BODY TEMPERATURE

TECHNICAL FIELD

The invention relates to a device for contactless measurement of body temperature, which can be used in the medicine and which is intended for measurement of the body temperature of immobile patients and/ or patients with limited mobility.

BACKGROUND OF THE INVENTION

A device is known for measuring the body temperature [1], consisting of a main body with bidirectional connection to a measurement element located at a predetermined distance from the main body. The main body consists of a first measuring unit whose output is connected to the input of a signal processing unit to which a first interface unit and a display are connected. The measurement element consists of a second measuring unit connected to a second interface unit connected to the input of the first interface unit of the main body. The first interface unit is a connection interface for wireless signal transfer between the main body and the measurement element. It receives signals transmitted from the measurement element and transmits these signals for conversion by the processing unit of the main body. The converted signals are transmitted to the display for displaying the result. The main body also contains a calibration unit for determination whether the measured result is within the preset temperature range. The first measurement unit may be executed as a contact thermometer or a contactless thermometer such as an infrared temperature measurement device.

The disadvantage of the known device is that it monitors the relative change of the body temperature compared to the initially measured temperature at the beginning of the given monitoring cycle and it does not measure the absolute (actual) body temperature. When the measurement unit is executed as a contactless infrared measurement device, no means are specified ensuring consistency and duration of the monitoring of the body temperature when the patient moves and exits the range of the contactless infrared measurement device or when the movements changes the monitored part of the body, which directly affects the measured temperature values. For the contactless temperature measurement, no means are specified for elimination of the noise and correction of the measured values. If in a specific moment the temperature of the patient is constant but the ambient temperature varies, this can affect the value measured by the device and can lead to a wrong signal for temperature change of the patient.

SUMMARY OF THE INVENTION

The purpose of the invention is to create a device for contactless measurement of body temperature with capability for remote measurement of the absolute value of the temperature, taking into account the change of the position of the body of the patient.

According to the invention, this purpose is achieved by a device including an infrared sensor for temperature measurement. The infrared sensor for temperature measurement is housed in a sensor module including also a sensor for measurement of distance. The two sensor units of the sensor module are situated next to each other. To the first input of the sensor module, the output of an electromechanical drive unit is connected, whose input is connected to a control unit to which a second input of the sensor module is connected. The outputs of the sensor module are connected to the inputs of a processing unit, while the output of the processing unit is the output of the device.

For faster response and better accuracy of the determination of the patient's body within the operation range of the device and when a displacement of the patient is detected during the monitoring of the temperature, it is advisable to connect to the sensor unit a sensor unit with a passive infrared sensor with Fresnel lens situated next to the infrared sensor and the distance measurement sensor.

The advantages of the invention are concluded in the possibility for continuous and automatic remote measurement of the absolute (actual) temperature of the patient, while monitoring and taking into account the displacement and the position of the body of the patient.

DESCRIPTION OF THE FIGURES

Figure 1 is a block diagram of the device according to the utility model; Figure 2 is a diagram illustrating an exemplary operation of the device within a preset operation range.

EXEMPLARY EXECUTION OF THE INVENTION As shown in Figure 1, the remote device for measurement of the body temperature includes the sensor module 1 comprising the distance measurement sensor 1.1 and the infrared temperature measurement sensor 1.2. The two sensors 1.1 and 1.2 of the sensor module 1 are situated next to each other. The output of the electromechanical drive unit 2 is connected to the input of the sensor module 1. The input of the electromechanical drive unit 2 and the second input of the sensor module 1 are connected to the control unit 4. The outputs of the sensor module 1 are connected to the inputs of the processing unit 3. The processing unit 3 and the control unit 4 have a bidirectional connection by means of a communication link (for data transmission). The output of the processing unit 3 is the output of the device.

The sensor module 1 includes also the sensor unit with a passive infrared sensor with Fresnel lens 1.3 situated next to the infrared temperature sensor 1.2 and the distance measurement sensor 1.1.

USE OF THE INVENTION

During the contactless temperature measurement by means of an infrared temperature sensor, it is very important to eliminate the influence of the environment for better accuracy of the measured temperature. The factors acting as sources of noise during the temperature measurement are mainly the distance from the infrared temperature sensor 1.2 to the object whose temperature is measured, the ambient temperature of the object and the ambient temperature on the temperature sensor itself.

During the contactless temperature measurement, the infrared temperature sensor 1.2 measures the mean value of the temperature of the surface within the field of view of the sensor. The field of view of the sensor 1.2 increases proportionally to the distance between the sensor and the object. This increases the influence of the ambient temperature of the object and respectively, the noise level during the contactless temperature measurement.

The sensor module 1 provides the necessary data to the processing unit 3 for calculation of the corrected contactless measured temperature (Tob _j _max_corrcct), while the distance measurement sensor 1.1 provides information about the distance (d ₀ bj) between the infrared temperature sensor and the object (the point) whose temperature is measured. The infrared temperature sensor 1.2 provides information about the contactless measured temperature values (T ₀ bj and T ₀ bj_amb) of the object in the current field of view of the infrared sensor. The ambient temperature of the object (T ₀ bj_amb) is determined by means of scanning (measurements) along the surface SI (Fig. 2), which surface determines the operation range of the device and includes the patient whose temperature is monitored (the patient is in field S2 in Fig. 2). The separate designations of the temperature values T ₀ bj and T ₀ bj_amb matters at logical level during the calculations in the processing unit 3. At physical level, both temperature values are provided by an infrared temperature sensor 1.2. The ambient temperature of the infrared temperature Sensor 1.2 (Xsens_amb) is the temperature value inside the physical environment of the sensor module 1 where all sensor blocks are arranged. For better accuracy, in practice the temperature inside the infrared sensor for contactless temperature measurement 1.2 is measured (in general, the conventional infrared temperature sensors can measure their internal temperature value and provide this information). The sensor unit with a passive infrared sensor with Fresnel lens 1.3 is optional for the device and serves only to enhance and accelerate the operation of the device. It is not included in the calculations for correction of the measured temperature. This sensor provides faster and more accurate detection of the patient's body within the operation range of the device and faster and more effective detection of the movement of the patient during the temperature monitoring.

The el ectromechanical drive unit 2 of the device has two degrees of freedom and provides actuation of the sensor module along the X and Y coordinates for two-dimensional shifting of the field of vision of the sensor module along the entire surface representing the operation range of the device SI indicated in Fig.2. The sensor system is located at a distance from the object (e.g. from 10 cm to 100 cm) and its position is fixed. Towards its fixed position, the sensor module 1 is driven and directed by the electromechanical drive unit 2 along the X and Y coordinates within the operation range of the device SI.

In practice, SI (with size covering a bed with given dimensions from X0Y0 to XmYn), is the surface on which the patient with the remotely measured temperature is lying, S2 is the surface of the non-covered part of the body of the patient (the patient's head), a section of the non-covered part of the patient's body (e.g., the patient's forehead) on which the highest temperature Tmax is measured.

The device performs an initial scan (measuring, saving and correcting) of the temperature values along the given surface SI determined by the XY coordinates (from X0Y0 to XmYn) as a matrix (Fig. 2).

After the initial scan along SI, a submatrix with surface S2 is sought and detected among the measured temperature values within the matrix (Fig. 2), which submatrix indicates the field with the highest temperatures within the human body temperature range. The measured and saved temperature values within SI and outside the field S2 illustrated in Fig.2 are used for determination of the ambient temperature of the patient Tobj_amb in Fig.l.

A secondary scan is performed, during which the temperature values are scanned accurately (dynamic correction) in field S2 marked as a sub-matrix with corresponding XY coordinates.

After the secondary scan, along S2 the XY coordinates of the "point" (part of the surface) are detected with the highest value T _max of the human body temperature range. It is assumed that the "point" with temperature Tmax is the non-covered part of the body of the patient with the highest temperature.

The device positions the sensor module 1 (indicates the field of view) along the XY coordinates of the "point" Tmax and continues with monitoring of the temperature in that section of the surface. To the measured temperature values, dynamic correction is applied continuously of the measured temperature of the object (the patient) Tobj depending on its distance d ₀ bj to the contactless infrared sensor 1.2, the ambient temperature of the object Tobj_amb, the ambient temperature of temperature sensor T _se ns_amb and the corrected contactless measured temperature of the object (the patient) T ₀ bj_max_coirect is calculated - Fig.l for better accuracy after the compensation of the error in the remote measurement of the temperature.

The passive infrared sensor 1.3 detects the movement (the displacement) of the observed object (the patient) for faster activation of the device for re-scanning and positioning T _m ax in case the object has exited the field of vision of the sensor module 1 . It is used for faster and more accurate positioning of the submatrix with surface S2, which is the target of the secondary scanning and in which the "point" T _max lays. The movement of the patient would be detected too without the passive infrared sensor 1.3 by detecting the sudden temperature changes after the movement of the patient. Therefore, the passive infrared sensor 1.3 is optional and may be incorporated into the device for better accuracy and faster operation.

Thus, the device according to the invention, provides fast and accurate continuous remote and automatic measurement of the absolute (real) temperature of the patient by means of monitoring and taking into account the displacement and the position of the body of the patient.