| While the scope of human activities is expanding,geological disasters,such as collapses,landslides,and mudslides,occur in large numbers in today’s society.The harm of geological disasters not only threatens the most precious life of human beings,but also hinders the further development of society to a certain extent.To illustrate,once the geological disaster occurs along the mountain road,it will cause irreparable huge losses to the road,passing vehicles and pedestrians,the buildings and the building heritage around the road.Therefore,it is important to construct a set of reasonable and efficient prevention and evaluation methods for geological disasters along mountain roads.In this paper,the linear range of X015 highway and slopes on both sides in Miyun District of Beijing is selected as the research object.Based on tilt photogrammetry,a complete set of operational procedures is designed to identify and evaluate geological hazards along mountain roads.This technical process covers UAV image data processing,micro-scale refined 3D real model construction,micro-scale refined 3D real model disaster identification,multi-source data geological disaster assessment.The main contents are as follows:(1)In view of the high viewing angle of UAV,the image is prone to a large area of high brightness areas such as lakes,white buildings,etc.,resulting in the failure of the dark channel prior dehazing algorithm,this paper proposes an atmospheric light estimation optimization method based on the color recovery module.It makes up for the image color distortion caused by the traditional dark channel dehazing method on large-area rivers,buildings and other objects.The experimental results confirm that the addition of the color restoration module can effectively ensure the balance between color and brightness,the overall picture contrast and brightness are close to the field scene and in line with the human eye vision,and the red road signs on the bright road have also been clearly restored.(2)In order to solve the problem of incomplete dehazing effect of dark channel prior algorithm due to the interaction of transmittance in different areas in UAV images with relatively consistent depth of field,this paper proposes a method to optimize estimated transmittance by constructing compensation function and training multi-layer perceptron model.This makes the transmittance more uniform and smooth,and improves the visual effect of the dehazing image while improving the dehazing effect.Experimental results confirm that the introduction of compensation function and training multilayer perceptron method can significantly eliminate the halo phenomenon of the image,and at the same time,when processing the exposed mountain part,the brightness and dehazing effect of the image are significantly improved,and the detailed information of the mountain is better restored to a certain extent,which can provide a real data basis for the subsequent microscopic scale fine oblique photography model construction and disaster evaluation.(3)This paper attempts to propose and realize a process of using UAV oblique photogrammetry technology to identify and evaluate geological hazards along mountain roads.On the basis of constructing a microscopic fine 3D reality model,the human-computer interaction method is used to realize the accurate identification of geological disasters in the research area,and the feasibility of the technical process is confirmed by the field verification process,which provides new technical support for disaster identification.Based on the DEM results of the oblique photography model,the Landsat satellite data,the basic geological data in the research area,and other multi-source data,eight disaster evaluation factors such as the normalized vegetation index(NDVI)were selected.The analytic hierarchy method(AHP)was used to construct the geological hazard risk assessment model and complete the hazard zoning map,which objectively and accurately realized the purpose of geological hazard risk assessment and research in the linear research area,thereby reducing the possibility of surrounding buildings and architectural heritage being affected by geological disasters,and contributing to the comprehensive management and control of geological disasters on road slopes in the capital area. |
