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With the availability of very high speed RAM refresh memories, it has
now been possible to build large data bases of 4096 x 4096 pixels
which can be partitioned and randomly accessed by multiusers for
different applications. One of the most significant aspects of such
System is intheir architecture design and feedback path that allows
the actual viewed imagery to be read back into the data base at TV
rates, The feedback also allows interative processing. Use of pipeline
processors, image manipulation, and processing circuits, all updata-
ble at video rates, allow a number of image processing techniques
to be carried out in realtime. Another significant aspect is the use of
firmware which allows turnkey operations which are the need of bulk
data processing. In true sense, these are parallel array processors
where à cycle time is 1/25th of à second and the array is 512 x 512
pixels x 8 bit deep.
Because of Several advantages ; these systems have found widespread
uses in thermal mapping, hydrology, forestry, agriculture, weather
prediction and analysis, non-destructive testing, quality control and
inspection, X-ray fluroscopy, and a host of other fields.
REAL TIME VS OFF-LINE VIDEO IMAGE PROCESSING SYSTEMS
A real time image processing system is required when (i) it is
necessary to make an important decision faster; (ii) raw image from
sensors or input device is inadequate in some way and requires
corrections; (iii) input image is changing; and (iv) it is necessary to
eliminate delays caused by off-line computer or film processing.
For instance, a standard frame of 512 x 512 pixels in a video image
contains 262,144 picture elements (pixels). This amount of informa -
tion is so large that most computers do not accept through a single
input (I/O) channel. Although there is an infinite amount of flexibility
in computer processing, speed of operation is limited.
Thus, a video-rate image processor with limited flexibility will
process this massive information in just 1/25th of a second while most
computers would need much longer time. In essence, a real time
image processing provides the following advantages:
(i) It allows an important decision to be made faster.
(ii) Once some specific image processing technique has been
selected, it can be used continuously or repeatedly as part of
overall process.
(iii) Before a particular function has been optimized, it is easy to
experiment with various processing functions while viewing
the results on a display. Thus, a technique can be easily
optimized by interaction between the user and the processor.
(iv) Because of easy user-processor (man-machine) interaction,
it is easy to continuously optimize processing functions as
external conditions change.
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