Expiration monitoring system and method

Abstract

A respiratory monitoring system and method are disclosed. The respiratory monitoring system includes a millimeter-wave radar device and a computer device. The millimeter-wave radar device emits radar waves to sense chest rise and fall of a user and outputs a plurality of phase signals accordingly. The computer device is electrically connected to the millimeter-wave radar device to receive the phase signals. The computer device includes a memory and a processor. The memory stores a plurality of instructions. The processor is electrically connected to the memory to load the instructions. The respiratory monitoring method includes: emitting radar waves to obtain the phase signals; calculating a first expiratory displacement based on a first and a second phase signal; calculating a second expiratory displacement based on a first and a third phase signal; and calculating disease indicators based on the first and second expiratory displacements.

Description

Technical Field

[0001] This disclosure relates to a respiratory monitoring system and method. In particular, it relates to a system and method for respiratory monitoring using millimeter-wave radar. Prior Technology

[0002] With the rapid development of science and technology and the economy, various respiratory monitoring systems have been developed to meet human needs for respiratory monitoring. Currently, clinical and home respiratory monitoring mostly uses contact-based methods, such as respiratory inhalation patch (RIP), electrocardiogram (ECG), or photoplethysmography (PPG). Although these methods can provide respiratory rate and heart rate data, they require wearing a monitoring device on the chest or skin. Prolonged use can cause discomfort and is not suitable for infants, the elderly, or critically ill patients.

[0003] In addition, non-contact respiratory monitoring methods include infrared photography or optical monitoring. These methods are susceptible to light, obstructions, and environmental conditions, leading to unstable signals. Current contact-based respiratory monitoring methods lack comfort and pose a risk of cross-infection, while current non-contact respiratory monitoring methods are limited by privacy and environmental interference, lack accuracy, and are difficult to maintain stably over long periods. Summary of the Invention

[0004] The purpose of this disclosure is to provide a respiratory monitoring system and method to solve the problems caused by the above-mentioned respiratory monitoring methods, and at the same time, to calculate disease indicators to help determine whether lung disease has occurred.

[0005] According to an embodiment of this disclosure, the respiratory monitoring system includes a millimeter-wave radar device and a computer device. The millimeter-wave radar device is used to emit radar waves to sense the rise and fall of the user's chest cavity and correspondingly output a plurality of sensing signals. The computer device is electrically connected to the millimeter-wave radar device to receive the sensing signals. The computer device includes a memory and a processor. The memory stores a plurality of instructions. The processor is electrically connected to the memory to load the instructions and perform the following steps: converting the sensing signals into a plurality of phase signals; calculating a first expiratory displacement based on a first and a second of the phase signals; calculating a second expiratory displacement based on a first and a third of the phase signals; and calculating disease indicators based on the first and second expiratory displacements.

[0006] In some embodiments, the first phase signal corresponds to the start time of exhalation for one of the users, the second phase signal corresponds to a time point one second after the start time of exhalation, and the third phase signal corresponds to the time point of maximum chest displacement for one of the users.

[0007] In some embodiments, when the processor calculates the first expiratory displacement based on the first and second phase signals, the processor calculates a first difference between the first and second phase signals, wherein the first difference is the first expiratory displacement.

[0008] In some embodiments, when the processor calculates the second expiratory displacement based on the first and third phase signals, the processor calculates a second difference between the first and third phase signals, wherein the second difference is the second expiratory displacement.

[0009] In some embodiments, when the processor calculates disease indicators based on the first expiratory displacement and the second expiratory displacement, the processor calculates the ratio of the first difference and the second difference.

[0010] According to the embodiments disclosed herein, the above-described respiratory monitoring method is applicable to the above-described respiratory monitoring system and includes: emitting radar waves to sense the chest rise and fall of a user and correspondingly outputting a plurality of sensing signals; converting the sensing signals into a plurality of phase signals; calculating a first expiratory displacement based on a first and a second of the phase signals; calculating a second expiratory displacement based on the first and a third of the phase signals; and calculating a disease index based on the first expiratory displacement and the second expiratory displacement.

[0011] In some embodiments, the first phase signal corresponds to the start time of exhalation for one of the users, the second phase signal corresponds to a time point one second after the start time of exhalation, and the third phase signal corresponds to the time point of maximum chest displacement for one of the users.

[0012] In some embodiments, the step of calculating the first expiratory displacement based on the first and the second phase signals includes: calculating a first difference between the first and the second phase signals, wherein the first difference is the first expiratory displacement.

[0013] In some embodiments, the step of calculating the second expiratory displacement based on the first and third phase signals includes: calculating a second difference between the first and third phase signals, wherein the second difference is the second expiratory displacement.

[0014] In some embodiments, calculating a disease index based on a first expiratory displacement and a second expiratory displacement includes: calculating the ratio of a first difference to a second difference. Simple Explanation of the Diagram

[0015] To make the above and other objects, features, advantages and embodiments of the present invention more apparent and understandable, the detailed description of the accompanying drawings is as follows: Figure 1 is a schematic diagram illustrating a respiratory monitoring system according to an embodiment of the present disclosure; Figure 2 is a functional block diagram illustrating a computer device according to an embodiment of the present disclosure; Figure 3 is a schematic diagram illustrating a millimeter-wave radar device according to an embodiment of the present disclosure; Figure 4 is a schematic flowchart illustrating a respiratory monitoring method according to an embodiment of the present disclosure; and Figure 5 is a schematic diagram illustrating the phase signal curve according to an embodiment of the present disclosure. Implementation

[0016] The following is a detailed description of the embodiments in conjunction with the accompanying drawings. However, the embodiments provided are not intended to limit the scope of the invention, and the description of the structural operation is not intended to limit the order of execution. Any structure resulting from the recombination of elements and producing a device with equivalent functionality is within the scope of the invention. Furthermore, the drawings are for illustrative purposes only and are not drawn to their original dimensions.

[0017] The terms "first," "second," etc., are used herein to describe different elements. These terms are only used to distinguish elements or operations described using the same technical terms. Unless the context clearly indicates otherwise, these terms do not specifically refer to or imply any order or sequence, nor are they intended to limit the invention.

[0018] Please refer to Figure 1, which is a schematic diagram of a respiratory monitoring system according to an embodiment of the present disclosure. The respiratory monitoring system includes a millimeter-wave radar device 110 and a computer device 120. The millimeter-wave radar device 110 is used to emit radar waves to sense the chest rise and fall of the user 130 and output a plurality of sensing signals accordingly. The computer device 120 is electrically connected to the millimeter-wave radar device 110 to receive the sensing signals transmitted by the millimeter-wave radar device 110. The computer device 120 can analyze the sensing signals to assess the respiratory status of the user 130, such as disease indicators and / or respiratory rate.

[0019] Please refer to Figure 2, which is a functional block diagram of a computer device 120 according to an embodiment of the present disclosure. The computer device 120 includes a memory 122 and a processor 124. The memory 122 is used to store a plurality of instructions. The processor 124 is electrically connected to the memory 122 to load the instructions stored in the memory 122 and process the sensed signals. In the embodiments of the present disclosure, the computer device 120 may be a personal computer, a laptop computer, a tablet computer, or a smartphone. However, the embodiments of the present disclosure are not limited thereto.

[0020] Please refer to Figure 3, which is a schematic diagram of a millimeter-wave radar device 110 according to an embodiment of the present disclosure. The millimeter-wave radar device 110 includes a signal generator 111, a power amplifier 112, a first antenna 113, a second antenna 114, a low-noise amplifier 115, a mixer 116, and an analog-to-digital converter 117. The signal generator 111 generates a first radar signal (e.g., a high-frequency sine wave) and transmits the first radar signal to the power amplifier 112. The power amplifier 112 amplifies the power of the first radar signal and transmits the first radar signal to the first antenna 113. The first antenna 113 transmits the first radar signal to a user 130 to sense the chest rise and fall of the user 130.

[0021] The second antenna 114 is used to receive the first radar signal (hereinafter referred to as the second radar signal) reflected by the user 130 and transmit the second radar signal to the low noise amplifier 115. The low noise amplifier 115 is used to amplify the second radar signal and transmit the second radar signal to the mixer 116. The mixer 116 is used to receive the first radar signal as a local reference signal and mix the first radar signal and the second radar signal to obtain a sensing signal. The sensing signal carries information about the displacement and distance change of the chest cavity surface. For example, when the user 130 inhales, the user 130's chest cavity will protrude, and the distance between the millimeter-wave radar device 110 and the user's chest cavity will decrease. Or, for example, when the user 130 exhales, the user 130's chest cavity will concave, and the distance between the millimeter-wave radar device 110 and the user's chest cavity will increase.

[0022] In this embodiment, in order to facilitate the processing of sensing signals, an analog-to-digital converter 117 is used to convert the analog sensing signals into digital sensing signals, so that the computer device 120 can process the sensing signals.

[0023] Please refer to Figure 4, which is a schematic flowchart illustrating a respiratory monitoring method 400 according to an embodiment of this disclosure. The respiratory monitoring method 400 is applicable to the aforementioned respiratory monitoring system, using a computer device 120 to calculate disease indicators and / or respiratory rate. When the computer device 120 receives a sensing signal from the millimeter-wave radar device 110, it first performs step 410 to convert the sensing signal into a phase signal. In the signal conversion operation, firstly, a fast Fourier transform is performed on the sensing signal to convert it from the time domain to the frequency domain. Then, a filter (e.g., a frequency domain filter) is used to remove static clutter from the sensing signal. Next, a range bin is selected for the sensing signal, and DC displacement correction is performed on the sensing signal. Then, phase expansion is performed on the sensing signal, and pulse noise is removed to obtain the phase signal. The phase signal represents the distance between the millimeter-wave radar device 110 and the user's chest cavity. For example, the amplitude value of the phase signal can represent the distance between the millimeter-wave radar device 110 and the user's chest cavity.

[0024] Then, steps 420-440 are performed sequentially to calculate the first expiratory displacement and the second expiratory displacement, and disease indicators are calculated based on the first expiratory displacement and the second expiratory displacement.

[0025] Please refer to Figure 5, which is a schematic diagram illustrating the phase signal curve 500 according to an embodiment of this disclosure, where the vertical axis represents amplitude and the horizontal axis represents time. In this embodiment, the user 130 performs respiratory detection within a 15-second respiratory detection period, and the phase signal measured during this respiratory detection period constitutes the phase signal curve 500. The phase signal curve 500 includes a phase signal 510 corresponding to the start of exhalation, a phase signal 520 corresponding to one second after exhalation, a phase signal 530 corresponding to the time of maximum chest displacement, and a phase signal 540 corresponding to the end of exhalation.

[0026] As shown in Figure 5, when the lung capacity testing program begins, user 130 begins to inhale. During inhalation, user 130's chest cavity gradually expands, causing the distance between the user's chest cavity and the millimeter-wave radar device 110 to gradually decrease. Therefore, the measured distance at this time is negative. When user 130 fully inhales and begins to exhale, user 130's chest cavity gradually shrinks / depresses, causing the distance between the user's chest cavity and the millimeter-wave radar device 110 to gradually increase. Therefore, the measured distance changes from negative to positive. When user 130 continues to exhale until the chest cavity reaches its maximum depression (phase signal 530), it indicates that exhalation is about to end. When user 130 finishes exhaling and begins to inhale, user 130's chest cavity gradually expands again, causing the distance between the user's chest cavity and the millimeter-wave radar device 110 to gradually decrease.

[0027] In the embodiment disclosed herein, when the user 130's chest cavity is flat, the distance between the user 130's chest cavity and the millimeter-wave radar device 110 is set to 0. Thus, the amplitude value of the phase signal represents the displacement of the user's chest cavity, where a negative amplitude value represents the expansion of the user 130's chest cavity, and a positive amplitude value represents the depression of the user 130's chest cavity.

[0028] Please refer back to Figure 4. In step 420 above, the first expiratory displacement is calculated based on the first and second phase signals. For example, the first expiratory displacement is calculated based on the phase signal 510 corresponding to the start of exhalation and the phase signal 520 corresponding to one second after exhalation. Specifically, the difference between the amplitude of phase signal 510 and the amplitude of phase signal 520 can be used to obtain the change in chest cavity displacement within one second of exhalation. In some embodiments, multiplying this change in chest cavity displacement by a preset compensation value (e.g., a compensation value representing the length and width of the chest cavity) represents the forced expiratory volume in 1 second (FEV1).

[0029] In step 430 above, the second expiratory displacement is calculated based on the first and third phase signals. For example, the second expiratory displacement is calculated based on the phase signal 510 corresponding to the start of exhalation and the phase signal 530 corresponding to the maximum chest displacement. Specifically, the difference between the amplitude of phase signal 510 and the amplitude of phase signal 530 can be used to obtain the maximum chest displacement change. In some embodiments, this maximum chest displacement change can be multiplied by a preset compensation value to represent the "forced vital capacity" (FVC).

[0030] In step 440 above, a disease indicator is calculated based on the first expiratory displacement and the second expiratory displacement. For example, the disease indicator can be obtained by calculating the ratio of the first expiratory displacement to the second expiratory displacement. Specifically, the disease indicator = first expiratory displacement / second expiratory displacement. In some embodiments, the first expiratory displacement and the second expiratory displacement are multiplied by a preset compensation value to obtain FEV1 and FVC, respectively. The ratio of FEV1 to FVC can be used as a disease indicator for judging airway obstruction. Since the preset compensation value is a fixed value, the ratio of FEV1 to FVC will be equal to the ratio of the first expiratory displacement to the second expiratory displacement. Therefore, the ratio of first expiratory displacement to second expiratory displacement can be used as a disease indicator.

[0031] As described above, the respiratory monitoring system and method of this disclosure can use radar waves to sense the displacement of the user's chest cavity and calculate disease indicators based on the displacement. Because the overall system is non-contact, real-time, and highly sensitive, it can provide hygienic monitoring for a wider range of age groups (such as children, the elderly, and patients with chronic obstructive pulmonary disease), offering a new solution for lung function monitoring.

[0032] In some embodiments, when the user 130 is breathing normally, the computer device 120 can calculate the user 130's breathing rate. For example, the user 130's breathing cycle can be obtained based on the time difference between the start times of two adjacent exhalations, and then the user 130's breathing rate can be calculated accordingly.

[0033] In some embodiments, the millimeter-wave radar device 110 may be controlled by a computer device 120. For example, the respiratory monitoring method 400 described above may further include a step of using the computer device 120 to control the millimeter-wave radar device 110 to emit radar waves to sense the rise and fall of the user's chest cavity, thus making the respiratory monitoring method 400 more convenient. In addition, the respiratory monitoring method 400 may also include a step of judging disease indicators. For example, the computer device 120 may determine whether a disease indicator exceeds a preset threshold (e.g., 80%). When a disease indicator exceeds the preset threshold, the computer device 120 may display a warning message to indicate signs of asthma or chronic obstructive pulmonary disease.

[0034] Although the present invention has been disclosed above with reference to several embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which this invention pertains may make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this invention shall be determined by the appended claims.

[0035] 110: Millimeter-wave radar device 111: Signal Generator 112: Power Amplifier 113: First Antenna 114: Second Line 115: Low Noise Amplifier 116: Mixer 117: Analog to Digital Converter 120: Computer device 122: Memory 124: Processor 130: User 400: Respiratory Monitoring Methods 410~440: Steps 500: Phase signal curve 510~540: Phase signal

[0036] none

Claims

1. A respiratory monitoring system comprising: a millimeter-wave radar device for emitting a radar wave to sense chest rise and fall of a user and correspondingly outputting a plurality of sensing signals; and a computer device electrically connected to the millimeter-wave radar device to receive the sensing signals, wherein the computer device comprises: a memory for storing a plurality of instructions; and a processor electrically connected to the memory to load the instructions to perform: converting the sensing signals into a plurality of phase signals; calculating a first expiratory displacement based on a first and a second of the phase signals; calculating a second expiratory displacement based on the first and a third of the phase signals; and calculating a disease index based on the first expiratory displacement and the second expiratory displacement. The first phase signal corresponds to the start time of the user's exhalation, the second phase signal corresponds to a time point one second after the start time of exhalation, and the third phase signal corresponds to the time point of the user's maximum chest displacement.

2. The respiratory monitoring system as claimed in claim 1, wherein when the processor calculates the first expiratory displacement based on the first and the second of the phase signals, the processor calculates a first difference between the first and the second of the phase signals, wherein the first difference is the first expiratory displacement.

3. The respiratory monitoring system as claimed in claim 2, wherein when the processor calculates the second expiratory displacement based on the first and the third of the phase signals, the processor calculates a second difference between the first and the third of the phase signals, wherein the second difference is the second expiratory displacement.

4. The respiratory monitoring system as claimed in claim 3, wherein when the processor calculates the disease index based on the first expiratory displacement and the second expiratory displacement, the processor calculates the ratio of the first difference to the second difference.

5. A respiratory monitoring method, applicable to a respiratory monitoring system, comprising: emitting a radar wave to sense chest rise and fall of a user and correspondingly outputting a plurality of sensing signals; electrically connecting a computer device to a millimeter-wave radar device to receive the sensing signals; storing a plurality of instructions in a memory; electrically connecting a processor to the memory to load the instructions in the memory and process the sensing signals; converting the sensing signals into a plurality of phase signals; calculating a first expiratory displacement based on a first and a second of the phase signals; calculating a second expiratory displacement based on the first and a third of the phase signals; and calculating a disease index based on the first expiratory displacement and the second expiratory displacement. The first phase signal corresponds to the start time of the user's exhalation, the second phase signal corresponds to a time point one second after the start time of exhalation, and the third phase signal corresponds to the time point of the user's maximum chest displacement.

6. The respiratory monitoring method as claimed in claim 5, wherein the step of calculating the first expiratory displacement based on the first and the second of the phase signals comprises: calculating a first difference between the first and the second of the phase signals, wherein the first difference is the first expiratory displacement.

7. The respiratory monitoring method as claimed in claim 6, wherein the step of calculating the second expiratory displacement based on the first and the third of the phase signals comprises: calculating a second difference between the first and the third of the phase signals, wherein the second difference is the second expiratory displacement.

8. The respiratory monitoring method as described in claim 7, wherein calculating the disease indicator based on the first expiratory displacement and the second expiratory displacement comprises: calculating the ratio of the first difference to the second difference.

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