Efficient Hardware Architecture of Convolutional Neural Network for ECG Classification in Wearable Healthcare Device

• Published in: IEEE transactions on circuits and systems. I, Regular papers Regular papers, 2021-07, Vol.68 (7), p.2976-2985
• Main Authors: Lu, Jiahao, Liu, Dongsheng, Liu, Zilong, Cheng, Xuan, Wei, Lai, Zhang, Cong, Zou, Xuecheng, Liu, Bo
• Format: Article
• Language: English
• Subjects: Accuracy; Artificial neural networks; Classification; Computation; Computer architecture; Consumption; Convolution; convolution neural network (CNN); Diagnostic systems; ECG classification; Electrocardiography; Feature extraction; global average pooling; Hardware; Health care; Heart beat; Medical diagnosis; Portable equipment; resource efficiency; Wearable healthcare; Wearable technology
• ISSN: 1549-8328; 1558-0806
• DOI: 10.1109/TCSI.2021.3072622

Nowadays, with the increasing shortage of traditional medical resources, the existing portable monitoring healthcare device is no longer satisfactory. Thus, wearable healthcare device with diagnostic capability is becoming much more desirable. However, the design of wearable healthcare device faces the challenge of limited hardware resource and high diagnostic accuracy. In this paper, an efficient hardware architecture is proposed to implement a 1-D CNN with global average pooling (GAP) specially for embedded electrocardiogram (ECG) classification. The GAP is implemented by substituting division into shifting operation without extra computing resource consumption and it can largely reduce the parameters of the network. The fully pipelined processing unit (PU) array is designed to increase computing efficiency. A sign bit based dynamic activation strategy is developed for removing redundant multiplications and resource consumption of ReLU. The proposed efficient hardware architecture is implemented on Xilinx Zynq ZC706 board and achieves an average performance of 25.7 GOP/s under 200-MHz with resource consumption of 1538 LUT, which makes resource efficiency improved by more than 3\times compared with non-optimized case. The averaged classification accuracy of five ECG beats classes is 99.10%. In brief, the proposed efficient hardware design is prospective for wearable healthcare device especially in ECG classification area.