Non-contact vital sign measurement system based on radar
Technical Field
The utility model relates to a biomedical engineering and radar signal processing field especially relate to a non-contact vital sign measurement system based on radar.
Background
At present, the traditional vital sign (respiration/heart rate/body movement) measurement method is to detect the pressure change caused by the abdomen fluctuation and the heart beat of the living body by the physical contact of a pressure sensor with the living body. The measurement realized in a contact way needs a living body to wear a specific sensor, so that the measured living body feels uncomfortable and is not suitable for long-time measurement. The parameter measurement of the life body is realized through the radar technology, the measured life body does not need to wear any sensor, and the non-contact non-inductive measurement can be realized only by lying in the monitoring range of the radar.
Therefore, how to provide a measurement system capable of acquiring vital signs through radar technology without contact is a technical problem that needs to be solved urgently by those skilled in the art.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a non-contact vital sign measurement system based on radar transmits high frequency microwave signal directive living body through the radar, and after receiving the echo that has vital sign information of living body reflection, can accomplish through a series of demodulation processing.
On the one hand, the utility model provides a non-contact vital sign measurement system based on radar, including the radio frequency transceiver module, signal acquisition device, signal processing apparatus and the display device who connects according to this:
the radio frequency transceiving module is used for transmitting a radar signal to a living body and receiving a radar echo signal reflected by the living body to form original echo data;
the signal acquisition device is used for acquiring original echo data and transmitting the original echo data to the signal processing module;
the signal processing device is used for processing the received original echo data to form life parameter data of the life body.
The display device is used for displaying the vital sign information of the life body.
Further, signal processing device includes Fourier change module, constant false alarm detection module and Kalman filtering module, the partly original echo data of signal acquisition device output pass through Fourier change module, constant false alarm detection module, behind the Kalman filtering module according to this, convert respiratory rate and the rhythm of the heart to the life body.
Furthermore, the signal processing device further comprises a clutter cancellation module and a signal intensity change rate detection module, and the other part of original echo data output by the signal acquisition device is converted into the body movement of the life body after sequentially passing through the clutter cancellation module and the signal intensity change rate detection module.
Furthermore, the radio frequency transceiver module is provided with a transmitting channel and a receiving channel, the transmitting channel contains a high-frequency signal source and a power amplifier for transmitting microwave radar signals, and the receiving channel contains a low-noise amplifier and a filter for outputting useful radar echo signals.
Furthermore, the measuring system also comprises a transmitting antenna and a receiving antenna, wherein the transmitting antenna is connected with the transmitting channel, and the receiving antenna is connected with the receiving channel.
Further, the living body is a human body, an animal body or one of other living bodies having respiratory or heartbeat characteristics.
Further, the body movement of the living body includes an unmanned state, a transient state, a steady state, a small motion state, a large motion state, and a state of entering a detection area.
Further, the different states of the body movement are respectively represented by numbers 0, 1, 2, 3, 4, and 5, where 0 represents an unmanned state, 1 represents a transient state, 2 represents a steady state, 3 represents a small motion state, 4 represents a large motion state, and 5 represents a state of entering a detection area.
Further, the display device also displays ID information and target distance information, wherein the ID information is used for distinguishing different life bodies to be detected, and the target distance is the distance between the radio frequency transceiver module and the life body.
Further, the vital sign information of the living body includes a respiration rate, a heart rate and body movement of the living body.
The utility model provides a non-contact vital sign measurement system based on radar uses microwave radar signal as the response medium, through to the life body transmission radar signal, and the radar echo signal after receiving the life body reflection is received to form original echo data, handles through processing module original echo data, on the one hand, has realized non-contact's measurement, has promoted the comfort of life body; on the other hand, the respiration rate, the heart rate and the body movement of the living body can be effectively extracted, and the purposes of real-time monitoring and early warning are achieved.
Drawings
The accompanying drawings, which form a part hereof, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without undue limitation. In the drawings:
fig. 1 is a schematic structural diagram of a radar-based non-contact vital sign measurement system according to an embodiment of the present invention;
fig. 2 is a flowchart of an embodiment of a radar-based non-contact vital sign measurement method according to the present invention;
FIG. 3 is an echo signal containing information of respiration and heart rate in one section of the present invention;
FIG. 4 is a graph of respiration and heart rate over a period of time in accordance with the present invention;
FIG. 5 is a graph showing the relationship between the body motion of a living body detected over time and the change with time in the present invention;
fig. 6 is a data state diagram displayed in the display device of the present invention.
Wherein: 1-transmit antenna 2-receive antenna.
Detailed Description
It should be noted that, in the present invention, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
For better understanding of the utility model, it should be noted that the body movement of the utility model refers to the behavior state of the living body; the respiration rate refers to the average number of breaths per minute; heart rate refers to the average number of beats per minute.
Transient calm state refers to a transition period when a living organism is detected to be present, but is in transition to a steady state calm state.
The small motion state refers to slight shaking motions such as turning, lifting the hand, etc.
The large motion state refers to the abrupt standing, the lazy waist stretching, the walking and other large-amplitude shaking motions.
Fig. 1 is a schematic structural diagram of a radar-based contactless vital sign measurement system according to an embodiment of the present invention. As shown in fig. 1, a radar-based non-contact vital sign measurement system includes a radio frequency transceiver module, a signal acquisition device, a signal processing device, and a display device, which are connected in this order, where the radio frequency transceiver module is used to transmit radar signals to a living body and receive radar echo signals reflected by the living body to form original echo data; the signal acquisition device is used for acquiring original echo data and transmitting the original echo data to the signal processing device; the signal processing device is used for processing the received original echo data to form vital sign information of a living body; the display device is used for displaying the vital sign information of the life body. Through the setting, the utility model discloses regard as the response media with the microwave radar signal, through radar transmission high frequency microwave signal directive life body, and after receiving the echo that has vital sign information of life body reflection, can accomplish through a series of demodulation processing, need not to wear any detection device, can not let the life body feel uncomfortable again when guaranteeing vital sign information measurement accuracy. Preferably, the display device may be a computer, a mobile phone or a tablet terminal device. It should be noted that the vital sign information of the present invention includes the respiration rate, the heart rate and the body movement of the living body. Fig. 3 is the echo signal containing respiration and heart rate information in one section of the present invention.
In a further technical scheme, the signal processing device specifically comprises a fourier change module, a constant false alarm detection module, a kalman filtering module, a clutter cancellation module and a signal intensity change rate detection module, wherein the fourier change module, the constant false alarm detection module and the kalman filtering module are respectively arranged in parallel with the clutter cancellation module and the signal intensity change rate detection module, and a part of original echo data output by the signal acquisition device is converted into the respiratory rate and the heart rate of a living body after sequentially passing through the fourier change module, the constant false alarm detection module and the kalman filtering module; the other part of original echo data output by the signal acquisition device is converted into the body movement of the life body after sequentially passing through the clutter cancellation module and the signal intensity change rate detection module. Fig. 4 is a graph of respiration rate and heart rate over a period of time. Meanwhile, as shown in fig. 1, the radar-based non-contact vital sign measurement system further includes a transmitting antenna 1 and a receiving antenna 2 respectively connected to the radio frequency transceiver module, specifically, the radio frequency transceiver module is provided with a transmitting channel and a receiving channel, and the transmitting antenna 1 is connected to the transmitting channel and is configured to transmit a radar signal to a living body; and the receiving antenna 2 is connected with the receiving channel and used for receiving radar echo signals reflected by the life body. Preferably, the transmitting channel comprises a high-frequency signal source and a power amplifier for transmitting microwave radar signals, and the receiving channel comprises a low-noise amplifier and a filter for outputting useful radar echo signals.
Furthermore, it should be mentioned that the living body of the present invention is not limited to a human body, but may be an animal body or one of other living bodies with breathing or heartbeat characteristics.
For the vital sign information of the accurate measurement life body, the utility model discloses well life body's physical stamina specifically divide into unmanned state, the quiet state of transient state, the quiet state of stable state, little action state, big action state and just get into five kinds of states of detection zone state, and figure 5 is promptly the utility model discloses the relation picture of the physical stamina of the life body that detects in a period changes with time, wherein, 0 represents unmanned state, and 1 represents the quiet state of transient state, and 2 represents the quiet state of stable state, 3 represents little action state, 4 represents big action state, 5 represents and just gets into detection zone state. As can be seen from fig. 5, the living body sequentially passes through the transient calm state → the steady calm state → the transient calm state → the small motion state → the steady calm state → the small motion state- → the steady calm state. Simultaneously, be worth noting in the utility model discloses in: when the human body is in a state 1 (steady state and calm state), the human body is in an optimal test state, the echo signal is good, and the respiratory rate and heart rate data are accurate and effective; when the human body is in 2 (transient calm), the human body is detected to exist, but the test signal is not good due to the position or posture of the human body, or the human body is in a transition period when the human body is converted to steady calm, and the respiratory rate and the heart rate have errors and are only used for reference; when a small motion (such as slight shaking, turning, lifting hands and the like) of the human body is detected, the state 3 is output, and the measurement of the respiration rate and the heart rate has errors and is only used for reference; when detecting that the human body has large movements (such as suddenly standing, stretching to the lazy waist and the like), the state 4 is output, and the measurement data of the respiratory rate and the heart rate are invalid. Invalid or invalid data can be eliminated through the setting, the accuracy of the detected respiratory rate and heart rate is further guaranteed, and the physical condition of a living body can be better monitored.
Preferably, the display device can display not only the respiration rate and the heart rate, but also ID information and target distance information, wherein the ID information is used for distinguishing different to-be-detected living bodies, and the target distance is a distance between the radio frequency transceiver module and the living body. Fig. 6 is a data state diagram displayed in the display device of the present invention. As shown in fig. 6, the ID display device number is 0, the target distance is 2.12m, the breathing frequency is 21 times/minute, the heartbeat frequency is 59 times/minute, and the body motion information is calm.
As shown in fig. 2, the non-contact vital sign measurement system of the present invention specifically measures vital signs by the following steps,
transmitting a radar signal to a living body, and receiving a radar echo signal reflected by the living body to form original echo data;
collecting original echo data;
converting a part of the collected original echo data into the respiratory rate and the heart rate of a living body after Fourier change processing, constant false alarm detection processing and Kalman filtering processing;
converting the other part of the acquired original echo data into the body movement of the living body after clutter cancellation processing and signal intensity change rate detection processing; and presenting the respiration rate, the heart rate and the vital sign information of the body movement of the living body.
To sum up, the technical scheme of the utility model regard as the response media with microwave radar signal, through radio frequency transceiver module to human transmission microwave radar signal, and receive the echo through human reflection to form original echo data, it is right through processing module original echo data are handled, form the vital sign information of the life body, finally show through display device. Through the arrangement, non-contact measurement is realized, and the comfort of a living body is improved; on the other hand, the radar microwave signals are harmless to the human body, so that the measurement accuracy of related data can be ensured while the respiration rate, the heart rate and the body movement of the living body are effectively extracted; and finally, the vital sign information displayed by the display device can achieve the purposes of real-time monitoring and early warning.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.