使用OpenCV如何获取图像某点的颜色值,并设置某点的颜色

#include <opencv2\opencv.hpp>
using namespace cv;
 
vector<char*> listFiles(const char * dir);
int main()
{
 Mat img = imread("D:\\OpencvTest\\test.jpg");
 Scalar color = img.at<Vec3b>(150, 150);//读取原图像(150, 150)的BGR颜色值，如果是灰度图像，将Vec3b改为uchar
 for (size_t row=0; row<50; row++)
 for (size_t col=0;col<img.cols;col++)
 {
  //设置原图像中某点的BGR颜色值
  img.at<Vec3b>(row, col) = Vec3b(color(0), color(1), color(2));
 
 }
 cv::circle(img, Point(150, 150), 4, cv::Scalar(0, 0, 255));//在图像中画出特征点，2是圆的半径
 imshow("img", img);
 waitKey(0);
 return 0;
}

#include<opencv2/core/core.hpp> 
#include<opencv2/highgui/highgui.hpp> 
#include<opencv2/imgproc/imgproc.hpp> 
#include <vector>
#include<iostream> 
#include<string>

using namespace std;
using namespace cv;
//bgr图像 
Mat bgr;
//HSV图像 
Mat hsv;
//色相 
int hmin = 0;//h分量取下限
int hmax = 180;//h分量取上限
int h_Max = 180; //h分量可取的最大值
//饱和度 
int smin = 0;//s分量取下限
int smax = 255;//s分量取上限
int s_Max = 255;//s分量可取的最大值
//亮度 
int vmin = 0;//v分量取下限
int vmax = 255;//v分量取上限
int v_Max = 255;//v分量可取的最大值

string windowName = "src";

string dstName = "dst";
//输出图像 
Mat dst;
//回调函数 
void callBack(int, void*)
{
  //输出图像分配内存 
  dst = Mat::zeros(bgr.size(), bgr.type());
   
  Mat mask;
  inRange(hsv, Scalar(hmin, smin, vmin), Scalar(hmax, smax, vmax), mask);
   
  for (int r = 0; r < bgr.rows; r++)
  {
    for (int c = 0; c < bgr.cols; c++)
    {
      if (mask.at<uchar>(r, c) == 255)
      {
        dst.at<Vec3b>(r, c)[0] = bgr.at<Vec3b>(r, c)[0];
        dst.at<Vec3b>(r, c)[1] = bgr.at<Vec3b>(r, c)[1];
        dst.at<Vec3b>(r, c)[2] = bgr.at<Vec3b>(r, c)[2];
      }
    }
  }
  imshow("mask", mask);
  //输出图片
  imshow("dst", dst);
}
int main()
{
  //输入图片 
  Mat srcImage = imread("C:\\Users\\Administrator\\Desktop\\0001.jpg");
  if (!srcImage.data){
    cout << "图片读取失败" << endl;
    system("pause");
    return -1;
  }
  imshow(windowName, srcImage);
  bgr = srcImage;
  //颜色空间转换 
  cvtColor(bgr, hsv, COLOR_BGR2HSV);
  //定义输出图像的显示窗口 
  namedWindow(dstName, 0);
  //调节色相 H 
  createTrackbar("hmin", dstName, &hmin, h_Max, callBack);
  createTrackbar("hmax", dstName, &hmax, h_Max, callBack);
  //调节饱和度 S 
  createTrackbar("smin", dstName, &smin, s_Max, callBack);
  createTrackbar("smax", dstName, &smax, s_Max, callBack);
  //调节亮度 V 
  createTrackbar("vmin", dstName, &vmin, v_Max, callBack);
  createTrackbar("vmax", dstName, &vmax, v_Max, callBack);
  callBack(0, 0);
  waitKey(0);
  return 0;
}