Automated Multi-Sensor 3D Reconstruction for the Web

Abstract

The Internet has become a major dissemination and sharing platform for 3D content. The utilization of 3D measurement methods can drastically increase the production efficiency of 3D content in an increasing number of use cases where 3D documentation of real-life objects or environments is required. We demonstrated a developed, highly automated and integrated content creation process of providing reality-based photorealistic 3D models for the web. Close-range photogrammetry, terrestrial laser scanning (TLS) and their combination are compared using available state-of-the-art tools in a real-life project setting with real-life limitations. Integrating photogrammetry and TLS is a good compromise for both geometric and texture quality. Compared to approaches using only photogrammetry or TLS, it is slower and more resource-heavy but combines complementary advantages of each method, such as direct scale determination from TLS or superior image quality typically used in photogrammetry. The integration is not only beneficial, but clearly productionally possible using available state-of-the-art tools that have become increasingly available also for non-expert users. Despite the high degree of automation, some manual editing steps are still required in practice to achieve satisfactory results in terms of adequate visual quality. This is mainly due to the current limitations of WebGL technology.

Interactive Geo-Information in Virtual Reality – Observations and Future Challenges

“…The mentioned polygon counts are vastly higher than those reported in game engine or other real-time rendered applications, e.g. 0.9M polygons in Kersten et al, (2018a); 0.7M in Tschirschwitz et al, (2019a) and 0.5M in final application produced in Julin et al, (2019). The challenge in applying photogrammetric or laser scanning data for game engines is in producing textured mesh models whilst maintaining sufficiently low data volumes.…”

“…However, mesh models produced via laser scanning or photogrammetry commonly contain extremely high polygon counts: in Kersten et al (2015), the photogrammetric model contained 6M polygons and the model formed by triangulation from laser scanning 10M. In Julin et al (2019) the "hybrid model" produced by a combination of TLS and photogrammetry contained 694M polygons prior to downsampling operations. The mentioned polygon counts are vastly higher than those reported in game engine or other real-time rendered applications, e.g.…”

Dynamic 3D Simulation of Flood Risk Based on the Integration of Spatio-Temporal GIS and Hydrodynamic Models

“…The core of the platform layer is a spatio-temporal GIS, which is based on a digital earth platform developed by the authors. The platform layer connects the preceding and the following procedures, performs data management for the following procedures, and provides service integration, calculations, and data for the preceding procedures [41,42]. The service layer encapsulates core modules or functions for services, which allow the application and operational system developers to focus on the business process and user demands and simplifies the development workload in the application layer.…”

A Comparison of Low-Cost Sensor Systems in Automatic Cloud-Based Indoor 3D Modeling

“…Traditionally, manual modeling techniques have been necessary to produce models with sufficient accuracy and completeness [19]. Manual modeling requires significant time and labor resources, particularly if using data from multiple sources [20], and the automatic modeling of the built environment has been widely explored as an alternative approach [9,12,21,22]. Approaches for the automatic generation of indoor models include surface-based methods [23], primarily for visualization purposes, fitting volumetric primitives to the measurement data, or constructing the room based on a shape grammar [24].…”

“…A recent increase in studies concerning 3D depth estimation from a single image has been noted [27], where neural networks are used for determining the presence and position of planes based on known ground truth, both for rectangular [28] and panoramic images [29]. The automation of image-based reconstruction has advanced in recent years, with automated modeling providing an efficient, low-cost alternative and results of good accuracy [22]. With personal cameras being ubiquitous, image-based modeling is a widely accessible method for indoor modeling [30], though the geometric information obtainable with TLSs or RGB-D cameras aids reconstruction, and areas with sparse features remain an issue [31].…”