Research On The Making Method Of The Unfolded Drawings Of Subway Maintenance And Management Based On Optical Image

Subway is an important and convenient means of transportation to ensure the normal operation of modern cities,maintain people’s lives,work,exchanges,and promote rapid economic development.In order to take advantage of the temporary maintenance and management of subways after a daily outage of the subway,high-resolution optical cameras are used to capture high-resolution optical images along the rails at regular intervals,and then the photogrammetric correlation processing finally meets the requirements of subway maintenance management.The image of demand is a quick,intuitive and effective method.Most of the domestic image mosaics are based on feature-based image matching methods,However,the feature extraction and matching calculations are relatively large,and the position and posture of a single original image in the stitched image are uncertain.Therefore,the stitched image formed by this method can only be used for browsing,and cannot be measured,In order to solve this problem,this paper adopts a method of combining camera calibration to conduct tight image mosaic.This paper introduces the integration of the six combined camera system,as well as the single-camera calibration and combo camera calibration.The virtual image mosaicing of the cylindrical projection model is performed on the image of the same camera captured by the Six-Film combination camera,and then the method of bundle adjustment is used to obtain the precise external orientation element between the images.The SFM method is used to extract the 3D point cloud of the tunnel to fit the tunnel section.Then,according to the three-dimensional model of the tunnel and the image of the accurate outer orientation elements are mapped to realize the close stitching of the image and the columnar map of the tunnel is obtained.Intercept the tunnel histogram according to a certain distance and expand it into a plane plan,and make a tunnel unfolded map that can be used for subway maintenance and management.This paper will conduct detailed research description and verification of related equipment and specific production methods.