dstripe Documentation

dstripe - Destripe image using a sequence of boxcar filters
This procedure performs a specialized spatial filtration to remove
stripes along the line or sample direction from an image. The
destriping operation proceeds by (1) lowpass filtering the image,
(2) highpass filtering the lowpass version to give an estimate of
the stripes by themselves, and (3) subtracting this stripe
estimate  from the original image. For proper results the first
(lowpass) filter should have a size along the stripes equal to
the minimum length of stripes to be removed, and a transverse
size of 1.  The second (highpass) filter should have a transverse
size equal to the maximum width of stripes to be removed, and a
size along the stripes of 1.  Thus, for example, to suppress
stripes 101 or more samples wide and 11 or less samples high, one
would set LINE1=1 SAMP1=101 LINE2=11 SAMP2=1.

If the stripe width is 3 pixels or more, WEIGHT should be set to
-1.0 to subtract the full stripe estimate.  If the stripe width
is only 1 pixel, however, set the width of the second filter to 3
and set WEIGHT to -0.75.  (This is a trick of approximating a
triangular filter using a boxcar.)
Programmer: Randolph Kirk - U.S.G.S., Flagstaff, Arizona
  00Nov22 Tammy Becker - USGS,Flagstaff-Modified for ISIS/UNIX

IMAGE TO BE DESTRIPED

NONE

DESTRIPED IMAGE

NONE

LINE DIMENSION OF
1ST (LPF) FILTER

1

SAMPLE DIMENSION OF
1ST (LPF) FILTER

1

LINE DIMENSION OF
2ND (HPF) FILTER

1

LINE DIMENSION OF
2ND (HPF) FILTER

1

AMOUNT OF STRIPE EST
TO SUBTRACT FROM
IMAGE

-1.0

ADDITIONAL NOTES:

Parm	Description
FROM	The image from which stripes are to be removed.
TO	The file to contain the destriped version of the image in FROM.
LINE1	Size in the line direction of the first (lowpass) filter operation. Must be odd. If the stripes to be removed are elongated along the line axis, LINE1 should be their maximum length; if they are elongated along the sample axis, LINE1=1.
SAMP1	Size in the sample direction of the first (lowpass) filter operation. Must be odd. If the stripes to be removed are elongated along the line axis, SAMP1=1; if they are elongated along the sample axis, SAMP1 should be their maximum length.
LINE2	Size in the line direction of the second (highpass) filter operation. Must be odd. If the stripes to be removed are elongated along the line axis, LINE2=1; if they are elongated along the sample axis, LINE2 should be their minimum width (or 3 if the width is 1 pixel).
SAMP2	Size in the sample direction of the second (highpass) filter operation. Must be odd. If the stripes to be removed are elongated along the line axis, SAMP2 should be their minimum width (or 3 if the width is 1 pixel); if they are elongated along the sample axis, SAMP2=1
WEIGHT	Multiple of the estimate of the stripes to add to the original image, i.e., TO = FROM + WEIGHT * STRIPES where STRIPES is the result of the two filtration operations. If the stripes are more than one pixel wide, WEIGHT=-1.0 should be used. If the stripes are only 1 pixel wide, WEIGHT=-0.75 should be used, and the second filter should have a width of 3 transverse to the stripes (see LINE2, SAMP2).