Frame of the Cameras

[SummeiL]

Hello, I am using you driver for a tracking object project.

I need to project a 3D point into the left and right camera plane. In the CameraInfo message there is the matrix P and in the message description it says:

"By convention, this matrix specifies the intrinsic (camera) matrix
of the processed (rectified) image. That is, the left 3x3 portion
is the normal camera intrinsic matrix for the rectified image.
It projects 3D points in the camera coordinate frame to 2D pixel
coordinates using the focal lengths (fx', fy') and principal point
(cx', cy') - these may differ from the values in K."

"It projects 3D points in the camera coordinate frame to 2D pixel coordinates"...but then I realize that both left and right cameras have the same frame "leap_optical_frame". I would like to know where is this frame placed...in the middle of the two cameras?

Thank you very much!