How to teach stereoscopic matching?

This paper describes a simple but non-trivial semidense stereoscopic matching algorithm that could be taught in Computer Vision courses. The description is meant to be instructive and accessible to the student. The level of detail is sufficient for a student to understand all aspects of the algorithm design and to make his/her own modifications. The paper includes the core parts of the algorithm in C code. We make the point of explaining the algorithm so that all steps are derived from first principles in a clear and lucid way. A simple method is described that helps encourage the student to benchmark his/her own improvements of the algorithm.