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erick

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11 Nov 2013 3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes Author: Kyung Sang Kim

Hi, I compared you work with the FDK equation in some papers, it seems that your FDK algorithm omited a factor. I added this factor in the "backprojection.m" of your algorithm, the code is shown as follows.

Ratio=param.DSO.^2./(param.DSO-ry).^2;
vol(:,:,iz) = Ratio.*interp2(uu,vv ,proj',pu,pv,'linear');

Do you think it is necessary to add this factor? I am waiting for your reply, Thank you.

28 Oct 2013 3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes Author: Kyung Sang Kim

Thank you for your answers. I have a few questions left.
If I have already got real projections from x-ray imaging system, for example, I got the projections of a mouse, do I need to do the "CTprojection"? Under this circumstance, if I only need to do "CTbackprojection", how to set following params about the reconstructed object:nx, ny, nz, sx, sy, and sz.
The params of the detector are setted as follows:
param.su=50;%mm
param.sv=50;%mm
param.nu=1024;
param.nv=1024;
param.DSD=700;
param.DSO=560;

Last question, would you please give some reference about FDK algorithm not using iso-center(DSO) domain.

Thank you.

27 Oct 2013 3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes Author: Kyung Sang Kim

I am wondering if I have real projected images, do I need to use the function "CTprojection"?

27 Oct 2013 3D Cone beam CT (CBCT) projection backprojection FDK MLEM reconstruction MATLAB codes for students 3D Cone beam CT (CBCT) projection backprojection MLEM FDK reconstruction MATLAB source codes Author: Kyung Sang Kim

Good work. I have some questions.
Firstly, in the file of "backprojection.m", you set "w = (param.DSD)./sqrt((param.DSD)^2+uu.^2 + vv.^2);", but in many books, they said that w should be setted as "w = (param.DSO)./sqrt((param.DSO)^2+uu.^2 + vv.^2);". Can you give me some reason?
Secondly, also in the "backprojection.m", I think the description of rx, ry, pu and pv should be:
rx=xx.*cos(angle)+yy.*sin(angle_rad);
ry=-xx.*sin(angle)+yy.*cos(angle_rad);
pu=rx.*(param.DSO)./(param.DSO-ry);
pv=param.zs(iz)*(param.DSO)./(param.DSO-ry);

Would you please give me some suggestion, thank you.

21 May 2013 SLM - Shape Language Modeling Least squares spline modeling using shape primitives Author: John D'Errico

Thank you, John. According to your suggestion, I have fitted my data again, but unfortunately, the results is worse than seperately fitting the two parts of the curve. I made a simple simulation, but I still got the similar result. Would you please take a few minutes to have a look at my simulation data, I will send it to you by email. Thank you.

I found the code written by Meyer on this web site "http://www.stat.colostate.edu/~meyer/srrs.htm", but it was written in R code, not matlab. I think I should learn R code these days. Meyer also did not give out how to fit the data with half convex and half concave, it seems still a long way for me to get out. Would you please give me some suggestion? Thank you.

I am looking forward to your new reply, Thank you again.

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