In this paper, an offline double density discrete wavelet transform based QRS complex detection of the electrocardiogram signal is discussed. Baseline wandering present in the signal is removed by using the double density discrete wavelet transformed approximation coefficients of the signal. The results are more accurate than other methods with less effort. This is an unsupervised method allowing the process to be used in offline automatic analysis of electrocardiogram. The measurement of timing intervals of ECG signal by automated system is highly superior to its subjective analysis. The heart rate signals are essentially non-stationary and contain indicators of current disease or warnings about impending diseases. The indicators may be present at all times or may occur at random in the time scale. Double density discrete wavelet transform is easier to implement, provides multiresolution and also reduces the computational time. In the pre-processing step, the baseline wandering is removed from the ECG signal. Then the R peaks/QRS complexes are detected. From the location of the R peaks, the successive RR intervals and heart rate are calculated. Fifty-two records from the MIT-BIH arrhythmia database are used to evaluate the proposed method. Sensitivity and positive prediction are used as performance measures. This method detects the R peaks with 100% sensitivity and 99.95% positive prediction. The performance of the proposed method is better than other methods existing in the literature.
A FPGA system for QRS complex detection based on Integer Wavelet Transform
