Research On Extracting Topographic Data From Non-Metric Digital Imagery

Nowadays the most common used methods for extracting small range topographic data are the total-station-based ground surveying and the photography-theodolite-based terrestrial photogrammetry. However, when surveying in some hilly areas using the former method, it would become over-workload and sometimes it would be too difficult and dangerous to handle the work. And the later one demands high quality of professional skills and equipages. On the other hand, because of its remarkable merits, such as low-cost, high-resolution, the feasibility of data acquisition, high speed to transmit and process, non-metric digital camera and its imagery are widely used in various domains. But the already proposed algorithms for non-metric digital cameras photogrammetry are mainly based on Direct Linear Transformation (DLT) or Bundle Adjustment, which has defects of demanding too highly for both the quantity and the distribution of the control points. And it is special to stereo-matching of normal close-digital imagery too.In order to overcome the application defects, this dissertation proposes a topographic data extraction technique that uses non-metric digital cameras to obtain data and has Close-Range Photogrammetry and digital image processing technique as it theory basis. As an non-metric camera, when used for photogrammetry, common digital camera has many defects. For example, it cannot provide the interior orientation parameters (IOP's) with sufficient accuracy, and the distortion of its imagery is comparatively large. Therefore, its image data processing algorithm differs from traditional photogrammetry. Hence, the research on the technique of three-dimension topographic data extraction from non-metric digital imagery is presented as follows:1. The calibration of non-metric digital cameras, including the determination of camera distortion and the IOP's. And the metricilized use of non-metric camera including the metricilized feasibility, the metricilized methodology and the nature of metriclizing common digital camera.2. The surveying process algorithm to normal close-digital imagery, including the establishment of image engineering coordination system, the photogrammetric algorithms for non-metric imagery such as exterior orientation parameters (EOP's) calculation, relative orientation , absolute orientation ,and the metricilized evaluation of their accuracy.3. Image stereo-matching method designed for normal close-digital imagery.4. The design and development of the topographic data extraction information system based on non-metric digital imagery.Various researches and experiments have proved that the proposed metricilized method, the surveying process algorithm and the stereo-matching method for non-metric digital cameras are valid and effective. With the proposed digital image surveying algorithm and the stereo-matching algorithm, the digital camera's metricilized utilization will effectively deskill and de-equip the use of Close-Range Photogrammetry.