Image Processing Reference
In-Depth Information
1
INTRODUCTION
1.1 Overview
This topic is a systematic and detailed description of the basics of 3D images
and their processing. Before beginning with specific details, however, we will
discuss an overview of 3D images and their processing, and also will introduce
the contents of each chapter in the topic.
1.1.1 3D continuous images
Generally, 2D images are printed onto paper or film or displayed on a screen.
Therefore, the brightness (luminosity or density), reflectivity, transmissivity,
etc. of a given point ( x, y ) on the screen can be clearly represented by a two-
variable real function f ( x, y ). The value of f is clearly defined physically as
the “density” or the “intensity” of the point.
The 3D images (more precisely, the 3D continuous images) covered in this
topic are formal extension of such 2D images into 3D. In other words, a point
( x, y, z ) in 3D space is taken as data with a density value function f ( x, y, z ).
The content of the density function f , however, will be completely different. It
will change greatly for each individual image, without the high commonality
of density as is found in 2D images. For the time being, however, this topic
will continue to use the term “density.” More precise definitions are given in
Chapter 2. Specific examples are given in Section 1.2.
1.1.2 3D digital images
This topic is concerned with digital image processing; in other words, image
processing using computers. In order for such processing to take place, the 3D
continuous image must be digitized. By analogy with 2D images, the screen
is split up into pixels and the density value of each is represented by a finite
number of bits. The pixels themselves also are extended to 3D and are called
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