INP=(A,B,C,D,E),
where:
A is the first image to be correlated.
B is the second image to be
correlated [or a ground control
point file in graphics-2 format --
NOT CURRENTLY SUPPORTED].
C is a file in graphics-1 format
containing polygonal contours (in
B, which must be an image).
D is the binary for the first image.
(0,1)
E is the binary for the second image.
OUT=(P,Q)
P is an IBIS tabular file that contains
the pairs of matching coordinate
locations together with editing
information such as correlation
value. See help file for format.
Q is a ground control point file in
graphics-2 format made from the
first image A at its matching
locations
-- NOT CURRENTLY SUPPORTED.
ITIE=(X1,Y1,...,XN,YN) This specifies three or more
control points in the first
input image to control
matching search and resampling
geometry.
OTIE=(P1,Q1,...,PN,QN) This specifies the correspon
ding control points in the
second image. If the second
input is a ground control
point file then these values
are latitude longitude pairs.
The number of values given to
OTIE must be the same as the
number to ITIE.
MAGNIFY=R This specifies that sampling
from both images is magnified
by R (default 1.0). The grid
is always 32 by 32 so this
increases the correlation area
without increasing computation.
The magnification can be speci-
fied separately for line and
sample directions.
SEARCH=S This specifies that the search
area in the first input is
initially an SxS square re-
gion. Allow for uncertainty
and nonlinearity in the esti-
mation of matching location by
ITIE, OTIE and add 12 more to
S for ineffectiveness of cor-
relation near the window edge.
S must be less than or equal
to 128 which is also the
default.
MSEARCH=T This specifies that the
initial search S can be
reduced upon successful
matching to a minimum value of
T. Note that successful
matches refine the image to
image geometric model allowing
a reduction in search with a
consequent savings of
computation. The default
value is 50 and miminum value
is 32.
MINCORR=V The value V sets a minimum
correlation value for
acceptance of a new point into
the image-to-image geometric
model (default .20).
ZWIND=W The program calculates and outputs
the average brightness values
at the matching coordinates.
The average is calculated using
a W by W window. Default is 10.
ZREJECT=(K,Z) The average brightness is rejected
by setting the output Z value to
-999 if more than K of the values
are below a DN value of Z. This
does not affect whether the corre-
lation is performed. The default
is (100000,0) .
MINL=M1,MINS=M2, These specify a set of grid
MAXL=M3,MAXS=M4, locations in the second input
NAH=M5,NAV=M6 image for correlation. The
program will attempt
(M5+1)*(M6+1) correlations in
a uniform grid bounded by the
values M1,...,M4. This is an
alternative to matching along
a set of points specified by a
third input data set.
CONTOUR=(A,B) This parameter must be given if
a third data set containing a
contour or point set for
matching is given. The third
data set is in graphics-1 format.
The parameter A specifies a
spacing to be followed along
the contour. The routine
always matches at contour
nodes hence a large spacing
turns the third input into a
simple set of points for
matching. The parameter B is
normally 0 (zero) but if it is
set to 1 then it reverses the
role of ITIE and OTIE. This
is a convenience when two
images are correlated twice
along contours in each of the
frames.
STOP=(N,T) This instructs the program to
stop after achieving N matches
with a correlation value above
a threshold T. This is useful
for saving CPU time while still
assuring a certain number of
good matches.
RETRY=(N,T,R) This instructs the program to
attempt more tries near a
location if a certain
correlation threshold is not
achieved. N is the number of
tries (1 to 5), with the first
try being the at the original point.
T is the correlation threshold
required to stop the retry at each
point. A failure number is
printed every time the threshold
test fails. If all retries for
a point fail then nothing is
written to the output files.
The retry pattern is to move
to the corners of a square
i.e. to move to (+/-R, +/-R) from
the original point.
PHASE=P P is a REAL*4 value in the
range 0 to 1.
Use PHASE=1
for phase correlation.
Use PHASE=0
for normal (NOPHASE) correlation.
"picmatch" divides each element of the
FFT of the cross-correlation
by the amplitude of the element raised
to the P power. Note that when
P is 0, this reduces to
dividing by 1. (The value of the
correlation is still normalized
to a maximum possible value of 1.)
"picmatch" runs slower for PHASE values
other than 0, .5, and 1.
The default for P is 1.
(See also the help for subroutine CROSSCORR.)
FILTER=P This parameter specifies the
power of the power law filter
that can be applied in the FFT
domain for the correlations.
The filter enhances the high
spatial frequencies relative
to the low ones, thus helping
the correlation key in on edges.
The radial power law filter
multiplies both of the FFT's.
The filtering is not recommended
for the phase (PHASE=1) corre-
lation. Default is P=0.
'NOPRINT This specifies that the normal
printout is to be suppressed.
Error messages will still be
printed.
'NOHPF This specifies that the
default high pass filter in
the correlation is to be shut
off. The high pass filter
consists of zeroing the low-
order row and column of the
DFT matrices.
'NOSUBPIX This specifies that subpixel
correlation is not to be
calculated (see operation)
'NOCORR This turns off correlation so
that the estimated points are
taken to be the matching
location. It is useful for
generating certain kinds of
output data sets.