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

ICT Project 3D VIVANT– Deliverable 2.3
Contract no.:
248420
User Acceptance Validation Plan
• From stereoscopic experience some strange phenomena are known. If the inter-ocular
distance is chosen too wide, the scene will be perceived like a dollhouse. This is the so
called Lilliputian effect. Is this in accordance with the director’s intention
• Another artefact is the so called window violation. An object in front of the screen which
is close to the lateral frame of the picture will be cut off by the picture frame in an
unnatural manner. In natural perception an object in front of the window cannot be
occluded by the window frame located at a further distance.
• The size of stereo rigs might be a problem for actors. It is harder for the actor to maintain
a viewing line, as the mirror of a stereo rig might be bulky and obstruct the viewing line
for the actor when she/he plays very near in front of the camera.
The stereographer can change the binocular perception by modifying the stereoscopic parameters
“inter-ocular distance” and “convergence”. Up to now, the film makers have not yet agreed on a
common set of rules, how binocular depth cues should be utilised in stereo-3D productions. We now
understand that 3D production obeys different rules than 2D productions. Consequently we can also
accept that holoscopic productions will require yet another rule set differing from the 2D grammar
and from the stereo-3D grammar.
A.2.2 PRE-PRODUCTION
Staging and decorations will have to be planned and built more accurately. A flat wall paper in the
background, for example, will not properly stimulate the sensation of a deep perspective. As the
cutting frequency will be slower in the stereo 3D, the props have to be worked out to a more detailed
degree, as the human eye will notice sloppiness more easily. For the same reason rehearsal and acting
will have to be more precisely.
A.2.3 SHOOTING
3D productions require more complex production tools. The 3D camera comprises two normal
cameras, mostly digital cameras like HDTV cameras or digital film cameras. In some rare cases
integrated 3D cameras are available, which already contain two 2D cameras mounted into a single
housing. In addition to the cameras, more equipment is needed, like stereo rig, rig control, means for
synchronization of camera output, synchronised lens control, synchronised recording and playback,
3D monitoring.
3D productions require additional personnel. The most important new person in the camera crew is
the stereographer. The stereographer cooperates with the DOP and the director to design the depth
perception of the picture. The stereographer determines the interocular distance and the convergence
angle of both cameras. In addition to the stereographer one or more stereo-technicians will be
required to operate the cameras.
In 3D productions, lenses with different focal lengths are being used than in 2D production. DOPs
tend to use shorter focal length lenses. In many cases DOPs also tend to use a smaller aperture than in
2D productions, as a shallow depth of field is often considered contradictory to binocular depth
perception. As a rule of thumb, panning speed should be slower than in 2D production. The human
eye also seems to be more sensitive to crushed shadows in 3D perception than in 2D.
Special care is needed to avoid unwanted differences between the left and right image. The human
eye expects only horizontally shifted pictures. Vertical disparities can happen easily, if the cameras
are not calibrated correctly. It is the task of the stereographer to avoid those errors. Typically, this
requires several hours of setup and calibration time for the stereoscopic camera. Differences in
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