Help for REGISTER2

PURPOSE:
To acquire tiepoints permitting images to be registered.
Register2 performs 9 registrations and writes the tiepoints into the output 
file.

EXECUTION STATEMENT:
register2 inp=listoffilenames out=tiepoints
superres inp=(listoffilenames,tiepoints) out=superresolutionimage

where:
listoffilenames is an ascii file with one input image file name per record.
tiepoints is an ascii file with tiepoints.

METHOD:
Register2 selects a large region near the picture center and correlates a
single tiepoint there. It then uses the offset to determine 9 tiepoints
across the image. These tiepoints are written to the output. 
Input images should be the same size.

The Gruen correlation scheme used here permits distortions between 
correlation areas of the form:
newline=line*A+sample*B+C
newsamp=line*D+sample*E+F
The task of the correlator is to determine the coefficients A-F which permit 
the best correlation value.

Output file format is as follows:

Picture 2
ref_line ref_sample line sample quality
ref_line ref_sample line sample quality
ref_line ref_sample line sample quality
...
Picture 3
ref_line ref_sample line sample quality
ref_line ref_sample line sample quality
...
Picture 4
...
end

ref_line & ref_sample refer to the first input file which is always the
reference. Picture 2 refers to the tiepoints connecting picture 2 to the
reference picture etc.
Line and sample refer to the other pictures.
Quality is a number from 0 to 1. Most good correlations have qualities
of around .95  .

PROGRAM HISTORY

Cognizant programmer: Jean Lorre

Revisions: 
  2019-08-06 Walt Bunch - IDS-7923 - replaced sprintf calls, misc -Wall cleanup,
                          added enable-log to tst.pdf, added seed to tst gausnois
                          and displayed tiepoints for test repeatability.
  2019-09-06 Walt Bunch - IDS-7922 - initialized some variables.

PARAMETERS: