Camera calibration

which is to calculate the intrinsic and extrinsic parameters of a camera in viewing

is one of the basic tasks for analyzing the geometry of a scene and determining the shapes and locations of objects in vision. Since the optical system of a real camera is not correspondence to an ideal pinhole optical system in generating a perspective view

there exist many types of distortions. These distortions must be taken into account in three dimension geometry reconstruction when high precision is needed

and this will cause the relation of perspective transformation nonlinear. Many efforts have been being made to solve the nonlinear calibration problem. This paper deals with camera calibration while radial distortion exists

which is the most common distortion and has a noticeable effect. A new multi step decomposition linear approach of calibration is introduced in this paper

which eliminates the nonlinear iterative calculation processes. The running experiment results show that the new approach is very efficient and the accuracy is good enough.