Signal Processing for Stereoscopic and Multi-View 3D Displays - Signal Processing Systems - page 3

1 Introduction

A real-world three-dimensional scene is a rich and complex visual phenomenon
processed and perceived only partially by the human vision system (HVS). For a
high-quality 3D scene representation it is sufficient to recreate only the perceivable
visual information and omit the “visually-unnecessary” features. In this way, less
data needs to be processed, while keeping the reproduced scene indistinguishable
from the real one. However, due to the technical limitations of today's display
devices, some visually important features might be lost, which results in perceptual
differences between the visual replica and the real scene and is interpreted by the
HVS as the presence of artifacts. By using appropriate signal processing techniques
it is possible to make these artifacts less noticeable and achieve more pleasant scene
visualization. Correspondingly, this chapter addresses two groups of problems.
First, it investigates upon what are the necessary components of a scene that
should be preserved and reproduced, and second, how to pre-process the scene
representation data in order to minimize the perceived distortion and decrease the
visibility of artifacts on a 3D display.
The chapter consists of five sections. Section 2.1 discusses which 3D features are
visually important and how these features can be included in a 3D scene representa-
tion. In Sect. 2.2 a 3D display classification is presented. The classification is based
on the method that each display uses to recreate the stereoscopic image. In Sect. 3.1 ,
the knowledge of display specifics is combined with HVS properties in an attempt
to explain the appearance and visibility of artifacts on 3D displays. Section 3.2
discusses which optical properties of a 3D display are important from the visual
quality point of view and presents a methodology to measure these properties. These
measurements allow one to derive the so-called quality profile of a given 3D display.
In Sect. 4 the understanding of artifact visibility and knowledge on optical quality
is used for a set of image processing algorithms which aim at a visual optimization
of a 3D scene. Section 5 provides some conclusions.

2 Principles of 3D Visualization

2.1 3D Scene Perception and Representation

An ideal 3D display would attempt creating a light field being a perfect visual
replica of a 3D scene. Such a replica, however, would also include components
which are not visible to human eyes. These components can be considered redundant
and can be omitted from the scene representation. The result is a visually-
indistinguishable replica of the scene. Furthermore, the typical display use case
does not require the scene to react to external light sources or to allow the observer
to walk through object in the scene. Thus, some visual information (e.g. light distri-
bution within scene objects) is unnecessary. Removing this information produces a