%GFCREATEFILTERF2 Create normalized 2-D Gabor filter in the frequency domain.%%   [G] = GFCREATEFILTERF2(F0,THETA,GAMMA,ETA,N,...) creates a%   two-dimensional normalized Gabor filter G with central%   frequency F0, orientation THETA, normalized width GAMMA along%   the wave orientation, normalized width ETA orthogonal to wave%   orientation,  and size N. Also, a two element vector N = [NX%   NY] can be used to specify the size.%%   G = GFCREATEFILTERF2(...,'PF',PF) determines that at least%   P percent of the Gaussian envelope of the filter must be%   included in the filter in frequency domain. For default,%   PF=0.998. %%   G = GFCREATEFILTERF2(...,'PT',PT) determines that at least%   P percent of the Gaussian envelope of the filter must be%   included in the filter in spatial domain. For default,%   PT=0.998. %%   Examples%%   See also GFCREATEFILTER2, GFCHECKFILTER2, GFCREATEFILTERF.%% References:%   [1] Kamarainen, J.-K., Kyrki, V., Kalviainen, H., Gabor%       Features for Invariant Object Recognition, Research%       report 79, Department of Information Technology,%       Lappeenranta University of Technology %% Author(s):%    Joni Kamarainen <Joni.Kamarainen@lut.fi>%    Ville Kyrki <Ville.Kyrki@lut.fi>%% Copyright:%%   The Gabor Features in Signal and Image Processing Toolbox is%   Copyright (C) 2000 by Joni Kamarainen and Ville Kyrki.%function [g]=gfcreatefilterf2(f0, theta, gamma, eta, N,varargin)%% Setting default valuesalpha = f0/gamma;beta = f0/eta;PT = 0.998;PF = 0.998;%% Parameter parsingif mod(length(varargin),2)>0,  error('Each parameter must be given a value.');end;currentarg = 1;while (length(varargin) > currentarg)  [param,value]=deal(varargin{currentarg:currentarg+1});  switch lower(param)   case 'pt'    PT = value;   case 'pf'    PF = value;   otherwise    error(['Unknown parameter ''' param '''.']);  end;  currentarg=currentarg+2;end;% filter sizeif length(N)>1,  Nx=N(1);  Ny=N(2);else  Nx=N;  Ny=N;end;% Check filter constraintsgfcheckfilter2(f0,theta,gamma,eta,N,PT,PF);% Check if save file exists and load itif (isunix)     [status userName] = unix('whoami');     if (size(userName,2) > 1)        useTempFiles = 1;        userName = userName(1,1:end-1);% remove line change        temporarySaveFileName = ...          fullfile(tempdir,['gf-' userName '-' ...				  num2str(f0)  '-' num2str(theta) ...				  '-' num2str(gamma) '-' num2str(eta) '-' num2str(Nx) ...				  '-' num2str(Ny) '-' num2str(PT) '-' num2str(PF) '.mat'])     else	useTempFiles = 0;     end;else     [status userName] = unix('echo %USERNAME%');     if (size(userName,2) > 1)        useTempFiles = 1;        userName = userName(1,1:end-1);% remove line change        temporarySaveFileName = ...          fullfile(tempdir,['gf-' userName '-' ...				  num2str(f0)  '-' num2str(theta) ...				  '-' num2str(gamma) '-' num2str(eta) '-' num2str(Nx) ...				  '-' num2str(Ny) '-' num2str(PT) '-' num2str(PF) '.mat'])     else	useTempFiles = 0;     end;end;% THIS WAS OLD WAY BUT IT DIDNT WORK IN WINDOWS AND SUFFERED USMASKS BETWEEN% DIFFERENT USERS IN THE SAME SYSTEM%temporarySaveFileName = fullfile%temporarySaveFileName = ['/tmp/gffilter-' num2str(f0)  '-' num2str(theta) ...%		    '-' num2str(gamma) '-' num2str(eta) '-' num2str(Nx) ...%		    '-' num2str(Ny) '-' num2str(PT) '-' num2str(PF) '.mat']if (useTempFiles==1 & exist(temporarySaveFileName) == 2)  load(temporarySaveFileName);else    g = zeros(Ny,Nx);    % SOLUTION 1: easy to understand, but may need whole lotta memory  nx = -Nx:1:Nx;  ny = -Ny:1:Ny;  u = nx/Nx; % frequencies that bank contains  v = ny/Ny;  [U,V]=meshgrid(u,v);  gf = exp(-pi^2*( (U*sin(theta)-V*cos(theta)).^2/beta^2 + ...		   (U*cos(theta)+V*sin(theta)-f0).^2/alpha^2 ));    % Calculating the filter using aliasing  g = g+gf(1:Ny,1:Nx); % A_1  g = g+gf(1:Ny,(Nx+1):(2*Nx)); % A_2  g = g+gf((Ny+1):(2*Ny),1:Nx); % A_3  g = g+gf((Ny+1):(2*Ny),(Nx+1):(2*Nx)); % A_4    if (useTempFiles) % save this filter    save(temporarySaveFileName, 'g');  end;end;