07-12-2012, 02:05 PM
Interference Cancellation in ECG Signals
ECG SIGNALS.ppt (Size: 4.1 MB / Downloads: 46)
Introduction
The Electrocardiogram (ECG or EKG) is a painless test that records the electrical activity of the functioning of the heart.
Based on ECG signal features, physicians diagnose different Arrhythmias
Problem Definition
ECG signals in their acquisition process are affected by various types of noise.
Noise degrades the signal quality and change tiny features that may be critical for clinical monitoring and diagnosis.
The power line frequency is 50Hz, within the spectrum of the ECG signal so the information contained in the signal gets superimposed by the interference.
It results in the incorrect diagnosis, so needs to be removed.
Empirical Mode Decomposition (EMD)
It is a method to decompose a non-stationary and non-linear signals into various intrinsic mode functions (IMFs), which represent oscillations present in the signal.
An IMF is defined as a function with equal number of extrema and zero crossings, may be equal or at most differ by one.
At each iteration new IMF is found and the difference between the sum of IMFs and the original signal yields a residue.
Therefore
Genetic Algorithm
Solves the problems that have discontinuous, non-differentiable, non-linear and stochastic objective function.
It does not require derivatives and searches the solution space widely.
Crossover allows the combination of best chromosomes, mutation adds diversity.
The two main components of GA are solution space and the fitness function.