【OpenCV学习】梯度化一张图片

#include "cv.h"
#include "cxcore.h"
#include "highgui.h"
#include 

int main(int argc, char **argv)
{
CvPoint center;//定义一个二维坐标的点
double scale = -3;
int i,j;
IplImage *image = argc ==2? cvLoadImage(argv[1],CV_LOAD_IMAGE_COLOR):0;//打开一张图片
if(!image)
return -1;
center=cvPoint(image->width/2,image->height/2);//构造这个二维坐标的点
for(i=0;iheight;i++)
for(j=0;jwidth;j++)
{
double dx=(double)(j-center.x)/center.x;
double dy=(double)(i-center.y)/center.y;
double weight =exp((dx*dx+dy*dy)*scale);

/*可以使用opencv定义的宏来提取象素值,
假设灰度图像image，存取其i行j列的象素可以这样：CV_IMAGE_ELEM(image, uchar, i, j)
如果是彩色图像就是
CV_IMAGE_ELEM(image, uchar, i, 3*j)
CV_IMAGE_ELEM(image, uchar, i, 3*j+1)
CV_IMAGE_ELEM(image, uchar, i, 3*j+2) */
uchar * ptr=&CV_IMAGE_ELEM(image,uchar,i,j*3);
ptr[0]=cvRound(ptr[0]*weight);// 将浮点数转化为整数。
ptr[1]=cvRound(ptr[1]*weight);
ptr[2]=cvRound(ptr[2]*weight);
}
cvSaveImage("copy.jpg",image);//保存图像

/*打开图像*/
cvNamedWindow("Window",1);
cvShowImage("Window",image);
cvWaitKey(-1);
return 0;
}