基于自适应中值滤波的脑事件关联电位单次提取

提出一种基于自适应中值滤波的脑事件关联电位单次提取方法。刺激方式为odd-ball模式，直接用实测的数据进行实验。背景噪声从波形上看呈现为脉冲状形式，中值滤波可以有效地去除脉冲噪声。利用零交叉方法估计各单次记录信号中噪声的脉冲宽度，取其最大值作为基准参数，自适应地动态确定各单次滤波时所用窗口的大小。在窗口大小确定后，对各单次记录到的信号进行中值滤波器处理，最后对结果进行低通平滑。实验结果表明，本文提出的方法不但具有良好的单次提取效果，而且具有很强的适应性和稳健性。

ESTIMATION OF SINGLE EVENT-RELATED POTENTIAL WITH ADAPTIVE MEDIAN FILTERING BASED METHOD

Event related potentials(ERP) is of great importance in medical research and clinical diagnosis. Estimation of single event related potential (sERP) is the goal of the ERP processing and is very difficult because of strong background noise. A new technique, adaptive median filtering based method for estimation of sERP, is presented. It can be seen that the waveform of the background noise resembles pulses in appearance. The pulse noise can be effectively removed by the median filtering. The estimation process is performed in two stages; first, the zero crossing method was used to measure pulse widths of the noises in each recorded signal, and the length of the window of median filtering was set adaptively for each recorded signal based on the maximum of all measured widths; then, the data from the odd ball trials were processed by the median filtering and sequentially by the low pass filtering. The experimental results showed that the performance of sERP estimation was excellent. The method proposed is suitable for removing pulse noise whether it is nonstationary colored non Gaussion ditributed or not. So it is robust enough to deal with sERP processing.