Evaluation of constrained extrinsic orientation parameters on the 3D photogrammetric model

Close range photogrammetry has proved powerful tool as a time-saving,cost- effective and easy-to-use method for 3d cultural heritage modeling and recording,due to its rapid improvements in both data acquisition and processing. the accuracy of extrinsic orientation parameters,expressed as camera position and attitude,governs greatly the realiability of the final 3d models. because these image orientation parameters are highly correlated,modeling this correlation is highly desirable in the bundle adjustment to ensure high precision and reliability of the least squares solution. the present paper addresses these motivations,by using a gps enabled- digital camera for images capture,to provide directly the required extrinsic orientation parameters,from attached gps receiver unit and digital compass. also,geometric constraints of both sets of image orientation parameters,whatever individually and/or combined together,are added to be solved as constrained bundle adjustment. the results shows the powerful of the gps digital camera for the final positional accuracy. in addition,significant improvements have been occurred due to the added combined geometric constraints with nearly up to 30 %.