CN113729673A - Monitoring method and device capable of preventing asphyxia - Google Patents
Monitoring method and device capable of preventing asphyxia Download PDFInfo
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/0507—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves using microwaves or terahertz waves
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/0205—Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/024—Detecting, measuring or recording pulse rate or heart rate
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
- A61B5/0816—Measuring devices for examining respiratory frequency
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7203—Signal processing specially adapted for physiological signals or for diagnostic purposes for noise prevention, reduction or removal
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/725—Details of waveform analysis using specific filters therefor, e.g. Kalman or adaptive filters
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
- A61B5/7235—Details of waveform analysis
- A61B5/7253—Details of waveform analysis characterised by using transforms
- A61B5/7257—Details of waveform analysis characterised by using transforms using Fourier transforms
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/74—Details of notification to user or communication with user or patient ; user input means
- A61B5/746—Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/74—Details of notification to user or communication with user or patient ; user input means
- A61B5/7465—Arrangements for interactive communication between patient and care services, e.g. by using a telephone network
- A61B5/747—Arrangements for interactive communication between patient and care services, e.g. by using a telephone network in case of emergency, i.e. alerting emergency services
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2503/00—Evaluating a particular growth phase or type of persons or animals
- A61B2503/04—Babies, e.g. for SIDS detection
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2503/00—Evaluating a particular growth phase or type of persons or animals
- A61B2503/08—Elderly
Abstract
A monitoring method and device capable of preventing suffocation, carry on IQ quadrature mixing to the transmitting wave and echo of the millimeter wave radar, output the target distance, speed, direction and phase information; performing correlation analysis through the modulus of the corresponding frequency point and amplitude transformation caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object; selecting the frequency of the maximum module value as the frequency of the current breath and the heartbeat respectively; comprehensively judging the respiration and heartbeat, analyzing whether the frequency of the current respiration and heartbeat is in a preset normal range, and if not, analyzing the duration and the trend quantity of increasing or decreasing; and according to the data of comprehensive judgment, if the duration of the breath which is not in the normal range exceeds a preset time value and the heartbeat exceeds the normal range, judging that the asphyxia occurs, and reporting the judgment result to perform local and remote alarm. The baby asphyxia detection device can actively find baby asphyxia in time and reduce baby risk; the application range is wide, and the life safety of the monitored object is effectively guaranteed.
Description
Technical Field
The invention relates to the technical field of infant monitoring, in particular to a monitoring method and device capable of preventing asphyxia.
Background
A baby monitor, also called a baby monitor or a baby monitor, belongs to a wireless family safety protection system, and provides real-time monitoring for babies by one action and one line by utilizing a monitoring end, a monitoring result can be sent to a background through a WIFI signal, and the background forwards the monitoring result to a mobile phone APP on a hand of the monitor according to a bound mobile phone and restores the monitoring result to video or audio. By using the baby monitor, parents or guardians no longer need to keep on the baby or the child in a short time to know the behaviors of the parents or the guardians, so that the influence on the rest of the baby due to frequent checking is avoided, and the parents or the guardians can immediately detect and process the abnormal conditions when the abnormal conditions occur.
The baby monitor does liberate parents and does not need the parents to stay at the baby's body at all times. With the development of intelligent technology, the monitor can remind parents of whether the baby wakes up or not in real time through the baby motion acquired by video and the baby crying acquired by the microphone, so that the parents have certain freedom while keeping good after the baby, and the safety of the baby is guaranteed to a certain extent.
However, the stomach of the newborn is horizontal, the volume is small, the cardia connected with the esophagus is wide, the closing effect is poor, the pylorus connected with the small intestine is tight, and the newborn usually inhales air when taking milk, so that milk easily flows back to the oral cavity to cause milk spitting. Milk regurgitation can cause the infants to suffocate very easily, the suffocation can cause the temporary oxygen deficiency of the brains of the infants, the cerebral palsy of the infants can be easily formed, and even the infants can die if the infants are not rescued in time. The traditional monitor cannot find the asphyxia of the baby through videos and sounds, and cannot remind parents of the asphyxia. Parents are difficult to keep around the baby at all times, and particularly, when the parents fall asleep at night, the parents cannot find the baby suffocation in time, so that tragedies which are difficult to recover are easily caused. There is a need for an infant monitoring solution that is resistant to asphyxia.
Disclosure of Invention
Therefore, the invention provides a monitoring method and a device capable of preventing asphyxia, which can actively judge whether an infant asphyxia, and solve the problem that the conventional infant monitor cannot actively find the asphyxia of the infant.
In order to achieve the above purpose, the invention provides the following technical scheme: a monitoring method capable of preventing asphyxia comprises the following steps:
IQ quadrature frequency mixing is carried out on the transmitted waves and the echoes of the millimeter wave radar, I, Q two paths of quadrature intermediate frequency information are output, ADC sampling is carried out on I, Q channels respectively, and discrete complex information is obtained;
performing digital sampling on the intermediate frequency information, performing FFT (fast Fourier transform), converting a digital time domain signal into a frequency domain signal, analyzing, and outputting target distance, speed, direction and phase information;
performing correlation analysis through the modulus of the corresponding frequency point and amplitude transformation caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object;
calculating the phase of the optimal vital sign point, unfolding the phase of the current vital sign point according to the phase difference of two adjacent frames, and calculating the phase difference of two adjacent frames according to the unfolded phase;
filtering the phase difference information to obtain phase difference information in a respiratory corresponding frequency range and phase difference information in a heartbeat corresponding frequency range;
performing FFT (fast Fourier transform) on the filtered phase difference information in the frequency range corresponding to the respiration and the filtered phase difference information in the frequency range corresponding to the heartbeat respectively, and transforming the time domain signals to a frequency domain for analysis;
respectively selecting the optimal frequency components in the corresponding ranges, and selecting the frequency with the maximum module value as the current respiration frequency and the heartbeat frequency respectively according to the module value of the frequency;
comprehensively judging the respiration and heartbeat, analyzing whether the frequency of the current respiration and heartbeat is in a preset normal range, and if not, analyzing the duration and the trend quantity of increasing or decreasing;
and according to the data of comprehensive judgment, if the duration of the breath which is not in the normal range exceeds a preset time value and the heartbeat exceeds the normal range, judging that the asphyxia occurs, and reporting the judgment result to perform local and remote alarm.
As a preferable scheme of the monitoring method capable of preventing asphyxia, the millimeter wave radar is integrated with a waveform generator, a transmitting antenna and a receiving antenna, the waveform generator is used for generating millimeter wave band radar waves, the transmitting antenna is used for transmitting the millimeter radar waves to the outside, and the receiving antenna is used for receiving echoes of the millimeter radar waves.
As a preferable scheme of the monitoring method capable of preventing asphyxia, IQ orthogonal frequency mixing is carried out on the transmitting wave and the echo of the millimeter wave radar through an IQ orthogonal frequency mixer;
filtering high-frequency information generated by the mixer through a low-pass filter;
and digitally sampling the intermediate frequency information through an analog-digital converter.
And as a preferable scheme of the monitoring method capable of preventing asphyxia, filtering the phase difference information by an IIR digital filter, and obtaining the phase difference information in a frequency range corresponding to respiration and the phase difference information in a frequency range corresponding to heartbeat after filtering.
As a preferred scheme of the monitoring method capable of preventing asphyxia, if the phase difference is greater than pi in the phase unfolding process, the current phase is-2 pi; if the phase difference is less than-pi, the current phase is +2 pi; if the phase difference is between-pi and pi, the current phase is unchanged.
As a preferable scheme of the monitoring method capable of preventing asphyxia, before the comprehensive evaluation of respiration and heartbeat, the method further comprises the following steps:
and smoothing the frequency of the respiration and the heartbeat, and removing abnormal points of sudden respiration and heartbeat caused by interference.
The invention also provides a monitoring device capable of preventing asphyxia, which adopts the monitoring method capable of preventing asphyxia and comprises the following steps:
the millimeter wave detection module is used for carrying out IQ (in-phase quadrature) frequency mixing on the transmitted wave and the echo of the millimeter wave radar, outputting I, Q two paths of orthogonal intermediate frequency information, and respectively carrying out ADC (analog-to-digital converter) sampling on I, Q channels to obtain discrete complex information;
the first FFT conversion module is used for carrying out digital sampling on the intermediate frequency information, carrying out FFT conversion on the intermediate frequency information, converting a digital time domain signal into a frequency domain signal, analyzing the frequency domain signal, and outputting target distance, speed, direction and phase information;
the vital sign point acquisition module is used for carrying out correlation analysis through the module value of the corresponding frequency point and amplitude conversion caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object;
the phase calculation module is used for calculating the phase of the optimal vital sign point;
the phase unfolding module is used for unfolding the phase of the current vital sign point according to the phase difference of two adjacent frames;
the phase difference acquisition module is used for calculating the phase difference between two adjacent frames according to the unfolded phase;
the filtering module is used for filtering the phase difference information to obtain phase difference information in a frequency range corresponding to respiration and phase difference information in a frequency range corresponding to heartbeat;
the second FFT conversion module is used for respectively carrying out FFT conversion on the phase difference information in the respiratory corresponding frequency range and the phase difference information in the heartbeat corresponding frequency range after filtering, and converting the time domain signal into a frequency domain for analysis;
the breath and heartbeat processing module is used for respectively selecting the optimal frequency components in the corresponding ranges, and selecting the frequency of the maximum module value as the frequency of the current breath and heartbeat according to the module value of the frequency;
the breath and heartbeat comprehensive evaluation module is used for comprehensively evaluating breath and heartbeat, judging whether the current breath and heartbeat frequency is in a preset normal range, and analyzing the duration time and the trend quantity of increasing or decreasing if the current breath and heartbeat frequency is not in the normal range;
the apnea judging module is used for judging that apnea occurs if the duration time of respiration out of the normal range exceeds a preset time value and the heartbeat exceeds the normal range according to the comprehensively judged data;
and the early warning module is used for reporting the judgment result to carry out local and remote warning.
As a preferable scheme of the monitoring device capable of preventing asphyxia, the millimeter wave radar is integrated with a waveform generator, a transmitting antenna and a receiving antenna, the waveform generator is used for generating millimeter wave band radar waves, the transmitting antenna is used for transmitting the millimeter radar waves to the outside, and the receiving antenna is used for receiving echoes of the millimeter radar waves;
carrying out IQ quadrature frequency mixing on a transmitting wave and an echo of the millimeter wave radar through an IQ quadrature frequency mixer;
filtering high-frequency information generated by the mixer through a low-pass filter;
performing digital sampling on the intermediate frequency information through an analog-digital converter;
and filtering the phase difference information through an IIR digital filter to obtain the phase difference information in a corresponding frequency range of respiration and the phase difference information in a corresponding frequency range of heartbeat after filtering.
As a preferred scheme of the monitoring device capable of preventing asphyxia, in the phase unwrapping module, if the phase difference is greater than pi, the current phase is-2 pi; if the phase difference is less than-pi, the current phase is +2 pi; if the phase difference is between-pi and pi, the current phase is unchanged.
The monitoring device for preventing asphyxia preferably further comprises an abnormal processing module which is used for smoothing the breathing and heartbeat frequency and removing abnormal points of breathing and heartbeat mutation caused by interference.
The invention has the following advantages: IQ quadrature frequency mixing is carried out on the transmitted waves and the echoes of the millimeter wave radar, I, Q two paths of quadrature intermediate frequency information are output, ADC sampling is carried out on I, Q channels respectively, and discrete complex information is obtained; performing digital sampling on the intermediate frequency information, performing FFT (fast Fourier transform), converting a digital time domain signal into a frequency domain signal, analyzing, and outputting target distance, speed, direction and phase information; performing correlation analysis through the modulus of the corresponding frequency point and amplitude transformation caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object; calculating the phase of the optimal vital sign point, unfolding the phase of the current vital sign point according to the phase difference of two adjacent frames, and calculating the phase difference of two adjacent frames according to the unfolded phase; filtering the phase difference information to obtain phase difference information in a frequency range corresponding to respiration and phase difference information in a frequency range corresponding to heartbeat; performing FFT (fast Fourier transform) on the phase difference information in the frequency range corresponding to the respiration and the phase difference information in the frequency range corresponding to the heartbeat after filtering respectively, and transforming the time domain signals to the frequency domain for analysis; respectively selecting the optimal frequency components in the corresponding ranges, and selecting the frequency with the maximum module value as the current respiration frequency and the heartbeat frequency respectively according to the module value of the frequency; comprehensively judging the respiration and heartbeat, analyzing whether the frequency of the current respiration and heartbeat is in a preset normal range, and if not, analyzing the duration and the trend quantity of increasing or decreasing; and according to the data of comprehensive judgment, if the duration of the breath which is not in the normal range exceeds a preset time value and the heartbeat exceeds the normal range, judging that the asphyxia occurs, and reporting the judgment result to perform local and remote alarm. The baby asphyxia detection system can actively find baby asphyxia in time, and can actively alarm parents at local and remote APP ends, so that the risk of babies is reduced; the life perception is not influenced by light rays and is not influenced by infant clothes, blankets and the like; can relieve safety anxiety and fatigue of parents in infant care; the system can also be applied to indoor safety protection of the old, safety protection in a car and life safety protection in a hotel, has wide application range and effectively ensures the life safety of the monitored object.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.
The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so that those skilled in the art can understand and read the present invention, and do not limit the conditions for implementing the present invention, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the functions and purposes of the present invention, should still fall within the scope of the present invention.
Fig. 1 is a schematic flow chart of a monitoring method for preventing asphyxia according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a technical architecture of a monitoring method for preventing asphyxia according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a monitoring device for preventing asphyxia according to an embodiment of the present invention;
fig. 4 is a schematic view of an arrangement of a monitoring device capable of preventing asphyxia provided in an embodiment of the present invention.
Detailed Description
The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1 and 2, a monitoring method for preventing asphyxia is provided, which comprises the following steps:
s1, IQ quadrature mixing is carried out on the transmitted waves and the echoes of the millimeter wave radar, I, Q two paths of quadrature intermediate frequency information are output, ADC sampling is carried out on I, Q channels respectively, and discrete complex information is obtained;
s2, performing digital sampling and FFT (fast Fourier transform) conversion on the intermediate frequency information, converting a digital time domain signal into a frequency domain signal for analysis, and outputting target distance, speed, direction and phase information;
s3, performing correlation analysis through the module value of the corresponding frequency point and amplitude conversion caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object;
s4, calculating the phase of the optimal vital sign point, unfolding the phase of the current vital sign point according to the phase difference of two adjacent frames, and calculating the phase difference of two adjacent frames according to the unfolded phase;
s5, filtering the phase difference information to obtain phase difference information in a frequency range corresponding to respiration and phase difference information in a frequency range corresponding to heartbeat;
s6, performing FFT (fast Fourier transform) on the filtered phase difference information in the respiratory corresponding frequency range and the filtered phase difference information in the heartbeat corresponding frequency range respectively, and transforming the time domain signals to the frequency domain for analysis;
s7, respectively selecting the optimal frequency components in the corresponding ranges, and selecting the frequency with the maximum module value as the current respiration and heartbeat frequency respectively according to the module value of the frequency;
s8, comprehensively judging respiration and heartbeat, analyzing whether the frequency of the current respiration and heartbeat is in a preset normal range, and if not, analyzing the duration and the trend amount of increasing or decreasing;
and S9, according to the data of the comprehensive judgment, if the duration time of the breath which is not in the normal range exceeds the preset time value and the heartbeat exceeds the normal range, judging that the asphyxia occurs, and reporting the judgment result to carry out local and remote alarm.
In this embodiment, the millimeter wave radar is integrated with a waveform generator, a transmitting antenna and a receiving antenna, the waveform generator is configured to generate millimeter wave band radar waves, the transmitting antenna is configured to transmit the millimeter radar waves to the outside, and the receiving antenna is configured to receive echoes of the millimeter radar waves.
Specifically, the millimeter wave radar adopts a 60GHz millimeter wave radar, the 60GHz millimeter wave radar is an FMCW detection radar working on a 60-64GHz frequency band, the wavelength of the FMCW detection radar is millimeter-wave level, compared with optical sensing such as infrared and laser, the millimeter wave radar has the advantages of strong fog, smoke and dust penetrating capability, no influence of light, all-weather (except heavy rainy days) and all-day characteristics, and can distinguish and identify very small targets.
Specifically, the 60GHz millimeter wave radar can distinguish micro motion with fluctuation more than 0.01mm according to the phase change of the reflected echo. Meanwhile, due to the breathing and heartbeat of the infant, the periodic fluctuation of the thoracic cavity of 0.01 to 1mm can be caused, the normal breathing frequency of the infant is 0.6 to 0.75Hz (36 to 45 times/min), and the normal frequency of the heartbeat is 2 to 2.33Hz (120 times/min). The millimeter wave radar transmits 20 frames of radio waves through 1S, and the breathing and heartbeat frequency of the baby can be analyzed through filtering and FFT processing according to the phase change of each frame of echo.
When the baby suffocates, the respiratory frequency analyzed by the millimeter wave radar is rapidly reduced, the heartbeat frequency is rapidly changed, and the main processor can judge whether the baby suffocates or not by judging the frequency change of the respiration and the heartbeat according to the rule. If the baby suffocates, accessible pilot lamp and loudspeaker carry out local warning, pass through WIFI network with the result of early warning to the backstage simultaneously, and the backstage is given corresponding APP on parents 'cell-phone with this early warning result propelling movement, reminds parents in real time through multiple means, and the prevention baby suffocates, protects baby's life safety.
In the embodiment, IQ orthogonal frequency mixing is carried out on the transmitting wave and the echo of the millimeter wave radar through an IQ orthogonal frequency mixer;
filtering high-frequency information generated by the mixer through a low-pass filter;
and digitally sampling the intermediate frequency information through an analog-digital converter.
Specifically, the frequency of the output signal obtained by the mixer is equal to the sum or difference of the two input signal frequencies or a circuit of other combinations of the two input signal frequencies. The mixer is usually made up of a non-linear element and a frequency selective loop. When two high-frequency voltages with different frequencies act on the nonlinear device, the current contains direct-current components, fundamental waves, harmonic waves, sum frequency components, difference frequency components and the like through nonlinear conversion. The difference frequency component is the intermediate frequency component needed by mixing, other unnecessary frequency components are filtered by an intermediate frequency band-pass filter, and the difference frequency component is taken out to complete mixing.
Specifically, the low-pass filter utilizes the principle of capacitance-pass high-frequency impedance low-frequency and inductance-pass low-frequency impedance high-frequency. For the high frequency needing to be cut off, the high frequency is not passed through by a method of absorbing inductance and obstruction by using a capacitor; for the low frequency needing to be released, the characteristics of high resistance of a capacitor and low resistance of an inductor are utilized to pass through the low frequency.
Specifically, an analog-to-digital converter, also called an a/D converter or ADC for short, is an electronic component that converts an analog signal into a digital signal. A typical analog-to-digital converter converts an input voltage signal into an output digital signal. Since digital signals do not have practical significance per se, only one relative magnitude is represented. Therefore, any analog-to-digital converter needs a reference analog quantity as a conversion standard, the most common reference standard is the maximum convertible signal size, and the output digital quantity represents the size of the input signal relative to the reference signal.
In this embodiment, the FFT, i.e., the fast fourier transform, is a general term for an efficient and fast calculation method using a computer to calculate a Discrete Fourier Transform (DFT), which is one of the most basic methods in time domain to frequency domain transform analysis.
The fast Fourier transform is proposed by J.W. Kury and T.W. graph base in 1965, the multiplication times required by a computer for calculating the discrete Fourier transform can be greatly reduced by adopting the algorithm, and particularly, the more the number N of the transformed sampling points is, the more the calculation amount of the FFT algorithm is saved.
In this embodiment, the phase difference information is filtered by an IIR digital filter, and phase difference information in a respiratory corresponding frequency range and phase difference information in a heartbeat corresponding frequency range are obtained after filtering.
Specifically, the IIR digital filter adopts a recursive structure, that is, the structure is provided with a feedback loop, and the operation structure is composed of basic operations such as time delay, multiplication of coefficients, addition and the like, and can be combined into four structural forms of direct type, normal type, cascade type and parallel type, and the IIR digital filter is provided with a feedback loop.
In this embodiment, in the phase unwrapping process, if the phase difference is greater than pi, the current phase is-2 pi; if the phase difference is less than-pi, the current phase is +2 pi; if the phase difference is between-pi and pi, the current phase is unchanged.
In this embodiment, before the comprehensive evaluation of respiration and heartbeat, the method further includes:
and smoothing the frequency of the respiration and the heartbeat, and removing abnormal points of sudden respiration and heartbeat caused by interference.
Specifically, because the respiration and heartbeat of a person are continuously changed, abnormal points of sudden changes of the respiration and heartbeat caused by interference are removed according to the characteristic. And then analyzing whether the current respiration and heartbeat frequency belongs to a normal range, and if not, analyzing the duration and the trend amount which is increased or decreased.
In this embodiment, according to the data of the comprehensive evaluation, if the respiration is not in the normal range, the duration exceeds 10S, and the result is lower than the normal value by 15 or less, and the heartbeat exceeds the normal range, which belongs to asphyxia, the result is reported, and local and remote alarm is performed.
In summary, the invention performs IQ quadrature mixing on the transmitted wave and the echo of the millimeter wave radar, outputs I, Q two paths of orthogonal intermediate frequency information, and performs ADC sampling on I, Q channels respectively to obtain discrete complex information; performing digital sampling on the intermediate frequency information, performing FFT (fast Fourier transform), converting a digital time domain signal into a frequency domain signal, analyzing, and outputting target distance, speed, direction and phase information; performing correlation analysis through the modulus of the corresponding frequency point and amplitude transformation caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object; calculating the phase of the optimal vital sign point, unfolding the phase of the current vital sign point according to the phase difference of two adjacent frames, and calculating the phase difference of two adjacent frames according to the unfolded phase; filtering the phase difference information to obtain phase difference information in a frequency range corresponding to respiration and phase difference information in a frequency range corresponding to heartbeat; performing FFT (fast Fourier transform) on the phase difference information in the frequency range corresponding to the respiration and the phase difference information in the frequency range corresponding to the heartbeat after filtering respectively, and transforming the time domain signals to the frequency domain for analysis; respectively selecting the optimal frequency components in the corresponding ranges, and selecting the frequency with the maximum module value as the current respiration frequency and the heartbeat frequency respectively according to the module value of the frequency; comprehensively judging the respiration and heartbeat, analyzing whether the frequency of the current respiration and heartbeat is in a preset normal range, and if not, analyzing the duration and the trend quantity of increasing or decreasing; and according to the data of comprehensive judgment, if the duration of the breath which is not in the normal range exceeds a preset time value and the heartbeat exceeds the normal range, judging that the asphyxia occurs, and reporting the judgment result to perform local and remote alarm. The baby asphyxia detection system can actively find baby asphyxia in time, and can actively alarm parents at local and remote APP ends, so that the risk of babies is reduced; the life perception is not influenced by light rays and is not influenced by infant clothes, blankets and the like; can relieve safety anxiety and fatigue of parents in infant care; the system can also be applied to indoor safety protection of the old, safety protection in a car and life safety protection in a hotel, has wide application range and effectively ensures the life safety of the monitored object.
Referring to fig. 3, the invention further provides an anti-asphyxia monitoring device, which adopts the anti-asphyxia monitoring method, and comprises the following steps:
the millimeter wave detection module 1 is used for carrying out IQ quadrature frequency mixing on the transmitted wave and the echo of the millimeter wave radar, outputting I, Q two paths of quadrature intermediate frequency information, and respectively carrying out ADC sampling on I, Q channels to obtain discrete complex information;
the first FFT conversion module 2 is used for carrying out digital sampling on the intermediate frequency information, carrying out FFT conversion on the intermediate frequency information, converting a digital time domain signal into a frequency domain signal, analyzing the frequency domain signal, and outputting target distance, speed, direction and phase information;
the vital sign point acquisition module 3 is used for carrying out correlation analysis through the module value of the corresponding frequency point and amplitude conversion caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object;
the phase calculation module 4 is used for calculating the phase of the optimal vital sign point;
the phase unfolding module 5 is used for unfolding the phase of the current vital sign point according to the phase difference between two adjacent frames;
the phase difference acquisition module 6 is used for calculating the phase difference between two adjacent frames according to the unfolded phase;
the filtering module 7 is configured to filter the phase difference information, and obtain phase difference information in a frequency range corresponding to respiration and phase difference information in a frequency range corresponding to heartbeat after filtering;
the second FFT conversion module 8 is configured to perform FFT conversion on the filtered phase difference information in the respiratory corresponding frequency range and the filtered phase difference information in the heartbeat corresponding frequency range, and convert the time domain signal to the frequency domain for analysis;
the breath and heartbeat processing module 9 is configured to select optimal frequency components in corresponding ranges, and select a frequency with a maximum module value as a current breath frequency and a heartbeat frequency according to the module value of the frequency;
the respiration and heartbeat comprehensive evaluation module 10 is used for comprehensively evaluating respiration and heartbeat, whether the current respiration and heartbeat frequency is in a preset normal range or not is judged, and if the current respiration and heartbeat frequency is not in the normal range, the continuous time and the trend quantity of increasing or decreasing are analyzed;
the asphyxia judging module 11 is used for judging that an asphyxia condition occurs if the duration time of the respiration out of the normal range exceeds a preset time value and the heartbeat exceeds the normal range according to the comprehensively judged data;
and the early warning module 12 is used for reporting the judgment result to carry out local and remote warning.
In this implementation, the millimeter wave radar is integrated with a waveform generator, a transmitting antenna and a receiving antenna, the waveform generator is used for generating millimeter wave band radar waves, the transmitting antenna is used for transmitting the millimeter radar waves to the outside, and the receiving antenna is used for receiving echoes of the millimeter radar waves;
carrying out IQ quadrature frequency mixing on a transmitting wave and an echo of the millimeter wave radar through an IQ quadrature frequency mixer;
filtering high-frequency information generated by the mixer through a low-pass filter;
performing digital sampling on the intermediate frequency information through an analog-digital converter;
and filtering the phase difference information through an IIR digital filter to obtain the phase difference information in a corresponding frequency range of respiration and the phase difference information in a corresponding frequency range of heartbeat after filtering.
In this implementation, in the phase unwrapping module, if the phase difference is greater than pi, the current phase is-2 pi; if the phase difference is less than-pi, the current phase is +2 pi; if the phase difference is between-pi and pi, the current phase is unchanged.
In this implementation, the device further includes an exception handling module 13, configured to smooth the breathing and heartbeat frequency, and remove abnormal points of sudden breathing and heartbeat caused by interference.
Referring to fig. 4, the hardware of the anti-asphyxia monitoring device of the invention can be installed at the head of a baby crib or installed at the top of the baby crib through a bracket, and the linear distance from the anti-asphyxia monitoring device to a baby is kept in the range of 0.5-1 m. When the baby suffocates, the respiratory frequency analyzed by the millimeter wave radar is rapidly reduced, the heartbeat frequency is rapidly changed, and the main processor can judge whether the baby suffocates or not by judging the frequency change of the respiration and the heartbeat according to the rule. If the baby suffocates, accessible pilot lamp and loudspeaker carry out local warning, pass through WIFI network with the result of early warning to the backstage simultaneously, and the backstage is given corresponding APP on parents 'cell-phone with this early warning result propelling movement, reminds parents in real time through multiple means, and the prevention baby suffocates, protects baby's life safety.
It should be noted that, because the contents of information interaction, execution process, and the like between the modules/units of the apparatus are based on the same concept as the method embodiment of the present application, the technical effect brought by the contents is the same as the method embodiment of the present application, and specific contents may refer to the description in the foregoing method embodiment of the present application, and are not described herein again.
It will be apparent to those skilled in the art that the modules or steps of the present invention described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present invention is not limited to any specific combination of hardware and software.
Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.
Claims (10)
1. A monitoring method capable of preventing asphyxia is characterized by comprising the following steps:
IQ quadrature frequency mixing is carried out on the transmitted waves and the echoes of the millimeter wave radar, I, Q two paths of quadrature intermediate frequency information are output, ADC sampling is carried out on I, Q channels respectively, and discrete complex information is obtained;
performing digital sampling on the intermediate frequency information, performing FFT (fast Fourier transform), converting a digital time domain signal into a frequency domain signal, analyzing, and outputting target distance, speed, direction and phase information;
performing correlation analysis through the modulus of the corresponding frequency point and amplitude transformation caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object;
calculating the phase of the optimal vital sign point, unfolding the phase of the current vital sign point according to the phase difference of two adjacent frames, and calculating the phase difference of two adjacent frames according to the unfolded phase;
filtering the phase difference information to obtain phase difference information in a respiratory corresponding frequency range and phase difference information in a heartbeat corresponding frequency range;
performing FFT (fast Fourier transform) on the filtered phase difference information in the frequency range corresponding to the respiration and the filtered phase difference information in the frequency range corresponding to the heartbeat respectively, and transforming the time domain signals to a frequency domain for analysis;
respectively selecting the optimal frequency components in the corresponding ranges, and selecting the frequency with the maximum module value as the current respiration frequency and the heartbeat frequency respectively according to the module value of the frequency;
comprehensively judging the respiration and heartbeat, analyzing whether the frequency of the current respiration and heartbeat is in a preset normal range, and if not, analyzing the duration and the trend quantity of increasing or decreasing;
and according to the data of comprehensive judgment, if the duration of the breath which is not in the normal range exceeds a preset time value and the heartbeat exceeds the normal range, judging that the asphyxia occurs, and reporting the judgment result to perform local and remote alarm.
2. A monitoring method for preventing asphyxia as claimed in claim 1, wherein the millimeter wave radar is integrated with a waveform generator, a transmitting antenna and a receiving antenna, the waveform generator is used for generating millimeter wave band radar waves, the transmitting antenna is used for transmitting the millimeter radar waves to the outside, and the receiving antenna is used for receiving echoes of the millimeter radar waves.
3. A monitoring method capable of preventing asphyxia as claimed in claim 1, wherein the transmitting wave and the echo of the millimeter wave radar are IQ-quadrature mixed by an IQ-quadrature mixer;
filtering high-frequency information generated by the mixer through a low-pass filter;
and digitally sampling the intermediate frequency information through an analog-digital converter.
4. The monitoring method according to claim 1, wherein the phase difference information is filtered by an IIR digital filter, and phase difference information in a respiratory corresponding frequency range and phase difference information in a heartbeat corresponding frequency range are obtained after filtering.
5. A monitoring method for preventing asphyxia as claimed in claim 1, wherein in the phase unwrapping process, if the phase difference is greater than pi, the current phase is-2 pi; if the phase difference is less than-pi, the current phase is +2 pi; if the phase difference is between-pi and pi, the current phase is unchanged.
6. An anti-asphyxia monitoring method according to claim 1, wherein the comprehensive evaluation of respiratory and heartbeat further comprises:
and smoothing the frequency of the respiration and the heartbeat, and removing abnormal points of sudden respiration and heartbeat caused by interference.
7. An anti-asphyxia monitoring apparatus using the anti-asphyxia monitoring method according to any one of claims 1 to 6, comprising:
the millimeter wave detection module is used for carrying out IQ (in-phase quadrature) frequency mixing on the transmitted wave and the echo of the millimeter wave radar, outputting I, Q two paths of orthogonal intermediate frequency information, and respectively carrying out ADC (analog-to-digital converter) sampling on I, Q channels to obtain discrete complex information;
the first FFT conversion module is used for carrying out digital sampling on the intermediate frequency information, carrying out FFT conversion on the intermediate frequency information, converting a digital time domain signal into a frequency domain signal, analyzing the frequency domain signal, and outputting target distance, speed, direction and phase information;
the vital sign point acquisition module is used for carrying out correlation analysis through the module value of the corresponding frequency point and amplitude conversion caused by respiratory vibration, and selecting the optimal vital sign point of the monitored object;
the phase calculation module is used for calculating the phase of the optimal vital sign point;
the phase unfolding module is used for unfolding the phase of the current vital sign point according to the phase difference of two adjacent frames;
the phase difference acquisition module is used for calculating the phase difference between two adjacent frames according to the unfolded phase;
the filtering module is used for filtering the phase difference information to obtain phase difference information in a frequency range corresponding to respiration and phase difference information in a frequency range corresponding to heartbeat;
the second FFT conversion module is used for respectively carrying out FFT conversion on the phase difference information in the respiratory corresponding frequency range and the phase difference information in the heartbeat corresponding frequency range after filtering, and converting the time domain signal into a frequency domain for analysis;
the breath and heartbeat processing module is used for respectively selecting the optimal frequency components in the corresponding ranges, and selecting the frequency of the maximum module value as the frequency of the current breath and heartbeat according to the module value of the frequency;
the breath and heartbeat comprehensive evaluation module is used for comprehensively evaluating breath and heartbeat, judging whether the current breath and heartbeat frequency is in a preset normal range, and analyzing the duration time and the trend quantity of increasing or decreasing if the current breath and heartbeat frequency is not in the normal range;
the apnea judging module is used for judging that apnea occurs if the duration time of respiration out of the normal range exceeds a preset time value and the heartbeat exceeds the normal range according to the comprehensively judged data;
and the early warning module is used for reporting the judgment result to carry out local and remote warning.
8. A monitoring device capable of preventing asphyxia as claimed in claim 7, wherein the millimeter wave radar is integrated with a waveform generator, a transmitting antenna and a receiving antenna, the waveform generator is used for generating millimeter wave band radar waves, the transmitting antenna is used for transmitting the millimeter radar waves to the outside, and the receiving antenna is used for receiving echoes of the millimeter radar waves;
carrying out IQ quadrature frequency mixing on a transmitting wave and an echo of the millimeter wave radar through an IQ quadrature frequency mixer;
filtering high-frequency information generated by the mixer through a low-pass filter;
performing digital sampling on the intermediate frequency information through an analog-digital converter;
and filtering the phase difference information through an IIR digital filter to obtain the phase difference information in a corresponding frequency range of respiration and the phase difference information in a corresponding frequency range of heartbeat after filtering.
9. A monitoring device capable of preventing asphyxia as claimed in claim 7, wherein in the phase unwrapping module, if the phase difference is greater than pi, the current phase is-2 pi; if the phase difference is less than-pi, the current phase is +2 pi; if the phase difference is between-pi and pi, the current phase is unchanged.
10. An anti-asphyxia monitoring device according to claim 7, further comprising an anomaly processing module for smoothing the breathing and heartbeat frequency and removing anomaly points of sudden breathing and heartbeat due to interference.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114176567A (en) * | 2021-12-29 | 2022-03-15 | 深圳融昕医疗科技有限公司 | Apnea detecting method and computer-readable storage medium |
| CN114491284A (en) * | 2022-04-15 | 2022-05-13 | 科学技术文献出版社有限公司 | Information pushing system based on multi-channel data analysis |
| WO2023173386A1 (en) * | 2022-03-17 | 2023-09-21 | 深圳迈瑞生物医疗电子股份有限公司 | Newborn/non-contact physiological sign monitoring method and system |
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2021
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114176567A (en) * | 2021-12-29 | 2022-03-15 | 深圳融昕医疗科技有限公司 | Apnea detecting method and computer-readable storage medium |
| CN114176567B (en) * | 2021-12-29 | 2023-01-17 | 深圳融昕医疗科技有限公司 | Computer-readable storage medium and terminal |
| WO2023173386A1 (en) * | 2022-03-17 | 2023-09-21 | 深圳迈瑞生物医疗电子股份有限公司 | Newborn/non-contact physiological sign monitoring method and system |
| CN114491284A (en) * | 2022-04-15 | 2022-05-13 | 科学技术文献出版社有限公司 | Information pushing system based on multi-channel data analysis |
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