A single-variable non-linear quantization scheme for wavelet-based ECG data compression

In this paper, a non-linear quantization scheme with single control variable is proposed for wavelet-based ECG data compression. This scheme provides high and low octave coefficients with small and large decimal quantization scales, respectively. This method is based on the association of non-recursive 1-D discrete periodized wavelet transform (1-D NRDPWT) and a reversible round-off linear transformation (RROLT) theorem. The use of 1-D NRDPWT and RROLT is to resist error propagation effect and normalize the significance of octave coefficients, respectively. The two error control mechanisms can effectively reduce the searching area of quantization scales in an 11-D grid space. By using the MIT-BIH arrhythmia database, the experimental results show that this new approach can obtain a superior compression performance, particularly in high CR situations.