根据一组点拟合曲线（需要opencv库）

matlab中跟据点拟合方程灰常容易，直接使用polyfit函数就行了。C++貌似没有直接拟合曲线的函数，在下不才，就用C++结合opencv的库函数写了个拟合曲线的函数。

#include <iostream>

#include <highgui.h>

#include <cv.h>

using namespace std;

//函数功能：根据vec中存储的点的坐标拟合曲线；

//vec为为存储点坐标的容器，index为存储拟合好曲线的数组，len既为拟合曲线的次数，也为数组index的长度；

void fittingCurve(vector<CvPoint2D64f> vec,double *index,int len)

{

double *px=new double [vec.size()];

double *py=new double [len*vec.size()];

int i=0;

for(vector<CvPoint2D64f>::iterator itr=vec.begin();itr!=vec.end();++itr)

{

px[i]=(*itr).x;

int j=0;

while (j<len)

{

py[len*i+j]=pow((*itr).y,double(j));

j++;

}

i++;

}

CvMat xMat=cvMat(vec.size(),1,CV_64FC1,px);

CvMat yMat=cvMat(vec.size(),len,CV_64FC1,py);

CvMat *yTransposedMat=cvCreateMat(yMat.cols,yMat.rows,CV_64FC1);

cvTranspose(&yMat,yTransposedMat);//求yMat的转置

double *a=new double [len*len];

for(int i=0;i<len*len;++i)

{

a[i]=0;

}

CvMat invMat1=cvMat(len,len,CV_64FC1,a);

cvGEMM(yTransposedMat,&yMat,1,NULL,0,&invMat1,0);//yMat的转置与yMat矩阵相乘

cvInvert(&invMat1,&invMat1,0);//求invMat的逆矩阵

double *b=new double [len];

for(int i=0;i<len;++i)

{

b[i]=0;

}

CvMat invMat2=cvMat(len,1,CV_64FC1,b);

cvGEMM(yTransposedMat,&xMat,1,NULL,0,&invMat2,0);//求yMat的转置矩阵与xMat矩阵相乘

cvGEMM(yTransposedMat,&xMat,1,NULL,0,&invMat2,0);//求yTransposedMat矩阵与xMat 矩阵的乘积

CvMat indexMat=cvMat(len,1,CV_64FC1,index);

cvGEMM(&invMat1,&invMat2,1,NULL,0,&indexMat,0);

cvReleaseMat(&yTransposedMat);

delete [] a;

delete [] b;

delete [] px;

delete [] py;

}

int main()

{

vector<CvPoint2D64f> vec;

int x[]={406,402,401,400,398,397,397,396,396,395,394,393,388,391,391,391};

int y[]={402,428,454,480,506,532,558,584,610,636,662,688,1078,1104,1130,1156};

for (int i=0;i<16;i++)

{

vec.push_back(cvPoint2D64f(x[i],y[i]));

}

double index[3];

fittingCurve(vec,index,3);

for (int i=0;i<3;++i)

{

cout<<index[i]<<endl;

}

return 0;

}