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overlays (cultural, soil, vegetation, etc.) may be con
structed, depending on the time available and the reason
of interest: attention is of course always primarily
directed to the individual problem at hand. For example,
a request may be for the expected projection of a single
producing mineralized vein or a regional search may be
requested for additional lineaments which could be miner
alized and which can then be quickly sampled by spot
geochemical methods. With the over $10/BBL oil, an in
creasingly common request is for the location of areas
of conjugate lineament sets which may control distribu
tion by providing the needed porosities/permeabilities.
The first step in this type of electronic enhancement
is to produce a normal view on a television monitor for
comparisons to enhanced views and for comparisons to
constructed overlays. The imagery is then projected
through the density slicer (Fig. 1) at the basic 8-color
rate and increased into the 32-color mode: at the same
time the image is appearing on the edge-enhancer. The
system is usually hooked in parallel so we get simulta
neous density slicing and edge-enhancement of the subject
view; however, in some cases it has been advantageous to
wire in series whereby we density slice the edge-enhanced
view. Poor-grade imagery can be "lightened” by a dashpot
control on the camera and Ronchi gratings and various
filters can be placed over the television lens to resolve
faint lineaments. Suspicious areas or areas of particular
interest are then enlarged by a 12 X 15 zoom lens which
can be combined with a tele-extender. Capabilities also
include an electronic planimeter and a density control
unit (DCU). We have found the DCU particularly useful
in extrapolating to possible mineralized areas, particu
larly when surface discoloration is present. Readings
are made by the movable cursors on known mineralized
outcrops and then other areas of similar appearing density
are measured. Those areas which do exhibit similar
density readings, particularly when associated with
structural features, are then field checked. Rather
than study the imagery on the monitors, 35 mm slides
are usually taken which, as you can see, can be enlarged
by projection.
CASE STUDY RESULTS
Whereas the methodology used and described is obvious,