<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt"><div>Hi,<br><br>I'm testing a code on matlab to see the result before doing it on itk or vtk.the error i have is a warning "out of memory". So i guess that i have to reduce the size of the dicom serie 3D that i use. I tried on matlab the imresize function but there are some problem with it.<br>If someone tells me how to do it on itk or vtk or even matlab.<br>Thank you<br><br>Regards<br>syrine<br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div style="font-family: arial,helvetica,sans-serif; font-size: 13px;"><font size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">De :</span></b> Roman Grothausmann <roman.grothausmann@helmholtz-berlin.de><br><b><span style="font-weight: bold;">À :</span></b>
insight-users@itk.org<br><b><span style="font-weight: bold;">Envoyé le :</span></b> Ven 13 Novembre 2009, 10 h 31 min 48 s<br><b><span style="font-weight: bold;">Objet :</span></b> Re: [Insight-users] equivalence of Gaussian and low-pass-FFT<br></font><br>Thanks every body for the answers. With Insight-book I mean Insight Into Images: <a href="http://www.akpeters.com/product.asp?ProdCode=2175" target="_blank">http://www.akpeters.com/product.asp?ProdCode=2175</a><br><br>So it's only equivalent if I multiply the FFT with the FFT of the convolution Kernel I use in real space.<br>I think though there's one difference: Using the FFT allows to reduce the discretization (a better discrete interpolation) of the result since it's calculated with floating point precision. Convolving with a (wide) Gaussian gives me very few grey values.<br><br>Regards,<br>Roman<br><br>C.Cagatay Bilgin wrote:<br>> Your question is actually independent of the ITK<br>>
usage. Convolution in time domain corresponds<br>> to multiplication in frequency domain, so gaussian<br>> filtering your image is actually multiplying the FFT<br>> of your image with the FFT of the gaussian filter you<br>> used (you might need some padding as most probably<br>> your gaussian filter is was smaller than your image).<br>> <br>> If you want to clean up your image a little, I would say<br>> do not go to FFT just do it in time domain using the<br>> gaussian filters provided in the toolkit as you will<br>> need less number of lines of code.<br>> <br>> By the way, is the Insight-Book are you referring<br>> the software manual or something else ?<br>> <br>> Regards,<br>> ---------------------------------------------------------------------------- <br>> Cemal Cagatay Bilgin,<br>> Ph.D Candidate in Computer Science Department at RPI<br>> <a ymailto="mailto:bilgic@cs.rpi.edu"
href="mailto:bilgic@cs.rpi.edu">bilgic@cs.rpi.edu</a> - <a href="http://www.cs.rpi.edu/%7Ebilgic" target="_blank">http://www.cs.rpi.edu/~bilgic</a><br>> Lally 01A, 110 8th Street Troy, NY 12180-3590, USA.<br>> Tel: (518) 276-8489, Fax:(518) 276-4033<br>> <br>> On Nov 12, 2009, at 10:46 AM, Roman Grothausmann wrote:<br>> <br><br><br>_____________________________________<br><span>Powered by <a target="_blank" href="http://www.kitware.com">www.kitware.com</a></span><br><br>Visit other Kitware open-source projects at<br><a href="http://www.kitware.com/opensource/opensource.html" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br><br>Kitware offers ITK Training Courses, for more information visit:<br><a href="http://www.kitware.com/products/protraining.html" target="_blank">http://www.kitware.com/products/protraining.html</a><br><br>Please keep messages on-topic and check the ITK FAQ at:<br><a
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