Research On Orthophoto Production And Application Based On UAV

In the era of rapid development of information technology,how to quickly and accurately acquire geographic information data is a concern in all fields,especially in areas with complex terrain and changeable climate,it is still difficult to acquire high-resolution image data at present.Some small examples are given.In the application of image data in surrounding areas,if traditional image acquisition methods are adopted,it often consumes cost and time.Unmanned aerial vehicles can effectively solve these problems and obtain high-resolution image data quickly and accurately.This paper mainly focuses on the acquisition,production and application of UAV images.The working flow of UAV aerial photography system is introduced in detail.In two different types of Surveying and mapping projects(linear and planar),the strict working flow is adopted.The UAV image acquisition without difference module is carried out,and the image processing is carried out by using Agisoft PhotoScan software,which meets the specifications and technical requirements of the project.Calculate the required results.On this basis,aiming at two different types of projects(linear and planar),a variety of image control point layout schemes are designed,and Orthophoto Image production is carried out respectively,and the related image accuracy is analyzed.By comparing and analyzing the mapping accuracy of different image control point layout schemes in detail,the optimal image control point layout scheme of UAV using undifferentiated module in different types of engineering projects is explored.Finally,the application of Orthophoto Image is introduced with the result image as the basic image data.The main research contents include:(1)Introduce the research background and significance of UAV aerial survey technology,expound the research and application status at home and abroad,the composition and function of UAV aerial photography system,and the detailed workflow of making orthophoto image;(2)Unmanned aerial vehicle(UAV)image is processed in-house based on Agisoft PhotoScan software.Data collection,route planning,image acquisition,image preprocessing and image production are carried out according to the working procedure to obtain the Orthophoto Image of the research area.(3)Aiming at the accuracy of Orthophoto mapping,we design a variety of image control point layout schemes,explore the influence factors of image control point layout on image accuracy,and carry out experiments on linear and planar research areas respectively.By using single point and point-to-point method,we study the influence of image control point spacing,number and other factors on the accuracy of Orthophoto mapping,and compare them.Analysis;(4)By making orthophoto images,land use information extraction and large-scale topographic map updating are applied respectively.(5)The research conclusion is that the result of high resolution Orthophoto Image is obtained,and the result images of various image control point layout schemes are obtained,and the accuracy of contrast image is verified one by one.It is concluded that the point-to-point layout is better than the single point layout when the image control points are evenly laid.The layout of image control points is not more accurate and higher.When the number or distance of image control points reaches a certain value,the mapping accuracy is stable and satisfied.The accuracy limit is poor,and there is no longer a big fluctuation;the optimal layout scheme of the study area in this paper is also obtained.The average 500 meters of a single image control point in a linear area can satisfy the accuracy of 1:500 topographic map plane mapping;four pairs of image control points in a square kilometer of a planar area can satisfy the accuracy of 1:500 topographic map plane mapping;and the land use information of the whole study area can be completed by using the results of two orthophoto map the study area.The classification work is extracted,and the classification accuracy is evaluated by confusion matrix.The 1:2000 topographic map is updated by orthophoto image,and the mapping accuracy meets the requirements of the corresponding specifications.