clear;

disp（‘Display?Original‘）
M=256;
N=256;
I?=?phantom（MN）;
figure（1）;
imshow（I）;

coordinateSource=[];
projMatrix=[];
detector=[];
proj=load（char（‘projection.mat‘））;
phyRatoDig=proj.phyRatoDig;
projMatrix=proj.projection;
yDetector=proj.yDetector;
nDetectors=proj.nDetectors;

figure（2）
showimge（projMatrix3605120max（max（projMatrix）））;

%?coordinateSource=proj.coordinateSource;
%?coordinateDetector=proj.coordinateDetector;
%?
D_dig=proj.focalDistance_dig;
sourceToDetector_dig=proj.focalDistance_dig+proj.detecDistance_dig;
s=[];
s=D_dig/sourceToDetector_dig*yDetector（1:）*phyRatoDig;
Detector=yDetector（1:）*phyRatoDig;
%?
?pe=[];
?M=D_dig./sqrt（D_dig.^2+s.^2）;
?nViews=proj.nViews;
%?
?for?i=1:nViews
????pe（i:）=projMatrix（i:）.*M;%加權投影
?????
?end
?figure（3）;
?showimge（pe3605120max（max（pe）））;


disp（‘Filtering‘）
filternum=128;
filter_ramp=zeros（filternum1）;
for?j=1:filternum???%?16?point?ramp?filter
????i=j-1-filternum/2;
????if（i==0）
?????filter_ramp（j1）=1/（8.0）;
????elseif?（mod（i2）==0）
????????????filter_ramp（j1）=0;
????elseif?（mod（i2）==1）
????????????filter_ramp（j1）=-0.5/（i*i*pi*pi）;
????end
end
m=1;
figure（4）;

plot（filter_ramp）;


pfilter=[];
length_conv=filternum+nDetectors-1;%639
pPro=zeros（length_conv1）;
temp_pro=zeros（nDetectors1）;
h_filter=filternum/2;%64
ii=length_conv-h_filter-nDetectors;%63
?for?s=1:nViews?%?sample-loop
????%?for??pp=1:h_filter
????pro_left?=（pe（s1）+pe（s2））/2.0;
????pro_right=（pe（snDetectors）+pe（snDetectors-1））/2.0;
????
????for?pp=1:h_filter;???????????????%left?part
????????pPro（pp1）=pro_left;??%左邊補零??????
????end
%????
????for?pp=1:nDetectors??????????????????????%middle?part
?????pPro（h_filter+pp1）=pe（spp）;%中間部分不變
????end
%????
???for?pp=h_filter+nDetectors+1:length_conv
????pPro（pp）=pro_right;%右邊補零
????end
%???result_conv????
???for?n=1:nDetectors?
???????result_conv=0;
???	for?jj=1:filternum%1：128
????????pPmove=pPro（n+jj-11）;
????????result_conv=result_conv+pPmove*filter_ramp（jj1）;
????end
????pfilter（sn）=result_conv;
???end
?
????
?end
figure（5）;
showimge（pfilter360512min（min（pfilter））max（max（pfilter）））;%輸出卷積濾波結果

%?%%%%%%%%%%%%%%%%%%%%%%reArrange%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%?
%?%%%%%%%%%%%%%%%%%%%%%%Back?projection%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%??deltaBeta=proj.deltaTheta;
%??xCoodinate=proj.xCoodinate;
%??yCoodinate=proj.yCoodinate;
%??
%??unitDis=?proj.unitDis;
%?Detector?=coordinateDetector（2:）;
disp（‘BackProjection‘）
detecLength=proj.detecLength;
unitDis=detecLength/（nDetectors-1）;
unitDis_dig=unitDis*phyRatoDig;

deltaBeta=2*pi/nViews;
?M=proj.M;
?N=proj.N;
?fReconstruct=[];
?for?i=1:M
??????x=i-（M+1）/2;%待重建點的橫坐標
?????for?j=1:N
????????y=（N+1）/2-j;%待重建點的縱坐標
???????r=sqrt（x^2+y^2）;
????????theta=atan2（yx）;%極坐標（rtheta）
%?????
????????result=0;?
?????for?s=1:nViews
?????beta=?（s-1）*deltaBeta;%中心線與y軸夾角
?????s1=D_dig*r*cos（beta-theta）/（D_dig+

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????3946??2011-08-12?14:41??FBPRec\FBPRec\FanRec.asv

?????文件???????3946??2011-08-12?14:42??FBPRec\FBPRec\FanRec.m

?????文件???????6367??2009-12-16?18:21??FBPRec\FBPRec\limited_Views.m

?????文件????1120183??2009-12-21?18:51??FBPRec\FBPRec\projection.mat

?????文件???????3622??2011-08-12?12:41??FBPRec\FBPRec\projecton.asv

?????文件???????3622??2011-08-12?12:42??FBPRec\FBPRec\projecton.m

?????文件????????365??2009-11-22?21:14??FBPRec\FBPRec\showimge.m

?????目錄??????????0??2011-08-12?13:41??FBPRec\FBPRec

?????目錄??????????0??2011-08-10?14:01??FBPRec

-----------?---------??----------?-----??----

??????????????1142051????????????????????9