A core body temperature measurement method, system and body temperature measurement device

Abstract

The application discloses a core body temperature measurement method, a core body temperature measurement system and a core body temperature measurement device, and belongs to the technical field of body temperature measurement. The method comprises the following steps: acquiring a heating side temperature, a skin side temperature, a skin side pressure and heating driving information within a preset time window after the start of active heating; calculating an interface thermal resistance between a heating probe and the skin of a target object according to the skin side pressure; calculating a human body side equivalent heat flow density based on a non-steady-state heat balance model according to the heating side temperature, the skin side temperature and the heating driving information; and determining a non-steady-state core body temperature of the target object according to the skin side temperature, the interface thermal resistance and the human body side equivalent heat flow density. The above scheme can quickly obtain the core body temperature without waiting for the probe and the skin to reach a steady-state heat balance, thereby improving the core body temperature measurement speed while ensuring the measurement accuracy of the core body temperature.

Description

Technical Field

[0001] This application relates to the field of body temperature measurement technology, and in particular to a core body temperature measurement method, system and body temperature measurement device. Background Technology

[0002] Core body temperature, as an important physiological parameter reflecting the metabolic state of deep organs in the human body, plays a crucial role in scenarios such as clinical anesthesia, intensive care, infection monitoring, and treatment in extreme heat environments.

[0003] To achieve non-invasive monitoring, indirect measurement methods such as those using the tympanic membrane, oral cavity, axilla, and skin surface have been developed in recent years, along with zero heat flow (ZHF) technology based on thermal conduction models. These methods establish thermal equilibrium through external heating to infer the temperature of deep tissues, achieving non-invasive core body temperature measurement to a certain extent. However, their measurement process relies on establishing steady-state thermal equilibrium, resulting in long response times (typically on the order of several minutes), making it difficult to meet the real-time monitoring needs in scenarios with rapid changes in body temperature. Therefore, a rapid core body temperature measurement method is urgently needed to improve the measurement speed. Summary of the Invention

[0004] Therefore, it is necessary to provide a core body temperature measurement method, system, and device to address the above problems, which improves the measurement speed while ensuring the accuracy of core body temperature measurement.

[0005] On one hand, this application provides a core body temperature measurement method, which is applied to a body temperature measurement device; the body temperature measurement device is equipped with a heating probe; the heating probe has an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor; the upper temperature sensor is used to collect the heating-side temperature of the active heating layer; the lower temperature sensor is used to collect the skin-side temperature; the pressure sensor is used to collect the pressure value between the heating probe and the skin side; The method includes: Within a preset time window after the start of active heating, the heating-side temperature, skin-side temperature, skin-side pressure, and heating drive information are acquired; the heating drive information is used to characterize the heating flux of the active heating layer. Calculate the interfacial thermal resistance between the heating probe and the skin of the target object based on the skin-side pressure; Based on the heating side temperature, the skin side temperature, and the heating drive information, the equivalent heat flux density on the human body side is calculated using an unsteady thermal equilibrium model. The unsteady core body temperature of the target object is determined based on the skin-side temperature, interfacial thermal resistance, and the equivalent heat flux density on the human body side.

[0006] On another front, a core body temperature measurement system is provided, which is applied to a body temperature measurement device. The body temperature measurement device includes a heating probe. The heating probe comprises an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor. The upper temperature sensor is used to acquire the temperature of the active heating layer on the heating side. The lower temperature sensor is used to acquire the temperature of the skin side. The pressure sensor is used to acquire the pressure value between the heating probe and the skin side. The system includes: The data measurement module is used to acquire the heating side temperature, skin side temperature, skin side pressure, and heating drive information within a preset time window after the start of active heating; the heating drive information is used to characterize the heating flux of the active heating layer. The thermal resistance calculation module is used to calculate the interfacial thermal resistance between the heating probe and the skin of the target object based on the skin-side pressure. The heat flux density calculation module is used to calculate the equivalent heat flux density on the human body side based on the heating side temperature, the skin side temperature and the heating drive information, using an unsteady thermal equilibrium model. The core body temperature calculation module is used to determine the unsteady core body temperature of the target object based on the skin side temperature, interface thermal resistance, and the equivalent heat flux density on the human body side.

[0007] Furthermore, a body temperature measuring device is provided, which is used in the above method, and the body temperature measuring device includes: A heating probe; the heating probe includes an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor; the upper temperature sensor is used to acquire the temperature of the active heating layer on the heating side; the lower temperature sensor is used to acquire the temperature of the skin side; the pressure sensor is used to acquire the pressure value between the heating probe and the skin side.

[0008] Compared with the prior art, the technical solution provided in this application has the following advantages: Within a preset time window during which the heating probe of the body temperature measurement device heats the skin of the target object, the heating-side temperature, skin-side temperature, skin-side pressure, and heating flux of the active heating layer can be acquired using temperature and pressure sensors, respectively. Then, the interfacial thermal resistance between the heating probe and the target object's skin can be calculated based on the skin-side pressure. An unsteady-state thermal equilibrium model is constructed based on the heating-side temperature, skin-side temperature, and heating drive information to calculate the equivalent heat flux density on the human body side. Finally, based on the skin-side temperature, interfacial thermal resistance, and equivalent heat flux density on the human body side, the core body temperature of the target object can be measured under unsteady-state conditions. This scheme, by utilizing the heating-side temperature, skin-side temperature, heating drive information, and real-time calculated pressure interfacial thermal resistance within a preset time window after the start of active heating, directly solves for the equivalent heat flux density on the human body side and inversely calculates the core body temperature based on the unsteady-state thermal equilibrium model. This eliminates the need to wait for the probe and skin to reach steady-state thermal equilibrium, thus rapidly obtaining the core body temperature while ensuring accuracy and speed. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of a heating probe according to an embodiment of this application; Figure 2 This is a schematic diagram of a sensor structure according to an embodiment of this application; Figure 3 This is a structural diagram of the measurement circuit involved in the embodiments of this application; Figure 4 This is a flowchart of a core body temperature measurement method provided in an embodiment of this application; Figure 5 This is a schematic flowchart of a core body temperature measurement method within a steady-state window provided in an embodiment of this application; Figure 6 This is a structural block diagram of a core body temperature measurement system shown in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of an electronic device provided in an optional embodiment of this application. Detailed Implementation

[0010] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0011] Currently, core body temperature measurement methods can be mainly divided into three categories: invasive measurement, non-invasive indirect measurement, and non-invasive measurement methods based on thermal models.

[0012] (1) Invasive and semi-invasive measurement methods In clinical practice, pulmonary artery catheters, esophageal temperature probes, and bladder temperature probes are commonly used to measure core body temperature. Among these, pulmonary artery temperature is considered the gold standard, with high accuracy. However, these methods require the insertion of sensors into the human body, which is significantly invasive, complex to operate, and has high requirements for the operating environment. They are usually only suitable for surgical or intensive care settings and are difficult to implement for continuous and widespread daily monitoring.

[0013] (2) Non-invasive indirect measurement method To reduce invasiveness, methods such as tympanic membrane temperature measurement, oral temperature measurement, axillary temperature measurement, and forehead infrared thermometry have been developed. These methods indirectly estimate core body temperature by measuring the surface or superficial temperature of the body cavity, and have advantages such as simplicity and non-invasiveness. However, due to the temperature gradient between the measurement location and the core region, and the susceptibility to factors such as ambient temperature, local blood flow, and measurement posture, the stability and accuracy of the measurement results are limited, making it difficult to reflect the true dynamic changes in core body temperature.

[0014] (3) Non-invasive measurement method based on zero heat flux (ZHF) In recent years, the zero-heat-flow method has become an important technical approach for non-invasive core body temperature measurement. This method achieves a "zero-heat-flow" state in the measurement area by placing a heating unit on the skin surface, thereby eliminating heat exchange between the body surface and the environment. It then uses thermal equilibrium conditions to estimate the temperature of deep tissues. Under steady-state conditions, this method can achieve high-accuracy core body temperature estimation.

[0015] However, this method has the following shortcomings: 1) Long response time: It relies on the establishment of thermal equilibrium, which usually takes several minutes, making it difficult to meet the needs of rapidly changing scenarios (such as anesthesia induction, early fever, heatstroke); 2) Sensitive to contact conditions: Changes in the pressure of the probe in contact with the skin can affect the heat conduction path, thus introducing measurement errors; 3) Difficulty in handling non-steady-state processes: During rapid changes in body temperature, the steady-state assumption does not hold, leading to measurement lag or bias.

[0016] Therefore, in order to solve the above problems, this application provides a core body temperature measurement method based on a body temperature measurement device. By applying a controllable unsteady thermal excitation at the human body contact interface and collecting multi-point temperature response information and contact pressure information, the core body temperature is calculated by combining a heat conduction model, thereby achieving rapid and accurate measurement of core body temperature under non-invasive conditions.

[0017] To facilitate understanding of the subsequent core body temperature measurement methods, this application first provides a brief description of the required body temperature measurement equipment. The body temperature measurement equipment provided in this application includes: A heating probe; the heating probe includes an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor; the upper temperature sensor is used to acquire the temperature of the active heating layer on the heating side; the lower temperature sensor is used to acquire the temperature of the skin side; the pressure sensor is used to acquire the pressure value between the heating probe and the skin side; The memory and the processor are interconnected and communicate with each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the following core body temperature measurement method.

[0018] In simple terms, this device consists of a heating probe and a measuring circuit. The heating probe includes a temperature sensing unit, a pressure sensing unit, a heating element, and insulation or heat-conducting material.

[0019] Specifically, Figure 1 This is a schematic diagram of the structure of a heating probe according to an embodiment of this application. Figure 1 As shown, the core body temperature measurement probe proposed in this application adopts a multi-layer flexible integrated structure design. From the outside to the side closest to the human skin, it includes an encapsulation protective layer, a heat insulation layer, an upper temperature sensing and active heating layer, an intermediate thermally conductive support layer, and a bottom temperature and pressure integrated sensing layer. Each functional layer works together to jointly construct a measurement platform that integrates active thermal excitation, thermal response acquisition, and contact state sensing.

[0020] The outermost layer is the encapsulation and protection layer, which can be made of Teflon tape 110. It is mainly used to fix the overall structure, provide electrical insulation and environmental protection, while ensuring that the device has a certain degree of flexibility and mechanical stability to meet the needs of long-term attachment or contact monitoring.

[0021] A heat insulation layer is provided below the encapsulation protective layer, which can be composed of an aerogel layer 120 and a bubble cotton layer 130. This encapsulation protective layer is mainly used to suppress heat loss to the environment, so that more of the heat generated by heating is transferred along the direction of the human body, thereby improving heat utilization efficiency, enhancing the effective thermal response signal, and reducing the impact of external ambient temperature fluctuations on measurement results.

[0022] Below the thermal insulation layer is the upper temperature sensing and active heating layer 140 of the device. This thermal insulation layer integrates a metal mesh heating unit 141 and an upper temperature sensing unit 142. The metal mesh heating layer is fabricated using SMM (Superfine Metal Mesh) or Metal Mesh technology, featuring low resistance, fast response, and good local heating stability. The heating wire is a continuous conductive structure, but it has different linewidths, line spacings, wiring densities, or local resistance distributions in different measurement areas. For a single local measurement area, the heating structure can achieve a relatively uniform local heat output; however, between different measurement areas, different local heating power densities can be formed through differences in geometric parameters, thereby generating spatially distributed thermal excitation. The upper temperature sensor, located near the heating layer, is used to acquire the temperature signal on the heating side in real time, serving as the upper temperature node in each measurement channel to characterize the temperature change state at the heat input end.

[0023] An intermediate thermally conductive support layer, primarily made of aerogel, is placed between the upper functional structure and the lower sensing structure. This intermediate thermally conductive support layer mainly serves to form a stable interlayer spacing and provide flexible buffering and structural support, maintaining a relatively fixed positional relationship between the upper heating element and the upper temperature sensor and the lower skin-side temperature and pressure sensing unit (including the lower temperature sensor and pressure sensor). Through this spacer layer, the upper and lower temperature sensors can form a dual-temperature node structure similar to the zero-heat-flow method, used to acquire the temperature difference and heat conduction status in the thickness direction. Simultaneously, the aerogel provides some thermal insulation and buffering, reducing the impact of localized mechanical pressure on the upper heating structure and the lower sensing structure, improving device adhesion stability and repeatability measurement consistency.

[0024] The side closest to the skin is the bottom integrated temperature and pressure sensing layer 150, which is built on an FPC (Flexible Printed Circuit) substrate and is the core sensing interface of this device. On the same FPC layer, both a lower temperature sensing unit and a pressure sensing unit 151 are arranged: the lower temperature sensor is placed close to the skin to collect the temperature of the human body contact interface in real time, serving as the lower temperature node in each measurement channel; the pressure sensor is used to synchronously sense the contact pressure and adhesion state between the device and the skin, reflecting changes in interface thermal resistance and serving as an important input parameter for subsequent thermal conduction model correction.

[0025] Furthermore, the electrodes of the temperature sensing unit and pressure sensing unit, as well as the guide wire structure of the heating element, are all processed using a modified metal mesh process. In this embodiment, the metal mesh heating layer can be prepared using a laser-cut template combined with metal filling. Figure 2 This is a schematic diagram of a sensor structure according to an embodiment of this application. Figure 2The specific illustrations show the first-level, second-level, and third-level interdigitated structures that the sensor can employ. Preferably, the embodiments of this application use a third-level interdigitated structure. Specifically, firstly, a pre-defined grid-like groove structure is formed on the surface of a flexible substrate material (such as PET or PI) using laser cutting. Subsequently, conductive metal paste (such as silver paste, copper paste, etc.) is embedded into the grooves using a scraping, printing, or filling process. A continuous conductive metal grid structure is then formed through thermosetting or subsequent electroplating to thicken the paste. This method achieves precise shaping of the conductive path through template confinement, combining lower processing costs, higher pattern flexibility, and good large-area fabrication capabilities. Simultaneously, the resulting conductive metal layer has a larger thickness and lower resistance, which is beneficial for achieving uniform and stable heat output, making it particularly suitable for the fabrication of flexible wearable heating devices. Furthermore, the flexible electrode adopts a third-level interdigitated structure design. By introducing multi-level branches, the effective edge length and the number of interface response units per unit area are significantly increased, thereby enhancing the local electric field control capability, improving the interface carrier response efficiency, and achieving higher temperature response sensitivity and output signal strength. To address the challenges in fabricating three-level interdigitated structures, such as small linewidth, narrow spacing, and complex branch regions prone to conductive discontinuities, uneven filling, and structural defects, this solution further incorporates an improved Metal Mesh electrode process. Leveraging its high conductivity, high continuity, and fine patterning capabilities, this approach effectively overcomes issues such as breakage, high resistance, and poor consistency of traditional conductive materials in microstructure fabrication. While ensuring stable fabrication of complex three-level interdigitated structures, it further enhances the conductive stability, response consistency, and long-term reliability of the device.

[0026] on the other hand, Figure 3 This is a structural diagram of the measurement circuit involved in an embodiment of this application. For example... Figure 3As shown, the measurement circuit of this application mainly includes a temperature / pressure acquisition module, a constant temperature heating control module, a main control processing module, a wireless communication module, and a power supply module, which together complete the functions of signal acquisition, thermal excitation control, data processing, and result output. The temperature / pressure acquisition module is used to acquire temperature signals from the upper and lower dual-layer temperature sensors in real time, and also simultaneously acquires pressure change information at the skin contact interface. The constant temperature heating control module is connected to the upper metal mesh heating element, achieving stable thermal excitation output through closed-loop feedback control, and dynamically adjusting the heating power using a PID control algorithm, enabling the heating layer to quickly reach the set temperature and maintain stability, reducing the impact of temperature fluctuations on the measurement results. The main control processing module, as the core of the system, is responsible for the synchronous acquisition, filtering, and preprocessing of multi-channel temperature and pressure signals, and deploys a core body temperature inversion algorithm. Combining heat flow information from the upper and lower temperature nodes, pressure compensation information, and an unsteady-state heat conduction model, it performs real-time calculation and dynamic updates of the human body's core temperature. The wireless communication module preferably uses Bluetooth Low Energy (BLE) for data transmission, which can send real-time temperature, pressure, and core body temperature estimation results to a host computer, mobile terminal, or monitoring system for remote display, data storage, and continuous monitoring. The overall measurement circuit integrates constant-temperature active thermal excitation, closed-loop precise control, multi-parameter synchronous acquisition, real-time algorithm calculation, and wireless intelligent transmission, providing complete hardware and algorithm support for rapid, continuous, and stable measurement of core body temperature.

[0027] Based on the aforementioned hardware structure, this application provides a core body temperature measurement method, which is applied to a body temperature measurement device, wherein the body temperature measurement device has, for example, the following features. Figure 1 The heating probe shown, Figure 4 This is a flowchart of a core body temperature measurement method provided in an embodiment of this application, as shown below. Figure 4 As shown, the core body temperature measurement method provided in this application includes the following steps: Step 401: Within a preset time window after active heating begins, acquire the heating side temperature, skin side temperature, skin side pressure, and heating drive information.

[0028] Among them, the heating drive information is used to characterize the heating flux of the active heating layer.

[0029] In one optional implementation, the heating side temperature is collected in real time by an upper temperature sensor for the active heating layer, reflecting the instantaneous temperature of the heating layer; The skin temperature is collected by the lower layer temperature sensor, reflecting the real-time changes in the skin surface temperature; The skin pressure is collected by a pressure sensor and characterizes the tightness of contact between the heating probe and the skin; The heating drive information records drive parameters such as the power or current of the active heating layer, which are used to describe the heating flux.

[0030] Furthermore, in this application, the pressure sensing unit employs an off-electric sensing mechanism, whose output signal is affected not only by external contact pressure but also by changes in ambient temperature and local operating temperature. Therefore, under the same pressure conditions, the sensor may output different capacitance or impedance signals at different temperatures, thereby affecting the accuracy of pressure measurement.

[0031] Furthermore, pressure not only affects the output of the pressure sensor but also the temperature measurement and core body temperature inversion process. Specifically, when the pressure between the device and the skin changes, the contact state of the skin-side temperature sensor, local heat dissipation conditions, and interfacial thermal resistance all change. Therefore, even if the skin-side temperature sensor itself measures accurately, neglecting the changes in thermal contact state caused by pressure can still lead to errors in core body temperature inversion.

[0032] Therefore, in order to improve the accuracy of subsequent core body temperature calculation, temperature and pressure decoupling needs to be performed first in this embodiment. At this time, both skin temperature and skin pressure refer to the values ​​after temperature and pressure decoupling.

[0033] Specifically, in this embodiment, the upper layer temperature of each measurement channel, the original acquisition temperature on the skin side, the original pressure directly output by the pressure sensor, and heating drive information, including the drive voltage, can be obtained first. Pulse width modulation duty cycle and the heating flux per unit area calculated or calibrated from the geometric parameters of the local heating wire. In the embodiments of this application, Indicates the first Each measurement channel can physically characterize the i-th measurement area in the heating probe.

[0034] After time synchronization, filtering, outlier removal, and channel alignment, the aforementioned data enters the temperature-pressure decoupling module, where it is used for rapid inversion of unsteady core body temperature and linear extrapolation calculation of the steady-state array, respectively. Subsequently, the data first enters the temperature-pressure decoupling module to correct the original acquired temperature and pressure to input values ​​closer to the actual physical state.

[0035] Specifically, in this embodiment, the original acquisition temperature of the lower temperature sensor and the original pressure acquired by the pressure sensor are first obtained; then, the temperature drift compensation curve of the pressure sensor is obtained; the temperature drift compensation curve is used to characterize the output of the pressure sensor under different temperature and pressure conditions; finally, based on the original acquisition temperature, the original pressure is compensated according to the temperature drift compensation curve to obtain the skin-side pressure.

[0036] The specific principle of the above-mentioned temperature-pressure decoupling is as follows: Assume the initial output of the target pressure sensor is Essentially, it is the pressure experienced by the target pressure sensor. and the local temperature of the target pressure sensor The coupling function can be expressed as:

[0037] in, This is the real-time measurement value (i.e., the original acquisition temperature) of the temperature sensor on the target skin side corresponding to the target pressure sensor. Since this temperature sensor and the target pressure sensor are integrated in the same FPC structure and located at the same contact interface, the temperature it measures can accurately reflect the actual operating temperature of the pressure-sensitive unit and can be used as an in-situ input parameter for temperature compensation.

[0038] During the system calibration phase, a reference temperature is used. Using 25℃ as a baseline, measure the corresponding output under different known pressure conditions to establish a standard pressure response curve:

[0039] Subsequently, pressure loading experiments were repeated at multiple different temperature points to obtain the response characteristics of the target pressure sensor at different temperatures, and a temperature drift compensation curve for the target pressure sensor was established. For the operating range where the temperature drift is approximately linear, the original output of the target pressure sensor can be... Represented as:

[0040] in, The temperature drift coefficient of the pressure sensor. For reference temperature; It is the theoretical pressure value experienced by the target pressure sensor. The calibration result can be obtained by calibrating the pressure sensor under different temperature and pressure conditions; when the temperature drift trend is similar under different pressures, a fixed method is adopted. Compensation should be performed; when temperature drift is related to pressure, the pressure-related temperature drift coefficient or a two-dimensional lookup table method should be used to determine it. The value is compensated.

[0041] As can be seen from the above theory, for any pressure sensor, the raw output measured in real time can be... Equivalent sensor output value after temperature compensation :

[0042] By further combining the standard pressure response curve established at the reference temperature, it can be deduced that, for any pressure sensor, the compensated skin-side pressure... :

[0043] Through the above processing, the temperature drift term in the original pressure output is effectively removed, allowing pressure results obtained under different temperature conditions to be uniformly mapped to the same reference state, thereby improving the consistency and accuracy of pressure detection. This algorithm is simple to implement, requiring only real-time temperature measurements from the skin-contact temperature sensor to complete dynamic compensation, without the need for an additional independent temperature calibration module, demonstrating good engineering feasibility. Furthermore, since the compensation temperature comes from an in-situ measurement point at the same spatial height as the pressure unit, compared to compensation using ambient temperature or the device's average temperature, it more accurately reflects the actual thermal state of the pressure-sensitive interface, further improving temperature compensation accuracy and providing a reliable pressure input for subsequent interface contact state identification and thermal resistance correction.

[0044] Furthermore, when obtaining the skin-side pressure, the original acquisition temperature can be corrected based on the skin-side pressure and the calibrated reference pressure to obtain the skin-side temperature.

[0045] Specifically, let the initial temperature collected by the lower layer temperature sensor on the skin side be... After the above compensation, the skin pressure is The effect of pressure on skin temperature readings can be approximated as follows:

[0046] in, This is the corrected true temperature on the skin side. To calibrate the reference pressure, This is the pressure-induced temperature reading offset coefficient. Therefore, the pressure-compensated skin temperature can be obtained using the following formula. :

[0047] Step 402: Calculate the interfacial thermal resistance between the heating probe and the skin of the target object based on the skin-side pressure.

[0048] Furthermore, pressure can also alter the interfacial thermal resistance between the device and the skin. Generally, increased pressure results in a more complete fit and a lower interfacial thermal resistance; conversely, decreased pressure can lead to poor local contact or tiny gaps, increasing the interfacial thermal resistance.

[0049] In this embodiment of the application, a preset thermal resistance can be obtained; the preset thermal resistance is used to characterize the interfacial thermal resistance under low pressure or reference conditions; and then the preset thermal resistance is corrected according to the (compensated) skin side pressure and the calibrated reference pressure to obtain the interfacial thermal resistance.

[0050] This relationship can be represented by a simple model as follows:

[0051] in, The preset thermal resistance is used to characterize the interfacial thermal resistance under low pressure or reference conditions, and can be collected under experimental conditions. This represents the pressure-thermal resistance coupling coefficient. For further simplification, a linear form can also be used:

[0052] In the subsequent core body temperature inversion, the fixed interfacial thermal resistance is no longer used; instead, the pressure-corrected interfacial thermal resistance is adopted. Therefore, core body temperature estimation It can be represented as:

[0053] in, This is the equivalent heat flux density on the human side estimated by the upper and lower temperature nodes, heating input, and heat conduction model. This formula indicates that core body temperature is not directly determined by skin temperature, but rather by the corrected skin-side temperature, the heat flux on the human side, and the current contact thermal resistance.

[0054] γ and It can be obtained through offline calibration under different pressure and temperature conditions, or it can be determined by linear fitting, logarithmic fitting, table lookup interpolation or individualized calibration methods according to the actual structure.

[0055] Step 403: Based on the heating side temperature, skin side temperature and heating drive information, calculate the equivalent heat flux density on the human body side using an unsteady thermal equilibrium model.

[0056] After the above processing, the embodiments of this application have obtained the heating side temperature, pressure-compensated skin side temperature, skin side pressure, pressure-corrected interface thermal resistance, and heating input information collected by the upper temperature sensor of each measurement channel. Based on this, the embodiments of this application further utilize the temperature change rate and heat input accumulation during the unsteady thermal response process to quickly invert the core body temperature of the human body before the measurement area has reached steady-state thermal equilibrium.

[0057] First, it should be noted that the following calculation logic can be executed individually for each measurement channel. Theoretically, even if there is only one measurement channel in the heating probe, the subsequent algorithm can still measure the unsteady core body temperature. In the following description, the i-th measurement channel is used as an example. This application does not limit the number of measurement channels.

[0058] In the unsteady state, for the first... There are 1 measurement channel, and the temperature on the heating side measured by the upper temperature sensor is 1. The skin temperature after pressure compensation, obtained through the temperature-pressure decoupling method described in this application, is: The temperature difference between the two is defined as:

[0059] Compared to directly using the original skin temperature ,use It can reduce the impact of changes in contact pressure, local adhesion state, and interfacial thermal resistance on subsequent core body temperature inversion.

[0060] The heating unit in the first The real-time heating power corresponding to each channel is denoted as . This can be calculated from the heating voltage, current, or pulse width modulation control quantity. Let the effective heating area of ​​this channel be... The heating flux per unit area input to the probe system is:

[0061] in, The unit is , is used to represent the heat flux density input from the heating unit to the measurement area per unit area.

[0062] Under steady-state equilibrium conditions, the temperature difference inside the probe and the heat input required to maintain that temperature difference can be approximately expressed as:

[0063] in, For the first The equivalent thermal conductivity parameters for each channel, in units of Used to characterize each increase in temperature difference The increased heat flux density required to maintain thermal equilibrium; This is the equivalent bias heat flux term, in units of It is used to characterize the system bias introduced by factors such as heating layer, encapsulation layer, environmental heat dissipation, and device background loss. and It can be obtained through steady-state calibration experiments.

[0064] During the unsteady-state measurement phase, since the probe has not yet reached thermal equilibrium, part of the input heat is used to change the equivalent thermal energy storage of the probe and its local contact area, while the other part is exchanged with the human tissue side. Based on the first The local energy conservation relationships of each channel can be used to establish the following unsteady-state thermal equilibrium model:

[0065] in, For the first The equivalent surface heat capacity parameters corresponding to each channel are used to characterize the comprehensive thermal inertia of the upper heating structure, the middle thermally conductive support layer, the lower sensing interface, and the local contact area. The equivalent heat flux density on the human side represents the equivalent heat exchange term between the probe and deep human tissue. In this paper, the following conventions are used... The direction from the skin side / probe side towards the deep part of the body is considered positive.

[0066] Rearranging the above equation, we get:

[0067] This formula shows that, after deducting the system bias, part of the effective input heat flux is used to change the equivalent heat storage of the probe system, and the other part participates in the core body temperature inversion as the equivalent heat flux on the human body side.

[0068] To avoid noise amplification caused by directly calculating the rate of temperature change, this application uses an integral form to process the aforementioned unsteady-state thermal equilibrium relationship. Within a time window... Integrating both sides of the equation, we have:

[0069] in, Indicates time window The instantaneous integral variable within.

[0070] Within a short measurement window, such as 20 s, 40 s, or 60 s, the measurement can be... If we consider it a constant, then the first integral can be simplified to:

[0071] make:

[0072] Then we have:

[0073] Furthermore, within a short time window, the equivalent heat flux density on the human body side... It can be approximated as a slowly changing quantity or a constant, that is:

[0074] therefore:

[0075] Substituting the above results back into the integral form of the energy conservation equation, we get:

[0076] For ease of engineering calculations, the following definition is provided:

[0077] The unsteady thermal equilibrium model can then be written in linear parametric form:

[0078] in, This is used to characterize the integral of the heating flux over time in the i-th measurement channel after removing the bias (subtracting the equivalent bias heat flux term); Let be the equivalent surface heat capacity parameter of the i-th measurement channel; Let be the equivalent heat flux density on the human side of the i-th measurement channel; The interlayer temperature difference at time t of the i-th measurement channel is the difference between the temperature difference at the beginning time; the interlayer temperature difference is the difference between the temperature on the heated side and the temperature on the skin side. Let t be the time difference between time t and the starting time.

[0079] After constructing the above-mentioned linear parameter form of unsteady thermal equilibrium model, in this embodiment of the application, multiple sampling times can be obtained within the preset time window; then, based on the heating side temperature, skin side temperature and heating driving information at the multiple sampling times, a matrix equation is constructed based on the unsteady thermal equilibrium model to solve for the equivalent heat flux density on the human body side.

[0080] For example, the preset time window is between 20 and 60 seconds after the start of active heating.

[0081] Specifically, the solution process is as follows: Within a measurement window, multiple sampling times are taken. The following matrix equation can be constructed:

[0082] in:

[0083] Because the model requires parameters to be determined and The relationship is linear, therefore the least squares method can be used to solve it:

[0084] In practical implementations, recursive least squares, sliding window least squares, weighted least squares, or constrained parameter estimation methods can also be used to improve the stability of the algorithm under conditions of noise, local contact disturbances, or insufficient short-window data. Through the above calculations, the equivalent heat flux density on the human body side can be directly estimated during the unsteady-state heating phase. This does not require waiting for the temperature to reach a steady state.

[0085] Step 404: Determine the unsteady core body temperature of the target object based on the skin side temperature, interfacial thermal resistance, and the equivalent heat flux density on the human body side.

[0086] According to the method described in step 402, after correcting the thermal resistance value of the i-th measurement channel by pressure, the interfacial thermal resistance of the i-th measurement channel can be obtained, denoted as . At this time, the core body temperature of the i-th channel It can be obtained by combining skin-side temperature, equivalent heat flux density on the body side, and dynamic thermal resistance:

[0087] Therefore, we can obtain the... Body temperature measurement channel for each measurement channel:

[0088] in, For the first Core body temperature estimated by one channel; This refers to the skin temperature after pressure compensation. Let be the interfacial thermal resistance of the i-th measurement channel; The equivalent heat flux density on the human side is estimated by the unsteady integral model.

[0089] The temperature measured by the i-th measurement channel is actually the unsteady core body temperature obtained by the sensor in the i-th measurement channel. If there is only one measurement channel in this embodiment, the temperature of that measurement channel can be directly used as the unsteady core body temperature.

[0090] In another optional embodiment of this application, the heating probe may contain temperature sensors with multiple measurement channels (e.g., Figure 2 (As shown); each measurement channel's temperature sensor includes a corresponding upper-layer temperature sensor and a lower-layer temperature sensor.

[0091] In this embodiment of the application, steps 403 and 404 can be executed for each measurement channel to obtain the measurement channel temperature corresponding to each measurement channel; then, the measurement channel temperatures corresponding to each measurement channel are weighted and fused to obtain the non-steady-state core body temperature of the target object.

[0092] The specific implementation process is as follows: If multiple temperature measurement channels are included, the above-described unsteady-state inversion process can be performed on each channel separately to obtain the core body temperature estimates for multiple channels. Subsequently, the results from multiple channels can be weighted and fused based on the contact pressure stability, temperature response signal-to-noise ratio, fitting residual, channel location, or historical consistency of each channel to obtain the final core body temperature estimate.

[0093] in, For the first The weights of each channel, satisfying:

[0094] In this embodiment, the weights of each measurement channel can be dynamically determined based on factors such as whether the channel pressure is within a reasonable range, whether the temperature response is continuous, whether the least squares fitting residual is small, and whether the results between channels are consistent. Since these factors change with variations in the heating probe hardware, this embodiment does not restrict the selection of weights, which can be calibrated under standard experimental conditions. This method can reduce the impact of poor contact in a single channel, localized temperature anomalies, or sudden pressure changes on the core body temperature estimation results.

[0095] Furthermore, based on the rapid calculation of unsteady core body temperature, after the heating process continues for a period of time, the upper layer temperature, skin side temperature, heating input and contact pressure of each measurement area gradually tend to stabilize, and the change in thermal energy storage inside the probe can be approximately ignored.

[0096] In this embodiment, each measurement channel corresponds to a measurement area in the heating probe. Different measurement areas have different local heating fluxes, thereby forming different steady-state skin-side temperatures and equivalent steady-state heat flux densities on the human body side within the steady-state time window. The set of steady-state skin-side temperatures and equivalent steady-state heat flux densities on the human body side formed by each measurement channel constitutes a steady-state measurement point.

[0097] At this point, this application further proposes a core body temperature calculation method based on linear extrapolation of different steady-state temperature points, so as to measure a more accurate core body temperature in the subsequent steady-state condition, based on the above-mentioned rapid measurement of core body temperature in the non-steady-state condition. That is, when the steady-state window is detected, the steady-state core body temperature can be used to verify, update or replace the non-steady-state core body temperature.

[0098] Figure 5 This is a schematic flowchart of a core body temperature measurement method within a steady-state window provided in an embodiment of this application. For example... Figure 5 As shown, the method includes: Step 501: When it is detected that all sensors of the heating probe are in the steady-state time window, the steady-state skin-side temperature and steady-state local heating flux of each measurement channel are acquired.

[0099] Specifically, in this embodiment of the application, during the continuous heating process of the active heating layer, the heating side temperature, skin side temperature, heating drive information, and the differential rate of change of skin side pressure with respect to time of each sensor are monitored in real time; when the differential rate of change of each sensor is less than the corresponding preset stable threshold, it is determined that each sensor of the heating probe is in a steady-state time window.

[0100] Specifically, the heating unit in this embodiment employs a continuous heating wire or a continuous metal mesh structure. Because the heating wire has different linewidths, spacings, wiring densities, or local resistance distributions in different measurement areas, different measurement areas will generate different local heating power densities and heating flux per unit area under a uniform heating current, uniform heating voltage, or pulse width modulation signal. Consequently, different measurement points will exhibit different skin-side temperature levels and different equivalent heat flux densities on the human body side in steady state. The system utilizes these different steady-state temperature points to construct temperature-heat flux relationship curves and obtains the core body temperature through linear extrapolation.

[0101] In steady state, for the first... There are several measurement areas, and the upper temperature (i.e., the heating side temperature) is set as follows: This represents the temperature node closest to the heating wire or heating layer; the true skin temperature after pressure compensation using the temperature-pressure decoupling algorithm is... , representing the skin-side temperature node after pressure compensation; The temperature difference between the upper layer temperature and the pressure-compensated skin-side temperature node in the i-th measurement region. Defined as:

[0102] In steady-state time window If the following conditions are met:

[0103] Then it is believed that the first Each measurement region reaches quasi-steady state or steady state conditions. Among them, , , and These are the upper layer temperature stability threshold, skin side temperature stability threshold, heating flux stability threshold, and pressure stability threshold, respectively. This is the actual contact pressure after temperature compensation.

[0104] Step 502: For each measurement channel, determine the human body equivalent steady-state heat flux density of each measurement channel based on the steady-state local heating flux and the corresponding channel equivalent bias parameters.

[0105] Specifically, within this steady-state window, define for The mean value within the steady-state window, which is the steady-state temperature on the skin side; for The mean value within the steady-state window; for and difference; for The mean within the steady-state window.

[0106] For a continuous heating wire structure, the first The local heating flux of a measurement area can be obtained from the local resistance of the heating wire and the overall driving conditions. Let the first... The linewidth of each local heating segment is , length is Thickness is The resistivity of the material is Then its local resistance It can be approximated as:

[0107] When the driving current of the heating wire is At that time, the first Heating power of each local heating section for:

[0108] If the first The effective heating area of ​​each measurement region is The heating flux per unit area for:

[0109] In practice, It can also be obtained through driving voltage, current, pulse width modulation duty cycle, local resistance calibration results, and heat flow calibration table.

[0110] Under steady-state conditions, the change in internal thermal energy storage of the probe is approximately zero, that is:

[0111] Therefore, the effective input heat flux after deducting the system bias can be approximately equal to the equivalent steady-state heat flux density on the human body side. It can be expressed by the following formula:

[0112] in, For the first The equivalent bias heat flux term for each measurement channel is used to characterize the system bias introduced by factors such as heat dissipation from the package layer, ambient heat loss, and device inherent loss.

[0113] Step 503: For each measurement channel, the equivalent steady-state heat flux density on the human body side and the steady-state skin side temperature constitute a steady-state measurement point; Specifically, based on the steady-state calibration relationship, we can obtain:

[0114] You can also get:

[0115] in, For the first The equivalent thermal conductivity parameters of each measurement channel. In other words, each steady-state measurement point can form a set of data points:

[0116] This data point represents the first... Under a localized thermal excitation intensity, the equivalent steady-state heat flux density on the human side Skin-side steady-state temperature The correspondence between them.

[0117] Step 504: Perform linear fitting on the steady-state measurement points corresponding to each measurement channel, and determine the ordinate of the linearly fitted line as the steady-state core temperature of the target object.

[0118] Specifically, based on the one-dimensional equivalent heat conduction relationship on the human body side:

[0119] It can be organized as follows:

[0120] Therefore, it can be concluded that within the same measurement period, if the core body temperature... If we approximate it as constant, then different steady-state temperature points It should be approximately distributed along a linear straight line. The slope of this line corresponds to the equivalent thermal resistance on the human side. The intersection of this straight line and the vertical axis corresponds to the core body temperature. .

[0121] For ease of engineering calculations, let: and

[0122] The formula for a linear straight line is as follows:

[0123] in: and

[0124] Therefore, by performing a linear fit at multiple steady-state temperature points, the core body temperature can be obtained from the ordinate of the fitted line:

[0125] In containing In the case of n steady-state measurement points, the matrix can be constructed in the following form:

[0126] in:

[0127] Therefore, the least squares method can be used to solve this problem.

[0128] obtained The second parameter is the estimated steady-state core temperature of the array; In another possible implementation, to improve the stability of the algorithm under conditions of contact pressure fluctuations, local heat dissipation anomalies, or anomalies at a single measurement point, a weighted least squares method can also be used. Let the... The weights of the steady-state measurement points are: If there are m channels, and i can be selected from 1 to m, then:

[0129] in:

[0130] Weight The weighting can be determined based on contact pressure stability, temperature stability, local heat flux rationality, and fitting residuals. For measurement points with excessively low pressure, excessive pressure fluctuations, temperatures not reaching steady state, abnormal local heating flux, or significant deviations from the fitted straight line, their weights can be reduced, and they can be removed if necessary.

[0131] In one implementation, the weights can be determined by the quality score of the steady-state measurement points. Normalization yields:

[0132] in:

[0133] in, Indicates the contact pressure quality factor. Indicates the temperature stability factor. Indicates the heat flow rationality factor. This represents the linear fitting residual factor. When the contact pressure at a measurement point is stable, the temperature fluctuation is small, the heat flow input is within a reasonable range, and the consistency with the fitted line is good, the weight of that point is higher; conversely, its weight is reduced.

[0134] If the system uses multiple integral heating steps, then the first step can be... The first step of the overall heating ladder Steady-state data from each measurement region are also included in the same linear fit. At this point, each steady-state measurement point is denoted as:

[0135] in, This indicates the kth overall heating step. Equivalent steady-state heat flux density of the human body side in each measurement region; This indicates the kth overall heating step. Steady-state skin temperature in each measurement area; And satisfy:

[0136] in, , All channels and all steady-state points under the overall heating steps participate in linear fitting:

[0137] in:

[0138] Obtained through least squares or weighted least squares fitting The second parameter This refers to the core body temperature measured under steady-state conditions.

[0139] The physical meaning of the above method is: when the equivalent heat flow on the human body side When the temperature approaches zero, there is no longer a temperature pressure drop caused by heat flow between the skin temperature and the core body temperature. At this point, the extrapolated value of the skin temperature is the core body temperature. Therefore, this application uses steady-state temperature response points under multiple different local thermal excitation intensities to fit a linear temperature-heat flow relationship, and obtains the core body temperature quickly and stably through the ordinate intercept.

[0140] This application utilizes a steady-state array core temperature algorithm, eliminating the need to calculate an independent core temperature result for each measurement point. Instead, it treats multiple steady-state temperature points as observation samples along the same heat conduction line. Compared to single-point steady-state measurement methods, this approach leverages multi-heat flux and multi-temperature response information generated by modulation regions of different linewidths to improve the stability of core temperature extrapolation calculations. Furthermore, by identifying abnormal measurement points through fitting residuals and weighting mechanisms, it reduces the impact of poor local contact, pressure changes, environmental heat dissipation, and single-point heat flux errors on the final core temperature estimation.

[0141] In summary, within the preset time window during which the heating probe of the body temperature measurement device heats the skin of the target object, the heating-side temperature, skin-side temperature, skin-side pressure, and heating flux of the active heating layer can be obtained through temperature and pressure sensors, respectively. Then, the interfacial thermal resistance between the heating probe and the target object's skin can be calculated based on the skin-side pressure. An unsteady-state thermal equilibrium model is constructed based on the heating-side temperature, skin-side temperature, and heating drive information to calculate the equivalent heat flux density on the human body side. Finally, based on the skin-side temperature, interfacial thermal resistance, and equivalent heat flux density on the human body side, the core body temperature of the target object can be measured under unsteady-state conditions. This scheme, by utilizing the heating-side temperature, skin-side temperature, heating drive information, and real-time calculated pressure interfacial thermal resistance within the preset time window after the start of active heating, directly solves for the equivalent heat flux density on the human body side and inversely calculates the core body temperature based on the unsteady-state thermal equilibrium model. Therefore, it can quickly obtain the core body temperature without waiting for the probe and skin to reach steady-state thermal equilibrium, improving the measurement speed while ensuring the accuracy of the core body temperature measurement.

[0142] Furthermore, in this embodiment, the temperature drift of the pressure sensor, the temperature shift on the skin side, and the change in thermal resistance of the contact interface are first corrected by the temperature-pressure decoupling method; then, the temperature change and heat input accumulation information during the unsteady thermal response process are used to achieve rapid estimation of core body temperature before thermal equilibrium is established; after the temperature response reaches steady state, the core body temperature is calculated with high confidence by combining multi-channel array information, steady-state thermal equilibrium relationship and channel quality evaluation mechanism.

[0143] Figure 6 This is a structural block diagram of a core body temperature measurement system illustrated in an embodiment of this application. The system is applied to a body temperature measurement device; the device includes a heating probe; the heating probe comprises an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor; the upper temperature sensor is used to acquire the temperature of the active heating layer on the heating side; the lower temperature sensor is used to acquire the temperature of the skin side; and the pressure sensor is used to acquire the pressure value between the heating probe and the skin side. Figure 6 As shown, the system includes: The data measurement module 601 is used to acquire the heating side temperature, skin side temperature, skin side pressure, and heating drive information within a preset time window after the start of active heating; the heating drive information is used to characterize the heating flux of the active heating layer. The thermal resistance calculation module 602 is used to calculate the interfacial thermal resistance between the heating probe and the skin of the target object based on the skin-side pressure. The heat flux density calculation module 603 is used to calculate the equivalent heat flux density on the human body side based on the heating side temperature, the skin side temperature and the heating drive information, according to an unsteady thermal balance model. The core body temperature calculation module 604 is used to determine the unsteady core body temperature of the target object based on the skin side temperature, interface thermal resistance and the equivalent heat flux density on the human body side.

[0144] In summary, within the preset time window during which the heating probe of the body temperature measurement device heats the skin of the target object, the heating-side temperature, skin-side temperature, skin-side pressure, and heating flux of the active heating layer can be obtained through temperature and pressure sensors, respectively. Then, the interfacial thermal resistance between the heating probe and the target object's skin can be calculated based on the skin-side pressure. An unsteady-state thermal equilibrium model is constructed based on the heating-side temperature, skin-side temperature, and heating drive information to calculate the equivalent heat flux density on the human body side. Finally, based on the skin-side temperature, interfacial thermal resistance, and equivalent heat flux density on the human body side, the core body temperature of the target object can be measured under unsteady-state conditions. This scheme, by utilizing the heating-side temperature, skin-side temperature, heating drive information, and real-time calculated pressure interfacial thermal resistance within the preset time window after the start of active heating, directly solves for the equivalent heat flux density on the human body side and inversely calculates the core body temperature based on the unsteady-state thermal equilibrium model. Therefore, it can quickly obtain the core body temperature without waiting for the probe and skin to reach steady-state thermal equilibrium, improving the measurement speed while ensuring the accuracy of the core body temperature measurement.

[0145] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0146] The system in this embodiment is presented in the form of functional units. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0147] Please see Figure 7 , Figure 7This is a schematic diagram of the structure of an electronic device provided in an optional embodiment of this application. This electronic device can serve as a controller or data processor in a body temperature measurement device, used to achieve, for example... Figure 6 The system shown includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise as required. The processors can process instructions executed within the electronic device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces).

[0148] The processor 10 may further include a hardware chip. This hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0149] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0150] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function. Furthermore, the memory 20 may include high-speed random access memory, and may also include non-transient memory, such as at least one disk storage device, flash memory device, or other non-transient solid-state storage device. The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk, or solid-state drive; the memory 20 may also include combinations of the above types of memory.

[0151] The electronic device also includes a communication interface 30 for communicating with other devices or communication networks.

[0152] This application also provides a computer-readable storage medium. The methods described in this application can be implemented in hardware or firmware, or implemented as recordable on a storage medium, or implemented as computer code downloaded over a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and subsequently stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the methods shown in the above embodiments are implemented.

[0153] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0154] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for measuring core body temperature, characterized in that, The method is applied to a body temperature measurement device; the body temperature measurement device is equipped with a heating probe; the heating probe has an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor; the upper temperature sensor is used to collect the temperature on the heating side of the active heating layer; the lower temperature sensor is used to collect the temperature on the skin side; the pressure sensor is used to collect the pressure value between the heating probe and the skin side; the heating probe has multiple temperature sensors with multiple measurement channels; each temperature sensor with a measurement channel includes a corresponding upper temperature sensor and a lower temperature sensor. The method includes: Within a preset time window after the start of active heating, the heating-side temperature, skin-side temperature, skin-side pressure, and heating drive information are acquired; the heating drive information is used to characterize the heating flux of the active heating layer. Calculate the interfacial thermal resistance between the heating probe and the skin of the target object based on the skin-side pressure; For each measurement channel, the equivalent heat flux density on the human body side is calculated based on the heating side temperature, skin side temperature, and heating drive information, using an unsteady thermal equilibrium model. The unsteady core body temperature of the target object is determined based on the skin-side temperature, interfacial thermal resistance, and the equivalent heat flux density on the human body side. The formula for the unsteady thermal equilibrium model is as follows: in, Used to characterize the integral of the bias-removed heating flux over time in the i-th measurement channel; Let be the equivalent surface heat capacity parameter of the i-th measurement channel; Let be the equivalent heat flux density on the human side of the i-th measurement channel; The interlayer temperature difference at time t of the i-th measurement channel is the difference between the temperature difference at the beginning time and the interlayer temperature difference; the interlayer temperature difference is the difference between the temperature on the heating side and the temperature on the skin side. Let t be the time difference between time t and the starting time.

2. The method according to claim 1, characterized in that, Determining the unsteady core body temperature of the target object based on the skin-side temperature, interfacial thermal resistance, and equivalent heat flux density on the human body side includes: For each measurement channel, the body temperature corresponding to the measurement channel is determined based on the skin-side temperature, interfacial thermal resistance, and equivalent heat flux density on the human body side. The body temperature of each measurement channel is weighted and fused to obtain the non-steady-state core body temperature of the target object.

3. The method according to claim 2, characterized in that, The step of calculating the equivalent heat flux density on the human body side based on the heating side temperature, skin side temperature, and heating drive information, using a non-steady-state thermal equilibrium model, includes: Within the preset time window, multiple sampling times are acquired; Based on the heating-side temperature, skin-side temperature, and heating drive information at multiple sampling times, a matrix equation is constructed based on the unsteady thermal equilibrium model to obtain the equivalent heat flux density on the human body side.

4. The method according to any one of claims 1 to 3, characterized in that, Acquire skin-side temperature and skin-side pressure, including: Obtain the raw temperature data from the lower-level temperature sensor and the raw pressure data from the pressure sensor; Obtain the temperature drift compensation curve of the pressure sensor; the temperature drift compensation curve is used to characterize the output of the pressure sensor under different temperature and pressure conditions; Based on the original acquisition temperature, the original pressure is compensated according to the temperature drift compensation curve to obtain the skin-side pressure; The original collected temperature is corrected based on the skin-side pressure and the calibrated reference pressure to obtain the skin-side temperature.

5. The method according to claim 4, characterized in that, Before determining the unsteady core body temperature of the target object based on the skin-side temperature, interfacial thermal resistance, and the equivalent heat flux density on the human body side, the method further includes: Obtain a preset thermal resistance; the preset thermal resistance is used to characterize the interfacial thermal resistance under low pressure or reference conditions; The preset thermal resistance is corrected based on the skin-side pressure and the calibrated reference pressure to obtain the interface thermal resistance.

6. The method according to claim 2 or 3, characterized in that, The method further includes: When it is detected that all sensors of the heating probe are in the steady-state time window, the steady-state skin-side temperature and steady-state local heating flux of each measurement channel are obtained; For each measurement channel, the equivalent steady-state heat flux density on the human side of each measurement channel is determined based on the steady-state local heating flux and the corresponding channel equivalent bias parameters. For each measurement channel, the equivalent steady-state heat flux density on the human body side and the steady-state skin side temperature constitute a steady-state measurement point; Linear fitting is performed on the steady-state measurement points corresponding to each measurement channel, and the ordinate of the linearly fitted line is determined as the steady-state core body temperature of the target object.

7. The method according to claim 6, characterized in that, Before obtaining the steady-state skin-side temperature and steady-state local heating flux for each measurement channel, the following steps are also included: During the continuous heating process of the active heating layer, the heating side temperature, skin side temperature, heating drive information, and the differential rate of change of skin side pressure with respect to time are monitored in real time by each sensor. When the differential rate of change of each sensor is less than the corresponding preset stability threshold, it is determined that each sensor of the heating probe is in a steady-state time window.

8. A core body temperature measurement system, characterized in that, The system is applied to a body temperature measurement device; the body temperature measurement device is equipped with a heating probe; the heating probe has an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor; the upper temperature sensor is used to collect the temperature of the active heating layer on the heating side; the lower temperature sensor is used to collect the temperature of the skin side; the pressure sensor is used to collect the pressure value between the heating probe and the skin side; the heating probe has multiple temperature sensors with multiple measurement channels; each temperature sensor with a measurement channel includes a corresponding upper temperature sensor and a lower temperature sensor. The system includes: The data measurement module is used to acquire the heating side temperature, skin side temperature, skin side pressure, and heating drive information within a preset time window after the start of active heating; the heating drive information is used to characterize the heating flux of the active heating layer. The thermal resistance calculation module is used to calculate the interfacial thermal resistance between the heating probe and the skin of the target object based on the skin-side pressure. The heat flux density calculation module is used to calculate the equivalent heat flux density on the human body side for each measurement channel based on the heating side temperature, skin side temperature and heating drive information, using an unsteady thermal equilibrium model. The core body temperature calculation module is used to determine the unsteady core body temperature of the target object based on the skin side temperature, interface thermal resistance, and the equivalent heat flux density on the human body side. The formula for the unsteady thermal equilibrium model is as follows: in, Used to characterize the integral of the bias-removed heating flux over time in the i-th measurement channel; Let be the equivalent surface heat capacity parameter of the i-th measurement channel; Let be the equivalent heat flux density on the human side of the i-th measurement channel; The interlayer temperature difference at time t of the i-th measurement channel is the difference between the temperature difference at the beginning time and the interlayer temperature difference; the interlayer temperature difference is the difference between the temperature on the heating side and the temperature on the skin side. Let t be the time difference between time t and the starting time.

9. A body temperature measuring device, characterized in that, The body temperature measuring device is used in the method as described in any one of claims 1 to 7, wherein the body temperature measuring device comprises: A heating probe; the heating probe includes an active heating layer, an upper temperature sensor, a lower temperature sensor, and a pressure sensor; the upper temperature sensor is used to acquire the temperature of the active heating layer on the heating side; the lower temperature sensor is used to acquire the temperature of the skin side; the pressure sensor is used to acquire the pressure value between the heating probe and the skin side.

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