Help for RESLOCVO

PURPOSE:

"reslocvo" will locate the reseau on Viking Orbiter images.  The (line,sample)
coordinates of each reseau mark are output as a reseau location record in a
MARK format.  The reseau location record may be input to the program RESSAR75
to cosmetically remove the reseau from the image.  "reslocvo" will optionally 
generate GEOMA parameters for removing the geometric distortions.

TAE COMMAND LINE FORMAT

	reslocvo INP=(IMG,NOM) OUT=LOC optional parameters
where
	IMG is the input Viking Orbiter image,
	NOM is an optional input reseau location record containing the
	  nominal reseau location,
	and LOC is the output reseau location record.

OPERATION:

The Viking Orbiter cameras include a reseau pattern consisting of 103 reseau
marks embedded on the face-plate of the vidicon.  The position of these
marks will vary from image-to-image due to time, temperature, and scene
dependent geometric camera distortions.

The location of the reseau requires a set of nominal locations to be
used as starting values. The nominal locations may be optionally input
as the second input file.  If the nominals are not input in this way, they
are retrieved from tables built into the program. 

"reslocvo" will search for each reseau mark in an NHOR x NVER area
centered about its nominal location.  Each mark is found by using an
NLW x NSW correlation window. As this window scans over the search area,
the underlying area is compared with a reseau shape function
(constant for all the marks) of the form: 
   	f(x,y) = 255(1 - exp(-(x**2 + y**2)/2s**2)
For a 9 x 9 window, the shape function is:

	254 254 254 254 254 254 254 254 254 254
	254 254 254 253 252 253 254 254 254 254
	254 254 250 234 220 234 250 254 254 254
	254 253 234 161 100 161 234 253 254 254
	254 252 220 100   0 100 220 252 254 254
	254 253 234 161 100 161 234 253 254 254
	254 254 250 234 220 234 250 254 254 254
	254 254 254 253 252 253 254 254 254 254
	254 254 254 254 254 254 254 254 254 254

Let A(i,j) represent the shape function, and B(i,j) be the area of the
picture being compared. Let uA, uB, tA, tB be the corresponding means and
standard deviations. The correlation function is a normalized variance of
the form: 
     p = (SIGMA(Aij-uA)(Bij-uB))/(N*tA*tB)
where N = NLW*NSW and the summation is performed over an NLW by NSW
window. 

Note: Marks near the boundaries of the picture are not located. Coordinates
for these marks are calculated by interpolating over its nearest neighbors.

If an output parameter file is specified via the GEOPAR parameter, then
GEOMA parameters are output to this file.  The GEOMA parameters can then
be input the program GEOMA to remove the geometric distortions.

EXAMPLE

	reslocvo INP=A OUT=RES GEOPAR=GEOM.PAR
	ressar75 (A,RES) B
	geoma B C PARMS=GEOM.PAR

"reslocvo" is used to locate the reseau in the frame stored in data set A. 
The resulting reseau locations (RES) are input to program RESSAR75 which
removes the reseau.  GEOMA parameters are also generated (GEOM.PAR) and
are input to program GEOMA to remove the camera distortions.

RESTRICTIONS:

The constants NLW, NSW, NHOR, NVER must satisfy the following: 
     1. Each must be odd;
     2. 6(NSW*NLW+NHOR+NSW) + 4*NHOR*NVER + 2408(NLW+NVER) <= 82414
        If NLW = NSW and NHOR = NVER, then the following
        simplified approximate formula may be used:
                NLW + NVER <= 32
TIMING:

The execution time of "reslocvo" is directly proportional to the window and
search dimensions NLW, NSW, NHOR, NVER. 

WRITTEN BY:                Steve Pohorsky		17 Jan 1985
COGNIZANT PROGRAMMER:      Gary Yagi
REVISIONS:
 26 May 94  Meredith Cox (CRI) -- Made portable for UNIX 
 20 Oct 87  Gary Yagi   -- Added GEOMA parameter output
 10 Oct 87  Gary Yagi	-- Parameter processing converted to Vicar2
 25 Jun 86  Joel Mosher -- I/O converted to Vicar2