Synthetic Images for Georeferencing Camera Images in Mobile Mapping Point-clouds

Abstract

Accurate three-dimensional mapping and digital twinning provides a powerful tool for effective maintenance of civil infrastructure and supports efficient future planning of new developments. Three-dimensional mapping can be efficiently performed with a Mobile Mapping System (MMS) that records geospatial data from platform-mounted sensors. However, it is expensive to continuously update datasets by re-capturing with MMS. This paper outlines a novel method allowing camera-only approaches for updating and change detection. It resolves key issues with inherent resolution differences between MMS laser scanner point-clouds and camera images. An intermediary is used to register two disparate datasets. This novel approach to synthetic camera images (SCIs) bridges the differences between MMS point-clouds and camera images and aid in coarse registration of camera images to an outdoor MMS point-cloud. SCI coarse registration precision is maximized by generating surfaces, interpolating intensity values, and reducing noise with a median filter. Landmark features coarsely register the camera image to the MMS point-cloud. The coarse registration is most precise when the whole scene is captured either from the same location as the SCI or further from the scene. Landmarks precisely detect scenes when changes are less than 20%, and foliage does not exceed 20% of the camera image.