SSVEP CLASSIFICATION WITH A LIMITED TRAINING DATASET

Five users aged 23, 25, 31, 42, and 46 participated in the experiment. The users sat comfortably in a chair. A green LED of 1 cm diameter was placed at a distance of about 1 meter from a person's eyes. EEG signals were recorded using g.USBAmp with 16 active electrodes. The users were stimulated with flickering LED lights with frequencies: 5 Hz, 6 Hz, 7 Hz, and 8 Hz. The stimulation lasted 30 seconds. The recorded signals were divided into the data used for training, the first 20 seconds, and the data used for testing, the next 10 seconds, for each signal. All sessions were held at the same time of the day to avoid circadian influences on the measurements. Electrodes were placed according to the international 10-20 system at the following positions: O2, AF3, AF4, P4, P3, F4, Fz, F3, FCz, Pz, C4, C3, CPz, Cz, Oz, O1. The EEG sampling frequency was 256 Hz. The signals were filtered using a Butterworth bandpass filter (0.1-100 Hz) and a notch filter (48-52 Hz) to correct a technical artifact of the power network. For every user, there are four files (for the stimuli of 5Hz, 6Hz, 7Hz and 8Hz each) for training and four files for testing. Data are provided in MATLAB format (*.mat) containing raw EEG signals (3 EEG channels O2, Oz, O1). Instructions: A database was created for research on brain-computer interfaces and SSVEPs. The signals reflect short EEG calibration sessions. The database can be used to check EEG signal augmentation methods in order to train classifiers requiring more examples (MLP, SVM, CNN).本次实验共有5名受试者参与，年龄分别为23、25、31、42与46岁。受试者舒适端坐于座椅上。一名直径1厘米的绿色发光二极管（LED）置于距受试者双眼约1米处。采用搭载16个有源电极的g.USBAmp设备采集脑电（EEG）信号。受试者接受闪烁LED灯光刺激，刺激频率分别为5Hz、6Hz、7Hz与8Hz，单次刺激时长为30秒。针对每一段采集到的信号，将其拆分为训练集数据（前20秒）与测试集数据（剩余10秒）。所有实验均于每日同一时段开展，以避免昼夜节律对测量结果的影响。电极按照国际10-20系统放置，具体点位包括：O2、AF3、AF4、P4、P3、F4、Fz、F3、FCz、Pz、C4、C3、CPz、Cz、Oz、O1。脑电信号采样率为256Hz。随后采用巴特沃斯带通滤波器（0.1~100Hz）与陷波滤波器（48~52Hz）对信号进行滤波处理，以消除电网工频干扰伪迹。 每名受试者对应4个训练集文件与4个测试集文件，分别对应5Hz、6Hz、7Hz、8Hz四种刺激频率。数据以MATLAB格式（*.mat）存储，内含原始脑电信号，包含O2、Oz、O1共3个脑电通道。 【说明】本数据集专为脑机接口（Brain-Computer Interface, BCI）与稳态视觉诱发电位（Steady-State Visual Evoked Potentials, SSVEPs）相关研究构建。信号源自短时脑电校准实验。该数据集可用于验证脑电信号增强方法，以训练对样本量需求较高的分类器，如多层感知机（Multi-Layer Perceptron, MLP）、支持向量机（Support Vector Machine, SVM）与卷积神经网络（Convolutional Neural Network, CNN）。