function?[I_recon_lin?I_recon_nnI_recon_lin1?I_recon_nn1]=BP（IMGM）

close?all;

I=IMG;
[rows?cols]=size（I）;

theta=creat_THETA（M）;
[Rxp]?=?radon（Itheta）;?%?Compute?（forward?）?projections

[N?K]?=?size（R）;
%?K?is?number?of?angles
%?N?is?number?of?detectors
xp_offset?=?abs（min（xp）?+?1）;
%?Fourier?Transform?of?the?projections
fft_N?=?512?;?%?Nearest?power?of?2?corresponding?to?367?is?512
R_fft?=?fft（R?fft_N）;
%?Define?the?ramp?filter?in?frequency
ramlak?=?[2?*?[0:（fft_N/2-1）?fft_N/2:-1:1?]‘?/?fft_N?];
plot（ramlak）;
%?Filtering?of?the?projections?in?frequency
[mn]=size（ramlak）;

for?i?=?1:K
R_filtered（:i）?=?R_fft（:i）?.*?ramlak;
%?R_unfiltered（:i）?=?R_fft（:i）./m;
R_unfiltered（:i）?=?R_fft（:i）;
end

%?Inverse?Fourier?Transform?of?the?filtered?projectio

?屬性????????????大小?????日期????時間???名稱
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?????文件???????2451??2017-09-17?18:57??附件-有無濾波器及插值方式的比較\BP.m

?????文件????????186??2017-09-17?19:44??附件-有無濾波器及插值方式的比較\creat_Phantom.m

?????文件?????????87??2017-09-17?19:44??附件-有無濾波器及插值方式的比較\creat_THETA.m

?????文件???????1412??2017-09-17?18:57??附件-有無濾波器及插值方式的比較\script.m

?????目錄??????????0??2017-09-19?21:36??附件-有無濾波器及插值方式的比較

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?????????????????4136????????????????????5