Opencv Matrix Operations

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OpenCV Matrix Operations

Since OpenCV is the most widely used image processing library, the matrix operation and basic linear algebra is inevidable.

1. Initialization

Remeber that you have to initialize a Mat from a array.

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#include <iostream>
#include <opencv2/core/core.hpp>
using namespace std;
using namespace cv;
 
void addMatrixExample() {
  float a[2][2] = {{1, 2},
                   {3, 4}};
  float b[2][2] = {{5, 6},
                   {7, 8}};

  Mat A = Mat(2, 2, CV_32FC1, a);
  Mat B = Mat(2, 2, CV_32FC1, b);
  Mat C;
  C = A + B;
  cout << "C =" << endl << " " << C << endl << endl;
}
 
int main() {
    addMatrixExample();
}

2. Point

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typedef Point_<int> Point2i;
typedef Point2i Point;
typedef Point_<float> Point2f;
typedef Point_<double> Point2d;
typedef Point3_<int> Point3i;
typedef Point3_<float> Point3f;
typedef Point3_<double> Point3d;

From the above we can see that Point, Point2i, Point_<int> are exactly the same.