TY - JOUR

T1 - AZTDIS - a two-phase real-time ECG data compressor

AU - Tai, S. C.

N1 - Funding Information:
This research was partially supported by the National Science Council of the Republic of China under contact NSC 82-0420-E-006-087.

PY - 1993/11

Y1 - 1993/11

N2 - An ECG sampled at a rate of 360 samples s-1 or more produces a large amount of redundant data that are difficult to store and transmit; we therefore need a process to represent the signals with clinically acceptable fidelity and with as small a number of code bits as possible. In this paper, a real-time ECG data-compression algorithm, AZTDIS, is presented. AZTDIS is an efficient algorithm which locates significant samples and at the same time encodes linear segments between them by using linear interpolation. The significant samples selected include, but are not limited to, the samples that have significant displacement from the encoded signal such that the allowed maximal error is limited to a constant ε{lunate}, which is specified by the user. The way that AZTDIS computes the displacement of a sample from the encoded signal guarantees that the high activity regions are more accurately coded. The results from AZTDIS are compared with those from the well-known data-compression algorithm, AZTEC, which is also a real-time algorithm. It is found that under the same bit rate, a considerable improvement of root-mean-square error (RMSerr) can be achieved by employing the proposed AZTDIS algorithm. An average value of RMSerr of 9.715 can be achieved even at an average bit rate of 0.543 bits per sample by employing AZTDIS. By tuning the allowed maximal error of AZTDIS such that it has similar bit rate to AZTEC, the average value of RMSerr achieved by AZTDIS is 5.554 while the average value of RMSerr achieved by AZTEC under the same bit rate is 19.368.

AB - An ECG sampled at a rate of 360 samples s-1 or more produces a large amount of redundant data that are difficult to store and transmit; we therefore need a process to represent the signals with clinically acceptable fidelity and with as small a number of code bits as possible. In this paper, a real-time ECG data-compression algorithm, AZTDIS, is presented. AZTDIS is an efficient algorithm which locates significant samples and at the same time encodes linear segments between them by using linear interpolation. The significant samples selected include, but are not limited to, the samples that have significant displacement from the encoded signal such that the allowed maximal error is limited to a constant ε{lunate}, which is specified by the user. The way that AZTDIS computes the displacement of a sample from the encoded signal guarantees that the high activity regions are more accurately coded. The results from AZTDIS are compared with those from the well-known data-compression algorithm, AZTEC, which is also a real-time algorithm. It is found that under the same bit rate, a considerable improvement of root-mean-square error (RMSerr) can be achieved by employing the proposed AZTDIS algorithm. An average value of RMSerr of 9.715 can be achieved even at an average bit rate of 0.543 bits per sample by employing AZTDIS. By tuning the allowed maximal error of AZTDIS such that it has similar bit rate to AZTEC, the average value of RMSerr achieved by AZTDIS is 5.554 while the average value of RMSerr achieved by AZTEC under the same bit rate is 19.368.

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U2 - 10.1016/0141-5425(93)90067-9

DO - 10.1016/0141-5425(93)90067-9

M3 - Comment/debate

C2 - 8277757

AN - SCOPUS:0027703535

SN - 0141-5425

VL - 15

SP - 510

EP - 515

JO - Journal of Biomedical Engineering

JF - Journal of Biomedical Engineering

IS - 6

ER -