四通道即時EEG訊號獨立事件分析之FPGA實現

Abstract

在真實世界的多感應器應用中，如何從混合訊號中分析出獨立訊號的瞎訊號分離是一個常見的問題，例如:音訊和生醫訊號處理。本論文提出一個基於資訊最大化之獨立事件分析方法應用於四通道EEG訊號分離。並用定點數實現於FPGA,再藉由藍芽傳輸分離後的訊號。經由實驗的結果，本論文所提出的硬體方式比軟體運算快56倍，且絕對相關係數和離線訊號處理比較至少有80% 。 最後，實際示範將用Altera DE2發展板展示，此設計使用16605邏輯單元。 而本論文所提出的四通道即時獨立事件分析系統也加入彈性的介面用於實際EEG訊號分離的應用。用資訊最大化演算法的即時生醫訊號分離其取樣頻率設定在64Hz，並藉由整合性的算術運算架構可讓整體操作速度在68MHz。

Blind source separation of independent sources from their mixtures is a common problem for multi-sensor applications in real world, for example, speech or biomedical signal processing. This thesis presents an independent component analysis (ICA) method with information maximization (Infomax) update applied into 4-channel one-line EEG signal separation. This can be implemented on FPGA with a fixed-point number representation, and then the separated signals are transmitted via Bluetooth. As experimental results, the proposed design is faster 56 times than soft performance, and the correlation coefficients at least 80% with the absolute value are compared with off-line processing results. Finally, live demonstration is shown in the DE2 FPGA board, and the design is consisted of 16,605 logic elements. The 4-channel On-line ICA accompanied with flexible communication interface for real EEG signal separation has been presented in this thesis. The proposed integrated mathematics architecture can allow high-speed at 68MHz and real-time biomedical signal separation with Infomax ICA at sampling rate 64 Hz.