UniCT | Progetti e programmi legati all'università

As far as I know, the function stereoRectify assumes that the camera axes are approximately parallel to each other. You can try stereoRectifyUncalibrated, as this function relies on fundamental matrix computation and will handle this case. Make sure you've read the note in the documentation.

Note:

While the algorithm does not need to know the intrinsic parameters of the cameras, it heavily depends on the epipolar geometry. Therefore, if the camera lenses have a significant distortion, it would be better to correct it before computing the fundamental matrix and calling this function. For example, distortion coefficients can be estimated for each head of stereo camera separately by using calibrateCamera(). Then, the images can be corrected using undistort(), or just the point coordinates can be corrected with undistortPoints().