%this program is written at 1995, and modified at 1380/4/5 and calculate the angular power spectrum
function [theta,ang_ps]=angpwr2
%ANGPWR    Angular power spectrum.
%          [ANGLE ANG_PS]=ANGPWR(sizem,FIN,FOUT) returns angular 
%          power spectrum of an (image) matrix with sizem sizem x sizem 
%          which exists in FIN file and stores it into FOUT file.
%
%          EXAMPLE: 
%
%          [beta pwr]=angpwr(256,'c:\par.val','c:\par.ang');

[filen,pathf]=uigetfile('New Folder\*.jpg','Choose a fabric image');
if filen==0 % Choose Cancel
   return
end
value=imread([pathf,filen]);
%value=value./mean2(value);
[r,c]=size(value);
if r >c 
   r=c;
end
value=value(1:r,1:r);

F=fft2(value);
%F=F./mean2(F);
sizem=r;
clear value
ps=F(1:sizem/2,1:sizem/2).*conj(F(1:sizem/2,1:sizem/2));
clear F
ps_ave=sum(sum(ps))/((sizem/2)*(sizem/2));
r=0:1:(sizem/2)-1;
for theta=0:1:200,
   th_rad=(90-abs(90-abs(180-theta)))*pi/180.0;%Convert to Radian
   x=round(r*cos(th_rad));
   y=round(r*sin(th_rad));
   pwr=0.0;
   for i=1:length(r),
      pwr=pwr+ps(x(i)+1,y(i)+1);
   end
   pwr=pwr-ps(1,1);
   ang_ps(theta+1)=pwr/ps_ave;
end
theta=0:1:200;
if nargout==0
      figure('numbertitle','off','name',[pathf,filen]);plot(theta,ang_ps);
end;