Baseline drift correction method for electrocardiosignal

An ECG signal and baseline drift technology, applied in the field of signal processing, can solve the problems of small amount of calculation, loss of physical meaning of decomposition results, difficulty in selecting baseline drift components, etc., and achieve the goal of reducing residual noise and eliminating modal aliasing Effect

Inactive Publication Date: 2015-11-11
GUANGDONG UNIV OF TECH
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Problems solved by technology

Although the method of applying median filtering to remove baseline drift has the advantages of small amount of calculation and fast speed, it will produce "step-like" distortion and low precision
When applying wavelet transform to remove baseline drift, it is necessary to use high-scale approximation components to approximate the baseline drift signal. At this time, it is necessary to select the appropriate wavelet function and the number of decomposition layers, and the wavelet function and the number of decomposition layers have a great influe

Method used

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  • Baseline drift correction method for electrocardiosignal
  • Baseline drift correction method for electrocardiosignal
  • Baseline drift correction method for electrocardiosignal

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Embodiment 1

[0072] This embodiment describes the relevant theories and specific implementation processes involved in the present invention.

[0073] When the present invention performs empirical mode decomposition and ensemble averaging on the original ECG signal ECG, a series of intrinsic mode functions can be obtained. Among them, small-scale high-frequency signals are separated first, and large-scale low-frequency signals are then decomposed, namely The frequency of the natural mode function roughly decreases from high to low in the order of filtering. The ECG baseline drift signal is a slowly changing low-frequency signal, so it will be decomposed into the last few intrinsic modal functions. Through the zero crossing rate of the natural mode function, the frequency of the natural mode function can be roughly estimated. In this embodiment, the intrinsic modal function with a zero-crossing rate of less than 1.5 is regarded as a baseline drift component, which can be directly removed from ...

no. 2 example

[0096] In this embodiment, the ECG data of No. 18177 in the MIT-BIHNormalSinusRhythmDatabase database is selected, as attached Figure 5 Shown. It can be seen from the time domain waveform diagram that the signal obviously contains baseline drift. The specific implementation process of baseline drift correction on this signal is as follows:

[0097] Applying step 1 to step 7 of the first embodiment of the present invention, the signal is subjected to empirical mode decomposition and collective averaging, and the baseline drift is removed. Among them, the added noise amplitude a k Both are 0.4 times the standard deviation of the signal to be decomposed, and the logarithm of the positive and negative noise is 500. After decomposition, 10 modal components (IMF, that is, intrinsic modal function) and a residual component (RES) are obtained. The results are as attached Image 6 Shown. Calculation attached Image 6 The zero-crossing rate (ZCR) of all the components in, the results are...

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Abstract

The invention discloses a baseline drift correction method for electrocardiosignal. The method includes the steps of conducting improved self-adaption noise set empirical mode decomposition on the original electrocardiosignal to obtain intrinsic mode functions and residual components, counting the zero-crossing rates of all the intrinsic mode functions and all the residual components, and removing the intrinsic mode functions with the zero-crossing rates smaller than the set threshold value and the residual components with the zero-crossing rates smaller than the set threshold value from the original electrocardiosignal to obtain the electrocardiosignal where baseline drift is removed. According to the method, by conducting improved self-adaption noise set empirical mode decomposition on the original electrocardiosignal, the mode aliasing phenomenon is eliminated, and residual noise is reduced; the step of conducting self-adaption baseline drift amount selection according to the zero-crossing rates is added, and therefore the problem of the lack of effective baseline drift component selection means in the prior art is solved. The method can be widely applied to the field of baseline drift correction of the electrocardiosignal.

Description

Technical field [0001] The invention relates to the field of signal processing, in particular to a method for correcting baseline drift of an ECG signal. Background technique [0002] The electrocardiogram is a data record of heart activity, which plays a very important role in the diagnosis of heart health in clinical medicine. However, in the process of human body ECG signal acquisition, due to the influence of medical equipment and the human body's own factors, it is unavoidable to be interfered by various noises, such as baseline drift, myoelectric interference and power frequency interference. Among them, the baseline drift is mainly caused by the human body's breathing motion and the sliding of the collection electrode, which is a slowly changing ultra-low frequency interference signal. This interference will raise the ST band of the ECG, causing serious distortion of the ECG trajectory, thus affecting the normal medical diagnosis. Therefore, preprocessing the ECG data to...

Claims

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Application Information

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IPC IPC(8): A61B5/0452
Inventor 蔡念黄威威谢伟叶倩梁永辉彭红霞杨志景
Owner GUANGDONG UNIV OF TECH
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