<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 Luca,</div><div><br></div><div>May I know where I can find the newly fixed itkHessianRecursiveGaussianImageFilter and tkHessianRecursiveGaussianImageFilterScaleSpaceTest for testing my program?<br></div><div><br></div><div>Regards,</div><div>Rahul</div><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><br><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><font size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Luca Antiga <luca.antiga@gmail.com><br><b><span style="font-weight: bold;">To:</span></b> itk Users <insight-users@itk.org><br><b><span style="font-weight: bold;">Sent:</span></b> Wed, April 28, 2010 3:25:41 PM<br><b><span style="font-weight:
bold;">Subject:</span></b> [Insight-users] Heads up on HessianRecursiveGaussian bug fix<br></font><br>
Hi all,<div> this is a heads up message on a bug that Oleksandr Dzyubak has found in itkHessianRecursiveGaussianImageFilter</div><div>(bug 0008990 in Mantis, <a rel="nofollow" target="_blank" href="http://public.kitware.com/Bug/view.php?id=10599)">http://public.kitware.com/Bug/view.php?id=10599)</a> and for which I recently submitted a fix.</div><div><br></div><div>The bug affected the behavior of the filter when NormalizeAcrossScale is set to true with dimensions > 2, and it has effects on multi-scale vesselness filters or multi-scale shape-detection filters in general (e.g. those using itk::MultiScaleHessianBasedMeasureImageFilter), and vessel-enhancing diffusion filters.</div><div><br></div><div>The bug caused incorrect normalization of the Hessian across scale-space, and, for instance, lead to a poor performance of vesselness filters when spanning several scales (vessels at smaller scales were washed out compared to how they appear after
the fix).</div><div><br></div><div>The fix has been committed after 3.18 was released, hence it will be in for ITK > 3.18. There is now a test (itkHessianRecursiveGaussianImageFilterScaleSpaceTest) that tests the scale-space behavior of the class quantitatively.</div><div><br></div><div>So, for whoever was using multi-scale Hessian-based filters in 3D and higher, please rerun your tests, since there's a very good chance (100% ?) that the results will have changed (most likely for the better).</div><div><br></div><div>I'm here for any clarification. Again, kudos to Oleksandr Dzyubak who highlighted the misbehavior through lots of testing.</div><div><br></div><div>Best regards</div><div><br></div><div><br></div><div>Luca</div><div><br></div><br><br><div><div style="word-wrap:break-word;"><div style="word-wrap:break-word;"><span class="Apple-style-span" style="border-collapse:separate;color:rgb(0, 0,
0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px;"><div style="word-wrap:break-word;"><span class="Apple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px;"><div style="word-wrap:break-word;"><span class="Apple-style-span" style="border-collapse:separate;color:rgb(0, 0, 0);font-family:Helvetica;font-size:medium;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;line-height:normal;orphans:2;text-indent:0px;text-transform:none;white-space:normal;widows:2;word-spacing:0px;"><div
style="word-wrap:break-word;"><div>--</div><div>Luca Antiga, PhD</div><div>Principal Scientist, OROBIX Srl</div><div>via L.A. Muratori 3, 24123 Bergamo, Italy</div><div><br></div><div>web: <a rel="nofollow" target="_blank" href="http://www.orobix.com/">www.orobix.com</a><br>mobile: +39.347.43.16.596<br><br>"This message originates from OROBIX Srl and its contents and attachments are privileged and confidential and are intended only for the individual(s) or entity(ies) named above. This message should not be forwarded, distributed or disclosed. Any unauthorized use, dissemination and duplication is strictly prohibited and may be unlawful. All personal messages express views solely of the sender, which are not to be attributed to OROBIX Srl, and may not be copied or distributed without this disclaimer. If you are not the intended recipient or received this message in error, please delete this message and notify the sender by reply e-mail.
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