<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">Dear all,</span></font><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">I am a newbie to ITK. </span></font><span class="Apple-style-span" style="font-family: 'Andale Mono'; font-size: 14px; ">I currently want to compute the hessian matrix, eigen vector out of some volume CT images. I found that I can use itk::MultiScaleHessianBasedMeasureImageFilter, or itk::HessianRecursiveGaussianImageFilter plus itk::SymmetricEigenAnalysis and SymmetricSecondRankTensor image iterator to finish the job. Am I right?</span></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">For the itk::MultiScaleHessianBasedMeasureImageFilter, I understand that I can turn the GenerateHessianOutputOn() function to compute the Hessian image and use GetHessianOutput() to get the SymmetricSecondRankTensor image. Is this a correct procedure? If yes, so here comes my question. Since the multi scale hessian filter is multi scale, if I use GetHessianOutput() function, what scale is the Hessian output of?</span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">Suppose my volume image dimension is 3, how can I access all the values in Hessian matrix? Can I use H[][] to access all 9 values? Or I can only access 6 and I need to fill up all the rest based on symmetric rule?</span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">For my second option, from HessianRecursiveGaussianImageFilter -> SymmetricSecondRankTensor image -> SymmetricEigenAnalysis -> eigen vector, will it work as predicted? </span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">Sorry for so many questions. </span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">Thank you and best regards,</span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">Zhimin</span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">Research Fellow</span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">Institute for Infocomm Research</span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;">A-STAR, Singapore</span></font></div><div><font class="Apple-style-span" face="'Andale Mono'" size="4"><span class="Apple-style-span" style="font-size: 14px;"><br></span></font></div><div><span class="Apple-style-span" style="font-family: Menlo; font-size: 11px; "><br></span></div>
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