Method for monitoring breathing state by using infrared rays

Abstract

The invention discloses a method for monitoring a breathing state by using infrared rays, which relates to medical equipment and comprises the following steps of: constructing an interference matrix caused by temperature drift according to temperature measurement data acquired in an ideal environment and an actual use environment of an infrared lens; and taking a difference value between the actual temperature measurement data acquired by the infrared lens and the interference matrix as real data acquired by the infrared lens. The temperature drift generated by data collected by the infrared lens can be calibrated, breathing data can be obtained after other interference factors are filtered out, and the accuracy is effectively improved; non-contact high-precision detection is achieved in clinical application, the purpose of monitoring changes of the period, strength and stability of human respiratory airflow can be well achieved, the vital sign state of the human body is reflected, meanwhile, due to the fact that the device is noninvasive, lossless and free of radiation, the mouth and nose information changes of the human body are completely utilized, and the detection accuracy is improved. The applicability of clinical application is greatly improved.

Description

Technical Field

[0001] The present invention relates to medical equipment, and more particularly to a method for monitoring respiratory status using infrared. Background Art

[0002] The respiratory state of a person is one of the important vital signs of a person, so in clinical practice, the respiratory rate, respiratory amplitude, respiratory rhythm, respiratory sounds, arterial oxygen partial pressure, etc. are often detected or monitored. In hospitals, especially high-level hospitals, there are various respiratory monitors for various tests on patients. Among them, according to the physical principle, there are: invasive monitoring, non-invasive monitoring, and remote sensing monitoring. According to the principle of respiratory monitoring, there are: chest and abdominal movement monitoring measures the displacement changes of the chest and abdomen during breathing to calculate the respiratory rate. Airflow monitoring uses airflow sensors to measure the airflow velocity during breathing, thereby calculating the respiratory rate. Sound monitoring extracts information related to breathing by analyzing the sound signals generated during breathing. Blood oxygen saturation monitoring indirectly reflects respiratory function by measuring the ratio of oxygenated hemoglobin and deoxygenated hemoglobin in the blood. However, in clinical applications, there is a problem with the above methods, which is that it is difficult to achieve non-contact, thereby increasing iatrogenic risks. Infrared temperature measurement can achieve non-contact. Although infrared temperature measurement can well achieve non-contact problems, these devices still have corresponding limitations in actual use. The main problem is that in actual clinical practice, the infrared lens used in the acquisition equipment cannot achieve high accuracy because the infrared lens has a large temperature drift. If the temperature drift cannot be overcome, the collected images will be affected by the temperature drift of the device itself, resulting in large errors in the results. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for monitoring respiratory status using infrared in view of the deficiencies in the prior art, thereby greatly improving the accuracy of the collected infrared data.

[0004] The method of using infrared to monitor respiratory status described in the present invention constructs an interference matrix caused by temperature drift based on the temperature measurement data collected in the ideal environment of the infrared lens and the actual use environment, and uses the difference between the actual temperature measurement data collected by the infrared lens and the interference matrix as the real data collected by the infrared lens.

[0005] Preferably, the interference matrix is ​​constructed by:

[0006] A standard matrix composed of the same standard temperature measurement data is collected through the infrared lens, and a temperature measurement matrix in an actual use environment is collected through the infrared lens to obtain the minimum absolute value in the temperature measurement matrix. A base value matrix is ​​constructed according to the difference between the elements in the temperature measurement matrix and the minimum absolute value, and the difference between the temperature measurement matrix and the base value matrix is ​​used as an interference matrix.

[0007] Preferably, the method for obtaining the standard matrix is:

[0008] When the infrared lens is powered on and reaches a steady state, a standard plate with a consistent surface temperature is placed in front of the infrared lens to cover the infrared lens, and the temperature measurement data collected by the infrared lens at this time is used as standard temperature measurement data.

[0009] Preferably, the standard plate is a foam plastic plate, and the standard plate completely blocks the infrared lens.

[0010] Preferably, when the infrared lens collects actual temperature measurement data, the infrared lens is aimed at the mouth and nose of the monitoring target.

[0011] Preferably, if the infrared lens cannot be directly directed at the mouth and nose of the monitored target, a periodic multi-graph analysis method is used to obtain real data.

[0012] Preferably, the periodic multi-graph analysis method is specifically:

[0013] An acquisition cycle is set, during which the infrared lens acquires N infrared data matrices of the mouth and nose of the head of the monitoring target, and after temperature drift calibration is performed by subtracting the N infrared data matrices from the interference matrix, the part with different data between the calibrated infrared data matrices is queried as the temperature change part, the lowest temperature point in the temperature change part is taken, and a temperature waveform is formed by arranging the lowest temperature points in each infrared data matrix as the real data for monitoring the breathing temperature of the monitoring target.

[0014] Preferably, an AND operation is performed on the calibrated current infrared data matrix and the calibrated infrared data matrix of the previous time node, and the parts with different temperatures in the two infrared data matrices are used as the temperature change part of the current infrared data matrix.

[0015] Beneficial Effects

[0016] The advantages of the present invention are: the present invention constructs an interference matrix based on an ideal environment and an actual use environment, which is used to calibrate the temperature drift generated by the data collected by the infrared lens. After filtering out other interference factors, the respiratory data can be obtained, and the accuracy can be effectively improved; the clinical application realizes non-contact high-precision detection, which can well achieve the purpose of monitoring the changes in the period, strength, and stability of the human respiratory airflow, thereby reflecting the state of the human body's vital signs. At the same time, because it is non-invasive, non-destructive, and radiation-free, it fully utilizes the changes in the human body's own mouth and nose information, which greatly increases the applicability of clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the system structure of the present invention using infrared to monitor respiratory status;

[0018] Figure 2 This is a rendering of data collected by an infrared lens when the system of the present invention does not implement the method of the present invention;

[0019] Figure 3 The diagram is an effect diagram of data collected by an infrared lens when the method of the present invention is implemented in the system of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0021] The present invention discloses a method for monitoring respiratory status by using infrared. According to the temperature measurement data collected by the ideal environment of the infrared lens and the actual use environment, an interference matrix caused by temperature drift is constructed, and the difference between the actual temperature measurement data collected by the infrared lens and the interference matrix is ​​used as the real data collected by the infrared lens. The present invention calibrates the temperature drift of the data of the infrared lens, and after filtering out other interference factors, respiratory data can be obtained, and the accuracy can be effectively improved; the clinical application realizes non-contact high-precision detection, and it has high sensitivity to temperature changes and good followability, and can well achieve the purpose of monitoring the changes in the cycle, strength, and stability of human respiratory airflow, thereby reflecting the state of human vital signs. At the same time, because it is non-invasive, non-destructive, and non-radiating, it fully utilizes the changes in the mouth and nose information of the human body, which greatly increases the applicability of clinical applications.

[0022] The temperature drift calibration of the infrared lens is specifically implemented through the following steps.

[0023] Step 1: Power on the infrared lens. After a period of time, when the infrared lens reaches a steady state, use a foam plastic whose surface is not disturbed by the temperature of other objects to completely cover the lens and take data. Assuming that the surface temperature of this foam plastic is uniform and consistent, and the surface temperature is constant as T, we use the measured temperature of each point in the infrared lens collection surface as a value in the matrix, and we can get a W×H matrix. All values ​​in the matrix are T, that is:

[0024]

[0025] Among them, {BT}(W, H) is a standard matrix; the infrared lens has a focal plane of W×H, where W is the width and H is the height.

[0026] Step 2: Generally, infrared lenses produce temperature drift due to various interference factors in the environment, so the infrared lens actually collects a non-ideal matrix. Therefore, the infrared lens collects the matrix in the actual use environment, that is, the temperature measurement matrix is ​​expressed as:

[0027]

[0028] Assume t min =min|{Bt}(W,H)| is the minimum absolute value in the temperature measurement matrix.

[0029] Step 3: Construct a basis value matrix based on the difference between the elements in the temperature measurement matrix and the minimum absolute value, which can be expressed as:

[0030]

[0031] Step 4: Use the difference between the temperature measurement matrix and the base value matrix as the interference matrix, that is:

[0032] {B}(W,H)={Bt}(W,H)-{BV}(W,H).

[0033] The interference matrix is ​​considered to be the data difference caused by the temperature drift of the infrared lens.

[0034] Step 5. In practical applications, the difference between each set of actual temperature measurement data collected by the infrared lens and the interference matrix is ​​used as the real data collected by the infrared lens:

[0035]

[0036] Among them, {BT}(W, H) is considered to be the real data after filtering out the interference caused by temperature drift on the data collected by the infrared lens.

[0037] When the infrared lens collects actual temperature measurement data, the infrared lens is aimed at the mouth and nose of the monitored target, which can effectively improve the authenticity of the data.

[0038] In clinical applications, for some special patients, it is difficult to require their mouth and nose to face the camera all the time and fully expose the mouth and nose. However, if this cannot be done, the temperature changes caused by breathing cannot be well collected through the infrared lens, and the patient's breathing data can be obtained. For this reason, the present invention adopts a periodic multi-graph analysis method to obtain real data when the infrared lens cannot directly face the mouth and nose of the monitoring target. Since the patient's breathing has the greatest impact on the air temperature change around the patient's face, and this change can be expressed as a function related to time t. Therefore, we can use this rule to extract the patient's breathing data through the surrounding air temperature changes even if the infrared lens fails to accurately aim at the patient's mouth and nose, that is, monitor the patient's breathing through the temperature changes caused by the airflow generated by mouth and nose breathing.

[0039] Specifically, the periodic multi-graph analysis method is as follows:

[0040] First, a collection cycle is set, during which the infrared camera collects N infrared data matrices of the mouth and nose of the head of the monitoring target. For example, four infrared data matrices are collected per second.

[0041] For each infrared data matrix, after performing temperature drift calibration by subtracting it from the interference matrix, the different parts of the data between the calibrated infrared data matrices are queried as the temperature change part. Specifically, the calibrated current infrared data matrix is ​​ANDed with the calibrated infrared data matrix of the previous time node, and the different temperature parts of the two infrared data matrices are taken as the temperature change part of the current infrared data matrix.

[0042] Then take the lowest temperature point in the temperature change part, and arrange the lowest temperature points in each infrared data matrix to form a temperature waveform as the real data for monitoring the target breathing temperature. This temperature waveform is the patient's breathing waveform. Generally, we believe that the temperature of the mouth, nose and surrounding air decreases when a person inhales, and the temperature of the mouth, nose and surrounding air increases when a person exhales (the room temperature is lower than the human body temperature, which is consistent with the indoor conditions of a general ward). Therefore, the peak of this waveform is the patient's exhalation, and the trough is the patient's inhalation. A peak and a trough are the time it takes for the patient to breathe once. In this way, it can be determined that the data collected in the above manner can effectively characterize the temperature data of the patient's breathing.

[0043] To implement the above method, Figure 1 As shown, the present invention also provides a system for monitoring respiratory status using infrared, which includes an infrared lens and a computer. The computer processes the data collected by the infrared lens through temperature drift, and then transmits the real data to a display for display, and also transmits it to a disk database for storage. Figure 2 and Figure 3 The following are infrared images collected in the same environment. Figure 2 This is the effect diagram of the data collected by the infrared lens when the system does not implement the above method. It can be seen from the figure that the maximum temperature difference can reach 23.0-22.5=0.5℃. Figure 3 In the experiment, after using the above method, the temperature difference is 23.17-22.77=0.08℃, the temperature drift is obviously suppressed, and the data accuracy is higher.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for monitoring respiratory status using infrared, characterized in that: An interference matrix caused by temperature drift is constructed based on the temperature measurement data collected in the ideal environment of the infrared lens and the actual use environment, and the difference between the actual temperature measurement data collected by the infrared lens and the interference matrix is ​​used as the real data collected by the infrared lens.

2. The method for monitoring respiratory status using infrared according to claim 1, characterized in that: The interference matrix is ​​constructed as follows: A standard matrix composed of the same standard temperature measurement data is collected through the infrared lens, and a temperature measurement matrix in an actual use environment is collected through the infrared lens to obtain the minimum absolute value in the temperature measurement matrix. A base value matrix is ​​constructed according to the difference between the elements in the temperature measurement matrix and the minimum absolute value, and the difference between the temperature measurement matrix and the base value matrix is ​​used as an interference matrix.

3. The method for monitoring respiratory status using infrared according to claim 2, characterized in that: The method for obtaining the standard matrix is: When the infrared lens is powered on and reaches a steady state, a standard plate with a consistent surface temperature is placed in front of the infrared lens to cover the infrared lens, and the temperature measurement data collected by the infrared lens at this time is used as standard temperature measurement data.

4. The method for monitoring respiratory status using infrared according to claim 3, characterized in that: The standard plate is made of a foam plastic plate, and the standard plate completely blocks the infrared lens.

5. A method for monitoring respiratory status using infrared according to any one of claims 1 to 4, characterized in that: When the infrared lens collects actual temperature measurement data, the infrared lens is aimed at the mouth and nose of the monitoring target.

6. The method for monitoring respiratory status using infrared according to claim 5, characterized in that: If the infrared lens cannot be directly directed at the mouth and nose of the monitored target, the periodic multi-image analysis method is used to obtain real data.

7. The method for monitoring respiratory status by infrared according to claim 6, characterized in that: The cycle multi-graph analysis method is specifically: An acquisition cycle is set, during which the infrared lens acquires N infrared data matrices of the mouth and nose of the head of the monitoring target, and after temperature drift calibration is performed by subtracting the N infrared data matrices from the interference matrix, the part with different data between the calibrated infrared data matrices is queried as the temperature change part, the lowest temperature point in the temperature change part is taken, and a temperature waveform is formed by arranging the lowest temperature points in each infrared data matrix as the real data for monitoring the breathing temperature of the monitoring target.

8. The method for monitoring respiratory status by infrared according to claim 7, characterized in that: The calibrated current infrared data matrix is ​​ANDed with the calibrated infrared data matrix of the previous time node, and the parts with different temperatures in the two infrared data matrices are used as the temperature change part of the current infrared data matrix.

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