Page 29 - Digital Analysis of Remotely Sensed Imagery

2 Cha pte r O n e

1.1 Image Analysis System
In order to function smoothly, a digital image analysis system must
encompass a few essential components in hardware, software, the
operating system, and peripheral devices (Fig. 1.1). Featured
prominently among various hardware components is the computer,
which, among other things, is made up of a central processing unit, a
monitor, and a keyboard. As the heart of the system, the central
processing unit determines the speed of computation. The keyboard/
mouse is the device through which the user interacts with the machine.
The monitor fulfils the function of displaying the image processing
software and visualizing image data, as well as any intermediate and
final results in tabular and graphic forms. The operating system
controls the operation of a computer’s activities and manages the
entry, flow, and display of remote sensing data within the computer.
These components are common to all computers.
Unique to image analysis is the software that executes computer
commands to achieve desired image processing functions. These
computer programs are written in a language comprehensible to
the computer. During image analysis these commands are issued by
the image analyst by clicking on certain buttons or icons of the
image processing system. So far, a number of image analysis systems
have been developed for processing a wide range of satellite data
and for their integrated analysis with non-remote sensing data.
An image analysis system is incomplete without peripheral
devices that input data into the system and output the results from

Data input/ Data analysis Results output/
import & display export

FIGURE 1.1 Confi guration of a typical digital image processing system.