Hello Deepac,
There are a number of image processing tools with source code
available on line. Perhaps the most comprehensive is ImageMagick
described at
http://www.imagemagick.org/
Some of its features includes:
o It is supported on a variety of operating systems (Unix, Windows,
MacOS, VMS, OS2)
o It has command line utilities to perform many operations (including
the ones you have described)
o It has function libraries that can be called from C, C++, Perl,
Python, and Java
o Source code is freely available
o Has extensive documentation and mailing lists to provide help using
the functions and applications.
For example, a sample C++ application is shown at
http://www.imagemagick.org/www/Magick++/Image.html
which reads a TIFF image, adds noise, and writes the TIFF image
[basically, the first and second steps you describe above]
and does this in five lines of code (look about 1/4 of the way down
the page).
The function for median filter is described on the same page - search
for medianFilter.
I can't tell for sure which neighborhood algorithm you want to use.
The choices are:
o Floyd/Steinberg error diffusion - search for quantize Dither
o Gaussian Blur - search for gaussianBlur
The command line utilities described at
http://www.imagemagick.org/www/ImageMagick.html#details-noise
also describes a method where a noisy pixel is replaced by one of its
neighbors, but I can't seem to find the function interface for that
particular operation. It may be "enhanceImage" or "reduceNoiseImage",
but I can't be sure. Be sure to ask in a clarification request if one
of these does not meet your needs.
Some suggestions on further searches, use phrases such as
source code image filtering neighborhood averaging
The third link was a site at
http://www.cs.cmu.edu/~cil/v-source.html
titled "Computer Vision Source Code" which has direct links to a
number of resources - ImageMagick was one of them.
--Maniac |
Request for Answer Clarification by
deepac-ga
on
21 Nov 2002 17:58 PST
Hi! Maniac,
thanx for showing ur concern in my problem. the C program sent by u
for loading image and adding noise is perfect. But unfortunately, i'm
not being able to get a source code for using median filter as well as
neighbourhood averaging filter to filter back the added noise. Could u
pls take the pains of finding out the code for the above two
operations(in C or matlab).I'll really appreciate it. As far as ur
query regarding the type of neighbourhood averaging filter is
concerned, u pls let me have a code of any type. Actually it doesn't
make a big difference for me. my project uses this problem as a small
part of the entire process. So what matters for me is the source code
in c or matlab for median filtering and any type of neighbourhood
averagin filtering to filter the noise from original image.
hoping for a quick n positive reply
--deepac
|
Request for Answer Clarification by
deepac-ga
on
22 Nov 2002 21:37 PST
Hi! Maniac,
This is the second time I'm asking for clarification of my
answer.i'm
not being able to get a source code for using median filter as well as
neighbourhood averaging filter to filter back the added noise.Could u
pls take the pains of finding out the code for the above two
operations(in C or matlab).I'll really appreciate it. As far as ur
query regarding the type of neighbourhood averaging filter is
concerned, u pls let me have a code of any type.what matters for me is
the source code in c or matlab for median filtering and any type of
neighbourhood averaging filtering to filter the noise from original
image.
hoping for a quick n positive reply
--deepac
|
Clarification of Answer by
maniac-ga
on
23 Nov 2002 19:00 PST
Hello Deepac,
At the ImageMagick site
http://www.imagemagick.org/www/archives.html
there is a list of sites that have the source code and binaries for
the applications and libraries. For example, choosing
ftp://ftp.yggdrasil.com/mirrors/site/ftp.simplesystems.org/pub/ImageMagick/
or
ftp://ftp.simplesystems.org/pub/ImageMagick/
from the list on the first page gives you a list of files.
Downloading the source should take between 10 and 15 minutes on a 56 K
modem line (one of the first few files listed). The references below
are for version 5.4.9-1. All are c source files.
Searching the files downloaded for the phrase "neighbor" and "median",
you can determine that the algorithms are implemented in the following
files / line numbers.
Neighborhood averaging
magick/effect.c:142 (comments - BlurImage - gaussian)
magick/effect.c:331 (BlurImage function)
magick/effect.c:1493 (comments - ReduceNoiseImage)
magick/effect.c:1575 (ReduceNoiseImage function)
Median Averaging
magick/effect.c:975 (comments)
magick/effect.c:1207 (MedianFilterImage function)
there are some supporting routines in this area as well
I looked at the description for Floyd/Steinberg further and it does
not appear to be what you need. If you want to look more at it, it is
hard to trace, but it appears that DitherImage is what implements it.
Good luck on your work.
--Maniac
|
Request for Answer Clarification by
deepac-ga
on
01 Dec 2002 12:19 PST
Hi! maniac,
this is in continuation to ur earlier search results for the matlab
or C code for my problem. I'm sorry to trouble u once more but acually
those search sites r not giving me a ready made matlab code(or a C
program) which i could directly compile n run to see the results. If u
remember, u sent me a c code in the very first reply which was for
loading an image and adding noise to it. That is the kind of results
i'm looking for my problem. A straight forward C or matlab code which
could load an image , add noise(of any type) to it,ilter that noise by
once using median filter n oonce using neighbourhood averaging filter.
i know i'm troubling u too much but pls help me out as i've nowhere
else to go. I'm supposed to give this problem by tuesday..pls try to
search for the above code rather than the links where i could download
some such things which will not serve my pupose.
hope to have a positive n prompt reply.
--deepac
|
Clarification of Answer by
maniac-ga
on
01 Dec 2002 20:15 PST
Hello Deepac,
Assuming you downloaded ImageMagick source as described previously and
are have a directory with the source. [steps for a Unix system]
At the top directory, generate and install ImageMagick
./configure
make
(as root)
make install
[If you don't have root access, check the documentation to change the
default install location and adjust your commands as approprite;
installation could be skipped if it is already installed on your
system.]
make check
(check the installation and generate the rwfile program used later)
In the tests directory, create a file named my.cpp with the following
contents:
#include <Magick++.h>
#include <iostream>
using namespace std;
using namespace Magick;
int main (int argc, char **argv) {
Image image;
image.read("logo.gif");
image.addNoise(GaussianNoise);
image.write("logo-noise.gif");
image.medianFilter(1.0); // filter w/ radius one
image.write("logo-median.gif");
image.read("logo-noise.gif");
image.reduceNoise();
image.write("logo-nonoise.gif");
return 0;
}
Then
./rwfile LOGO: logo.gif
(to generate the input file)
c++ -o my my.cpp `/usr/local/bin/Magic++-config --cxxflags
--cppflags --ldflags --libs`
(to generate the my application; all on one line, note the direction
of the ` used to get the output of Magic++-config used as command line
parameters)
./my
(read logo.gif and generate the output files)
Review the files logo.gif, logo-noise.gif, logo-median.gif (median
filter), and logo-nonoise.gif (after noise removal - neighborhood
replacement) with an image viewing program to see the effects. The
gaussian noise added was a little subtle - you may want to repeat that
step more than one time to get the image "noisy".
Good luck.
--Maniac
|
