The Key Technology Of Aerial Triangulation For Oblique Photogrammetry

Oblique digital camera is taken for a typical example In the field of aerial photography technology.Compared with the traditional digital camera, oblique digital camera can apperceive the comprehensive information of the complex scene with the way of high precision and large range. It has great potential in the new generation of the city data infrastructure. But the inclination and high overlap of the image has put forward a big challenge for the digital photography system. As a key technology, aerotriangulation needs to solve the problem caused by oblique image.The paper carry on corresponding researchs on this aspect such as initial topological relation of images, feature point extraction,muti-view image matching algorithm,and aerotriangulation precision,trying to solve the problem that traditional photogrammetry do not adapt to the oblique image.The main contents of the paper are as follows:(1)the establishment of topological relations among imagesThe paper introduced the common coordinate system in photogrammetry, analyzed the relationship between image coordinate system and installed location of oblique digital camera, put forward a algorithm that can determine the muti-view image’s rotation direction automatically,proposed another algorithm that arranges the strips by pos,which rebuild the initial topological relations among images.(2)feature extraction and matching of oblique imageThe paper introduced the common feature extraction operator,and used the repetition rate as the evaluation index,choosed the feature extraction operator which adapted to the oblique image by means of experiment.The paper also introduced the basic knowledge of image matching and multi-view dense matching methods, analyzed the inadaptability of oblique image,put forward a algorithm suitable for the oblique image adopting the grouping strategy and step-by-step strategy,vertify the feasibility and effectiveness of the improved algorithm finally.( 3) investigation into the Precision of aerial triangulation for oblique photogrammetryThis paper provides an investigation into how the pose of image make a difference to the precision of aerial triangulation. Three experiments have been designed using data collected by oblique digital camera TOPDC-5 in Anyang, to verify the precision of aerial triangulation. Aerial triangulation is executed for vertical image, oblique image, and combined vertical and oblique image respectively. It proves that the oblique image will reduce the precision of plane and height simultaneously compared to traditional photogrammetry.