DUConnect #8: 3D reality capture for subsurface utility mapping


In recent times, an increasing number of so-called 3D reality capture solutions for scanning, surveying, mapping, and modeling subsurface utilities have become available on the market. Utilising devices that are relatively easy to access such as hand phones and tablet PCs, these solutions paint a future where the capture of 3D, high-resolution data on subsurface utilities is relatively fast, affordable, and easy to use. Early adopters in Singapore and beyond have already started using these for scanning and capturing data from open utility laying and trial trenches. Can critical obstacles towards consistent and reliable mapping of subsurface utilities, such as the lack of sufficient skilled manpower and a limited window of opportunity for open trench data capture, indeed be cleared?


In the eighth session of Digital Underground Connect, stakeholders within the digital utility mapping ecosystem participated in a hybrid event to discuss the benefits, challenges, and road towards adoption of 3D reality capture solutions for utility surveying and mapping.


A video replay of the webinar can be accessed here.


The session was opened with a word of welcome by Dr Victor Khoo, Director of Survey and Geomatics Division at the Singapore Land Authority. Victor introduced Digital Underground Connect and indicated that more sessions were being planned, including one at the upcoming Geo Connect Asia conference in March 2023.


* Digital Underground Connect is a platform for government, industry, and academia to share and exchange knowledge about the latest developments in underground utilities. The Singapore Land Authority does not endorse any technologies demonstrated during the event.


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SmartSurvey: An introduction to 3D reality capture technology


The first presentation of the event was delivered by Dr Lasse Hedegaard Hansen, Industrial Postdoctoral Researcher at IT34 A/S and Aalborg University in Denmark and Visiting Researcher with the Digital Underground project in Singapore.


In his presentation, Lasse introduced the concept of 3D reality capture technology, a container concept in which various technologies including drones, laser scanners, and other devices, can be used to produce a variety of three-dimensional representations of reality. In particular, Lasse focused on close-range photogrammetry, in which various two-dimensional images can be used to recreate a three-dimensional scene. For this, IT34 has developed a low-barrier-to-entry solution, SmartSurvey, in which commonly available smartphones are converted into 3d scanners that can produce 3D point clouds. These can be used to document open trenches in which utilities are visible.

The SmartSurvey workflow for surveying and mapping utilities starts with a preparation by spray-painting ground control points (GCPs) close to the trench and placing a scalebar. Subsequently, the trench, GCPs, and scalebar are captured in a single video recording which is then uploaded to the cloud for further processing. While the scalebar helps to ensure a high degree of relative accuracy (±1cm), the ground control points can be surveyed before or after data capture and even after backfilling to achieve a geo-reference and absolute accuracy. Alternatively, a GNSS receiver can be mounted on the phone for geo-referencing purposes.


3D reality capture solutions can potentially restructure utility surveying and mapping workflows. Lasse showed how surveyors would no longer have to wait at the site for the right moment to capture exposed utilities and that, while it is still important to employ good practices for capturing the video, an easy to learn video recording routine that could yield results of reasonable quality.

After Lasse's presentation on 3D reality capture technology, the audience were asked to give their input on what they believed to be the benefits of reality capture technology. These benefits include affordability, ease of use, workflow speed, data quality, and the ability to support downstream applications including visualisation. Accessibility, new use cases, and reliability were, among other benefits, rated highest by the audience.


The slides shared by Lasse can be downloaded here.



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Adoption of reality capture technology – a contractor’s perspective


In the next presentation, Mr Shane Shi, Managing Director of HSC Pipeline Engineering, shared his perspective and experiences on adopting reality capture technology in his company’s daily practices. HSC is a pipe laying contractor based in Singapore that has been active for over 30 years.

Shane described how the process of utility laying on the roads of Singapore can be challenging and hectic. The available time to perform all necessary activities from excavation to pipe laying to the eventual reinstatement is limited and has to be adhered to at all times. The window of opportunity to capture as-builts of newly built pipes is extremely limited and, as a consequence, it may not be possible to capture the most reliable information on the location of underground assets. Besides a lack of available time, Shane shared that, from a contractor’s perspective, conventional surveying workflows are labour-intensive and manpower-intensive. To fully adhere to Singapore’s utility survey standards, each excavation team would effectively have to be matched with one survey team. Such skilled manpower is not available and it would likely make projects very costly.

To deal with these challenges, HSC has adopted a solution comprising a smartphone with photo and laser scanning capabilities, a GNSS RTK receiver, and the Pix4DCatch and Pix4DCloud solutions for data capture and cloud processing. Shane highlighted the advantages from a business perspective. Utilising this solution, HSC has managed to make utility surveying more efficient in terms of manpower used (from 2-person to 1-person teams) and workflow speed (virtually no stoppage of ongoing utility works) while documenting utilities in a rich and detailed representation that enables virtually revisiting the site at any time in the future without excavation.


The slides presented by Shane can be downloaded here.


After a short break, the event continued with another audience poll. When asked about the most important challenges to address towards uptake and implementation of 3D reality capture technology, the audience mentioned that asset owners' readiness to handle 3D data, demand for 3D data and applications, and governance and regulation were considered the most important to address. Additionally, costs of adoption and the need for financial support from the government for purchase of technology and upskilling were important issues for audience members.


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3D reality capture for subsurface asset management


Another perspective in the utility information value chain is that of the asset owner. Ms Michaela Bloch Eiris is the project manager at Novafos Utillities in Denmark and has an extensive track record of introducing and implementing workflows based around 3D point clouds within various utility companies. In her presentation, Michaela shared how a small number of forward-thinking utility companies in Denmark have joined forces and have started working with point clouds. Along with conventional GIS based registration of the companies’ utility assets as points, lines, and polygons, these companies have started documenting open trenches as point clouds. As a stunning example, Michaela shared how Novafos Utilities has captured around 6000 point clouds since embedding reality capture in their on-site practices four years ago.

Capturing trenches and the utilities inside as point clouds has already proven to offer various benefits to the utility companies. In the first place, it serves as a reliable and complete documentation of construction work. This helps the company to evaluate and control the quality of construction activities and resolve any disputes that may arise regarding, for example, the amount of soil that was moved to excavate and backfill a trench. Second, this new, supplementary registration enables the company to perform various digitally-enabled workflows that include visualisation, performing measurements, planning, and design. And lastly, utility works and surveying works in particular were performed faster than before.

While point clouds already provide tangible benefits to the utility company, Michaela shared that she believes that an even greater potential of the use of 3D point clouds is yet to be realised. By sharing 3D information among asset owners and excavation contractors, it will be possible to compare existing utility records with reliable observations of the actual location of these assets. Although certain legal challenges need to be overcome, such 3D data sharing could be facilitated in future iterations of existing data sharing platforms such as Denmark’s LER system. Other future applications of 3D reality capture technology include automatic recognition of information relevant for asset management captured in QR codes and visualisation of 3D data on-site using augmented reality.


The slides presented by Michaela can be downloaded here.



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Adoption and implementation of 3d reality capture solutions for utility surveying and mapping


The event concluded with a panel discussion on adoption and implementation of reality capture solutions for subsurface utility surveying and mapping. The discussion was moderated by Dr Lasse Hedegaard Hansen. He was joined by co-speakers Shane and Michaela along with Dr Victor Khoo (SLA) and Mr Mak Weng Tat (Singapore Institute of Surveyors and Valuers). Altogether, four different perspectives (government, surveyors, pipe laying contractors, asset owners) were represented!


Who should lead adoption and implementation?

After gathering input from the audience, the discussion kicked off with the question on who should be in the lead to further the adoption and implementation of reality capture solutions as part of subsurface utility surveying and mapping practices.


Victor indicated that the government is keen to embrace a role as leader and coordinator of these efforts and that it had already undertaken various activities which include the Digital Underground project and DUConnect itself. SLA has recognised the need for and benefits of reliable 3D data, and intends to continue to facilitate engagements between various stakeholders. However, he reminded the audience that buy-in and support from other key stakeholders is critical to achieving a workable solution and that these stakeholders would have to join forces to achieve success.


Reflecting on her experiences from Denmark, despite having taken the lead previously, Michaela agreed that the government should lead, especially if the goal is to establish a national standard and nation-wide implementation.


Shane added that typically, in Singapore, regulation comes first and then everything else follows suit. However, when looking only from a financial perspective at the matter, it makes sense to involve everyone as new requirements will likely lead to additional costs for upskilling, equipment purchase, and additional tasks to be performed in the workflow.


Collaboration between contractors and surveyors in the surveying and mapping workflow

As demonstrated in the presentations, new technology may affect the way certain surveying and mapping tasks are performed and by whom. Shane and Mr Mak, who represent a contractor’s and surveyor’s perspective, jointly concluded that, while responsibilities may shift, contractors and surveyors are both essential for achieving reliable data on underground utilities. An encouraging perspective for sure!


Shane observed that one reason to do so is because of sheer necessity. Singapore has to deal with a tight labour market with a limited supply of capable individuals with a surveying education and credentials. There may simply not be enough capable surveyors available to perform all required tasks themselves.


However, Mr Mak added that it is critical that a skilled and certified professional is able to evaluate the quality of results produced by others and endorse them. Point clouds and other metadata could actually support such quality control. Simply because technology is becoming much easier to use, does not mean that the results are always reliable and of sufficient quality. His statements were echoed by participants from the audience.


Keys to successful adoption

All panelists were asked to provide a closing statement on what they believe to be the key to successful widespread adoption of reality capture technology. Different and equally valuable answers were presented, including the ease of use or low barrier to entry for these new solutions, the need to consider matters holistically and to not overlook other aspects such as capacity development, and understanding the importance of value of reliable 3D data. Michaela concluded the exchange with the powerful statement that another key to adoption is belief and to simply start using the technology: value will undoubtedly arise over time.


We thank Lasse, Shane, Michaela, and Mr Mak for their contributions and sharing their insights!


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Resources

Slide decks


SmartSurvey: An introduction to low-barrier-to-entry data capture solutions by Dr Lasse Hedegaard Hansen


Adoption of reality capture solutions for open trench mapping by Shane Shi


3D reality capture for subsurface asset management by Michaela Bloch Eiris

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