Calibrating a camera
Camera calibration is the process by which the different camera parameters (that is, the ones appearing in the projective equation) are obtained. One can obviously use the specifications provided by the camera manufacturer, but for some tasks, such as 3D reconstruction, these specifications are not accurate enough. By undertaking an appropriate camera calibration step, accurate calibration information can be obtained.
An active camera calibration procedure will proceed by showing known patterns to the camera and analyzing the obtained images. An optimization process will then determine the optimal parameter values that explain the observations. This is a complex process that has been made easy by the availability of OpenCV calibration functions.
How to do it...
To calibrate a camera, the idea is to show it a set of scene points for which their 3D positions are known. Then, you need to observe where these points project on the image. With the knowledge of a sufficient number...
