Quantitative evaluation of overlaying discrepancies in mobile augmented reality applications for AEC/FM

Abstract

14Augmented Reality (AR) is a trending technology that provides a live view of the real and 15 physical environment augmented by virtual elements, enhancing the information of the scene 16 with digital information (sound, video, graphics, text or geo-location). Its application to 17 architecture, engineering and construction, and facility management (AEC/FM) is 18 straightforward and can be very useful to improve the on-site work at different stages of the 19 projects. However, one of the most important limitations of Mobile Augmented Reality (MAR) 20 is the lack of accuracy when the screen overlays the virtual models on the real images captured 21 by the camera. The main reasons are errors related to tracking (positioning and orientation of 22 the mobile device) and image capture and processing (projection and distortion issues). 23 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http:// creativecommons.org/licenses/by-nc-nd/4.0/ This paper shows a new methodology to mathematically perform a quantitative evaluation, in 24 world coordinates, of those overlaying discrepancies on the screen, obtaining the real-scale 25 distances from any real point to the sightlines of its virtual projections for any AR application. 26Additionally, a new utility for filtering built-in sensor signals in mobile devices is presented: 27 the Drift-Vibration-Threshold function (DVT), a straightforward tool to filter the drift suffered 28 by most sensor-based tracking systems. 29 30 Engineering; AEC/FM; Geo-Location; Sensors. 33 34 However, the most sophisticated and up-to-date 3D techniques for designing, modelling and 46 representing construction projects have not been able to substitute definitely paper layouts 47on site yet. Digital devices, such as tablets, smartphones or laptops, are often used on site for 48 illustrating the traditional 2D blueprints that have traditionally been used in projects, usually 49 by means of 2D on-screen pdf or CAD files. Even though mobile computing is a field in 50 evolution, its possibilities are not widely spread in current practices. Human skills (e.g. spatial 51relations, spatial orientation, spatial visualization, etc.) are still required for processing the 2D 52 documents and understanding their meaning in real world, i.e. interpreting classical 2D 53 representations to recognize their 3D implications. These limitations can be overcome by 54 means of adequate technologies, for example the Augmented Reality. 55This paper presents an efficient solution for developing an outdoor application for portable 56 devices, based on Mobile Augmented Reality (MAR), to represent the virtual model of a 57 project in its construction site. As will be explained throughout this work, there are different 58 factors that affect the accuracy and efficiency of this technology, i.e. the geo-location of the 59 mobile device, its orientation, and the techniques for accurately overlaying virtual models 60 (dealing with projection and distortion issues), which motivated the authors to o...

Assessment of 3D Models Placement Methods in Augmented Reality

“…Ref. [13] proposed a methodology to evaluate AR placement errors. The main objective of their study was to present a reproducible methodology for calculating the real distances between any real point and the lines of sight of its virtual projections to obtain a quantitative evaluation of these superimposed deviations for any AR application.…”

“…Several AR placement methods have been proposed in the literature. Furthermore, many authors [12][13][14] have addressed the AR placement issue. However, we note a lack of studies assessing the existing approaches and methods of 3D model placement in an AR environment.…”

“…This concept was used by some authors [15][16][17], who defined it as the positioning of a model to be enhanced on location. Several references [12][13][14]18] as well as Microsoft have used the word "Alignment" to describe how the augmented reality application "SnapToReality" performed during testing. The placement of virtual items in the real world is also referred to as "overlaying" [19,20].…”

Evaluation of Augmented Reality-Based Building Diagnostics Using Third Person Perspective

“…The identified hazardous information is then overlain on worker's view through AR. Gomez-Jauregui et al presented CEsARe [25], a mobile AR application for visualizing virtual models on construction sites. An up-to-date survey on mobile AR applications in construction can be found in [26].…”

“…When it comes to tasks that rely on tool precision and accuracy, reports on the impact of system inherent errors are naturally scarcer. Although studies like [14,25] indeed comprise detailed error analysis, the authors only considered errors stemming from the systems while factors introduced by users were neglected. However, we believe that, like any other tools, no matter how well-crafted an AR system is, it will eventually have to be put into a user's hands to realize its purpose and hence user factors such as perception and cognition also play an integral part in evaluating the overall task performance.…”