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Contents
Summary
Developments in image capture technology allow developers of
multimedia applications to incorporate source material of varying
physical characteristics. However the multimedia developer
drawing up a specification for a capture system is faced with a
bewildering choice of equipment for which there is little
comparative information on the relationship between equipment
specification and captured image quality. This report provides
guidelines for decisions on the choice of appropriate capture
pathways within the context of higher education.
This project evaluated two equipment scenarios, differentiated
on cost for hardware with associated software, and PhotoCD
origination for capturing images for inclusion in multimedia
applications. Classes of image relevant to teaching in a range
of university departments were identified. Original source
material was captured using different hard copy and electronic
media, digitised and stored on an optical disc. The different
versions of each image were ranked against each other and
qualitatively scored for spatial resolution (sharpness), colour
faithfulness and contrast ratio. Standard charts used in
broadcasting to test spatial resolution, contrast ratio and grey
scale were used to provide quantitative assessment. The effect
of compression and image manipulation are not considered in this
report which is part of the ongoing research programme.
On the basis of the results obtained, guidelines were drawn up
on systems specification and image capture for developers of
multimedia application in higher education. The guidelines
recognised that photographic, video and computing skills, and
high quality source materials are as important as having suitable
hardware if high quality images are to be obtained. Overall the
results indicated that the best digitised image on the basis of
the three established quality criteria was obtained from a
combination of a 35mm slide or negative plus digitisation via
PhotoCD. Of the other options there was no clear winner between
video rostrum cameras and scanners. The use of the still video
camera and single frames from a video tape failed to produce
acceptable results. Whilst PhotoCD produced the best result for
three dimensional subjects and flat art, for photomicrography the
use of a rostrum camera offered the distinct advantage of being
able to view the displayed image before capture.
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