<div dir="ltr">Hi,Simon and Chao,<div><div>i want to test the cuda performance in SART algorithm.</div><div>but when i looked in the parameters in forwardprojection and backprojection. i got the enum:</div><div><br></div><div>enum enum_fp { fp__NULL = -1, fp_arg_Joseph = 0, fp_arg_RayCastInterpolator, fp_arg_CudaRayCast };</div><div>enum enum_bp { bp__NULL = -1, bp_arg_VoxelBasedBackProjection = 0, bp_arg_Joseph, bp_arg_CudaVoxelBased, bp_arg_NormalizedJoseph };</div></div><div><br></div><div>So if i want to use the trilinear intrtpolation forwardprojection you mentioned , how should i set the -b and -p in SART? or how to choose -b and -p that i can get a fastest reconstruction in SART in this case??</div><div><br></div><div>thanks for your help in advance.</div><div>Best</div><div>Guangming</div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><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"><br></div></div></div></div>
<br><div class="gmail_quote">2014-11-18 19:47 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>The trilinear version is available with CUDA: <br><a href="http://www.openrtk.org/Doxygen/classrtk_1_1CudaForwardProjectionImageFilter.html" target="_blank">http://www.openrtk.org/Doxygen/classrtk_1_1CudaForwardProjectionImageFilter.html</a><span class="HOEnZb"><font color="#888888"><br></font></span></div><span class="HOEnZb"><font color="#888888">Simon<br></font></span></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Nov 18, 2014 at 5:43 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><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi Chao,<div>Thanks very much for your prompt and so kind reply.</div><div>I will recheck the process of setting carefully with your suggestions and a short report may be given later.</div><div> BTW, do you have any plan recently to add other interpolation filter(e.g.<span style="color:rgb(80,0,80)">Kaiser-Bessel or Trilinear</span>)??</div><div>Thanks for your time.</div><div>Regards</div><span><font color="#888888"><div>Guangming </div></font></span><div><div><div class="gmail_extra"><div><div><div dir="ltr"><div style="line-height:23.3240013122559px"><font face="arial, helvetica, sans-serif"><b><i><font color="#073763"><br></font></i></b></font></div><div style="line-height:23.3240013122559px"><br></div></div></div></div>
<br><div class="gmail_quote">2014-11-18 19:09 GMT+03:00 Chao Wu <span dir="ltr"><<a href="mailto:wuchao04@gmail.com" target="_blank">wuchao04@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">Hi Guangming,<div><br></div><div>To reconstruct a volume from a series of tiff files you have to let the algorithm know the geometrical relationship among the source, the volume and the projections stored in the tiffs. The idea is the same: RTK uses projection matrices and image coordinates to understand the positioning of those projections. The projection matrices are based on a lot of geometrical parameters like gantry angle, source position, detector position, in-plane and out-of-plane rotation angles of the detector etc. I won't go though all since most of them have no differences if you use tiff files or whatever format as input. I focus on some tiff tips.</div><div><br></div><div>In the simplest situation, the tiff files contain correct resolution (DPI) information, then you need to do nothing on these files. You have to specify the correct detector offset though, since in the tiff image coordinates the origin is the first pixel (corner pixel) which is apparently not the intersection of the central ray and the detector. The detector offsets in x and y actually mean the position of the image origin (the first pixel) in the coordinate system centred at the intersection. Since the direction cosines is an identity matrix and pixel sizes are positive, the detector offsets in x and y will be negative.</div><div><br></div><div>If the resolution information of the tiff files is not correct, you have to rewrite this information. You can of course perform a pre-processing to change the DPI of all tiff files with a third-party software, or you can alter the RTK code to allow such changes after reading the images, by using a itk::ChangeInformationImageFilter filter.</div><div><br></div><div>Another non-geometrical issue with tiff files is that when their integer pixel values are converted into attenuation, the maximum possible integer is used as the reference value. This may not be correct in practice, e.g. in your 16-bit tiffs you use 62000 to represent air (no attenuation) leaving the integer range from 62001 to 65535 for statistical fluctuation. If for instance you only use the lower 14 bits for your data then this problem is more severe. For sure you can correct this by changing the code and specify the correct reference value.</div><div><br></div><div>Hope these can help.</div><div><br></div><div>Regards,</div><div>Chao</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>2014-11-18 15:09 GMT+01:00 Guangming Zang <span dir="ltr"><<a href="mailto:guangming.zang@kaust.edu.sa" target="_blank">guangming.zang@kaust.edu.sa</a>></span>:<br></div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div><div><div dir="ltr">Thanks</div><div class="gmail_extra"><br clear="all"><div><div><div dir="ltr"><font style="line-height:23.3240013122559px" face="arial, helvetica, sans-serif" color="#674ea7"><b><i>Guangming Zang (Alex)</i></b></font><div style="line-height:23.3240013122559px"><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:23.3240013122559px"><span style="font-family:arial;font-size:13px;line-height:20.0200004577637px"><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:23.3240013122559px"><br></div></div></div></div>
<br><div class="gmail_quote">2014-11-18 16:46 GMT+03:00 Guangming Zang <span dir="ltr"><<a href="mailto:guangming.zang@kaust.edu.sa" target="_blank">guangming.zang@kaust.edu.sa</a>></span>:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">Hi,<div>I am using the sart reconstruction in RTK, it works well.Thanks for your great work.</div><div>and i was wondering do you have any plan to add other filters except Joseph, such as Kaiser-Bessel??? ( described here <a href="http://wscg.zcu.cz/wscg2003/papers_2003/herman.pdf" target="_blank">http://wscg.zcu.cz/wscg2003/papers_2003/herman.pdf</a>)</div><div>BTW, i have read the messages sent by other users(<a href="http://public.kitware.com/pipermail/rtk-users/2014-October/000573.html" target="_blank">http://public.kitware.com/pipermail/rtk-users/2014-October/000573.html</a>)</div><div>but i still can not make it. can u help me and explain again about using a series of .tiff images ans sart algorithms to get the volume.</div><div>Thanks in advance <br clear="all"><div><div><div dir="ltr">Best<br><div style="line-height:23.3240013122559px"><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:23.3240013122559px"><span style="font-family:arial;font-size:13px;line-height:20.0200004577637px"><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:23.3240013122559px"><br></div></div></div></div>
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