Triangulation results are not realistic

Hello community
I’m new to opencv.
I’m trying to get the coordinates of objects relative to the camera position of the left image using a stereo pair.
I’m trying to do the same here.

However, I am getting results that are not true. I don’t understand where my mistakes is

I have the following questions.

  1. Should I use rectified images or primary sources?
  2. For the camera intrinsic matrix, in what units (mm or pixels) should the focal length of the camera and the coordinates of the center of the image be set?
  3. For the Camera intrinsic matrix, set the focal length and center coordinates for the sensor or for the image?

Thanks in advance