OpenCV更改函数内的Mat(Mat范围)

Question

我将Mat传递给另一个函数并在被调用函数内更改它.我原本以为它是一个更复杂的类型,它通过引用自动传递,因此矩阵在调用函数中会发生变化,但事实并非如此.有人能指出我如何从函数中正确返回更改的Mat的解释吗？

这是代码片段:

void callingFunction(Mat img)
{
  Mat tst(100,500,CV_8UC3, Scalar(0,255,0));
  saveImg(tst, "Original image", true);
  testImg(tst);
  saveImg(tst, "Want it to be same as inside testImg but is same as Original", true);
}

void testImg(Mat img)
{
  int rs = 50; // rows
  int cs = 100; // columns
  img = Mat(rs, cs, CV_8UC3, Scalar(255,0,0));
  Mat roi(img, Rect(0, 0, cs, rs/2));
  roi = Scalar(0,0,255); // change a subsection to a different color

  saveImg(img, "inside testImg", true);
}

谢谢!

Answer 1

您必须定义Mat为参数引用(&).这是编辑过的代码:

void callingFunction(Mat& img)
{
  Mat tst(100,500,CV_8UC3, Scalar(0,255,0));
  saveImg(tst, "Original image", true);
  testImg(tst);
  saveImg(tst, "Want it to be same as inside testImg but is same as Original", true);
}

void testImg(Mat& img)
{
  int rs = 50; // rows
  int cs = 100; // columns
  img = Mat(rs, cs, CV_8UC3, Scalar(255,0,0));
  Mat roi(img, Rect(0, 0, cs, rs/2));
  roi = Scalar(0,0,255); // change a subsection to a different color

  saveImg(img, "inside testImg", true);
}