Smartphone-Based Reality Capture for Subsurface Utilities: Experiences From Water Utility Companies in Denmark

Abstract

Abstract. Inaccurate and inconsistent documentation of subsurface utilities is a reoccurring problem in the construction industry affecting not only the end-users, but all actors involved in designing, constructing, and maintaining pipes, cables and other utilities hidden underground. In this study, a new method for 3D capturing of subsurface utilities, based on a newly developed Smartphone-based Reality Capture (RC) solution is explored. The research was divided into two parts. Firstly a testing of the method accuracy and secondly, an investigation of the usability of the method. The research results firstly showed that the RC solution is a feasible surveying method, that facilitate capturing of as-built utility assets, which can be used as a supporting tool to conventional surveying methods or alone, as the testing showed an accuracy of ±5 cm for the generated point clouds. Secondly the usability testing revealed that the RC solution benefited the utility owners by allowing time-savings on construction projects, as well as generating visual-realistic 3D models of exposed subsurface utilities to be used for quality assurance and planning of future utility work.

Potential of Consumer-Grade Cameras and Photogrammetric Guidelines for Subsurface Utility Mapping

“…These findings are in alignment with existing literature in observing that digital cameras outperform mobile phone cameras due to their better camera quality (Akca & Gruen, 2009). The results of the smartphones' horizontal errors were largely similar to the results in Hansen et al (2021) where a RMSEXY of 30.4mm was achieved. However, the vertical errors differed by around 20mm (the authors reported a RMSEZ of 32.6mm).…”

“…Many of the existing photogrammetric applications are applied to the 3D reconstruction of objects situated above a surface, leaving a gap in understanding the photogrammetric potential for mapping excavated trenches. A commendable study by Hansen et al (2021) assessed the locational accuracy of water utilities by comparing two approaches: SfM technique with total station and GNSS-RTK. Smartphone-based video recordings of excavated pits were recorded, and it was concluded that the photogrammetric technique was a useful surveying method for capturing as-built utilities.…”

A Simple Way to Reduce 3D Model Deformation in Smartphone Photogrammetry

“…In the case of geological issues, the analysis of rock porosity and roughness is a common topic [ 65 , 66 ], while in geomorphology it is popular to create digital models of various types of geomorphological forms (e.g., cliffs, caves) [ 70 , 71 ]. In terms of industrial applications, it is worth noting displacement determination [ 78 , 79 ] and utility networks modeling [ 75 , 76 ].…”

Instant Segmentation and Fitting of Excavations in Subsurface Utility Engineering

“…Hansen et al [19] suggest using construction and maintenance projects to improve documentation quality, and propose on-site documentation using photogrammetry or laser scanning, as well as utilizing…”