vards
deo tape,
70-mm
d.
)-mm
he re-
'e metric
)roces -
gnetic
irs after
the most
1e inde -
relati-
ates of
iined,
join each
lates
cessive
e other
sa
ie, For
ljusted
ips by
ontal
| of this
otrian-
s having
tograph
e second
of cor-
phs for-
h point
ve center
ram is
strips
programs
st size,
m of the
colli-
1e point
ion is
s and to
60 by
USGS, Allcomputations, including preliminary processing of comparator coordinates, are per-
formed in one computer run. The photographs of a block are adjusted simultaneously by enforcing
the condition that all corresponding rays must intersect and by mathematically constraining points
to known ground coordinates.
Two computer programs with emphasis on rigorousness and utility have been prepared
by private organizations, One of the programs, known as MUSAT, was developed by Autometric /
Raytheon from successive modifications to the original direct geodetic restraint program of the
U.S. Army Topographic Command (TOPOCOM). The program is useful for error propagation
studies as well as for solving production problems, The second was prepared by DBA Systems,
Inc, Like the NOS program, it is based on the collinearity equations, It also is useful for solving
practical problems as well as error-propagation studies.
Image Correlator and Measuring System - An automatic instrument for correlating corres-
ponding image points on overlapping photographs, built for USGS by the BAI Corp., has been im-
proved and is now ready for operational use. It scans an annular area of a photograph, or other
form of imagery, and develops an analog signal, or signature, which uniquely describes the
scanned scene, The signature is then converted to digital form and stored on a punched card, Subse-
quently, the reference signature can be reestablished from the punched card, and a corresponding
scene from other imagery can be scanned and correlated with micrometer accuracy.
A radial amplification module was added to the image correlator, which permits the shape
of the annular scan ring on the image-disector camera to be altered electronically. The ring diame-
ter can now be varied to accomodate a considerable scale change. The scan ring can also be elec-
tronically stretched into an ellipse with the major axis in either x or y, and the annulus width can
be held constant or differentially varied, This feature is expected to alleviate some of the scanning
problems caused by anamorphic distortions in sloping terrain that has been imaged from two or
more widely separated perspective points, Some of the mechanical and elctronic linkage for driving
the monocomparator carriage is now being modified for easier pointing and positioning.
Map compilation
Universal Automatic Map Compilation Equipment (UNAMACE) - The UNAMACE is an
automated stereoplotter developed by the U.S. Army for automatically producing orthophotographs,
altitude charts (drop-lines), and profile elevation data, Until recently contour maps were compiled
by manually tracing the edges of contour bands of the drop-lines, but TOPOCOM has now prepared
software which efficiently and economically uses profile data to generate automatic plotter instruc -
tions with a computer and automatically draws contours by means of an x-y plotter. The new program,
replacing an older, inefficient program, uses a rectangular network of elevations derived from the
profile tapes. An entry and exit point ig established for each contour crossing a rectangle, and
by connecting entry and exit points, a contour line segment is defined for each contour crossing a
rectangle, The connection of these line segments defines the rough path of the contour. An efficient
smoothing technique is then applied to the contours and the instructions for the automatic plotter
are recorded on magnetic tape,
Analytical Stereoplotter - Many innovations have been made in the AS11 (analytical stereo-
plotter) hardware and software since it was installed by the U. S. Air Force in 1961, This instru-
ment accommodates any two photographs that can be geometrically defined and compensates for
any systematic image displacements that can be mathematically defined. The highly accurate opto-
mechanical viewing instrument is controlled by a computer which maintains relative and absolute
orientation of photographs in local areas by x and y incremental shifts of the diapositives as the
floating mark is moved about the stereomodel.
The AS11C system has been equipped with an automatic image correlating system and
will perform the following operations :
- Automatic contouring with both coordinatograph and magnetic tape output
- Automatic profiling with both coordinatograph and magnetic tape output
- Automatic parallax and elevation measurement
- Automatic compilation of an orthophotograph.
TOPOCOM reports that software has been developed for the AS11A to compile topographic
—103--