<div dir="ltr"><div class="gmail_default" style="font-family:trebuchet ms,sans-serif;color:#0000ff">Hi simon, </div><div class="gmail_default" style="font-family:trebuchet ms,sans-serif;color:#0000ff">i see, thanks for the help and explanation. after following your advice, it works fine now.</div><div class="gmail_default" style="font-family:trebuchet ms,sans-serif;color:#0000ff">Regards</div><div class="gmail_default" style="font-family:trebuchet ms,sans-serif;color:#0000ff">Guangming</div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><font style="line-height:23.32400131225586px" face="arial, helvetica, sans-serif" color="#674ea7"><b><i>Guangming Zang (Alex)</i></b></font><div style="line-height:23.32400131225586px"><font face="arial, helvetica, sans-serif"><b><i><font color="#0b5394">King Abdullah University of Science and Technology</font><font color="#073763">(KAUST)</font></i></b></font></div><div style="line-height:23.32400131225586px"><span style="font-family:arial;font-size:13px;line-height:20.020000457763672px"><font color="#0b5394"><b><i>University of Chinese Academy of Sciences(UCAS)</i></b></font></span><font face="arial, helvetica, sans-serif"><b><i><font color="#073763"><br></font></i></b></font></div><div style="line-height:23.32400131225586px"><span style="font-family:arial;font-size:13px;line-height:20.020000457763672px"><font color="#0b5394"><b><i><br></i></b></font></span></div><div style="line-height:23.32400131225586px"><span style="font-family:arial;font-size:13px;line-height:20.020000457763672px"><font color="#0b5394"><b><i><br></i></b></font></span></div><div style="line-height:23.32400131225586px"><br></div></div></div></div></div></div>
<br><div class="gmail_quote">2015-07-31 8:55 GMT+03:00 Simon Rit <span dir="ltr"><<a href="mailto:simon.rit@creatis.insa-lyon.fr" target="_blank">simon.rit@creatis.insa-lyon.fr</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hi,<br>It looks to me that you haven't converged. I'm not the specialist of this algorithm and the specialist won't be near a computer in the coming weeks but when I try with more iterations in the data attachment term:<br> rtkadmmtotalvariation -p . -r proj.mha -o admmtv.mha -g geo.xml --spacing 1 --dimension 128 --alpha 1 --beta 1000 -n 10<br></div><div>it's more satisfactory. There are rings at the top and the bottom of the cone-beam which should be reduced with more TV (greater alpha, see doc <a href="http://www.openrtk.org/Doxygen/classrtk_1_1ADMMTotalVariationConeBeamReconstructionFilter.html" target="_blank">here</a>) or with a finer spacing (see <a href="http://dx.doi.org/10.1088/0031-9155/49/1/010" target="_blank">this publication</a>).<br></div><div>Simon<br></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Thu, Jul 30, 2015 at 2:16 PM, Guangming Zang <span dir="ltr"><<a href="mailto:guangming.zang@kaust.edu.sa" target="_blank">guangming.zang@kaust.edu.sa</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr"><div class="gmail_default" style="font-family:trebuchet ms,sans-serif;color:#0000ff"><p class="MsoNormal">Hi Simon and Chao,</p><p class="MsoNormal">i am currently do some comparisons between different reconstruction methods for Shapp-Logan dataset.</p><p class="MsoNormal">the commands are:</p><p class="MsoNormal">rtksimulatedgeometry -n 360 --arc -360 -o geo.xml --sdd=955.4050067 --sid=500.0 </p><p class="MsoNormal">rtkprojectshepploganphantom -g geo.xml --phantomscale 64 -o proj.mha --dimension 512,512</p><p class="MsoNormal"> </p>
<p class="MsoNormal">when using FDK or SART algorithm from RTK, I can got pretty good
results indeed(to see clearly, set contrast as [0.95,1.13], i.e., windows as
0.09 and levels as 1.04 for all results got). When running ADMMTV command
below, though the geometry is as same as SART and FDK, the result got from ADMM looks weird.(pls see attached central slice of ground truth and ADMM, same contrast with other algorithm)</p>
<p class="MsoNormal">rtkadmmtotalvariation -p . -r proj.mha -g geo.xml -o SL_ADMM_0.001_0.01.mha --dimension 128,128,128 --spacing
1,1,1 -n 2 --CGiter 3 --origin
-64,-64,-64 --alpha 0.001 --beta 0.01 --time 1 </p>
<p class="MsoNormal"> <img src="cid:ii_14edee1be578ddf6" alt="内嵌图片 1" style="color:rgb(34,34,34);font-family:arial,sans-serif;line-height:23.3240013122559px;margin-right:0px" height="174" width="218"><img src="cid:ii_14edee23190e6ced" alt="内嵌图片 2" style="color:rgb(34,34,34);font-family:arial,sans-serif;line-height:23.3240013122559px;margin-right:0px" height="175" width="218"></p>
<p class="MsoNormal">Is it because the CG algorithm used by ADMM, or parameters
setting issues here?? if it is parameters setting problem , would you help me and give a nice values for alpha and bate used here?</p>
<p class="MsoNormal">BTW, I had tried the –alpha from [0.001,1] and –bate[0.01,10]
already (including default value)</p>
<p class="MsoNormal">Thanks and regards</p><p class="MsoNormal">Guangming</p><p class="MsoNormal"><br></p><div class="gmail_default" style="line-height:23.3240013122559px;display:inline"></div></div><div><div><div dir="ltr"><div><div dir="ltr"><font style="line-height:23.32400131225586px" face="arial, helvetica, sans-serif" color="#674ea7"><b><i>Guangming Zang (Alex)</i></b></font><div style="line-height:23.32400131225586px"><font face="arial, helvetica, sans-serif"><b><i><font color="#0b5394">King Abdullah University of Science and Technology</font><font color="#073763">(KAUST)</font></i></b></font></div><div style="line-height:23.32400131225586px"><span style="font-family:arial;font-size:13px;line-height:20.020000457763672px"><font color="#0b5394"><b><i>University of Chinese Academy of Sciences(UCAS)</i></b></font></span></div><div style="line-height:23.32400131225586px"><span style="font-family:arial;font-size:13px;line-height:20.020000457763672px"><font color="#0b5394"><b><i><br></i></b></font></span></div><div style="line-height:23.32400131225586px"><div class="gmail_default" style="font-family:'trebuchet ms',sans-serif;color:rgb(0,0,255);display:inline"></div><br></div></div></div></div></div></div>
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