A new approach for exterior camera parameters estimation based on Hough transform is presented.By using the collinear equations to model the camera and combining the feature points on the image plane and in the object space to set votes for a certain point in the discrete parameter space

the point with the maximum number of hit is defined the right parameter. An iterative estimation procedure is adopted to process the nonlinearity in the collinearity equations and the correlation of the exterior parameters. Unlike the conventional methods

the new technique can estimate the exterior parameters without making a correspondence between the feature points on the image plane and in the object space. Two experiments are carried out to examine the validity of the proposed algorithm. Experimental results show that the errors of the camera coordinates and the pose angles are less than 15 m and 1° respectively. The estimated parameter results can meet the requirements of the combat using ship borne guns.