Level 2 Help for PICREG

INP

 Vicar labelled input files (IN,REF,OLDTP)
	IN - the image to be registered..byte format 
	REF - the image used as reference..byte format
 	OLDTP - optional file containing the raw tiepoints from a
 		previous unfinished run of PICREG.  See the
		format of NEWTP below.


OUT

 Vicar labelled output files (NEWTP,PAR):

  NEWTP - file containing the raw tiepoint values which is
          updated for each tiepoint collected.  Up to 10
          records, each of 3200 bytes of real*4 data. The order of the
          tiepoints is  Lref,Sref,Lin,Sin.
          The purpose of this file is to save tiepoints for
          possible future runs of PICREG.  This file is NOT
          used as an interface to any other program!

          WARNING: immediately upon startup, PICREG initializes  
          this dataset to contain 0 tiepoints.  Therefore, the   
          user should be careful not to re-enter a previous NEWTP
          file in this position, or the accumulated tiepoints will
          be lost!

  PAR -   optional file to receive the formatted parameter file
          for the chosen Geom program.  It will be a Vicar2
          parameter file in XVPOUT format.


SIZE

 Vicar SIZE field - ignored by PICREG
 default = (1,1,0,0)


SL

 Starting line of  size field
 default = 1


SS

 Starting samp of size field
 default = 1


NL

 Number of lines of size field
 default = 0


NS

 Number of samps of size field
 default = 0


EXIT

 Interactive keyword which terminates the program.  Note that the apostrophe
 can be ommitted.  Both 'EXIT and EXIT are valid.


PGM

 Interactive parameter which specifies, in response to a prompt,
 the Geom program which will be run on the output parameters.
 Valid = GEOMA, LGEOM, MGEOM.
 Default=GEOMA
 


U

 Specifies that the display window for both images move up by the
 indicated number of pixels.
 Default=0.


D

 Specifies that the display window for both images move down by the
 indicated number of pixels.
 Default=0.


L

 Specifies that the display window for both images move left by the
 indicated number of pixels.
 Default=0.


R

 Specifies that the display window for both images move right by the
 indicated number of pixels.
 Default=0.


U1

 specifies that the display window for the left image move up by the
 indicated number of pixels. default=0.


U2

 specifies that the display window for the right image move up by the
 indicated number of pixels. default=0.


D1

 specifies that the display window for the left image move down by the
 indicated number of pixels. default=0.


D2

 specifies that the display window for the right image move down by the
 indicated number of pixels. default=0.


L1

 specifies that the display window for the left image move left by the
 indicated number of pixels. default=0.


L2

 specifies that the display window for the right image move left by the
 indicated number of pixels. default=0.


R1

 specifies that the display window for the left image move right by the
 indicated number of pixels. default=0.


R2

 specifies that the display window for the right image move right by the
 indicated number of pixels. default=0.


SL1

 specifies that the display window for the left image begin at the
 indicated pixel. default=1.


SL2

 specifies that the display window for the right image begin at the
 indicated pixel. default=1.


SS1

 specifies that the display window for the left image begin at the
 indicated pixel. default=1.


SS2

 specifies that the display window for the right image begin at the
 indicated pixel. default=1.


HOME

 specifies that both display windows are to begin at (1,1).


LOCATE

 will move both windows so that the tiepoint indicated is located in
 the center of each window.  This is true unless the tiepoint is located near 
 the left edge, or near the top edge of the image.  In this case, the image 
 will be displayed starting at sample 1, or line 1, and the tiepoint will
 be at the corresponding sample or line. default=1


TEXTSIZE

 Height (in pixels) of tiepoint numbers on screen.  The program starts with
 a value of 18 if the screen size is bigger than 512 by 512 or a value of 12
 if the screen size does not exceed 512 by 512.  1<= textsize<=99.  The user
 can effectively turn off the  numbering by setting TEXTSIZE to 1 as long as
 desired. 


ZOOM

 Indicates an integer which specifies the magnification or reduction 
 applied to both images.  If the value is >0, the pic is entlarged by that
 factor.  If it is <0, the pic is reduced by the factor 1/value.  
 Compressions can facilitate fewer window movements, give a better idea
 of where the user is in the file , and display the tiepoint in a more global
 sense.   zoom=0 is interpreted as no zoom, the same as zoom=1.
 The maximum value for zoom is 8.  There is no minimum value for zoom other
 than the limit of -2**31 for valid integers.  This means the compression
 may be as large as is useful.  The default for zoom is 1.


Z1

 the left image will be zoomed by this factor.  default=1


Z2

 the right image will be zoomed by this factor.  default=1


STRETCH

 stretch=(lo,hi)
 specifies that both images will have a linear contrast stretch applied.
 lo goes to 0 dn,  hi goes to 255 dn.  default=(0,255).
 (There is no restriction keeping hi from being greater than 255, but this is
 generally not done since it makes the image display darker.  It would not
 allow the image files to contain DNs outside the range 0 to 255 since the
 images must have byte format.)
 Currently there is no provision for stretching the left and right
 sides independently.  If the two input images require separate stretches,
 the stretches must be performed prior to entering PICREG.


LINEAR

 linear=(lo,hi)
 specifies that both images will have a linear contrast stretch applied.
 lo goes to 0 dn,  hi goes to 255 dn.  default=(0,255).
 (There is no restriction keeping hi from being greater than 255, but this is
 generally not done since it makes the image display darker.  It would not
 allow the image files to contain DNs outside the range 0 to 255 since the
 images must have byte format.)
 Currently there is no provision for stretching the left and right
 sides independently.  If the two input images require separate stretches,
 the stretches must be performed prior to entering PICREG.


DSTAT

 will cause the sl, ss, and zoom factor to be printed for each image.


MODE

 valid=(corr,point)
 determines whether PICREG will accept the user cursor locations as the
 final tiepoint values (point) or try to optimize the locations using a
 fft cross-correlation technique.  default=point.
 If MODE=CORR is selected, POWER defaults (is set) to 6.


POWER

 Tells PICREG to use fft correlation.  The value indicates the 
 the size of the correlation window.  size= 2**power.  The default is 0,
 which means to not use fft correlation, unless MODE=CORR (or 'CORR) is 
 selected.  If MODE=CORR is selected, POWER defaults (is set) to 6.
 Thus, when fft correlation is selected, the correlation window size is
 64 by 64 (pixels) unless explicitly changed using the POWER parameter.


HIPASS

 VALID=(HPF,NHPF)
 determines whether, in the fft correlation, the vertical and horizontal
 frequencies which lie on axes passing through the DC term are zeroed 
 out (hpf) or not (nohpf).  default=hpf.


PHASE

 This keyword determines whether or not phase correlation is used when
 correlating tiepoints.  In phase correlation, the complex fourier
 transform coefficients are divided by their amplitudes before computing
 the correlation function.


INTERP

 valid=(inte,noin)
 determines whether, in the fft correlation, the centroid of the cor-
 relation peak is determined to nearest-pixel (noin) or sub-pixel
 (inte) accuracy.  If 'inte is specified, PICREG tries to repeat
 the correlation until it converges to within .1 pixels.
 If 'noin is specified, PICREG tries to repeat
 the correlation until it converges to within 1.1 pixels.
 default=noin.  (See also Example 2 in the main HELP for PICREG.)


AREA

 invokes the area mode of correlation and supplies the size of the box
 used. In this mode, PICREG will compute two buffers containing the sums
 of rows and of columns of dn's in an area about the tiepoint location.  The 
 final positions will be set to the minimum or maximum positions of
 each buffer.  default=20.


CONV

 valid=(min,max)
 indicates whether, in the area mode, to pick the maximum or the minimum
 positions of the buffers.  default=min.


REDO

 specifies which tiepoint number is to be deleted and redone.  default=0


DELETE

 Specifies a range of tiepoint numbers to be deleted.  default=(0,0).
 Note that any following tiepoints will be renumbered. 


SHOW

 results in a display on the left image graphics plane of tiepoint displacements
 from their location in the left image relative to their location in the 
 right image.  This is done relative to the first tiepoint ( it will always show
 no displacement) and is only done for those tiepoint presently displayed.


FIT

 picks a type of least squares surface, and fits it to the current set of
 tiepoints.  The meanings of the values are:
	1. rotation + offset
 	2. rotation + offset + scale
	3. first order unconstrained
	4. scale + offset
	5. offset
	6. second order unconstrained
	7. third order unconstrained
 PICREG will print the mean error and the number and error of the worst
 fitting point. 
 This keyword is used to check for tiepoint location errors and to test how well
 a specifc surface fits prior to using that surface to generate an output
 grid of regularly spaced tiepoints for use with a Geom program.
 1<= fit <= 7.   default = 1


TPFORM

 This keyword formats the second output file for later use with TIECONM,
 GEOMA, LGEOM, or MGEOM.  Value values and their meanings are:
	1-7. The corresponding surface as described under the fit parameter
	     (also below) is used to generate a nhor by nver grid of
 	     regularly spaced tiepoints in GEOMA, LGEOM, or MGEOM format.
	     These tiepoints, along with all necessary parameters are then
	     written to the second output file.
		 The meanings of the TPFORM values in the range 1 to 7 are:
			1. rotation + offset
		 	2. rotation + offset + scale
			3. first order unconstrained
			4. scale + offset
			5. offset
			6. second order unconstrained
			7. third order unconstrained
	8.   The region of the reference picture which is encompassed
	     by the output tiepoint network will be samlpled in a nhor by
	     nver grid.  At each grid intersection, a transformation will
	     be computed by least squares using the relations:
			y1 = ax + by + c
			x1 = dx + ey + f
	     between the reference pic (x,y) and the input picture (x1,y1)
	     using the n closest tiepoints to that grid location. (n is set
	     using the USE parameter.)  
	9.   This invokes the TIECONM option.  No re-sampling is done in
 	     this case.  Instead, the raw tiepoints and all necessary TIECONM
	     parameters are written to the second output.  This parameter
	     file can then be used with TIECONM which will in turn format
	     the tiepoints for use with GEOMA, LGEOM or MGEOM.  The TIECONM
	     triangulation method for surface fitting is useful in cases
	     where an image has areas of significant distortion.
 In any case, the user will be prompted for which Geom program he plans to
 use.  If GEOMA is specified, the output grid will be transformed into
 triangles.  Applicable keywords (nhor,nver,minl,mins,maxl,maxs,use) should
 be specified prior to or on the same line as the tpform keyword.


NHOR

Specifies the number of columns of tiepoints in the output grid, for the case
of TPFORM = 6, 7, or 8.  This is the number of tiepoints in a horizontal line
of the output tiepoint grid. 

If TPFORM <= 5 is chosen, then this parameter is ignored, and NHOR=2 is
used (since 4 points suffice to determine a first-order transformation).

Note that if GEOMA format is chosen for the tiepoints, then the value
of NHOR is almost doubled (NHOR = 2*NHOR-1) in order to make triangular
tiepoint areas.

Default=20.


NVER

 Specifies the number of rows of tiepoints in the output grid, for the case
 of TPFORM = 6, 7, or 8.  This is the number of tiepoints in a vertical line
 of the output tiepoint grid. 

 If TPFORM <= 5 is chosen, then this parameter is ignored, and 
NVER=2 is
 used (since 4 points suffice to determine a first-order transformation).

 Default=20.


MINL

 minimum line number of the output grid tiepoints. default is based on raw 
 tiepoints.


MINS

 minimum samp number of the output grid tiepoints. default is based on raw 
 tiepoints.


MAXL

 maximum line number of the output grid tiepoints. default is based on raw 
 tiepoints.


MAXS

 maximum samp number of the output grid tiepoints. default is based on raw
 tiepoints.


PRINT

 valid=(print,noprint)
 enables the printing of least squares fit information when the fit is
 specified and results in a printout of all raw tiepoint locations upon exit
 default=noprint.


USE

 the number of tiepoints used to determine each output tiepoint location. 
 Applies to tpform=8 only.  4<= use <= 10  . default=4


CURSOR

 selects the shape of the cursor by specifying its number.  The number
 scheme is installation or display-type dependent, and may be changing.  
 At present, the following are available on the DeAnza:

	        .                |               -----
	1 =   . . .       2 = ---|---       3 = |  .  | 
                .                |              |_____|

                                                               ______
            ||                                \  /            |      |
    4 =   ==  ==     5 = complement       6 =  \/        7 =  |------|
            ||             of 4                /\             |______|    
                                              /  \                       
 The cursor shapes for values 1 to 6 are also valid under the X Window System.


POSITION

POSITION values are used instead of the trackball cursor position.
POSITION values are in terms of image line and sample coordinates.
This parameter is useful in testing PICREG since it bypasses the trackball
and allows testing to be repeatable.