08-17-2017, 02:49 AM
Hardware for image processing - Basics Eye Human vision sensor
History
Photography appeared in XIX century.
Ideas for developing fax machines and usage of telegraphic lines for
image submission was born during the World War I.
The idea about TV development was born around 1930.
The key event in digital image processing was development of the
first electronic computing machines. These machines enabled simple
and fast image processing.
The second important event was astronomical exploration and race
to space.
JPL from California had the first task related to the digital image
processing within NASA USA space program.
Image Acquisition
Optical system can deform image.
Companies producing systems can estimate distortion
caused by h(x,y) and they can develop techniques to
reduce effects of distortion.
The second important element in optical system is sensor
that transforms optical signal into electrical equivalent.
We will not study sensors since they are subject to quite
fast development and we will not consider it within this
course.
Some details related to sensors are given in our textbook
but development in this area is quite fast and some of
them can already be too old.
TV
Digital TV (DVB) is in rapid progress presently.
Digital TV standard is called the HDTV.
Since there is rapid development it can happen that
other standards emerge.
High compression lower quality formats are
developed for video streaming over the Internet.
Development of new generations of digital video-
discs requires also new high quality video and image
formats.
Computers in image processing
Revolution in development and application of the digital
image processing algorithms begins with development of fast
and reliable image processing machines.
Development of new devices for image processing is very
rapid and data given in the textbook just couple of years old
can be assumed just as historical overview.
Commonly PCs used for general purpose have special
graphic card (its duty is to process graphical data and to
submit them to monitor).
This card can contain processor used for data processing as
well as the memory.
The main purpose of the processor is usually data
compression while memory commonly has special
construction to allow processing of huge amount of data.
Printing
Laser printers print material in single color and due to
the imperfection of human visual system we see
different amounts of the same color as different
colors.
There are numerous alternative printing schemes and
apparatus.
Two the most important characteristics of printers
are dpi=dots per inch (determines printer resolutions
and how fine is our printed page; 600dpi is today
assumed as reasonable minimum) and ppm=page
per minute.