RESEARCH ON THE MAPPING OF LARGE-SCALE TOPOGRAPHIC MAPS BASED ON LOW-ALTITUDE DRONE AERIAL PHOTOGRAPHY SYSTEM
Keywords: UAV aerial survey system, Digital Orthophoto Map (DOM), Digital Elevation Model (DEM), GPS
Abstract. The field data collection and in-house data processing of the aerial photography system of the uavouring aircraft are studied, combined with their working examples in this paper. The aerial survey of the Bowen School of Management of Guilin University of Technology is carried out by using the Southern Sky Patrol AS1200 aerial survey system, and the obtained data is processed and studied in the internal and external industry. In order to successfully complete this research, this article (1) first of all to the external industry collected data inspection, that is, the quality of the aircraft film inspection, the main content of the inspection is the detection of the image of the tone, resolution, level, whether the film can clearly identify the main objects, such as houses, roads, etc. can be clearly identified; - Whether the film is ghosting, whether there is misalignment and fuzziness, etc. , if the film has blurred or other quality problems, it is necessary to carry out retest or retest, this step is mainly to ensure the quality of research data, for the industry processing data to do a basic guarantee. (2) For the processing of in-house data, this paper uses a correction model for image data distortion pre-processing, the method of arithmetic and the edge detection operator method of extracting the image feature, and the image matching method Greenfeld-Schenk method based on the feature, Bamard-Thompson method and jump method and other methods to match the image, at the same time, this paper also takes the aerial triangulation method of the processing of internal data, complete the measurement control point encryption work, so as to calculate the spatial coordinates of the encryption control point, reduce the field laying work like control points, and thus reduce the working time of the field. (3) For improving the accuracy of the topographic elevation point in the aviation area, this paper uses polymorphic curve to be legal, using the field elevation measured value of the checkpoint and the three-dimensional measurement value does not match the difference, using the least square-by-multiply method to fit, so that the elevation checkpoint curve fitting value change and the actual difference is the smallest, with the measurement area elevation accuracy.