Hi AlessandroB
The Spatial Location Calculator node uses the center of the depth map as the origin for the x, y, z coordinates. The x, y coordinates are the relative positions of the center of the Region of Interest (ROI) to the center of the depth map.
While it might seem more intuitive to use the optical center as the origin, the choice of the depth map center is due to the fact that the depth map is the primary source of spatial information in DepthAI. The depth map is generated by the stereo pair of cameras, and the center of this map is a logical choice for the origin of the spatial coordinate system.
When the depth image is aligned to RGB, the depth map is scaled to match the resolution of the RGB sensor. Therefore, even in this case, the center of the depth map (now aligned and scaled to the RGB image) is used as the origin of the spatial coordinates.
The OAK camera uses a right-handed (Cartesian) coordinate system for all spatial coordinates.
Thanks,
Jaka
