Advanced Real-Time Dynamic Programming in the Polygonal Approximation of ECG Signals for a Lightweight Embedded Device

Seungmin Lee,Kil Houm Park,Yoosoo Jeong,Daejin Park,Junho Kwak

doi:10.1109/access.2019.2952399

Abstract

Arrhythmia is less frequent than a normal heartbeat in an electrocardiogram signal, and the analysis of an electrocardiogram measurement can require more than 24 hours. Therefore, the efficient storage and transmission of electrocardiogram signals have been studied, and their importance has increased recently due to the miniaturization and weight reduction of measurement equipment. The polygonal approximation method based on dynamic programming can effectively achieve signal compression and fiducial point detection by expressing signals with a small number of vertices. However, the execution time and memory area rapidly increase depending on the length of the signal and number of vertices, which are not suitable for lightweight and miniaturized equipment. In this paper, we propose a method that can be applied in embedded environments by optimizing the processing time and memory usage of dynamic programming applied to the polygonal approximation of an ECG signal. The proposed method is divided into three steps to optimize the processing time and memory usage of dynamic programming. The first optimization step is based on the characteristics of electrocardiogram signals in the polygonal approximation. Second, the size of a data bit is used as the threshold for the time difference of each vertex. Finally, a type conversion and memory optimization are applied, which allow real-time processing in embedded environments. After analyzing the performance of the proposed algorithm for a signal length L and number of vertices N, the execution time is reduced from O(L 2 N) to O(L), and the memory usage is reduced from O(L 2 N) to O(LN). In addition, the proposed method preserve a performance of fiducial point detection. In a QT-DB experiment provided by Physionet, achieving values of -4.01 ± 7.99 ms and -5.46 ± 8.03 ms.

Highlights

With the development of life science and technology, the percentage of deaths from heart disease is gradually increasingThe associate editor coordinating the review of this manuscript and approving it for publication was Donghyun Kim .as society ages due to the increased average life expectancy
In this paper, we propose an improved Polygonal approximation (PA) method that enables real-time processing in an embedded environment by optimizing the dynamic programming (DP) based on the characteristics of ECG signals
The proposed method can improve the performance by effectively analyzing the characteristics of ECG signals and the DP method for a one-dimensional signal

Summary

INTRODUCTION

With the development of life science and technology, the percentage of deaths from heart disease is gradually increasing. ECG signals require a long measurement time, which significantly increases the number of bits allocated to the time information, resulting in a lower compression ratio To solve this problem, in this paper, we propose an improved PA method that enables real-time processing in an embedded environment by optimizing the DP based on the characteristics of ECG signals. DYNAMIC PROGRAMMING In the PA, DP optimizes the location information of the vertices selected in the sequential PA This minimizes the error between the approximated signal and the input signal and helps to represent the fiducial point as a vertex, which is the boundary point separating the baseline region from the waveform region. For a signal with length L, the optimization of the partial signal from i to j, including the k vertices, is recursively

10 Function

MEMORY OPTIMIZATION

SUMMARY OF THE EXPERIMENTS

Findings

CONCLUSION