DEliverable 2.3 - the School of Engineering and Design - Brunel ...

ICT Project 3D VIVANT– Deliverable 2.3
Contract no.:
248420
User Acceptance Validation Plan
These will set certain standards in terms of what the user expects with respect to e.g., colour,
resolution, brightness, contrast, etc., which the project results will have to meet. Although this may
sound like a challenge, comparison with other technologies may also show advantages, such as
independence from the need to wear special glasses, etc. The following two sub-sections will outline
features of 3D technologies suitable for comparison tests.
Nevertheless, since the 3D holoscopic technology is in its infancy, the tests envisaged in the project
should be considered more as useful guidelines for the future developments of this technology rather
than competitive comparisons aimed to persuade about the need of giving up any other existing 3D
visual technology.
Consequently, the methods and approaches reported in the aforementioned publications will be
practiced as required in order to obtain valid results, but it is assumed that they may have to be
relaxed when deemed necessary. In this case the corresponding WP7 deliverables will mention the
actual modifications with respect to the standardized rules.
User Acceptance Tests on 3D holoscopic video content will primarily be conducted with
questionnaires comprised of closed questions to explore limits of quality acceptance and open
questions to allow for individual input. For a detailed description of the tests, see Section 4.1.
2.2.1 Stereoscopic 3D
Most of the currently available 3D technologies are based on stereoscopic images. In this approach,
one image is produced for each eye and delivered to the appropriate eye during playback. The
separation of the images is usually done using special 3D glasses, for home users usually with activeshutter
or polarised glasses.
For the production of live-action stereoscopic content, stereo setups of two cameras in mirror or sideby-side
rigs are used. This requires a high degree of accuracy when setting up the cameras since the
cameras have to be accurately aligned and work exactly frame synchronously. In addition, to achieve
good results, the properties of the lenses also have to match perfectly.
One of the main disadvantages of the stereoscopic method is the need to wear some kind of special
3D glasses. Moreover, in stereoscopic viewing, the eyes’ convergence and accommodation do not
work in unison in contrast to normal human viewing. This leads to eye fatigue and in some cases even
to headaches. Another shortcoming of stereoscopic 3D is the dependency on the viewing angle. Since
only two different perspectives are present, a sideways movement of the observer results in a
sideways shear of the stereoscopic image.
2.2.2 Multiview Auto-stereoscopic 3D
Auto-stereoscopic approaches are generally based on the same principles as the stereoscopic 3D. But
in contrast to the classical stereoscopic 3D, for the multiview auto-stereoscopic case a larger number
of perspectives (views) are used. To view the content, mostly LCD-based displays with lenticular
lenses are used. They distribute the multiple views horizontally across the entire field of view of the
display. Depending on the position, every viewer can see exactly one pair of these views, a
stereoscopic image pair. The main advantage of auto-stereoscopic displays is that the viewer does not
need glasses and that a larger area of parallax can be shown. With a larger number of different views,
the effect of shear distortion can also be reduced. The main disadvantage, on the other hand, is that
the more views a display offers the more the resolution is reduced in comparison with 2D of
stereoscopic 3D systems.
Unless intermediate view interpolation or extrapolation is used, in general, for the production of
content for auto-stereoscopic displays the number of cameras required is the same as the number of
views offered, normally at least five to nine. This significantly increases the effort and expenditure,
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