Not sure if it’s OpenSource, but it’s Freeware alright.
digilab.uni-hannover.de/docs/manual.html
Description: Well, it tracks camera from image sequences, and that camera can be imported to 3D stuff. Good for mixing live action with 3D footage.
Yes its free but not for commercial use.
its 3d camera tracking and used in blender/other 3d packages.
But I dont see its use here 
i tried this software not long ago, but at the end you figure that is easier start modeling the scene by yourself, is interesting but i should not say it can actually be easier or useful than modeling something from scratch taking a picture as your reference, i’m talking as a Blender user =p
It’s not the purpose of that software to scan the video and make a 3D scene out of it. The tracking points are just created for reference that you know where you should put the objects that you want to add to the video. This software is for tracking the motion so that you don’t have to move 3D-objects frame by frame if you add them into the video so that they match the camera motion. 
That software is similiar to what you seem to mean: 2d3.com/product/?v=23