Machine Vision, 3rd Edition

CHAPTER 21 Image Transformations and Camera Calibration

21.1 Introduction

When images are obtained from 3-D scenes, the exact position and orientation of the camera sensing device are often unknown, and there is a need for it to be related to some global frame of reference. This is especially important if accurate measurements of objects are to be made from their images, for example, in inspection applications. On the other hand, it may sometimes be possible to dispense with such detailed information—as in the case of a security system for detecting intruders, or a system for counting cars on a motorway. There are also more complicated cases, such as those in which cameras can be rotated or moved on a robot arm, or the objects being examined ...