# EFFICIENT SOURCE CODING IN A THRESHOLDING-BASED ECG COMPRESSOR USING THE DISCRETE WAVELET TRANSFORM

### Carlos Hernando Ramiro, Manuel Blanco Velasco, Eduardo Moreno-Martínez, Fernando Cruz Roldán, José Sáez Landete

#### Abstract

The aim of electrocardiogram (ECG) compression is to achieve as much compression as possible while the significant information for diagnosis purposes is preserved in the reconstructed signal. The source coding stage allows us to modify the compression ratio without quality degradation through a lossless encoder. In this work, the performance of this stage is analyzed in a compression scheme that has already presented good results among those from the state of the art. The compressor is based on discrete wavelet transform, thresholding and two-role encoder. The study consists of fixing all the stages except the source coding one in order to obtain an upper compression ratio bound. The assessment is based on the entropy of the independent symbols and the minimum expected length of the codewords. The results reveal a gap to improve the compression ratio, so from the previous entropy study an alternative compression method is proposed. For this purpose the symbols probabilities are analyzed through the normalized histogram. Thus, a Huffman encoder instead of the two-role one is applied in the new compressor to attain the maximum compression ratio. In this way a significant improvement is obtained without decreasing the original retrieved quality.

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#### Paper Citation

#### in Harvard Style

Ramiro C., Velasco M., Moreno-Martínez E., Roldán F. and Landete J. (2009). **EFFICIENT SOURCE CODING IN A THRESHOLDING-BASED ECG COMPRESSOR USING THE DISCRETE WAVELET TRANSFORM** . In *Proceedings of the International Conference on Bio-inspired Systems and Signal Processing - Volume 1: BIOSIGNALS, (BIOSTEC 2009)* ISBN 978-989-8111-65-4, pages 259-264. DOI: 10.5220/0001533502590264

#### in Bibtex Style

@conference{biosignals09,

author={Carlos Hernando Ramiro and Manuel Blanco Velasco and Eduardo Moreno-Martínez and Fernando Cruz Roldán and José Sáez Landete},

title={EFFICIENT SOURCE CODING IN A THRESHOLDING-BASED ECG COMPRESSOR USING THE DISCRETE WAVELET TRANSFORM},

booktitle={Proceedings of the International Conference on Bio-inspired Systems and Signal Processing - Volume 1: BIOSIGNALS, (BIOSTEC 2009)},

year={2009},

pages={259-264},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0001533502590264},

isbn={978-989-8111-65-4},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the International Conference on Bio-inspired Systems and Signal Processing - Volume 1: BIOSIGNALS, (BIOSTEC 2009)

TI - EFFICIENT SOURCE CODING IN A THRESHOLDING-BASED ECG COMPRESSOR USING THE DISCRETE WAVELET TRANSFORM

SN - 978-989-8111-65-4

AU - Ramiro C.

AU - Velasco M.

AU - Moreno-Martínez E.

AU - Roldán F.

AU - Landete J.

PY - 2009

SP - 259

EP - 264

DO - 10.5220/0001533502590264