ECG SIGNAL COMPRESSION TECHNIQUE BASED ON DWT AND EXPLOITATION OF INTERBEATS AND INTRABEATS CORRELATIONS

Abstract

A hybrid ECG compression technique based on DWT and reducing the correlation between signal samples and beats has been presented in this paper. It starts by segmenting the ECG signal into blocks; each has 1024 samples. Then, DPCM approach is adopted by removing the redundancy between successive samples. This yields to residual signal with QRS-complex like waveform without the presence of P-, T- and U-waves. Then the first QRS-complex like wave is isolated and all the succeeding ones are subtracted from the preceding ones to remove the redundancy between signal beats. The next process depends on the application. For telediagnoses, the resulting residual signal is wavelet transformed while for telemonitoring both the first QRS-complex like wave and the residual signal are wavelet transformed. In both cases the resulting wavelet coefficients are thresholded based on energy packing efficiency and coded using modified run-length algorithm. The performance of the proposed algorithm has been tested on records extracted from MIT-BIH arrhythmia database. Simulation results illustrate the excellent quality of the reconstructed signal with percentage-root-mean square difference less than 1.5% and compression ratios greater than 20.