Digital Signal Processing Reference
In-Depth Information
Image
quality
3D visual
experience
Depth
perception
Figure 6.1
3D visual experience
notion of visual experience can be defined as shown in Figure 6.1. The factors
affecting perception of image quality and depth are examined in Sections
6.2.1 and 6.2.2 respectively.
6.2.1 ImageQuality
The human visual system can identify various types of impairments in video
contents. Some of them are spatial while others are temporal impairments.
Spatial impairments include blockiness, ringing, contouring, posterizing, and
structural discontinuities. Jerkiness, freezing, and mosquito noise are a few
examples of temporal impairments. The most accurate way of quantifying
the impact of these impairments on the visual experience is by subjective
assessments. These assessments involve human subjects, who grade the
impaired video [7]. However, subjective assessments are too inconvenient,
expensive, and time-consuming for most applications.
6.2.2 VisualPerceptionofDepth
The human visual system uses both physiological and psychological cues to
comprehend the depth in sensed images. Some physiological cues require
both eyes to be open (binocular), others are available also when looking
at images with only one open eye (monocular). It should be noted that all
the psychological cues are monocular. In the real world the human visual
system automatically uses all the available depth cues to perceive the depth.
The availability of binocular depth cues in a video depends entirely on the
capabilities of the particular video reproduction system in use. Nevertheless,
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