opencv读取图像像素值

#include<opencv2\opencv.hpp>
#include<iostream>
using namespace cv;
using namespace std;
bool flag = false;
int xvalue = 0;
int yvalue = 0;
Mat image,image1,image2;
void mousecallback(int event, int x, int y, int flags, void* userdata);
int main(int argc, char* argv[])
{
namedWindow("imageshow", 0);
Mat image = imread("F:\\6.jpg", 1);
if(!image.data)
{
cout<<"the image is error"<<endl;
return 0;
}
imshow("imageshow", image);
image.copyTo(image1);
cv::setMouseCallback("imageshow", mousecallback, 0);
waitKey(0);
return 0;
}
void mousecallback(int event, int x, int y, int flags, void* userdata)
{
image1.copyTo(image2);
switch (event)
{
case EVENT_LBUTTONDOWN:
{
flag = true;
}
break;
case EVENT_LBUTTONUP:
{
if(flag)
{
xvalue = x;
yvalue = y;
flag = 0;
int b = image1.at<Vec3b>(yvalue, xvalue)[0];
int g = image1.at<Vec3b>(yvalue, xvalue)[1];
int r = image1.at<Vec3b>(yvalue, xvalue)[2];
cout<<"B:"<<b<<' '<<"G:"<<g<<' '<<"R:"<<r<<endl;
}
}
break;
}
}