No subject

low frequencies from the image, hence equivalent to enhancing
high spatial frequencies.

You may want to go a step further and multiply the smoothed
image by a constant to get some control on how much you
attenuate the low frequencies.

In pseudocode you end up with


  Sharpened image =3D Image - K . Smoothing( Image, Sigma )


    Typically K will be in the range [0,1].


and... you may want to go with a large Sigma, (e.g. spanning
more pixels than the details that you want to enhance).




   Regards,


        Luis


---------------------------------------------------------------------------=
-----
On Tue, Jun 9, 2009 at 9:34 AM, Michael Knopke <Michael.Knopke at gmx.de>wrote=
:

>  Hi ,
>
>
>
> Thanks for the hint David, that=92s what I want to do later (needs bridgi=
ng
> between vtk-itk first).
>
> I just wanted to have some simple sharpen filter to apply onto the image
> (just like vtkImageGaussianSmooth but for sharpening).
>
> I know about vtkButterworthHighpass, but this is no option since it is
> terrible slow=85
>
> Anybody else?
>
>
>
> Michael
>
>
>
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
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>

--000e0cd15744ac3089046beb0556
Content-Type: text/html; charset=windows-1252
Content-Transfer-Encoding: quoted-printable

<br>Hi Michael,<br><br>Assuming that you are doing this just for the purpos=
e of providing<br>an image for visualization, as opposed to an image that i=
s going <br>to undergo further processing...<br>
<br><br>You can build a quick sharpen filter by taking the original image<b=
r>and subtracting from it its smoothed version.<br><br><br>From the spectra=
l point of view, this is equivalent to removing<br>low frequencies from the=
 image, hence equivalent to enhancing<br>
high spatial frequencies.<br><br>You may want to go a step further and mult=
iply the smoothed<br>image by a constant to get some control on how much yo=
u<br>attenuate the low frequencies.<br><br>In pseudocode you end up with<br=
>
<br><br>=A0 Sharpened image =3D Image - K . Smoothing( Image, Sigma )<br><b=
r><br>=A0=A0=A0 Typically K will be in the range [0,1].<br><br><br>and... y=
ou may want to go with a large Sigma, (e.g. spanning<br>more pixels than th=
e details that you want to enhance).<br>
<br><br><br><br>=A0=A0 Regards,<br><br><br>=A0=A0=A0=A0=A0=A0=A0 Luis<br><b=
r><br>---------------------------------------------------------------------=
-----------<br><div class=3D"gmail_quote">On Tue, Jun 9, 2009 at 9:34 AM, M=
ichael Knopke <span dir=3D"ltr">&lt;<a href=3D"mailto:Michael.Knopke at gmx.de=
">Michael.Knopke at gmx.de</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"border-left: 1px solid rgb(204, =
204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">








<div link=3D"blue" vlink=3D"purple" lang=3D"EN-US">

<div>

<p>Hi ,</p>

<p>=A0</p>

<p>Thanks for the hint David, that=92s what I want to do
later (needs bridging between vtk-itk first).</p>

<p>I just wanted to have some simple sharpen filter to apply
onto the image (just like vtkImageGaussianSmooth but for sharpening).</p>

<p>I know about vtkButterworthHighpass, but this is no option
since it is terrible slow=85</p>

<p>Anybody else?</p>

<p>=A0</p>

<p>Michael</p>

<p>=A0</p>

<p>=A0</p>

</div>

</div>


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<br></blockquote></div><br>

--000e0cd15744ac3089046beb0556--