Virtual Time Travel – Exploring the Past With

Virtual Time Travel – Exploring the Past With Google Cardboard
Adeola Fabola (aef6@st-andrews.ac.uk) - First year research student
Supervisor: Dr Alan Miller (alan.miller@st-andrews.ac.uk)
School of Computer Science, University of St Andrews
Introduction
Combining digital reconstruction with mobile technologies has the potential of
enriching visitors’ experience to historic sites. This work discusses the design
and implementation of a mobile App for the Google Cardboard which acts as
a digital guided tour of the remains of St Andrews Cathedral, thus leveraging
technology already in peoples’ pockets to provide immersive onsite
exploration of historic sites. The App brings together traditional media such as
audio, images, panoramas, 3D video and 4 Pi Steradian (or 360°) video with a
mobile smartphone and Google Cardboard to provide a tour of one of
Scotland’s most important historic sites.
St Andrews Cathedral
St Andrews Cathedral represents an important figure in Scottish history as it
was central to religious life in Scotland for many years. It was the largest
church in Scotland and was home to eminent religious figures and activities in
its prime [1]. Significant fires and the Scottish reformation heralded a series of
events that caused the Cathedral to gradually descend into ruins, which still
constitute a popular tourist attraction to this day.
Fig 1: Reconstructed view of the Cloister as it stood in
1318
Fig 7: Equirectangular projection of the interior of the St
Andrews Cathedral Chapter House
Fig 8: Stereoscopic video of the reconstructed St
Andrews Cathedral
System Evaluation
The system was deployed to and tested on both the Android (Google Nexus
7, Samsung Galaxy Note 4) and iOS (iPhone5, iPhone6) platforms, which
uncovered varying levels of support for WebGL and 3DCSS on Android and
iOS devices.
An on-going work is the development of the system for use on the Samsung
VR Gear (see fig 9c), to take advantage of the high-end hardware (e.g. headtracking sensors which translate to less latency and improved levels of
immersion). This would facilitate a comparison of the two versions of the
system and provide an insight into the relationship between the quality of
service and quality of experience in virtual reality systems. Preliminary user
studies have been conducted (see figs 9a-c) to compare the experience using
the light-weight VR system (Google Cardboard) and a higher-fidelity system
(Samsung Gear VR) and an interesting comparison has emerged, thus
necessitating further investigation into how interaction techniques and
technological composition of HMDs affect user experience.
Fig 2: Real world view of the Cloister at the remains of the
St Andrews Cathedral
Design and Implementation
To provide an engaging experience in the mobile exploration of cultural
heritage sites, a Virtual Tour App was developed by capturing panoramic
images from a 3D reconstruction of the St Andrews Cathedral (see Figs 1 –
2). Stereoscopy was incorporated into the system and the Google Cardboard
[2] (shown in Fig 4) was leveraged to produce a light-weight, virtual reality
system – an app that features a strong immersive experience without the
encumbrances and cost implications of venerable VR headsets like the
Oculus Rift [3].
Fig 9: Exploring the St Andrews Cathedral using a) plastic Google Cardboard headset (top-left) b) cardboard Google
Cardboard headset (bottom-left) and c) Samsung Gear VR headset (right)
Fig 3: Google Cardboard. Source: [2]
Fig 5: Trail location: Cathedral Cloister
Fig 4: Top level menu for visual trail
Fig 6: Trail location: Cathedral Nave
Features
1. Visual Trail: Several 360°image and video panoramas – where each
represents a location – linked together to form a trail.
a. Stereoscopic Image Panoramas: Cubic panoramas made from six
images, with incorporated stereoscopic effects (see Figs 5 – 6).
b. 4 Pi Steradian Video Panoramas: Videos in equirectangular
projection (see Fig 7), mapped around the surface of a sphere.
2. Audio Narratives: Recordings associated with each site to reinforce users’
knowledge.
3. Stereoscopic Videos: Video flythrough with offset perspectives for the left
and right views to provide transition effects from one location to the next
(see Fig 8).
4. 3D Objects: Hotspots embedded within each location to facilitate user
interaction.
5. Hands-free navigation:
a. Manual navigation: Focusing a crosshair selector on a hotspot (see
Fig 4) triggers an action (e.g. navigating to the next site).
b. Location-based navigation: Automatic navigation to a site when a
user is within a (user-defined) threshold radius (e.g. 20 meters),
facilitated by GPS.
c. Time-based navigation: Automatic navigation from one site to the
next after a defined period (e.g. 60 seconds).
Conclusion
The combination of a smartphone and a lightweight virtual reality headset like
the Google Cardboard opens up new possibilities for onsite exploration of
heritage sites and arguably provides an improved user experience, by tackling
some of the challenges that have been uncovered in previous works. The
system design (which taps into the inbuilt GPS of smartphones) detailed in
this work occludes the need for translating real world latitude and longitude
coordinates to virtual world coordinates. As a user explores the site, the
system periodically polls the device’s GPS for location data, compares the
latitude and longitude values to those of the different locations present around
the site, and triggers a navigation effect when the user is within range of a site
location. This eliminates the overhead that arises from translating real world
coordinates to virtual world coordinates and thus constitutes an improvement
on performance. In addition, the enclosure of the smartphone in the VR
headset provides a level of immersion that may not be available when viewing
objects on a device’s screen. Furthermore, it makes the system well-suited for
onsite exploration of a site, as the casing serves an additional function of
eliminating any glare (from the sun) that hampers vision; an issue which may
arise when viewing objects on a screen outdoors.
References
1. S. Kennedy, et al. ”Exploring canons & cathedrals with Open Virtual Worlds: The recreation of St
Andrews Cathedral, St Andrews day, 1318” 2013 Digit. Herit. Int. Congr., pp. 273-280, Oct. 2013.
2. Google. Google Cardboard [Online]. Available: https://www.google.com/get/cardboard/ . [Accessed:
23 May 2015].
3. Oculus VR. Oculus Rift – Virtual Reality Headset for 3D Gaming [Online]. Available:
https://www.oculus.com. [Accessed: 23 May 2015].