Camera calibration is a fundamental task in computer vision and photogrammetry. This paper presents an approach for automatic estimation of intrinsic parameters from images by using vanishing points with orthogonal directions. Firstly, image lines are extracted and are clustered into groups corresponding to three dominant vanishing points. Second, camera parameters including the radial distortion are estimated by adjusting linear parameters locating the images. Finally, the rotation matrix of the projection matrix is computed from the vanishing points, and the image edges and the translation matrix are obtained with the help of additional translation motion between the viewpoints. Our approach does not need any a priori information about the cameras being used. Experiments to evaluate the performance of this approach on synthetic and real data are reported.