COMPARATIVE ANALYSIS OF DIGITAL FILTERS FOR ELECTROGASTROGRAPHY (EGG) SIGNAL PREPROCESSING

This paper presents a comparative analysis of three digital bandpass filters—Butterworth, Chebyshev Type I, and FIR Hamming window—for enhancing electrogastrography (EGG) signal preprocessing. EGG signals are severely compromised by physiological interference (~0.25 Hz respiration, ~1 Hz cardiac activity) and motion artifacts in the ultra-low-frequency band (0.015–0.15 Hz). Using synthetic EGG signals, filter performance is quantified using signal-to-noise ratio (SNR) improvement. Results demonstrate that FIR Hamming achieves the highest SNR improvement (+16.88 dB), while Butterworth produces the smoothest temporal output suitable for clinical interpretation, and Chebyshev Type I offers optimal computational efficiency. These findings provide practical guidance for filter selection based on clinical diagnostic and machine learning requirements.本论文针对三类数字带通滤波器——巴特沃斯（Butterworth）、切比雪夫I型（Chebyshev Type I）以及FIR汉明窗（FIR Hamming window）——开展对比分析，用于优化胃电图（electrogastrography, EGG）信号的预处理流程。胃电图信号在超低频段（0.015–0.15 Hz）中，会受到生理干扰（约0.25 Hz的呼吸活动、约1 Hz的心脏活动）与运动伪影的严重影响。本研究采用合成胃电图信号，以信噪比（signal-to-noise ratio, SNR）提升量作为量化指标对各滤波器的性能进行评估。实验结果表明，FIR汉明窗滤波器的信噪比提升效果最优（+16.88 dB）；巴特沃斯滤波器生成的时域输出最为平滑，适用于临床解读；而切比雪夫I型滤波器则具备最优的计算效率。上述研究结果可为基于临床诊断与机器学习需求的滤波器选型提供实用指导。