CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
Architectural Heritage’ into the virtual environment. This
methodology covers the combination of visual and acoustical
features of the architectural spaces in interactive 3D virtual
environments. Through the utilization of this methodology in
situations where architectural conservation and restoration are
not available, virtual conservation and restoration will be
provided. The methodology of the project consists of the
following steps:
1. Identification and Evaluation
• Objective identification and evaluation
(measurements, calculations)
• Subjective identification and evaluation
(psycho-acoustical surveys)
2. Creation of the Virtual Environment
• Visual simulation (simulation of spaces,
simulation of people)
• Acoustical simulation
• Combined 3D real time simulation with virtual
people
3. Evaluation
• Examination of the specific acoustical
properties of selected worship spaces
• Assessment of the psycho-acoustical
characteristies of these worship spaces
• Determination of the optimum acoustical
conditions for mosques.
• Conservation and restoration of the architectural
heritage of selected monuments (acoustical and
visual) in a virtual environment
3. WORK CARRIED OUT ON THE PROJECT
After the examination of the bibliography, the worship spaces to
be worked on in the project were selected. Table 1 shows the
selected mosques and churches.
In order to create the basic database for the research project
architectural projects, data on the acoustical [1] and visual
properties of surface materials and data on religious acoustical
activities have been collected and monitored. The alterations
having visual and acoustical importance occurring with respect
to time were determined in order to create the data base for the
virtual restitution of the selected worship spaces.
For the acoustical identification of the spaces, objective means
such as measurements and calculations and subjective means
such as psycho acoustical surveys have been planned. Room
acoustic measurements were carried out basically following
methodologies of ISO 3382. Two teams executed the
measurements in order to obtain comparative data.
Measurements were taken to determine the realistic usage of the
spaces. Impulse responses obtained from each measurable
combination of source and receiver position provided data for
monaural and binaural analysis of the sound field [2]. Analysis
of the data is almost complete.
The measurement of the acoustical properties of the interior
materials was among the tasks. Floors, which are covered with
carpets, have a special importance in the sound field of
mosques. Therefore, a model was produced and tested in a
reverberation chamber to obtain the absorption coefficients [3].
To find out the effect of the dome, a scaled model was made,
measurements taken, and results evaluated.
To characterise the acoustic signals delivered inside worship
places, solo and choral pieces of Islamic and Byzantine vocal
music were recorded in anechoic chamber and in real spaces
(Kadirga Sokullu Mosque, Siileymaniye Mosque and St. Irene
Church). These recordings are used as a database for
auralisations, subjective tests and assessment of signals
delivered in mosques and churches.
Acoustical simulations were carried out by modelling the six
worship places in the room acoustic simulation program Odeon
[4]. The findings derived from the simulations were compared
with the measured results. Auralisation was another important
task which depended on simulation. Auralisations are to be used
in two ways: to be included in visual simulations in order to
create a realistic environment and to be used in subjective tests.
Using the anechoic recordings, auralisations of the places were
carried out. 56 sound signals were prepared, combining two
stimuli (song and speech), two volumes (5700 m 3 and 115 000
m 3 ), seven reverberation times, and two source-receiver
positions for the subjective tests.
Visual simulations were restricted to four of the selected places;
Kadirga Sokullu Mosque, Siileymaniye Mosque, S.S. Sergius
and Bacchus Church and St. Sophie. A work methodology was
developed [5]. The 3D models of the selected historical
monuments were virtually constructed from available
architectural drawings and visual data from the recordings by
using 3D Max and Photoshop software. Furthermore, the
‘Lightscape’ software package was utilized in order to enhance
the photo-realistic aspect of the 3D reconstructed models of the
monuments. The work on the simulation of life inside the
mosques is ongoing.
For the subjective evaluation of the worship places, a social
survey and laboratory simulation experiments have been
planned [6]. The evaluation of the acoustics of the mosques is
comprised of three steps: a psycho-social survey of 120 users, to
find their spontaneous opinions on the relative importance of
acoustics, two sets of 14 interviews with specialists in acoustics
so as to get their impressions on registered and auralised sounds
and to select the main acoustical parameters of their judgment,
and an experiment on a sample of 90 people consisting of three
sub-samples, using the 56 auralised sounds. Analysis of the data
is completed.
Two different media for presenting acoustical and visual
environments are proposed: one is a semi-interactive CD-ROM
based on a high quality hybrid presentation platform; the other
is for broader dissemination on the Internet, where users can
walk through the monuments by downloading a VRML model.
The first media will enable the presentation of very high quality
results to the academic community, whereas the other will
permit anyone who is interested to access the ‘medium quality’
3D models. A scenario is designed to present the virtual
acoustical conservation.
The architectural, aural, acoustical and visual data collection of
the CAHRISMA project and also the acoustical and visual
simulations, which include virtual interactive life so as to create
more realistic visual environments, have been completed.
Analyses and assessments of specific acoustical properties of
ancient spaces other than mosques and churches have also been
held.
