Hi Gaëtan,<br><br>thank you for your support. Actually, I thought that there's a difference in the number of segments between using <long> or colormapper for the output of watershed filter. It seemed to me that I receive more segments by using a RGB output. I found out that the problem lies in the viewer I use to watch the images. It had a wrong color level and showed the image to bright, so that a lot of segments disapeared.<br>
The clue of watershed is, that it delivers no single segment I'm looking for, but all segments it can find. To extract a single segment, I want to use Connected Threshold (with seed) afterwards. That was the reason I asked for help.<br>
<br>Regards, Michael <br><br><br><br><div class="gmail_quote">2009/8/31 Gaëtan Lehmann <span dir="ltr"><<a href="mailto:gaetan.lehmann@jouy.inra.fr">gaetan.lehmann@jouy.inra.fr</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
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Le 31 août 09 à 15:33, Michael Xanadu a écrit :<div><div></div><div class="h5"><br>
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<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi,<br>
<br>
I've got a watershed filtered image processed by a colormapper. So it's an image of type:<br>
<br>
typedef itk::RGBPixel<short> RGBPixelType;<br>
typedef itk::Image<RGBPixelType, 2> RGBImageType;<br>
<br>
Now I want to filter that image with a connected threshold filter, because I need it this way.<br>
But ConnectedThresholdImageFilter can't process such RGB images.<br>
I tryed to convert the image into a short type by using CastImageFilter, too.<br>
But I always get:<br>
<br>
error C2440: 'static_cast' : cannot convert from 'itk::RGBPixel<TComponent>' to 'short'<br>
<br>
So how can I cast from RGB to short? Or how to filter a RGB image with a connected threshold filter?<br>
<br>
</blockquote>
<br></div></div>
You can extract one of the channels with VectorIndexSelectionCastImageFilter or go to an intensity image with RGBToLuminanceImageFilter, but I doubt that's what you want. The color image is only a representation of the watershed output easier to read for humans, but not for computer. If you want to work on the output of the watershed, it's better to not use a color mapper, but directly on the output image of the watershed - the image should be of type itk::Image< unsigned long, 2 >.<br>
<br>
And even if you don't use a color mapper, it may not be a good idea to process the output of the watershed filter (a labeled image) with a filter (ConnectedThresholdImageFilter) made to work on a grayscale images.<br>
<br>
Can you explain what you want to achieve?<br>
<br>
Regards,<br>
<br>
Gaëtan<br><font color="#888888">
<br>
-- <br>
Gaëtan Lehmann<br>
Biologie du Développement et de la Reproduction<br>
INRA de Jouy-en-Josas (France)<br>
tel: +33 1 34 65 29 66 fax: 01 34 65 29 09<br>
<a href="http://voxel.jouy.inra.fr" target="_blank">http://voxel.jouy.inra.fr</a> <a href="http://www.itk.org" target="_blank">http://www.itk.org</a><br>
<a href="http://www.mandriva.org" target="_blank">http://www.mandriva.org</a> <a href="http://www.bepo.fr" target="_blank">http://www.bepo.fr</a><br>
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