Production And Comparative Analysis Of The True Orthophoto Map Based On INPHO And Pixel Factory

With the improvement of the resolution of aerial images and the development of digital city and other emerging technologies,due to the building tilt,shelter and information loss,the traditional orthophoto map(DOM)is difficult to combine with other spatial data and has become increasingly unable to meet requirements of the actual production.The true orthophoto map(TDOM)is a more advanced geomatics product than the traditional orthophoto map,the digital surface model(DSM)or the digital building model(DBM)is used for digital differential correction of the original image,and then conduct the detection and compensation of the shaded area,there is no building tilt and shelter on the true orthophoto map.However,in actual production,the true orthophoto map is usually replaced by the traditional orthophoto map,that has not been widely used.In this paper,some RCD aerial images of a region of Changsha have been used to produce the true orthophoto map by INPHO and Pixel Factory software.Through the comparison of the process,efficiency and result integrity of two different methods,the application of the two methods is summarized and the corresponding solutions to the problems encountered in the experiment are put forward,which can provide some references for the mass production of the true orthophoto map in the future and provide some bases for the planning and construction of the city.Through the experiment and analysis,the following conclusions are obtained:(1)The automation and intelligence of the pixel factory is higher than that of INPHO,and the process of INPHO is relatively complicated and heavy workload.The efficiency for the true orthophoto map produced by Pixel Factory is about14 times that of INPHO.For dense urban areas,Pixel Factory has more advantages than INPHO.(2)The accuracy of the true orthophoto map produced by INPHO mainly depends on the accuracy of DBM.The higher accuracy of DBM,the fewer correct residues around buildings,and the higher integrity of the building.The accuracy of the true orthophoto map produced by Pixel Factory mainly depends on the accuracy of DSM.The higher accuracy of DSM,the fewer image garland and dislocation,and errors of buildings,and the higher integrity of the building.(3)Buildings on the true orthophoto map produced by INPHO were corrected to the correct locations and geometry characteristics of edges are obvious,without image garland,which is suitable for the census of geographical conditions and the construction of Digital City.Buildings on the true orthophoto map produced by Pixel Factory were corrected to the correct locations,geometry characteristics of edges are not as obvious as INPHO,a small part of edges of these buildings have image garland and matching errors.However,the pixel factory has the advantages of high efficiency and timeliness,which is suitable for environmental monitoring and urban planning.