Preliminaries - Real-Time Rendering: Computer Graphics with Control Engineering - page 10

FIGURE 2.4 (See colour insert.) Samples of surface shading effects that can be achieved
with pixel programs.
Image-based rendering techniques are often classified according to the degree by
which geometry information is used. More importantly and in recent years, there has
been a confluence of image-based techniques with polygon-based rendering in many
applications due to the close continuum in 3D and 2D space in computer graphics.
As volume and image-based rendering are topics beyond the scope of this
research, they are introduced here as auxiliary information on alternative 3D ren-
dering techniques and more information can be found on the Internet and major
research publication portals.
2.2 SYSTEM IDENTIFICATION
The goal of system identification is to derive a mathematical model of a dynamic
system based on observed input and output data. Usually a priori information per-
taining to a system will be useful for postulating the preliminary model structure.
The system may then be modelled according to empirical data (black-box modelling)
or conceivable mathematical functions such as physical laws (white-box modelling).
Often, real world systems are non-linear and operate with reliance on state memory.
The systems are dynamic and thus their outputs may depend on a combination of pre-
vious inputs, outputs, and states. The combination provides the basis for time series
and regression mathematical expressions (models) for different reproducible systems.
System identification is an iterative procedure that can be summarised briefly
by the flowchart in Figure 2.5. A model structure is chosen in advance based on