Are there open algorithms for generating a 3D model from a series of photographs of the same object from different angles?

Question

Programming

Well, or at least "in which direction to look."
I know that ready-made solutions on this topic are available in the form of some programs, but the algorithm is directly of interest.

Answer 1

cvgl.stanford.edu/teaching/cs231a_winter1415/prev/... and on through the bibliography.

Answer 2

Projection onto a plane.

Answer 3

from available software: 123D Catch