Nonlinear ECG filtering by group normalized wavelet packets
Zhuoer Shi, Zheng Bao, Licheng Jiao, Kun Ma · 2002
The group normalized wavelet packet transform is presented to extract ECG components from the additive noise on time-frequency tilings together with the time-frequency masking technique. FIR filters with linear phase is the natural requirement for anti-aliasing. However, linear phase compactly supported real wavelet packets are non-orthogonal so that coefficients at different scale have correlated redundancy and destroy the energy conservation. We design group-normalization to make our entropy definition follow a comparable standard.