hi,<div><br></div><div>You definitly want to work in 3D.</div><div><br></div><div>You can either check the filters that support he spacing information with your original dataset (my wild guess is that most recent filters like Chan and Vesse level set should),</div>
<div>or resample your 3D image to get an isotropic image.</div><div><br></div><div>regards,</div><div><br></div><div>alex.</div><div><br><br><div class="gmail_quote">2010/8/14 Jay Li <span dir="ltr"><<a href="mailto:chyumm@yahoo.com">chyumm@yahoo.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top" style="font:inherit">Hi Dženan,<br><br>I appreciate your suggestions/answers. Thank you very much. It's really helpful.<br>
<br>Regards,<br>Jay<div class="im"><br><br>--- On <b>Fri, 8/13/10, Dženan Zukić <i><<a href="mailto:dzenanz@gmail.com" target="_blank">dzenanz@gmail.com</a>></i></b> wrote:<br></div><blockquote style="border-left:2px solid rgb(16, 16, 255);margin-left:5px;padding-left:5px">
<div class="im"><br>From: Dženan Zukić <<a href="mailto:dzenanz@gmail.com" target="_blank">dzenanz@gmail.com</a>><br>Subject: Re: [Insight-users] How ITK handles non-equal spacing images<br>To: "Jay Li" <<a href="mailto:chyumm@yahoo.com" target="_blank">chyumm@yahoo.com</a>><br>
Cc: <a href="mailto:insight-users@itk.org" target="_blank">insight-users@itk.org</a><br></div>Date: Friday, August 13, 2010, 3:28 AM<div><div></div><div class="h5"><br><br><div>Hi Jay!<div><br></div><div>That approach is called 2.5D. It was common 10-15 years ago, but it is no longer common because you basically ignore information using it. I also deal with similarly anisotropic images (0.625 in x and y, 4.4 in z). And yes, low Z resolution is a pain in the butt,
but if you restrict yourself to sequence of 2D slices, good results become harder to achieve.<div>
<br></div><div>But reading your arguments, I can see the point - I haven't given it much thought until now. And I don't consider myself to be an expert either.</div><div><br></div><div>Regards,</div><div>Dženan<br>
<br><div>2010/8/13 Jay Li <span dir="ltr"><<a rel="nofollow" href="http://mc/compose?to=chyumm@yahoo.com" target="_blank">chyumm@yahoo.com</a>></span><br>
<blockquote style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex"><table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td style="font:inherit" valign="top">
Hi Dženan,<br><br>Thanks for your input. I'm hoping to get a feeling on how to choose appropriate algorithms/filters for 3D non-equal spacing images in general. I was told that it would be more appropriate to perform 2D filters than 3D filters to the image I described in the first email (0.2 mm spacing along x, y, 1 mm spacing along z), because the spacing in z direction is five times of it along x and y. As I'm not an expert in image processing, I don't know if this is a common approach in the industry. I'm kind of hoping experts on this forum could give me some insights. Thank you again.<br>
<br>Regards,<br>Jay<br><br>--- On <b>Tue, 8/10/10, Dženan Zukić <i><<a rel="nofollow" href="http://mc/compose?to=dzenanz@gmail.com" target="_blank">dzenanz@gmail.com</a>></i></b> wrote:<br><blockquote style="border-left:2px solid rgb(16, 16, 255);margin-left:5px;padding-left:5px">
<br>From: Dženan Zukić
<<a rel="nofollow" href="http://mc/compose?to=dzenanz@gmail.com" target="_blank">dzenanz@gmail.com</a>><br>Subject: Re: [Insight-users] How ITK handles non-equal spacing images<br>To: "Jay Li" <<a rel="nofollow" href="http://mc/compose?to=chyumm@yahoo.com" target="_blank">chyumm@yahoo.com</a>><br>
Cc: <a rel="nofollow" href="http://mc/compose?to=insight-users@itk.org" target="_blank">insight-users@itk.org</a><br>Date: Tuesday, August 10, 2010, 9:12 AM<div><div></div><div><br><br><div>Hi Jay,<div><br></div><div>ITK image has support for different spacings along each axis, unfortunately not all filters take this information into account (most should though). The best way to check is to take a look at the source code.</div>
<div><br></div><div>Regards,</div><div>Dženan<br><br><div>On Tue, Aug 10, 2010 at 02:54, Jay Li <span dir="ltr"><<a rel="nofollow" href="http://mc/compose?to=chyumm@yahoo.com" target="_blank">chyumm@yahoo.com</a>></span> wrote:<br>
<blockquote style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td style="font:inherit" valign="top"><div>Dear ITK Users,</div>
<div> </div>
<div>I have a question regarding how ITK handles images with non-equal spacings in general. For example, I have a 3D volume with the spacing of 0.2 mm along X and Y axis respectively, but 1 mm spacing in Z direction. If I apply a 3-D level set segmentation algorithm to the image, is this going to be a concern due to the larger spacing in Z direction? Or instead should I try 2-D level set segmentation slice by slice on X-Y plane? Any suggestion is appreciated. Thank you.</div>
<div> </div>
<div>Regards,</div>
<div>Jay</div></td></tr></tbody></table><font color="#888888"><br>
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