image acquisition systems which were built by our research team for
specific purposes.
A microcomputer-based image processing system manufactured by
International Robomation/Intelligence Inc. of Carlsbad Ca. (IRI) is used
for near-realtime image computation and realtime image acquisition. The
application of this system to automated measurement of object coordinates
will be discussed in a later section. The system is utilized for studying
algorithms such as automated target measurement and correlation (matching)
for close range photogrammetric applications. This work has clearly
demonstrated the value of digital techniques. The hardware of the IRI
system (figure II) includes a Motorola MC68010 central processor operating
at 12.5 MHz. It has 1 MB of memory expandable to 15 MB. Images can be
stored in four frame buffers or a 40 MB Winchester disk. Program load is
accomplished through a 1 MB floppy disk. Up to four cameras can be
connected simultaneously. Image acquisition is performed at 30 frames per
second on a 256 by 256 image with 8 bits of dynamic range. The image is
displayed on a monochromatic monitor, either in realtime or "freeze"
frame. Four standard RS232 terminal ports are available. Built-in
coprocessor hardware provides 50 MOPS computing power supported by an
effective library of preprogrammed routines. Additional arithmetic
hardware is provided for the specific tasks of histogramming and intensity
mapping. :
The ARIES-II image processing system, manufactured by DIPIX Ltd.
of Ottawa, Canada is used for both computational and display aspects of
digital image processing (figure III). This system does not have high
speed image processing power like the IRI system but it does offer a very
powerful and flexible colour image display capability. The surface of the
display monitor can be divided into rectangular windows with any image in
memory displayed in any of these windows. Each image is composed of
several layers. Three "feature" layers are usually used to define the red,
green and blue (RGB) colours. Opaque "theme" layers provide overlays
typically used for graphics. The architecture was designed for Landsat
type applications, but is nicely suited to photogrammetric image viewing.
With so many aspects of the display programmable, it provided a good
vehicle for studying aspects of digital stereoscopic image presentation
for measurement. By defining display topologies with dual images, stereo
digital imagery has been generated for experimental purposes. Control of
image position and scale is available through software or interactive
bitpad commands. The image control capabilities of this system are used in
the study of image manipulation techniques for online digital
photogrammetric measurement systems. The ARIES-II has three fundamental
components which are loosely coupled through a dual port memory interface
(DPI). This interface allows the three components to access the 2 MB of
video memory array and the register memory (VMA), each through its own
address space. The image processing system host (IPS) and the image
display system controller (IDS) each have an 8 KB window into the video
memory array and register memory, while the video display system hardware
(VDS) can address the entire VMA on its system bus. Interaction between
the systems, apart from sharing image data, is accomplished by a complex
table structure and a message packet exchange system between the IPS and
the IDS (figure IV).
The image processing system (IPS) of the ARIES-IT performs direct
image computations either memory to memory or disk to disk. This general
purpose minicomputer has been used for numeric analysis of geometric
precision and for development of automated moire fringe ordering and
surface modeling. The advantages of a sophisticated colour display through
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