The Real-Time R-wave Detection
Based on FPGA
Tongqing Li, Yide Ma Member IEEE, Yurun Ma, Xiangyu Lu
School of Information Science and Engineering
Lanzhou University
Lanzhou, China
litq12@lzu.edu.cn,
yidema@gmail.com, yurunma@gmail.com, luxy2012@lzu.edu.cn
Abstract—R-wave detection is one of the most significant parts in
Electrocardiogram (ECG) signal studies and plays an important
role in the automatic ECG analysis system. In this research, we
design a prototype of portable automatic ECG analysis system
based on field programmable gate array (FPGA) using Altera
DE2-70 development board. The system includes four parts:
1)Data input, 2)ECG denoising, 3)ECG analysis and R-wave
detection, 4) Results display. In this paper, we use the data from
the well-known MIT/BIH arrhythmia database. CDF9/7 wavelet
filter is used to remove the high-frequency noise and the
threshold method is used to detect the R-wave. In addition, In the
Quartus II 9.0 development environment, we complete the
simulation and synthesis. Experimental results based on the
system show that proposed architecture can detect R-wave
accurately and the utilization percent of resource is low, just 6%.
Keywords-ECG, R-wave detection, CDF9/7 wavelet filter,
Threshold, FPGA.
I. INTRODUCTION
Electrocardiogram (ECG) signal is one of the earliest
biological signals studied and applied to clinical medicine. At
present, ECG analysis is still one of the simplest noninvasive
diagnostic methods for heart and cardiovascular disease. With
the rapid development of electronic science technology and
family medicine, the computer aided diagnosis system and
portable ECG monitoring devices are developed, which make
the ECG automatic analysis become a research focus in the
field of Biomedical Engineering. However, automated analysis
of ECG beats is a challenging problem because the
morphological and temporal characteristics of ECG signals
show significant variation for different patients under different
physical conditions [1].
It is important that the reliable and accurate detection
algorithm of the basic characteristic features of the signal for
the automatic ECG analysis system. QRS wave is the most
important part in ECG signal and used as the reference point
for beat alignment. In recent years, there have been a lot of
R-wave detection algorithms proposed, such as difference
threshold value algorithm [2] [3], wavelet transform algorithm
[4] [5] [6], template matching algorithm [7], neural network
algorithm [8] [9], and others that combine the basic algorithms
above [10] [11]. However, most of these algorithms are in the
stage of theoretical research and processed offline. The studies
of the hardware implementation of the algorithm are relatively
small.
Nowadays, Field Programmable Gate Array (FPGA) is at
the forefront of digital signal processing technology. We
generally use the hardware description language, VerilogHDL
or VHDL, to configure the FPGA. FPGA allows designers to
add some new circuits, or reconfigure the hardware resources
for the special functions even after the program has been
downloaded into chips. The fast growing speed and circuit
density of FPGAs have made them a significant player in
domains earlier dominated by Application Specific Integrated
Circuits (ASIC). Besides being used for general purpose logic
design, modern FPGAs are equipped with building blocks for
specialized applications such as DSP and embedded system
design [12]. In recent years, FPGA has also been widely used
in the field of ECG signal processing, such as ECG denoising
system [13] [18], QRS wave detection [12] [14] and feature
extraction. In [15], an accurate FPGA based ECG Analysis
system is described. That design is based on popular software
based QRS detection.
Our previous research [16] succeeded making lots of
simulations for the real-time R-wave detection using CDF9/7
wavelet filter and difference method. In this paper, we try to
implement them on a prototype of portable automatic ECG
analysis system based on FPGA using Altera DE2-70
development board. FPGA system has high speed and the
plentiful leaving resources, which make other more circuits can
be easily join this design to form a larger system that has more
functions. Moreover, at present, the researches for portable
ECG device tend to be small size, low power and real-time data
processing. So the portable ECG devices based on FPGA have
a great advantage.
This paper is organized as follows. In section II, we
describe the algorithm used in this system. This algorithm is
our previous research, so we introduce the algorithm
implementation process briefly and some improved places for
more suitable for FPGA implementation. Section III introduces
the design and implementation of ECG analysis system on
FPGA. It is the most important part of our paper. We use
MIT/BIH Arrhythmia Database to test system and give the data
analysis and comparison in Section IV. Finally, the conclusions
are made in section V.