Research On Calibration Of Vehicle-Borne Stereo-CCD Camera For Terrain Photogrammetry

The real world is tridimensional.We can describe and explain objects with tridimensional data, the basic path depicting it is collecting and getting the spatial data. There are many kinds of methods, using vehicle-borne tridimensional data collection is one of them. Different data collecting methods have complementary relationships between them. Vehicle-borne collecting tridimensional data system is composed of close range photogrammetric system(stereo-CCD camera),Laser scanner and Globel position system/Inertia Navigation System, installed on a vehicle. The system can carry out the collection of tridimensional and texture data, modeling, rapid catching of integrated spatial information.The stereo-CCD camera on the system can catch planar images of objects' surface. The final aim is getting spacial information. So based on vehicle-borne collecting tridimensional data system, on one hand, how to calculate tridimensional spatial information of interested object target synchronously has been researched in which camera calibrationon is key content, on the other hand, how to optimize calculating model for improving precision has been researched.In this paper stereo-CCD camera calibration methods are discussed on the condition of high precision tridimensional calibration field, based on vehicle-borne collecting tridimensional data system. Main contents are as follow :1) the calibration of camera inner parameters. Other exsisted methods on calibration field are compared, direct linear transfom and non-linear iterative calibration three -stage algorithm is presented which can improve precision.2) Calculation of relative stereo model. Dual images which have certain overlap can found stereo model in order to get the pose of objects shot .After cameras' inner parameters have getted, the model can be founded through the relative orientation method or spatial frontage method, each model has been discussed and analysed.3) stereo-CCD camera absolute calibration. CCD cameras are integrated on the vehicle-borne collecting tridimensional data system, the relative stereo model is stable,then absolute calibration parameters can be calculated through the spatial relationship of GPS/INS and relative stereo model.The main results are: a improved inner parameters calibration method—DLT and non linear iterative calibration three-stage algorithm is presented; relative stereo model founding with relative orientation algorithm; synchronously get tridimensional spatial information from planar images;the completion of digital stereo close range photogrammetric system software and relative application.Theory analysis and experiment results indicate that the CCD camera calibration method have higher precision and stronger stability. It can satisfy the precision need of vehicle-borne collecting tridimensional data system, also can apply to other several-source data integrated systems.