Landslide Accumulation Three-dimensional Reconstruction And Volume Calculation Based On Mobile Photography Image

China is a country with many geological disasters,and landslides,as one of the most common geological disasters,seriously threaten the ecological environment and the safety of people’s lives and property.The qualitative identification of landslide parameters and quantitative calculation of associated parameters have important reference values for post-disaster risk assessment and emergency rescue.However,the traditional field measurement methods,with a heavy workload and low efficiency,can not meet the needs of post-disaster emergency rescue.Non-contact remote sensing measurement methods such as photogrammetry and three-dimensional laser scanning can improve the processing efficiency,but they have higher requirements for equipment and require surveyors to have a solid knowledge base of Surveying and mapping.Therefore,for the post-disaster rescue work,it is urgent to develop a set of simple and automatic landslide parameter calculation system,so that non-professional mapping personnel can obtain the landslide panorama and volume and other parameters at the first time,to speed up the progress of landslide disaster assessment and debris clearance and other rescue work.In view of the shortcomings of traditional landslide accumulation volume measurement methods,such as heavy workload,high cost,and technical requirements,this paper proposes a set of technical solutions and develops a landslide accumulation volume calculation system for mobile imaging equipment.Through the application demonstration of landslides in the field,the system calculation results are compared with the 3D laser scanning calculation results to verify the effectiveness of the system.The main contents and achievements of this paper are as follows:(1)According to the actual needs of users in landslide emergency rescue,a fast3 D reconstruction technology scheme is provided.The rapid 3D reconstruction technology is to select a high-time technology method suitable for three-dimensional reconstruction of landslides accumulation on the premise of ensuring the model accuracy after comparing and analyzing the difference of time efficiency and reconstruction accuracy between different feature point detection methods and SFM strategies.(2)Aiming at the shortcomings of traditional scale restoration methods in 3D reconstruction,an automatic scale restoration method based on computer vision is proposed.The QR code marker plate with the known size is placed in the landslide scene,and then the landslide scene images with different perspectives are obtained.The algorithm of automatic detection of 2D codes is embedded in the 3D reconstruction work to obtain the real-scale 3D model automatically.Secondly,when the reference plane of landslide is missing in the three-dimensional model of landslide,the depth of the three-dimensional model is used to fit the datum plane of landslide,to realize the purpose of calculating the volume of landslide accumulation through the3 D landslide model.(3)Integrating 3D reconstruction algorithm and landslide accumulation volume calculation method,a prototype system of landslide accumulation 3D reconstruction and parameter calculation for mobile imaging equipment is designed and developed.The prototype system consists of two parts,mobile terminal and server terminal.The main functions of the mobile terminal are data acquisition,achievement display,and volume calculation;The server terminal mainly completes the 3D reconstruction calculation based on image sequence and the automatic scale recovery of the 3D scene.Finally,the volume of a field landslide accumulation is calculated by using the3 D reconstruction and volume calculation system based on mobile imaging equipment.The results show that the system can complete the 3D reconstruction of landslide accumulation and calculate the volume of landslide accumulation through 3D model.Compared with the volume measurement results of the 3D laser scanner,the volume accuracy calculated by the fast reconstruction of the 3D model can reach 74%,and the volume accuracy calculated by the complete reconstruction can reach 90%.The results show that the system can provide reliable 3D models and landslide accumulation volume parameters for non-professional surveyors after landslide disaster,which is of great significance for post-disaster rescue and disaster assessment.