Help for TOPOMAP

PURPOSE:
To generate relative elevation maps from either a tracker3 MARK
file or a pair of MARSCORR line,sample DISPARITY files.
No knowledge of camera pointing is necessary. Only use this
program if you do not have spice information or camera models.
(See programs LSTOXYZ & TOTOPO if you do.)

EXECUTION:
tracker3 inp=image out=mark
tptedt2 inp=mark out=editedmark  ( optional )
topomap inp=(image,editedmark) out=topo
or
marscorr inp=(left,right) out=(linedisp,sampledisp)
topomap inp=(left,linedisp,sampledisp) out=topo

An output smoothing operation is advisable.


METHOD:
Processing steps are as follows:

1. Determine the epipolar direction from the greatest vector trend.

2. Compute the vector scalar component along the epipolar direction
   for each pixel in the MARK or DISPARITY file
   and place in the output image as a real dn value.

3. For each zero dn pixel (those values between input vectors) collect
   all the non zero pixels within RADIUS and, if the number is MINPTS
   or more, interpolate over the central pixel. Store these values
   until done with this iteration over the entire image.

4. Add the interpolated pixels to the output.

5. Go to step 3 MAXPASS times.

The first input image is only used to get the size of the output.

INTERPOLATION FORMULA:

Given a location (i,j), a set of N dn values DN(x,y), 
and a set of N weights R which are the squares of the distances
between (i,j) and (x,y),
we compute the DN value at (i,j) from:

         DN(x1,y1)    DN(x2,y2)           DN(xN,yN)
         ---------  + ---------  .....  + ---------
         R(x1,y1)     R(x2,y2)            R(xN,yN)
DN(i,j)=-------------------------------------------
             1            1                   1
         ---------  + ---------  .....  + ---------
         R(x1,y1)     R(x2,y2)            R(xN,yN)

HISTORY:
3-2001  J Lorre. 
COGNIZANT PROGRAMMER:  Jean Lorre