python提取脑电微分熵特征
时间: 2023-07-26 15:43:22 浏览: 63
脑电微分熵是一种常用的脑电信号分析方法,可以用来评估脑电信号的复杂度和不规则性。以下是提取脑电微分熵特征的Python代码示例:
```python
import numpy as np
from scipy.signal import hilbert
def differential_entropy(signal, tau=1):
"""计算微分熵"""
n = len(signal)
m = 2 # 窗口大小
r = 0.1 * np.std(signal) # 阈值
x = np.zeros((n - m + 1, m)) # 构造向量矩阵
for i in range(n - m + 1):
x[i] = signal[i:i+m]
d = np.zeros((n - m + 1, n - m + 1)) # 构造距离矩阵
for i in range(n - m + 1):
for j in range(i, n - m + 1):
d[i, j] = max(abs(x[i] - x[j]))
d[j, i] = d[i, j]
count = 0
for i in range(n - m + 1):
for j in range(i + 1, n - m + 1):
if d[i, j] < r:
count += 1
p = count / ((n - m + 1) * (n - m) / 2)
if p == 0:
return 0
else:
return -np.log(p)
def extract_features(eeg_data, fs):
"""提取微分熵特征"""
# 带通滤波
b, a = butter(4, [1, 30], btype='band', fs=fs)
eeg_data = filtfilt(b, a, eeg_data)
# 希尔伯特变换
analytic_signal = hilbert(eeg_data)
amplitude_envelope = np.abs(analytic_signal)
# 计算微分熵
diff_entropies = []
for i in range(len(eeg_data)):
if i + fs < len(eeg_data):
segment = amplitude_envelope[i:i+fs]
diff_entropy = differential_entropy(segment)
diff_entropies.append(diff_entropy)
return diff_entropies
```
以上代码中,`eeg_data`为原始脑电信号数据,`fs`为采样频率。首先对信号进行带通滤波和希尔伯特变换,然后对每个时段(时长为1秒)计算微分熵,并将所有微分熵值作为特征返回。