"How long is the fish?" Frederik Schaffalitzky University of Oxford http://www.robots.ox.ac.uk/~fsm/ Abstract: I will describe an application of Markov chain Monte Carlo (MCMC) simulation to a very specialized photogrammetry problem. The objective is to estimate the size of an object from 1-3 photographs of a man holding the object, but standing in different poses. I will give a little background about single-view reconstruction methods and why I thought they were not sufficient for the application. I will talk about the model I constructed and the tricks I used to make the simulation efficient.