Image Orientation By Combined Bundle Djustment With Fixed Imageries

As is now well known, the key task for aerial photogrammetry is to determine the orientation parameters of aerial imageries quickly and correctly. For a long time, this goal has been indirectly achieved by aerotriangulation with a lot of ground control points (GCPs). In order to reduce GCPs in photogrammetry, researchers look forward to use some measure to get exterior orientation elements directly.In the 1990s, combined use of GPS and inertial measurement unit (IMU) was studied to determine the orientation parameters during the photo flights in aerial photography. According to current experiments, even if use calibration field to carry out strict system calibration and the data of DGPS/IMU is combined handled correctly, the accuracy of exterior orientation elements cannot satisfy the requirements of photogrammetry at large scale. With the development and widely application of the digital photogrammetry, a great count of 4D products (DEM, DOM, DLG, DRG) has been produced and corresponding database have been set up, and there has been a lot of aerial imageries with perfectly determined exterior orientation data. With the rapid development of national economy, the earth's surface changes greatly and rapidly. The update of base geography information is staring us in the face. This brings up a question whether these data can be used for the orientation of new images. This would liberate us from GCPs and control surveying can be avoided, the aerial photogrammetry will become greatly simplified.Based on this thought, this paper studies the theory and method of solving exterior orientation elements of the new imageries by using fixed imageries in the same area, and a satisfied result is gotten through corresponding experiments carried out with simulated imageries and real imageries. The main points of this paper are presented as follows:1. According to self-calibration bundle block adjustment, a mathematical model which solves exterior orientation elements of the new imageries by using fixed imageries in the same area is set up. With experiments of simulated aerial imageries, the correctness of the mathematical model is proved.2. This paper sets up a platform of automatics image measure. The system includes the management of imageries, automatics interior orientation and automatic tie point extraction. With this system, transferring tie points and measuring same time and different time imageries can be realized.3. Using the platform of automatics image measure, author finished automatic measure of three sets of imageries which are photographed respectively at 2002 and 2004 of the same area. Adjustments of three sets of imageries are operated by conventional bundle block adjustment software WuCAPS. Under the condition of without GCPs, this paper realizes the solution of the exterior orientation parameter and block adjustment. The result shows that the accuracy of solved exterior orientation elements and 3D coordinates of the photogrammetric points satisfies the requirement of the specifications for aero-photogrammetry.