心率算法（参照网上资料提供的算法编程）

/*-------------------------------------------------------------*- File name: hr_alg.c Author:Yorkchang Version:1.00 Date:3.20,06 Description:本模块为心率计算模块。 Function List: 1.unsigned char rhythmcount(unsigned char *fifo) 心率计算函数 History: <author> <time> <version > <desc> Yorkchang 3.20 1.0 参照网上资料提供的算法编程 ----------------------------------------------------------------- 心率计算模块 -*--------------------------------------------------------------*/ #include "main.h" #include "hr_alg.h" /************************************************* Function: rhythmcount Description:计算心率值 Calls: -- Called By: real_sample() 函数入口：数据区首地址 Return: rhythm 心率值 *************************************************/ unsigned char rhythmcount(unsigned char *fifo) { signed char i; signed char diff[max_data]; //求导数数据区 signed char dif_max=0; //导数最大值 signed char thr_max; //阈值最大值 unsigned char j=0; signed char k[8]; //最大值数组 unsigned char rhythm; float DR_R; //R-R间距 *diff=0; //数据区首两个数据导数置0 *(diff+1)=0; for(i=2;i<max_data-2;i++) //按DIFF(i)=f(i+1)-f(i-1)+2*f(i+2)-2*f(i-2)公式计算导数 { *(diff+i)=(signed char)(*(fifo+i+1))+2*(signed char)(*(fifo+i+2))-(signed char)(*(fifo+i-1))-2*(signed char)(*(fifo+i-2)); } *(diff+max_data-1)=0; //数据区末两个数据导数置0 *(diff+max_data)=0; for(i=0;i<max_data;i++) //求导数最大值 { if((dif_max)>*(diff+i)) dif_max=*(diff+i); } thr_max=(dif_max>>1)-(dif_max>>3); //设定阈值，为导数最大值的0.375倍 for(i=1;i<max_data-1;i++) //将满足f(i)>thr_max和f(i)*f(i+1)<0这两个条件的值找到,即为R波最高点 { if((*(diff+i)>thr_max)&&(((*(diff+i))^(*(diff+i+1)))>>7)) k[j++]=i; } DR_R=(k[j-1]-k[0])/(j-1); //计算R-R间距 rhythm=(unsigned char)(12000/DR_R); //通过公式200*60/DR-R求得心率值 return rhythm; } /*-----------------------------------------------------------------*- --------------------END OF FILE------------------------------------ -*-----------------------------------------------------------------*/