Derivation of camera parameters based on geometric meaning

The process of solving camera intrinsic and extrinsic parameters has been presented by using geometric techniques. In contrast with traditional method, which is a pure algebra process, the geometric technique accomplishes the camera parameters more intuitively and easily. If the perspective projection matrix is given, according to the geometric meaning of perspective projection camera model, the coordinates of optical centre can be directly estimated in the world coordinate system. Then rotation matrix and translation vector can be obtained from the matrix. Finally, we can derive camera intrinsic parameters. During the process of derivation, for any given 3 by 4 matrix, the constraint conditions have been discussed in another way when the matrix could be described as a perspective projection transformation. Although it has the same result as pure algebra progress, it´s of great significance to understand the geometric meaning among the intrinsic and extrinsic camera parameters