Rendering, Adaptation and 3D Displays - 3DTV: Processing and Transmission of 3D Video Signals - page 135

Initial disparity map Sub-pixel mask applied to

the disparity map

Texture without de-aliasing Texture with de-aliasing

Figure 5.9 Interpolated texture samples with and without de-aliasing [5]

In the final stage of 3D video displaying, scrambling needs to be applied on
the interpolated and rendered texture images, depending on the particular
display type. For stereoscopic 3D video content, specific processing is applied
instead to ensure interoperability, i.e. to convert the rendered content into
a universal format accepted by most standard 3D displays. Side-by-Side
or Top-Bottom formats are among the most common display formats for
stereoscopic 3D video content, which was previously mentioned in Chapter
1. These are also known as ''frame-compatible'' formats, where the pair
of images belonging to the views from the left eye and the right eye are
downsampled in space by two in one of the x or y directions, and then
combined to produce a single image that has the same spatial resolution as
the original left eye and right eye images. Another format that is known
as ''frame sequential'' is also available, which does not involve any sub-
sampling of images, but consists of a sequence of alternating frames wherein
each successive frame carries the image meant for the right or the left eye.
Figure 5.10 depicts the formation of these formats considering the original
stereoscopic image pairs at Full-HD resolution (1920 1080).

To address multi-view displays, the details of which are discussed in
Section 5.4, the display scrambler is usually directly linked to the display's
specific pixel arrangement. A multi-view display can show a different number
of views and thus a different scrambling operation is necessary depending
on the display type. Moreover, multi-view displays show reduced resolution
images to the different directions. Due to the way they are constructed,
they allocate a fixed amount of pixels available in the underlying display
panel to certain viewing directions. For instance, if a multi-view display
can show nine views, then the number of pixels shown in one direction is
approximately one-ninth of the full display resolution. The loss in the spatial
resolution is usually evenly distributed between the horizontal and vertical
resolutions. Figure 5.11 outlines the overview of the 3D rendering framework
for multi-view displays, including the sub-sampling and tiling.

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