Opencv获取并改变图像的像素值

#include
using namespace std;

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

#pragma  comment(lib,"cxcore.lib")
#pragma  comment(lib,"cv.lib")
#pragma  comment(lib,"ml.lib")
#pragma  comment(lib,"cvaux.lib")
#pragma  comment(lib,"highgui.lib")
#pragma  comment(lib,"cvcam.lib")

int main(int argc, char* argv[])
{
    IplImage *img = cvLoadImage("101.jpg",1);
    CvScalar s;
 cvNamedWindow("Image",1);

 cvShowImage("Image",img);
    for(int i = 0;i < img->height;i++)
 {
        for(int j = 0;j < img->width;j++)
  {
   s = cvGet2D(img,i,j); // get the (i,j) pixel value
   s.val[0]=255;
   s.val[1]=34;
   s.val[2]=123;
   cvSet2D(img,i,j,s);//set the (i,j) pixel value
        }
    }
    cvShowImage("Image",img);
    cvWaitKey(0); //等待按键
 
    cvDestroyWindow( "Image" );//销毁窗口
  //cvReleaseImage( &img ); //释放图像
 
    return 0;
}

上述的方法在效率方面不好，还有更快速的方法获取像素值：

IplImage img;
for (i = 0;i < img->height;i++)
{
	for (j = 0;j < img->width;j++)
	{
		sum += ((uchar *)(img->imageData + img->widthStep * i))[j];//获取像素值
		num++;
	}
}