the opencv tutorial says: "The depth of a point in a scene is inversely proportional to the difference in distance of corresponding image points and their camera centers. " According to this paper https://www.ri.cmu.edu/pub_files/pub2/willson_reg_1993_1/willson_reg_1993_1.pdf there are a lot of different camera centers. What kind of camera center should I use?
Should I use the principal point Cx,Cy from the camera matrix? That doesn't quite make sense since they differ between cameras. If I just use the Center of the frame in pixels, it doesn't take into account projection center. I'm lost in all these centers. Tutorial makes it look so easy. Anyone has practical experience with the topic? Also my cameras have different focal values. Which one do I use?
PS>also why does the right arrow, next to x' points to the right, as if suggesting that it takes the distance from the left camera center.