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4.3.1 
4.3.1.1 
4.3.1.2 
4.3.1.3 
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hardware for efficient implementation. The overall system concept 
and system configuration is illustrated in Fig. 1 
Processing Hardware 
Image Data Base 
This forms the main building block of the system. Availability 
of high speed and high density memory devices of 16K and 64K bits 
with access time as low as 33 nsec makes it possible to develop 
memory planes of 512 x 512 x 1 bit or 512 x 512 x 8 bit cycling at 
6.5 mega pixels/sec. These memory blocks can be stacked together 
to represent a 4096 x 4096 pixels (128 MBits) or even larger data 
base with following design features: 
a. The image data base can be arranged in spatial configuration 
of 512 x 32,768 or 32,768 x 512 pixels. 
b. The data base can be dynamically partitioned to allow multipli- 
city of applications and users. The memory block can be sub- 
divided into 512 x 512 x 8 bit monochrome or 1024 x 1024 x 24 
bit colour images. 
c. The memories are dual ported which allow read/write functions 
independently or simultaneously and yet independent of display 
presentations. This also has random addressability to a single 
Picture element. 
d. A number of functions such as zooming, convolutions, freeze 
frame and loop movie functions can be achieved. Graphic 
overlay memories are used for annotations, labeling and 
outlining. 
Pipeline Processors (PLP) and Arithmetic Logic (ALU) 
PLP are hardwired tables connected to each possible image and 
graphic plane and are loaded during horizontal and vertical blanking 
periods. PLP stores functions to be applied to gray scale data for 
non-linear contrast enhancement, multiplication, generation of 
pseudo-colour, statistics tables such as histogram and standard 
deviations, etc. ALU takes two input images and produces an 
arithmetic or logical result such as addition, Subtraction, comple- 
menting, multiplication, convolutions and correlations etc. These 
functions are performed by use of ultra high speed devices in 
V LSI form. 
Feedback and Iterative Processing 
The most significant aspect of the total system configuration 
is the use of feedback that allows the actual viewed imagery to be 
read back into the memory in 1/25th of a second. Feedback is a 
natural configuration for recursive filtering on an image to image 
basis and thus allowing the user in evaluating effects of numerous 
filters in a very short time span. It also allows iterative processing 
alongwith PLP and ALU. 
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