Virtual Reality: Concepts and Technologies

Location sensors 115

Figure 6.4 Augmented reality using ARToolkit. (Illustration: Yvan Poupyrev, with permission)

camera’s own parameters are also called its intrinsic parameters. Generally, they include

the distance between the optical centre and the image plane (focal length), and the

projection of the optical centre in the image plane. Parameters of distortion created

by the lens can also be added. All these parameters are obtained by a procedure called

calibration. Several methods are available, but the principle of all these methods is the

acquisition of images of an object whose geometrical structure is perfectly known. As

for the relative position ...