25-07-2014, 10:21 AM
ECG R-Peaks Detection
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INTRODUCTION
ECG- ECG stands for Electrocardiogram.
ECG is representative signal containing information about the condition of the heart .
It is measure of the electrical activity associated with the heart.
It is characterized with different frequency content QRS complex , P & T waves.
R-peaks detection
The basic task of electrocardiogram (ECG) processing is R-peaks detection. There are some difficulties one can encounter in processing ECG: irregular distance between peaks, irregular peak form, presence of low-frequency component in ECG due to patient breathing etc. To solve
the task the processing should contain particular stages to reduce influence of those factors. The aim is to show results of processing in main pipeline stages.
Hilbert Transform
The accurate detection algorithm of QRS wave ,R peak height,T peak,ECG base modulation technique based on first derivative of Hilbert Transform is proposed.First derivative which is implemented on smooth ECG signal is basically a high pass filtering which allow high frequency, QRS complex and attenuate low frequencyP&T wave region. Now hilbert transform is implemented on that diffrentiated signal. Maximum amplitude of that transformed signal is found out
FFT TRANSFORM
Fast Fourier transforms are used to identify the peaks in the ECG signal and then Neural Networks are applied to identify the diseases.
In FFT( Fast Fourier transform ) that produces the signal into an infinite length of sine and cosine wave functions. However , the transform losses the information is about time domain and gives only spectral information in frequency domain and vice versa
WAVELET TRANSFORM
The Wavelet Transform is a time-scale representation that has been used successfully in a broad range of applications, in particular signal compression.
Recently, Wavelets have been applied to several problems in Electrocardiology, including data compression, analysis of ventricular late potentials, and detection of ECG characteristic points.