GNU/Linux |
CentOS 5.3 |
|
![]() |
pgmdeshadow(1) |
![]() |
pgmdeshadow
Updated: 06 July 2006
Table Of Contents
NAME
pgmdeshadow - Deshadow a PGM image
SYNOPSIS
pgmdeshadow [pnmfile]
DESCRIPTION
This program is part of Netpbm.
pgmdeshadow removes gray shadows
from an image. This is useful for an image
containing text, such as a scanned book pages, where a
shadow typically
appears near the book crease or near one side of the image.
pgmdeshadow
recognizes a gray shadow as an area of smoothly changing
color, starting
from the outer edges of the image. The program uses a simple
image
reconstruction algorithm to determine the local shadow gray
level, then
divides each pixel’s gray level by the local shadow
gray level.
The algorithm is the "fast
hybrid grayscale reruction" algorithm from Luc
Vincent, "Morphological Grayscale Reruction in Image
Analysis: Applications
and Efficient Algorithms.
OPTIONS
None.
REFERENCES
* Luc Vincent,
"Morphological Grayscale Reruction in Image Analysis:
Applications and Efficient Algorithms," IEEE
Transactions on Image
Processing, vol. 2, no. 2, April 1993, pp. 176-201.
SEE ALSO
ppmshadow, pgm
HISTORY
pgmdeshadow was added to Netpbm
in Version 10.35 (August 2006).
_________________________________________________________________
Table Of Contents
* SYNOPSIS
* DESCRIPTION
* OPTIONS
* REFERENCES
* SEE ALSO
* HISTORY
![]() |
pgmdeshadow(1) | ![]() |