I have a philosophical question of sorts for users familiar with a multi-view stereo setup. Imagine that I need to measure the dimensions of a large building and I take several photos of the building from different viewpoints. After calibrating the camera (intrinsic and extrinsic), I compute matches between points in these images and map them to 3D points. The output of this entire process is a cloud of 3D points. If I specify a scale, origin and co-ordinate axes, then I can perform measurements between points in this cloud which relate to the real-world scene (the building) that I captured. My question is this: how do I determine how accurate was my reconstruction.
Basically, this camera apparatus forms a measurement device. To compare a measurement, one typically needs to use another measurement device that is much more accurate that it. How do I measure the accuracy of a such a system?