<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hello everyone,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'>I have two questions regarding ITK Gradient Magnitude Recursive Gaussian Image Filter:<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:"Arial","sans-serif"'><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-family:"Arial","sans-serif"'>In this filter, as far as we know, a <b><span style='color:#C00000'>finite difference approach</span></b> is used to calculate gradient magnitude of an image. My question is <b><span style='color:#C00000'>what formula is used</span></b> by the finite difference approach implemented in this filter?<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-family:"Arial","sans-serif"'><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-family:"Arial","sans-serif"'>The ITK Software Guide tells us that the computation process of this filter is equivalent to first <b><span style='color:#C00000'>smoothing the image </span></b>by convolving it with a Gaussian kernel and then applying a differential operator. My question is that is there a way to get <b><span style='color:#C00000'>an output of the smoothed image</span></b>? I want to visualize the computation process.<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>If any of you have any idea regarding the two questions, it would be very appreciated if you share it with me. Thank you in advance.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Best regards,<o:p></o:p></p><p class=MsoNormal>Yang<o:p></o:p></p></div></body></html>