The Study Of The Real Projective Image Based On TDOM

As an important basic surveying and mapping product,DOM has the geometric precision and image features of topographic map,and can be used as background control information to evaluate the accuracy,reality and integrality of other data,and its production has been tremendously developed in recent years.However,for artificial buildings,trees and bridges and other ground targets may appear occlusion,ghosting and other problems;if the GIS vector base map is superimposed with the DOM,the road vector line will cross the building,and the DOM will lose its value as the geographical bottom map.To make up for the lack of DOM,true digital orthophoto map(TDOM)are born.TDOM is an orthophoto that simultaneously eliminates projection distortion of terrain and ground targets.The buildings that really shoot the images,trees and other artificial objects have been adjusted to its correct position,will not be able to block other features,the true meaning of the rich texture information and topographic map of the geometric attributes,can be better used for image stitching,and topographic mapping and three-bit landscape map generation,By many experts and scholars at home and abroad,At present,it is widely used in many fields such as Digital city,emergency protection,land survey,land right and so on.Based on the actual production,this paper completes the modeling work of An Hong by using the existing three-dimensional modeling software(Smart3D),and makes the mapping products such as DSM and DOM(TDOM).Based on the existing real image algorithm,some improvements are made to the algorithm of the real shooting of UAV tilt photography.For the production of the real shooting image,this article completes the following work content:(1)The research background of the true digital orthophoto map is expounded,and the basic principle of digital differential correction is explained.In this paper,an improved method is proposed based on the algorithm of angle masking detection.The algorithm reduces the number of angles in the occlusion judgment,makes the occlusion area more efficient,and realizes the goal of quickly judging the shaded area.In this paper,a comparison is made between the detection algorithms of some commonly used masking areas,such as whether to leak,time consuming,pseudo occlusion and pseudo visibility,and to illustrate that the improved angle detection algorithm is a relatively efficient and accurate algorithm for masking area detection.At the same time,the scanning cycle mode has been modified,so that it can better adapt to the digital photo traversal;(2)A method of making high precision digital surface model(DSM)is presented.DSM is usually produced by using digital building model(DBM)combined with relevant elevation information to create DSM,the DSM is not precise,the more complex the periphery of the building is,the more inaccurate the DSM is built.In this paper,using the method of Tilt photogrammetry,the Smart3 D software is used to generate three-dimensional model automatically,and then a more accurate DSM model can be made with the modification of third party software.(3)Detailed description of the application of Smart3 D software processing UAV tilt photographic data flow.Using Smart3 D software can efficiently deal with aerial data,can automatically generate large area three-dimensional model,and the model precision is high,based on the introduction of DSM production process,the corresponding DOM(TDOM)is generated on the basis of actual data.