BLAM - Geometry camera matching add-on - BlenderNation
add on - Estimation of focal length when using BLAM - Blender Stack Exchange
Blender Add-on: BLAM - the camera calibration toolkit - YouTube
GitHub - stuffmatic/blam: 🚨 No longer maintained. Check out fSpy instead 🚨 A camera and projector calibration toolkit for Blender that also does automatic 3D reconstruction of geometry with rectangular faces.