二次线性插值图像缩放算法

void FiResize(const FiMat &src, FiMat &dst, double fx, double fy)
{

 dst.Resize(src.rows*fx,src.cols*fy,src.nchannel);

 int step1,step2,channels;
 int kp,kq;
 double kx,ky;
 float scalex=fx;
 float scaley=fy;

 channels = src.channels();
 step1= src.cols*channels;
 step2= dst.cols*channels;

 uchar* data1= (uchar*)src.data;
 uchar* data2= (uchar*)dst.data;

 for (int j = 0; j < dst.rows; j++)
 {
  for (int i = 0;i < dst.cols; i++)
  {  

   kx=(double)(i+0.5)/scalex-0.5;
   ky=(double)(j+0.5)/scaley-0.5;
   kp = kx;
   kq = ky;
   double u,v;
   u = kx -kp;
   v = ky - kq;

   kp = max(0,kp);
   kp = min(kp,src.cols-2);

   kq = max(0,kq);
   kq = min(kq,src.rows-2);

   for (int k =0;k<3;k++)
   {
    data2[j*step2+i*3+k] = (1-u)*(1-v)*data1[kq*step1+kp*3+k] + (1-u)*v*data1[(kq+1)*step1+kp*3+k] +
     u*(1-v)*data1[kq*step1+(kp+1)*3+k] +u*v*data1[(kq+1)*step1+(kp+1)*3+k] ;
   }
  }

 }

}

总结一下：

原来把

   kp = max(0,kp);
   kp = min(kp,src.cols-2);

   kq = max(0,kq);
   kq = min(kq,src.rows-2);

的src分别写成了dst调了半天多定位到这个函数才解决，粗心害死人啊!