在 OpenCV Mat 图像中显示 Vec3b 像素值

Question

我想知道 Mat 图像中 Vec3b 像素的值。我不是真正的 OpenCV expert.My Vec3b 是，如果我打印 Vec3b :

Vec3b centralIntensity;
cx=70; cy=700;
centralIntensity = (Vec3b)imgTemp->at<Vec3b>(cx, cy);
cout<<"I:["<<cx<<","<<cy<<"]="<<centralIntensity<<endl;

我得到：

I:[70,700]=[150, 162, 160]

如果我打印单个值：

 cout<<"***Uchar:["<<cx<<","<<cy<<"]="<<int(centralIntensity[0])<<","<<int(centralIntensity[1])<<","<<int(centralIntensity[2])<<endl;

我得到：

Uchar:[70,700]=127,0,0

我注意到如果我改变坐标，最后的打印总是一样的。由于我必须比较不同通道上的强度像素，这样做并了解 BGR 通道中的像素值的好方法是什么？

***EDIT1：这就是我创建 Mat 图像的方式（我已经有一个 Mat imgIn 作为输入）并且我以另一种方式显示 Vec3b：

Mat *imgTemp;
uchar cblue, blue, cgreen;
imgTemp = new Mat(imgIn->size(), CV_8UC3);
imgIn->convertTo(*imgTemp, CV_8UC3);
Vec3b centralIntensity;
centralIntensity = (Vec3b)imgTemp->at<Vec3b>(cx, cy);
cout<<"I:["<<cx<<","<<cy<<"]="<<centralIntensity<<endl;
centralIntensity[0] = cblue;
centralIntensity[1] = cgreen;
centralIntensity[2] = cred;
cout<<"I:["<<cx<<","<<cy<<"]="<<centralIntensity<<endl;
cout<<"***Uchar:["<<cx<<","<<cy<<"]="<<int(centralIntensity[0])<<","<<int(centralIntensity[1])<<","<<int(centralIntensity[2])<<endl;
cout<<"***Uchar:["<<cx<<","<<cy<<"]="<<int(cblue)<<","<<int(cgreen)<<","<<int(cred)<<endl;

我得到：

I:[70,700]=[150, 162, 160]

***Uchar:[70,700]=127,0,0

***Uchar:[70,700]=127,0,0

如果我改变坐标？

I:[300,400]=[109, 123, 105]

***Uchar:[300,400]=127,0,0

***Uchar:[300,400]=127,0,0

Answer 1

对于Vec3b，可以这样实现，

Mat image = imread("img_Path");
for(int y=0;y<img.rows;y++)
{
   for(int x=0;x<img.cols;x++)
   {
      // get pixel
      Vec3b color = image.at<Vec3b>(x, y);

      //color.val[0] // B
      //color.val[1] // G
      //color.val[2] // R
   }
}

Answer 2

您正在用未初始化的值 cblue、cred、cgreen 覆盖 centralIntensity，其中将包含随机值.

只需更正作业：

cblue = centralIntensity[0];
cgreen = centralIntensity[1];
cred = centralIntensity[2];

在 OpenCV Mat 图像中显示 Vec3b 像素值

Show Vec3b pixel values in OpenCV Mat image

c++

opencv

mat