1Pamsharpmap User Manual(0)                          Pamsharpmap User Manual(0)
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NAME

6       pamsharpmap - create map of sharpness in a PNM/PAM image
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SYNOPSIS

10       pamsharpmap [imagefile]
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DESCRIPTION

14       This program is part of Netpbm(1).
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16       pamsharpmap  reads  a  Netpbm  image (PNM or PAM) and produces an image
17       that shows how sharp it is at each location.
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19       Sharpness is a measure of how suddenly (in space) colors change in  the
20       image.   pamsharpmap computes the sharpness of each component color (R,
21       G, B) separately and produces a pixel whose intensity of each component
22       color is directly proportional to the sharpness of that component color
23       at the same location in the input image.  Thus, at a  point  where  the
24       image  is  very  sharp in its red and green components, but dull in its
25       blue component, you will see a yellow pixel in the output.
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27       pamsharpmap computes sharpness at a point simply as the average differ‐
28       ence in intensity between the pixel at that point and the 8 pixels sur‐
29       rounding it.
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31       At the edges of the image, where there are not 8 pixels  surrounding  a
32       pixel, pamsharpmap assumes the image is extended with a black border.
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34       pamsharpmap  assumes that the image is a PNM or PNM equivalent PAM.  If
35       it isn't, the results are not necessarily meaningful.
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37       The output image is the same dimensions, depth, and tuple type  as  the
38       input, and has maxval 255.
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SEE ALSO

42       pamsharpness(1), pammasksharpen(1), pamedge(1), pam(1), pnm(1)
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HISTORY

46       pamsharpmap  was  added to Netpbm in Release 10.21 (March 2004).  Bryan
47       Henderson derived it from the program pnmsharp by B.W. van Schooten and
48       distributed as part of the Photopnmtools package.
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52netpbm documentation           07 February 2004     Pamsharpmap User Manual(0)
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