已知心率信号x,用c语言提取高频分量,低频分量,并计算标准差与均方根插的完整代码
时间: 2024-03-20 17:41:55 浏览: 21
以下是一个简单的示例代码,用于提取心率信号的高频分量、低频分量,并计算标准差和均方根差:
```c
#include <stdio.h>
#include <math.h>
#define PI 3.14159265358979323846
// 计算傅里叶变换
void fft(double *x, double *y, int n)
{
int i, j, k, m;
double xt, yt, r, t, c, s;
for (i = 0, j = 0; i < n; i++)
{
if (j > i)
{
xt = x[j];
yt = y[j];
x[j] = x[i];
y[j] = y[i];
x[i] = xt;
y[i] = yt;
}
m = n / 2;
while (m >= 2 && j >= m)
{
j -= m;
m /= 2;
}
j += m;
}
for (k = 1, m = 2; k < n; k *= 2, m *= 2)
{
for (j = 0; j < k; j++)
{
c = cos(-PI * j / k);
s = sin(-PI * j / k);
for (i = j; i < n; i += m)
{
r = c * x[i + k] - s * y[i + k];
t = s * x[i + k] + c * y[i + k];
x[i + k] = x[i] - r;
y[i + k] = y[i] - t;
x[i] += r;
y[i] += t;
}
}
}
}
// 计算心率变异信号的高频分量和低频分量
void hrv(double *x, int n, double *hf, double *lf)
{
int i;
double fs = 4.0; // 采样频率(Hz)
double f0 = 0.04; // 低频分量截止频率(Hz)
double f1 = 0.15; // 高频分量截止频率(Hz)
double df = fs / n; // 频率分辨率
double *Xr = (double *)malloc(n * sizeof(double));
double *Xi = (double *)malloc(n * sizeof(double));
double *H = (double *)malloc(n * sizeof(double));
double *L = (double *)malloc(n * sizeof(double));
double Hf = 0.0;
double Lf = 0.0;
// 计算心率变异信号的傅里叶变换
for (i = 0; i < n; i++)
{
Xr[i] = x[i];
Xi[i] = 0.0;
}
fft(Xr, Xi, n);
// 计算每个频率点的幅值
for (i = 0; i < n; i++)
{
H[i] = 0.0;
L[i] = 0.0;
if (i < n / 2)
{
double f = i * df;
double P = Xr[i] * Xr[i] + Xi[i] * Xi[i];
if (f >= f0 && f <= f1)
{
H[i] = P;
}
else if (f > f1)
{
L[i] = P;
}
}
}
// 计算高频分量和低频分量的幅值总和
for (i = 0; i < n / 2; i++)
{
Hf += H[i];
Lf += L[i];
}
// 将幅值总和乘以2,除以n,再除以df,得到高频分量和低频分量的幅值
*hf = Hf * 2.0 / (n * df);
*lf = Lf * 2.0 / (n * df);
free(Xr);
free(Xi);
free(H);
free(L);
}
// 计算标准差和均方根差
void sdnn_rmssd(double *x, int n, double *sdnn, double *rmssd)
{
int i;
double sum = 0.0;
double sum_sq = 0.0;
// 计算RR间期的总体变异性和短期变异性
for (i = 0; i < n; i++)
{
sum += x[i];
sum_sq += x[i] * x[i];
}
*sdnn = sqrt((sum_sq - sum * sum / n) / (n - 1));
*rmssd = sqrt(sum_sq / (n - 1));
}
int main()
{
double x[] = {1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9}; // 心率信号
int n = sizeof(x) / sizeof(x[0]);
double hf, lf, sdnn, rmssd;
// 提取高频分量和低频分量
hrv(x, n, &hf, &lf);
// 计算标准差和均方根差
sdnn_rmssd(x, n, &sdnn, &rmssd);
printf("High frequency component: %f\n", hf);
printf("Low frequency component: %f\n", lf);
printf("SDNN: %f\n", sdnn);
printf("RMSSD: %f\n", rmssd);
return 0;
}
```
需要注意的是,这只是一个简单的示例代码,实际应用中需要根据具体的需求进行调整和优化。另外,代码中的心率信号是手动输入的,实际应用中需要根据具体情况进行读取和处理。