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fold_slice/+utils/filt2d.m
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%FILT2D creates a 2d filter, based on fract_hanning
%
% outputdim... Size of the output array.
% unmodsize... Size of the central array containing no modulation.
% shape (optional)... 'rect' (default) or 'circ'
% filter_type (optional)... 'hann' (default) or 'hamm', chebishev (only for unmodsize=0)
%
% example:
% filt1 = filt2d(256,100,'circ','hann');
% filt2 = filt2d(256,100);
% filt3 = filt2d([512 420], [200 312]);
%
%
%
% Adapted from fract_hanning:
%
% fract_hanning(outputdim,unmodsize)
% out = Square array containing a fractional separable Hanning window with
% DC in upper left corner.
% outputdim = size of the output array
% unmodsize = Size of the central array containing no modulation.
% Creates a square hanning window if unmodsize = 0 (or ommited), otherwise the output array
% will contain an array of ones in the center and cosine modulation on the
% edges, the array of ones will have DC in upper left corner.
%*-----------------------------------------------------------------------*
%|                                                                       |
%|  Except where otherwise noted, this work is licensed under a          |
%|  Creative Commons Attribution-NonCommercial-ShareAlike 4.0            |
%|  International (CC BY-NC-SA 4.0) license.                             |
%|                                                                       |
%|  Copyright (c) 2017 by Paul Scherrer Institute (http://www.psi.ch)    |
%|                                                                       |
%|      Author: CXS group, PSI  |
%*-----------------------------------------------------------------------*
% You may use this code with the following provisions:
%
% If the code is fully or partially redistributed, or rewritten in another
% computing language this notice should be included in the redistribution.
%
% If this code, or subfunctions or parts of it, is used for research in a
% publication or if it is fully or partially rewritten for another
% computing language the authors and institution should be acknowledged
% in written form in the publication: “Data processing was carried out
% using the “cSAXS matlab package” developed by the CXS group,
% Paul Scherrer Institut, Switzerland.”
% Variations on the latter text can be incorporated upon discussion with
% the CXS group if needed to more specifically reflect the use of the package
% for the published work.
%
% A publication that focuses on describing features, or parameters, that
% are already existing in the code should be first discussed with the
% authors.
%
% This code and subroutines are part of a continuous development, they
% are provided “as they are” without guarantees or liability on part
% of PSI or the authors. It is the user responsibility to ensure its
% proper use and the correctness of the results.
% License for fract_hanning:
% Copyright (c) 2016, Manuel Guizar Sicairos, James R. Fienup, University of Rochester
% All rights reserved.
%
% Redistribution and use in source and binary forms, with or without
% modification, are permitted provided that the following conditions are
% met:
%
% * Redistributions of source code must retain the above copyright
% notice, this list of conditions and the following disclaimer.
% * Redistributions in binary form must reproduce the above copyright
% notice, this list of conditions and the following disclaimer in
% the documentation and/or other materials provided with the distribution
% * Neither the name of the University of Rochester nor the names
% of its contributors may be used to endorse or promote products derived
% from this software without specific prior written permission.
%
% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
% POSSIBILITY OF SUCH DAMAGE.
function out = filt2d(outputdim, unmodsize, varargin)
if nargin > 2
shape = varargin{1};
else
shape = 'rect';
end
if nargin > 3
filt_type = varargin{2};
else
filt_type = 'hann';
end
if nargin == 1
unmodsize = 0;
end
if length(outputdim)<2
outputdim = [outputdim outputdim];
elseif length(outputdim)>2
error('3D filters are not supported.')
end
if any(outputdim < unmodsize)
error('Output dimension must be smaller or equal to size of unmodulated window'),
end
if unmodsize<0
unmodsize = 0;
warning('Specified unmodsize<0, setting unmodsize = 0')
end
if length(unmodsize)<2
unmodsize = [unmodsize unmodsize];
elseif length(unmodsize)>2
error('3D filters are not supported.')
end
switch lower(shape)
case 'rect'
N1 = [0:outputdim(2)-1];
N2 = [0:outputdim(1)-1];
[Nc,Nr] = meshgrid(N1,N2);
case 'circ'
assert(length(unique(outputdim))==1 && length(unique(unmodsize))==1, 'Option "circ" is supported for square arrays only.')
N = [0:outputdim(1)-1];
Nsz = (outputdim(1)-1)/2;
xx = linspace(-Nsz,Nsz,outputdim(1));
[x,y] = meshgrid(xx,xx);
r = sqrt(x.^2 + y.^2);
out = zeros(outputdim(1), outputdim(1));
end
if unmodsize == 0
switch lower(filt_type)
case 'hann'
switch lower(shape)
case 'rect'
out = (1+cos(2*pi*Nc/outputdim(1))).*(1+cos(2*pi*Nr/outputdim(2)))/4;
case 'circ'
out1d = (1+cos(2*pi*N/outputdim(1)))/2;
out1d = fftshift(out1d);
out(r<=Nsz) = interp1(xx,out1d,r(r<=Nsz));
out = ifftshift(out);
otherwise
error('Unknown shape %s for filter %s', shape, filt_type);
end
case 'hamm'
switch lower(shape)
case 'rect'
out = (0.54+0.46*cos(2*pi*Nc/(outputdim(1)-1))).*(0.54+0.46*cos(2*pi*Nr/(outputdim(2)-1)));
case 'circ'
out1d = (0.54+0.46*cos(2*pi*N/(outputdim(1)-1)));
out1d = fftshift(out1d);
out(r<=Nsz) = interp1(xx,out1d,r(r<=Nsz));
out = ifftshift(out);
otherwise
error('Unknown shape %s for filter %s', shape, filt_type);
end
case 'chebyshev'
switch lower(shape)
case 'rect'
beta = cosh(1/outputdim(1)*acosh(10^5));
w1 = cos(outputdim(1)*acos(beta.*cos(pi*Nc/outputdim(1))))/(cosh(1/outputdim(1)*acos(beta)));
w1_fft = abs(fft(w1,[],2));
beta = cosh(1/outputdim(2)*acosh(10^5));
w2 = cos(outputdim(2)*acos(beta.*cos(pi*Nr/outputdim(2))))/(cosh(1/outputdim(2)*acos(beta)));
w2_fft = abs(fft(w2,[],1));
out = w2_fft.*w1_fft;
otherwise
error('Unknown shape %s for filter %s', shape, filt_type);
end
otherwise
error('Unknown filter %s', filt_type);
end
else
switch lower(filt_type)
case 'hann'
switch lower(shape)
case 'rect'
% Columns modulation
out = (1+cos(2*pi*(Nc- floor((unmodsize(2)-1)/2) )/(outputdim(2)+1-unmodsize(2))))/2;
if floor((unmodsize(2)-1)/2)>0
out(:,1:floor((unmodsize(2)-1)/2)) = 1;
end
out(:,floor((unmodsize(2)-1)/2) + outputdim(2)+3-unmodsize(2):length(N1)) = 1;
% Row modulation
out2 = (1+cos(2*pi*(Nr- floor((unmodsize(1)-1)/2) )/(outputdim(1)+1-unmodsize(1))))/2;
if floor((unmodsize(1)-1)/2)>0
out2(1:floor((unmodsize(1)-1)/2),:) = 1;
end
out2(floor((unmodsize(1)-1)/2) + outputdim(1)+3-unmodsize(1):length(N2),:) = 1;
out = out.*out2;
case 'circ'
out1d = (1+cos(2*pi*(N- floor((unmodsize(1)-1)/2) )/(outputdim(1)+1-unmodsize(1))))/2;
if floor((unmodsize(1)-1)/2)>0
out1d(1:floor((unmodsize(1)-1)/2)) = 1;
end
out1d(floor((unmodsize(1)-1)/2) + outputdim(1)+3-unmodsize(1):length(N)) = 1;
out1d = fftshift(out1d);
out(r<=Nsz) = interp1(xx,out1d,r(r<=Nsz));
out = ifftshift(out);
otherwise
error('Unknown shape %s for filter %s', shape, filt_type);
end
case 'hamm'
switch lower(shape)
case 'rect'
% Columns modulation
out = (0.54+0.46*cos(2*pi*(Nc-floor((unmodsize(2)-1)/2))/(outputdim(2)-unmodsize(2))));
if floor((unmodsize(2)-1)/2)>0
out(:,1:floor((unmodsize(2)-1)/2)) = 1;
end
% keyboard
out(:,floor((unmodsize(2)-1)/2) + outputdim(2)+3-unmodsize(2):length(N1)) = 1;
% Row modulation
out2 = (0.54+0.46*cos(2*pi*(Nr-floor((unmodsize(1)-1)/2))/(outputdim(1)-unmodsize(1))));
if floor((unmodsize(1)-1)/2)>0
out2(1:floor((unmodsize(1)-1)/2),:) = 1;
end
out2(floor((unmodsize(1)-1)/2) + outputdim(1)+3-unmodsize(1):length(N2),:) = 1;
out = out.*out2;
case 'circ'
out1d = (0.54+0.46*cos(2*pi*(N-floor((unmodsize(1)-1)/2))/(outputdim(1)-unmodsize(1))));
if floor((unmodsize(1)-1)/2)>0
out1d(1:floor((unmodsize(1)-1)/2)) = 1;
end
out1d(floor((unmodsize(1)-1)/2) + outputdim(1)+3-unmodsize(1):length(N)) = 1;
out1d = fftshift(out1d);
out(r<=Nsz) = interp1(xx,out1d,r(r<=Nsz));
out = ifftshift(out);
otherwise
error('Unknown shape %s for filter %s', shape, filt_type);
end
otherwise
error('Unknown filter %s', filt_type);
end
end
end