阅读说明：本技术 一种实时动态心率监测装置及监测方法 (Real-time dynamic heart rate monitoring device and monitoring method ) 是由 许微伟 邓瀚林 张磊 陈欢婷 孙榕雪 于 2016-05-04 设计创作，主要内容包括：本发明公开了一种实时动态心率监测装置及监测方法,装置包括基线漂移消除模块,带通滤波模块,频域分析模块,心率频点选择模块；所述基线漂移消除模块用于消除导致脉搏波信号的基准线出现漂移的干扰信号；所述带通滤波模块用于获取属于心率频段的频率信号分量同时消除心率频段外的噪声信号；所述频域分析模块用于获取脉搏波信号在预先设置的特定频段区间内的信号频谱；所述心率频点选择模块用于获取心率对应的频点并输出频点。本发明排除人体运动、肌肉活动对心率分析的影响,减少了硬件成本,可以灵活地选择关注频段区间,仅在关注频段区间内提高信号的频域精度,避免带来过大的计算和存储开销。(The invention discloses a real-time dynamic heart rate monitoring device and a monitoring method, wherein the device comprises a baseline drift elimination module, a band-pass filtering module, a frequency domain analysis module and a heart rate frequency point selection module; the baseline wander elimination module is used for eliminating interference signals causing wander of a baseline line of the pulse wave signals; the band-pass filtering module is used for acquiring frequency signal components belonging to a heart rate frequency band and eliminating noise signals outside the heart rate frequency band; the frequency domain analysis module is used for acquiring a signal frequency spectrum of the pulse wave signal in a preset specific frequency band interval; the heart rate frequency point selection module is used for acquiring a frequency point corresponding to the heart rate and outputting the frequency point. The invention eliminates the influence of human body movement and muscle activity on heart rate analysis, reduces hardware cost, can flexibly select the concerned frequency band interval, improves the frequency domain precision of signals only in the concerned frequency band interval, and avoids causing excessive calculation and storage expenses.)

1. A pulse wave signal processing method for real-time dynamic heart rate monitoring, comprising:

acquiring a pulse wave signal;

selecting a specific frequency band interval comprising an initial frequency point, an ending frequency point and a frequency point subdivision number according to the pulse wave signal;

calculating the real part and the imaginary part of the frequency domain signal corresponding to each frequency point in the specific frequency band interval; the specific calculation process is as follows: representing a pulse wave signal sequence with a data length of N by q (N), wherein N =0, 1, … …, N-1, calculating a real part of the frequency domain signal by a first transform polynomial and calculating an imaginary part of the frequency domain signal by a second transform polynomial;

the calculating the real part of the frequency domain signal using the first transform polynomial includes:

Qr=q(0)+q(1)*cos(f)+q(2)*T(2)+…+q(N-1)*T(N-1)

the process of calculating the imaginary part of the frequency domain signal by the second transform polynomial includes:

Qi=-q(1)*sin(f)–q(2)*sin(f)*U(2)-…-q(N-1)*sin(f)*U(N-1)

wherein T (n) is a first transform polynomial, U (n) is a second transform polynomial, and f is a frequency bin;

calculating according to the real part and the imaginary part of the frequency domain signal corresponding to the frequency point to obtain the power of the pulse wave signal at the frequency point;

superposing the power to generate a signal frequency spectrum of the pulse wave signal in the specific frequency band interval;

acquiring a heart rate frequency point in an initial state according to the signal spectrum;

and setting a tracking period, and dynamically tracking the heart rate frequency points.

2. The method of claim 1, further comprising: and after the pulse wave signal is obtained, eliminating a baseline drift interference signal of the pulse wave signal.

3. The method of claim 2, wherein eliminating the baseline wander disturbance signal of the pulse wave signal comprises: obtaining a baseline drift trend term signal with the same length as the original pulse wave signal by a signal filtering method or a curve fitting method;

storing the original pulse wave signals and the baseline shift trend item signals by using row vectors or column vectors, and then subtracting the baseline shift trend item signals from the original pulse wave signals according to a matrix addition rule to obtain the pulse wave signals with the baseline shift eliminated.

4. The method of claim 2, further comprising: and after eliminating the baseline drift interference signal of the pulse wave signal, carrying out filtering processing and reserving the signal component belonging to the heart rate frequency band.

5. The method of claim 4, wherein the filtering process comprises: and acquiring preset pass band lower limit and upper limit frequencies, stop band lower limit and upper limit frequencies, pass band internal attenuation coefficients and stop band internal attenuation coefficients, calculating to obtain filter orders and coefficients, and then inputting the pulse wave signals with the baseline wandering interference signals eliminated for filtering.

6. The method according to any one of claims 1 to 5, wherein the obtaining of the heart rate frequency point in the initial state comprises: and when the human body is in a quiet state, setting the frequency point where the spectrum peak of the signal spectrum is as the heart rate frequency point in the initial state.

7. The method of claim 6, wherein dynamically tracking the heart rate frequency points comprises: and selecting a specific frequency band interval by taking the heart rate frequency point output in the last period of the tracking period as a center, calculating a signal frequency spectrum of the pulse wave signal in the specific frequency band interval, and taking the frequency point position of a spectrum peak as the heart rate frequency point of the current tracking period.

Technical Field

The invention relates to the field of electronics, in particular to a real-time dynamic heart rate monitoring device and a monitoring method.

Background

Along with the application and the development of mobile internet technology in the medical health field, a large amount of forms such as intelligent wrist-watch, intelligent bracelet, intelligent wrist strap have appeared in the market and have been varied, possess the wearable removal healthy product of medical physiological parameters such as measurement rhythm of the heart, blood pressure, blood oxygen concentration, respiratory frequency. The heart rate is defined as the number of heart beats per minute of a human body, and is an important medical routine physiological parameter for evaluating the health state of the human body. The heart rate monitoring has very important significance for disease risk early warning, disease diagnosis and annual routine physical examination. In particular, exercise modes such as fitness activities and outdoor running have wide application requirements on real-time dynamic heart rate monitoring.

At present, the heart rate monitoring technology adopted by most mobile health products is based on a photoelectric transmission measurement method. In the hardware design of the product, a sensor in contact with the skin of a person emits a beam of light that impinges on the skin while measuring the light reflected or transmitted through the skin. Because blood has absorption effect on light with specific wavelength, the heart blood pumping process directly influences the change of the light signal intensity measured by the sensor, and the hardware records the signal intensity change according to the set sampling rate to acquire the original data, namely the pulse wave signal. And the data analysis software unit runs a heart rate monitoring algorithm to process the pulse wave signals and output a heart rate value. The heart rate monitoring algorithm is a key core technology of heart rate measurement products, and determines the accuracy and reliability of heart rate measurement values. In practical applications, heart rate monitoring includes static heart rate monitoring and real-time dynamic heart rate monitoring, and the latter has a wider application space and also provides a great challenge to the prior art.

Actual tests show that the current technical situation of the dynamic heart rate monitoring algorithm of most of the current mobile health products is that the following defects are exposed in the application scene of real-time monitoring of the heart rate of a human body in a motion state by combining traditional signal time domain waveform analysis or signal frequency domain analysis with accelerometer reading for auxiliary judgment. Firstly, due to noise interference, characteristic points on a signal time domain waveform are not obvious, so that an algorithm cannot acquire complete input information; secondly, the rule of signal time domain waveform matching is set too much, and the specific numerical value setting of the algorithm parameter is difficult; thirdly, for the embedded module, the calculation complexity of the waveform matching algorithm is large; fourthly, the traditional signal frequency domain analysis method can increase calculation and data storage expenses when improving the frequency spectrum precision; fifth, accelerometers increase hardware costs, while also increasing resource overhead in terms of computation, storage, and energy consumption.

Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a real-time dynamic heart rate monitoring device and a monitoring method, and aims to overcome the defects that when the dynamic heart rate monitoring device monitors the heart rate, the algorithm is high in calculation complexity, the hardware cost is high, and the resource overhead in the aspects of calculation, storage and energy is large.

The technical scheme of the invention is as follows:

a real-time dynamic heart rate monitoring device comprises a baseline drift elimination module, a band-pass filtering module, a frequency domain analysis module and a heart rate frequency point selection module;

the baseline wander elimination module is used for eliminating interference signals causing wander of a baseline line of the pulse wave signals;

the band-pass filtering module is used for acquiring frequency signal components belonging to a heart rate frequency band and eliminating noise signals outside the heart rate frequency band;

the frequency domain analysis module is used for acquiring a signal frequency spectrum of the pulse wave signal in a preset specific frequency band interval;

the heart rate frequency point selection module is used for acquiring a frequency point corresponding to a heart rate and outputting the frequency point;

the baseline drift elimination module is connected with the band-pass filtering module, the band-pass filtering module is connected with the frequency domain analysis module, and the frequency domain analysis module is also connected with the heart rate frequency point selection module;

the real-time dynamic heart rate monitoring device comprises a baseline drift elimination module, a baseline drift trend term signal extraction unit and a signal linear superposition unit, wherein the baseline drift elimination module comprises a baseline drift trend term signal extraction unit and a signal linear superposition unit;

the baseline drift trend item signal extraction unit is used for acquiring a baseline drift trend item signal which is as long as the original pulse wave signal;

the signal linear superposition unit is used for subtracting the baseline drift trend term signal from the original pulse wave signal to obtain a pulse wave signal without the baseline drift;

the baseline drift trend term signal extraction unit is connected with the signal linear superposition unit.

The real-time dynamic heart rate monitoring device is characterized in that the band-pass filtering module specifically comprises a filtering parameter setting unit and a filtering unit,

the filter parameter setting unit is used for setting the lower limit and the upper limit frequency of a pass band, the lower limit and the upper limit frequency of a stop band, the attenuation coefficient in the pass band and the attenuation coefficient in the stop band;

the filtering unit is used for filtering the pulse wave signals of which the base lines are eliminated by the base line drift elimination module after acquiring the order and the coefficient of the filtering module, and acquiring the pulse wave signals of which the noise is eliminated;

and the filtering parameter setting unit is connected with the filtering unit.

The real-time dynamic heart rate monitoring device comprises a frequency domain analysis module, a frequency point power calculation module and a signal spectrum acquisition module, wherein the frequency domain analysis module specifically comprises a specific frequency band interval setting unit, a frequency point power calculation unit and a signal spectrum acquisition unit;

the specific frequency band interval setting unit is used for setting a starting frequency point, an ending frequency point and a frequency point subdivision number of a specific frequency band interval;

the frequency point power calculation unit is used for calculating the real part of the frequency domain signal by using a first transformation polynomial, calculating the imaginary part of the frequency domain signal by using a second transformation polynomial and calculating the power of the pulse wave signal at the frequency point according to the real part and the imaginary part of the frequency domain signal;

the signal spectrum acquisition unit is used for acquiring the power of the pulse wave signals in the specific frequency band interval at each frequency point, and generating the signal spectrum of the pulse wave signals in the whole concerned frequency band interval after superposition;

the frequency point power calculation unit is respectively connected with the specific frequency band interval setting unit and the signal spectrum acquisition unit.

The real-time dynamic heart rate monitoring device is characterized in that the heart rate frequency point selection module specifically comprises a heart rate frequency point selection unit and a heart rate frequency point dynamic tracking unit,

the heart rate frequency point selection unit is used for acquiring the frequency point position where a spectrum peak in a pulse wave signal spectrum is located as a heart rate frequency point in an initial state;

the heart rate frequency point dynamic tracking unit is used for carrying out high-precision frequency domain analysis in a frequency spectrum range with a specific width at the left and right of the center by taking the heart rate frequency point output in the previous tracking period as the center in a preset fixed tracking period, and selecting the frequency point position where a spectrum peak is positioned as the heart rate frequency point to output;

the heart rate frequency point selection unit is connected with the heart rate frequency point dynamic tracking unit.

The real-time dynamic heart rate monitoring device, wherein the first and second transform polynomials are orthogonal polynomials.

The real-time dynamic heart rate monitoring device, wherein the first transformation polynomial is one of legendre polynomial, jacobian polynomial, laguerre polynomial, chebyshev polynomial and hermitian polynomial;

the second transformation polynomial is one of Legendre polynomial, Jacobian polynomial, Laguerre polynomial, Chebyshev polynomial and Hermite polynomial.

A monitoring method based on the real-time dynamic heart rate monitoring device comprises the following steps:

A. acquiring a pulse wave signal, and eliminating a baseline drift interference signal through a baseline drift elimination module;

B. the band-pass filtering module filters the signal output by the baseline drift elimination module and reserves the signal component belonging to the heart rate frequency band;

C. the frequency domain analysis module acquires a signal frequency spectrum of the pulse wave signal in a preset specific frequency band interval;

D. and the heart rate frequency point selection module acquires and outputs a frequency point corresponding to the heart rate according to the signal frequency.

The real-time dynamic heart rate monitoring method comprises the following specific steps:

a1, obtaining a baseline drift trend term signal with the same length as the original pulse wave signal by a signal filtering method or a curve fitting method;

a2, storing the original pulse wave signals and the baseline wandering trend item signals by using row vectors or column vectors, and then subtracting the baseline wandering trend item signals from the original pulse wave signals according to a matrix addition rule to obtain the pulse wave signals with the baseline wandering removed.

The real-time dynamic heart rate monitoring method comprises the following specific steps:

b1, acquiring preset pass band lower limit and upper limit frequencies, preset stop band lower limit and upper limit frequencies, preset pass band internal attenuation coefficients and preset stop band internal attenuation coefficients;

and B2, after the order and the coefficient of the filtering module are obtained, filtering the pulse wave signals of which the baseline drift is eliminated by the baseline drift elimination module to obtain the pulse wave signals of which the noise is eliminated.

The invention provides a real-time dynamic heart rate monitoring device and a monitoring method, which can eliminate the influence of human body movement and muscle activity on heart rate analysis, reduce hardware cost, flexibly select an attention frequency band interval, improve the frequency domain precision of signals only in the attention frequency band interval, avoid bringing excessive calculation and storage expenses, select a technical route of signal spectrum analysis, and avoid the problems that time domain signal waveform characteristic points are difficult to find and specific values of algorithm parameters are difficult to determine.

Drawings

Fig. 1 is a functional block diagram of a preferred embodiment of a real-time dynamic heart rate monitoring apparatus according to the present invention.

Fig. 2 is a flowchart of a monitoring method of a real-time dynamic heart rate monitoring apparatus according to a preferred embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention also provides a functional schematic diagram of a preferred embodiment of a real-time dynamic heart rate monitoring device, as shown in fig. 1, wherein the device comprises a baseline drift elimination module 100, a band-pass filtering module 200, a frequency domain analysis module 300, and a heart rate frequency point selection module 400;

the baseline wander elimination module 100 is configured to eliminate an interference signal causing a wander of a baseline of the pulse wave signal; the band-pass filtering module 200 is configured to obtain a frequency signal component belonging to a heart rate frequency band and eliminate a noise signal outside the heart rate frequency band; the frequency domain analysis module 300 is configured to obtain a signal spectrum of the pulse wave signal in a preset specific frequency band interval; the heart rate frequency point selection module 400 is configured to obtain a frequency point corresponding to a heart rate and output the frequency point; the baseline drift elimination module 100 is connected with the band-pass filter module 200, the band-pass filter module 200 is connected with the frequency domain analysis module 300, and the frequency domain analysis module 300 is further connected with the heart rate frequency point selection module 400.