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Discussion Groups | Image Signal Processing | Gaussian smoothing

Technical Discussions related to Image Processing (image coding, compression, digital effects, mpeg, etc)

  

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Gaussian smoothing - ujjavalsuthar - Mar 29 3:19:00 2004



Can anybody explain me how gaussian smoothing works for image smoothing?
I mean to say how does that affect the image after operation. What
changes it makes to image pixels, so that we get less noisy image?

tx.






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Re: Gaussian smoothing - Andrew Nesterov - Mar 29 13:39:00 2004

--- In , "ujjavalsuthar" <ujjavalsuthar@y...>
wrote:
> Can anybody explain me how gaussian smoothing works for image
> smoothing?
> I mean to say how does that affect the image after operation. What
> changes it makes to image pixels, so that we get less noisy image?
>
> tx.

It uses the same principle as a common averaging algorithm

average = SUM w(i)*x(i)

athough in case of averaging, the weights are all 1/N, while
gaussian smoothing uses gaussian weights.

Thus, averaging a pixel value over a close region to it and
using non rectangular weight function, has the same effect
of getting a mean estimate from a set of values of a random
variable. It removes noise in the outer (high frequency) part
of the spectum, however the image might also be contaminated in
the center (low frequency) part of the spectrum.

Rgds,

Andrew




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ZOOM - adrien grosjean - Mar 29 15:00:00 2004

Hi all,

I have to built a optimized zoom in a PAL Picture for
a DSP application. I
want to know if someone has alredy do this sort of
algorithm.
In this case, what sort of interpolation have you used
? (bicubic, nearest
neighbor, fratal)
Is it possible to use a Zero Padding algorithm ?
Is it possible to use a covolution ?
Any enlightening ideas, suggestions, comments will be
greatly appreciated.

Thanks in advance,

Adrien Bonjour,
Je travaille actuellement sur un algorithme de Zoom
pour une application DSP
(format de l'image PAL)
Est ce que quelqu'un a déjà travaillé sur un
algorithme de zoom ?
Quel type d'interpolation avez vous utilisée ?
(bicubic, nearest neighbor,
fratal)
Est ce qu'il est possible d'utiliser un algorithm basé
sur du Zero Padding ?
Est ce qu'il est possible de traiter l'image avec une
covolution ?
Je suis preneur de toutes les idées, conseils,
commentaires, suggestions qui
pourront m'aider.

D'avance merci

Adrien
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