FFT in imagej for noise removal

[donny008]

hello

for pre processing of my image, i wanted to remove noise from it. i googled
and
found that FFT was used in photoshop to do it. and i also saw the result.
however when i tried the same thing in imagej. i wasnt exactly successful. i
am
not very sure if i did the part of removing the noise spikes from the fft in
the
right way. and therefore when i apply inverse fft all i get is a dark image.

would someone be kind enough to guide me to use FFT in imagej please. with
the
wikis on imagej, i have not yet seen a useful one to serve my purpose

any help would be of great assistance


thankyou


--
Donny George

[Gluender-4]

Donny George,

my experience over decades with students and colleagues is that the
sound use of the Fourier-transformation (FT) isn't as easy as it may
look like and that the FFT and its sound application requires a
profound understanding of the FT and its theorems. There are many
books about the FT but only very few are worth studying.

With respect to your problem:
Optimum noise reduction by spatial frequency filtering actually
requires more knowledge than that of the FT or FFT and it requires
quite some knowledge about your image and the noise.

>hello
>
>for pre processing of my image, i wanted to remove noise from it. i googled
>and
>found that FFT was used in photoshop to do it. and i also saw the result.
>however when i tried the same thing in imagej. i wasnt exactly successful. i
>am
>not very sure if i did the part of removing the noise spikes from the fft in
>the
>right way. and therefore when i apply inverse fft all i get is a dark image.
>
>would someone be kind enough to guide me to use FFT in imagej please. with
>the
>wikis on imagej, i have not yet seen a useful one to serve my purpose
>
>any help would be of great assistance
>
>thankyou
>
>Donny George

Best
--

                   Herbie

          ------------------------
          <http://www.gluender.de>

[Andreas Maier]

Hi Donny George,

if you want to remove noise while preserving edges, you may want to have
a look at Bilateral Filtering:

http://wbgn013.biozentrum.uni-wuerzburg.de/ImageJ/bilateral-filter.html

Best,

Andreas

Am 7/28/2010 8:43 AM, schrieb Gluender:

> Donny George,
>
> my experience over decades with students and colleagues is that the
> sound use of the Fourier-transformation (FT) isn't as easy as it may
> look like and that the FFT and its sound application requires a
> profound understanding of the FT and its theorems. There are many
> books about the FT but only very few are worth studying.
>
> With respect to your problem:
> Optimum noise reduction by spatial frequency filtering actually
> requires more knowledge than that of the FT or FFT and it requires
> quite some knowledge about your image and the noise.
>
>> hello
>>
>> for pre processing of my image, i wanted to remove noise from it. i
>> googled
>> and
>> found that FFT was used in photoshop to do it. and i also saw the
>> result.
>> however when i tried the same thing in imagej. i wasnt exactly
>> successful. i
>> am
>> not very sure if i did the part of removing the noise spikes from the
>> fft in
>> the
>> right way. and therefore when i apply inverse fft all i get is a dark
>> image.
>>
>> would someone be kind enough to guide me to use FFT in imagej please.
>> with
>> the
>> wikis on imagej, i have not yet seen a useful one to serve my purpose
>>
>> any help would be of great assistance
>>
>> thankyou
>>
>> Donny George
>
> Best

--
Dr.-Ing. Andreas Maier
Stanford University
Department of Radiology
The Lucas Center for Imaging
Mail Code 5488, Route 8
Stanford, CA  94305
http://med.stanford.edu/profiles/Andreas_Maier/