temperature by correcting the exposed portion temperature to a temperature after acclimation to the measurement environment based on the acclimation curve.

2. A data storage unit is further provided for storing a plurality of pieces of data of the acclimation curves measured by changing the environmental temperature, The body temperature measuring device according to claim 1 , wherein the body temperature is calculated by referring to the acclimation curve corresponding to a temperature difference between an outside air temperature estimated from the unexposed portion temperature and the environmental temperature.

3. When the temperature difference between the environmental temperature and the non-exposed portion is equal to or greater than a threshold value, the infrared camera captures the infrared image again after a predetermined time has elapsed; The body temperature measuring device according to claim 1 , wherein the exposed portion temperature and the unexposed portion temperature are measured based on the infrared image captured again.

4. Taking an infrared image of a subject using an infrared camera; measuring a temperature of an exposed part of the subject's skin based on the infrared image; measuring a temperature of an unexposed part of the subject's skin based on the infrared image; Measuring an environmental temperature of a measurement environment in which the measurement subject is present; and calculating a body temperature of the subject based on the exposed portion temperature, the non-exposed portion temperature, and the environmental temperature. In the step of calculating the body temperature, Refer to the previously measured habituation curve data, Calculating the body temperature by correcting the exposed portion temperature to a temperature after acclimation to the measurement environment based on the acclimation curve; A body temperature measuring method, wherein the acclimatization curve includes data on changes in the exposed part temperature and the unexposed part temperature over time.

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