photo-realism in the classroom

VIRTUALSITE: PHOTO-REALISM IN THE CLASSROOM
I. Dickinson, R.C.T. Ellis, A. Riley, and J. Tenant
School of the Built Environment, Leeds Metropolitan University, Leeds, LS1 3HE, UK
ABSTRACT
Virtualsite is an on-line construction resource which enables users to interrogate photorealistic, three-dimensional, virtual construction objects and to explore linked
panoramic scenes using a computer mouse or keyboard. The web-site (and hybrid
CDROM) caters for children who are curious to know more about the construction
process, for young people considering a career in the industry and for students in
Higher Education reading for a construction-related award. Hence, Virtualsite appeals
to a wide variety of users, providing a vibrant and novel source of multi-media
teaching and learning resources.
Nodes embedded in panoramic scenes, via Realviz Stitcher, QuickTimeVR (QTVR)
and VRWorx, allow learning resources e.g. construction details, careers information
and URLs, to be accessed directly from the site. Moreover, QuickTime multi-row
object movies give the illusion of being able to “hold” various items of equipment and
construction materials. The case study illustrates the key stages in the development of
QTVR movies and describes how directional sound can be added in order to create a
stimulating and interactive environment.
Whilst Virtualsite is a HEFCE funded project, which can offer a range of teaching and
learning opportunities in Higher Education Institutions, this case study concludes that
the concept and technologies underpinning this project have widespread use beyond
construction-related education. Examples of QTVR movies can be found in areas as
diverse as property, design and experimental research. Accordingly, potential
applications depend very much upon the client’s needs and the skills of the system
developer.
Keywords: multimedia, panorama, object movies, construction.
INTRODUCTION
Information and communications technology (ICT) offers exciting opportunities for
educational development, whether this is for children working towards their SATs in
primary school or for students reading for a degree in Higher Education. This case
study outlines the development of one such computer-based learning resource,
Virtualsite, which finds application in a variety of educational settings1.
QuickTimeVR movies are linked together to create a photo-realistic construction site
that users can wander through and explore. Moreover, drawing on the interactive
approach adopted by many computer “adventure” games such as Myst and Riven,
these scenes also provide an interface for accessing a variety of media, for example:
photographs; sketches; movies; animation; detailed drawings; and quizzes. Hence
Virtualsite seeks not only to bring the construction site into the classroom, but also to
encourage users to learn more about the people who are involved in construction and
the processes necessary for the creation of the built environment.
CREATING A WEB-BASED PHOTO-REALISTIC
CONSTRUCTION SITE
Development of the Virtualsite interface is a three-stage process which comprises the
assembly of panoramic scenes, the creation of linked QTVR movies and the
establishment of a bespoke website.
Panoramic scenes
The principles used for the creation of digital panoramic scenes are similar to those
that have been used by photographers for many years. With the aid of a camera and
tripod, a series of overlapping images are “stitched” together in an appropriate
software package. The field of view is improved simply by taking images in portrait
mode and by the selection of an appropriate wide angle lens.
The most time intensive method, although arguably the one which offers the greatest
control over the final image, is to merge each image in a photo rendering package
such as Adobe Photoshop (see Fig.1). A variety of tools enable the boundaries
between individual images to be adjusted - correcting successive images for both
exposure and perspective – so that the final panorama appears seamless.
1
http://www.leedsmet.ac.uk/teaching/vsite
Figure 1: Individual images imported into Adobe Photoshop
Alternatively, other applications are available which automate this process. For
example, Realviz Stitcher, simulates the cylindrical nature of the image and, having
assembled the images in the correct order, manipulates each image to provide the best
possible “overlap”, before exporting the scene in jpeg format (see Fig.2).
Adobe Elements performs similar operations. However Adobe’s Photomerge
command applies cylindrical mapping and advanced blending to adjust images for
"bow tie" distortion, which occurs when perspective correction is applied, and to
minimise colour inconsistencies resulting from blending images with exposure
differences2. Dependent on the precision with which the images are taken, the ragged
edge of the panoramic scene is cropped to provide a regular image for exporting into
VRWorx. Alternatively, Kaidan’s 360 One VR optic3 and PhotoWarp software offers
a simpler, if more expensive, solution.
2
3
Adobe (2003) Adobe Elements User Guide
http://www.kaidan.com
Figure 2: Images merged in Realviz Stitcher
QTVR Movies
Whichever photo-rendering package is used, VRWorx4 creates a virtual panoramic
movie by linking the left and right edges of the scene to form a cylindrical shape. The
software allows the system developer to define the scale and window size of the
finished movie together with the compression settings. A balance between file size
and image quality must be achieved – something that is particularly important when
considering web or intranet delivery. VRWorx also enables multiple QTVR movies
to be connected together, with multi-node scenes allowing the user to “travel”
between various scenes to view the whole site. However, it was felt that the
navigation in QTVR was not sufficiently clear for a first time user, therefore Virtualsite
uses a series of icons (developed in Adobe Photoshop) to aid this process.
Hotspots are added over the icons and close-up images are linked back to the main
movie, again with custom created icons (see Figs. 3 and 4).
Figure 3: Icons created in Photoshop to aid navigation and content
4
VRWorx version 2, VR Toolbox
Figure 4: Icon to allow navigation back to main movie
Web-site delivery
Whilst it is possible to link panoramic scenes within a single QTVR movie, the issue
of file size remains a key concern in the delivery of an internet resource. One means
of reducing file size is to create hotspots in VRWorx, which function as HTML links
to other scenes, before exporting each scene individually through VRWorx. Web
pages are built using basic html which is edited within Dreamweaver.
Embedding the panoramic movie within a web page allows a key for the icons and
instructions regarding the use of Quicktime controls to be created. Virtualsite has a
“virtual room” interface, drawn from scratch in Photoshop, which enables users to
become familiar with Quicktime controls and allows access to the construction site
and other Virtualsite facilities via a series of doors. A site plan on the webpage
provides the user with an additional means of accessing the movies. Each movie is
numbered and the scene that is currently being viewed is highlighted accordingly.
Clicking on the number also takes the user immediately to the scene (see Fig. 5).
Figure 5: Virtualsite website
EMBEDDING MULTI-ROW OBJECT MOVIES WITHIN
VIRTUALSITE
Inter-linked panoramic scenes characterise the development of Virtualsite. However,
object movies offer a valuable extension to this technology. Object movies give the
user the illusion of “holding” some of the construction components that they have
seen on site. Kaidan’s object rigs, such as the Magellan M-2000, are custom built for
photographing objects and, with the aid of VR Worx software, enable QTVR Object
Movies to be created. Figure 6 shows an automatic optical level placed on the Kaidan
rig.
Figure 6: Kaidan’s Magellan M-2000 Object Movie rig
A photograph is taken at every 10 degrees. The camera remains at 90 degrees on the
same plane as the object. Each shot forms one part of a “column” within a complete
row of 36 images. Care must be taken to ensure that the object is perfectly central on
the turntable and that the camera is central to the object. A laser pen may be used to
check correct alignment of the camera arm (see Fig. 7).
Figure 7: Placing objects on the Kaidan rig
Of course, single row object movies only allow the user to rotate an image in a
horizontal plane. Therefore, to create a 360 degree (ten row) object movie, 360
photographs are needed. Photographs begin with the camera directly above the object
pointing down and to eliminate camera wobble and thus blurry photographs, remote
control is used (see Fig. 8).
Figure 8: Half way through the shoot
Photographs are imported via iphoto (see Fig. 9) on a Macintosh G5 into VRWorx
and compressed, before being exported as a QTVR object movie.
Figure 9: Photographs stored in Apple’s “iphoto” software
Once complete (see Fig. 10) the viewer can interact with the object, revealing
different views either by clicking and dragging the object with the mouse or by using
the keyboard commands5.
Figure 10: Multi-row object movie
5
Proni, D. & Weisman, T.D. (1999) The VRWorx Integrated Authoring Environment for
QuickTimeVR: User Manual, VR Toolbox Inc.
FUTURE DEVELOPMENT
Ongoing developmental work is being undertaken to determine the most effective
means of adding labels and hotspots onto multi-row object movies. The former will
allow the user to view additional information about the object (see Fig. 11) whilst the
latter, in the example given, might allow the user to take staff readings through the
sight. Early attempts to insert labels, which fade in and out of the movie as the user
rotates the object, have been both tedious and time consuming to produce, as they
require labels at various perspectives and transparencies to be added to at least 15
stills.
Figure 11: Labels created in Adobe Photoshop
It is commonly acknowledged that the perceived quality of the visual image is
increased by inclusion of sound. Moreover, sound can also be used to enhance the
realism of an otherwise silent construction site. Experiments carried out using
LiveStage Professional to determine whether sound can be added to QTVR movies
have proved successful (see Fig. 12). As the user scrolls around the panoramic scene,
directional sound e.g. a cement mixer, hammering or earthmoving plant, specific to
the view is played.
Many virtual learning environments in an educational setting are characterised by an
array of icons which enable the student merely to download learning materials.
Distance learning resources of this nature are often viewed as being “sterile” or
“cold”6. Interlinked QTVR movies offer an exciting opportunity to create dynamic
interfaces that actively encourage users to interrogate the resources that are available.
As such, these technologies are perceived to have widespread application in the
educational sector.
6
Ellis, R.C.T., Thorpe, A. and Wood, G. (2003) Distance learning and postgraduate education in the
Built Environment, CIB W89 International Conference on Building Education and Research,
University of Salford
However, there are also an increasing number of websites in other disciplines that are
making use of QTVR. For example: Keane Mahony Smith estate agents provide
virtual tours of properties for sale (http://www.k-m-s.com/virtual.shtml); Herman
Miller Architects show QTVR movies of their National Design Centre in Chicago
(http://www.hermanmiller.com); and LAB-VR uses panoramic pictures as an
interface to gain access to scientific content developed in research institutions and
laboratories (http://www.ideum.com). A virtual tour of Beale Street in Memphis
(http://www.seebeale.com), provides another interesting example, using both QTVR
movies and directional sound to create a novel and immersive environment. Indeed
examples such as these demonstrate the potential that this technology has to offer.
Figure 12: QTVR movies amended in LiveStage Professional
CONCLUSION
Anecdotal feedback received during the Recent Advances in Built Environment
Teaching (RABET) symposium suggests that this HEFCE funded project will
complement other innovative FDTL funded construction-related education projects
e.g. SITECAM, which seek to exploit the use of ICT. However, the nature and scope
of Virtualsite will be informed by the findings of RICS funded research7, which seeks
to capture children’s views of careers in construction, and the views of students who
have used Virtualsite in the undergraduate curriculum.
There seems little doubt that the technologies described in this case study have
widespread use in an educational context. However, there is increasing evidence that
interactive panoramic and object movies might have huge potential in the land,
property and construction sectors. The authors of this case study would welcome
suggestions and ideas on the future application of these technologies from academics,
researchers and practitioners alike.
7
Keel, D., Hartley-Jones, S. & Ellis, R.C.T (2004) Careers in construction: what children have to say!
COBRA Proceedings, Royal Institution of Chartered Surveyors, Leeds Metropolitan University.