How to use triangulatePoints function?

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Could anyone show example How to use triangulatePoints function? I can get MAT from a camera. But what is InputArray projMatr1, InputArray projMatr2, InputArray projPoints1, InputArray projPoints2? How can I calculate the distance by OutputArray points4D? Simply put, how can I get the following parameters?

projMatr1 – 3x4 projection matrix of the first camera.
projMatr2 – 3x4 projection matrix of the second camera.
projPoints1 – 2xN array of feature points in the first image. In case of c++ version it can be also a vector of feature points or two-channel matrix of size 1xN or Nx1.
projPoints2 – 2xN array of corresponding points in the second image. In case of c++ version it can be also a vector of feature points or two-channel matrix of size 1xN or Nx1.
points4D – 4xN array of reconstructed points in homogeneous coordinates.