1. A system for determining one or more camera calibration parameters, comprising: a processor configured to: provide a first pattern for display on a display screen; receive a first image from a camera viewing the display screen; provide a second pattern for display on the display screen; receive a second image from the camera viewing the display screen, wherein the relative position of the display screen and the camera are the same as when the first image was captured using the camera; and determine an image location which is a projection of a known physical location on the display screen by using at least in part a first feature identified in the first image and a second feature identified in the second image; and determine one or more calibration parameters based at least in part on the determined image location; and a memory coupled to the processor and configured to provide the processor with instructions.