Vector quantization for compression of multichannel ECG

A scheme is proposed which is based on vector quantization (VQ) for the data-compression of multichannel ECG waveforms. N-channel ECG is first coded using m-AZTEC, a new, multichannel extension of the AZTEC algorithm. As in AZTEC, the waveform is approximated using only lines and slopes; however, in m-AZTEC, the N channels are coded simultaneously into a sequence of N+1 dimensional vectors, thus exploiting the correlation that exists across channels in the AZTEC duration parameter. Classified VQ (CVQ) of the m-AZTEC output is next performed to exploit the correlation in the other AZTEC parameter, namely, the value parameter. CVQ preserves the waveform morphology by treating the lines and slopes as two perceptually distinct classes. Both m-AZTEC and CVQ provide data compression, and their performance improves as the number of channels increases.