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88 lines
3.6 KiB
Matlab
88 lines
3.6 KiB
Matlab
% fract_hanning(outputdim,unmodsize)
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% out = Square array containing a fractional separable Hanning window with
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% DC in upper left corner.
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% outputdim = size of the output array
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% unmodsize = Size of the central array containing no modulation.
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% Creates a square hanning window if unmodsize = 0 (or ommited), otherwise the output array
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% will contain an array of ones in the center and cosine modulation on the
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% edges, the array of ones will have DC in upper left corner.
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% February 8, 2007
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% Slight update on August 17, 2009
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% Added a warning
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% Copyright (c) 2016, Manuel Guizar Sicairos, James R. Fienup, University of Rochester
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% All rights reserved.
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%
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% Redistribution and use in source and binary forms, with or without
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% modification, are permitted provided that the following conditions are
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% met:
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%
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% * Redistributions of source code must retain the above copyright
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% notice, this list of conditions and the following disclaimer.
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% * Redistributions in binary form must reproduce the above copyright
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% notice, this list of conditions and the following disclaimer in
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% the documentation and/or other materials provided with the distribution
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% * Neither the name of the University of Rochester nor the names
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% of its contributors may be used to endorse or promote products derived
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% from this software without specific prior written permission.
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%
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% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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% POSSIBILITY OF SUCH DAMAGE.
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function out = fract_hanning(outputdim,unmodsize);
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if nargin > 2,
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error('Too many input arguments'),
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elseif nargin == 1,
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unmodsize = 0;
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end
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if outputdim < unmodsize,
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error('Output dimension must be smaller or equal to size of unmodulated window'),
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end
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if unmodsize<0,
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unmodsize = 0;
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warning('Specified unmodsize<0, setting unmodsize = 0')
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end
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N = [0:outputdim-1];
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% N = ifftshift([-floor(outputdim/2):ceil(outputdim/2)-1]);
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% N = [-floor(outputdim/2):ceil(outputdim/2)-1];
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[Nc,Nr] = meshgrid(N,N);
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if unmodsize == 0,
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out = (1+cos(2*pi*Nc/outputdim)).*(1+cos(2*pi*Nr/outputdim))/4;
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else
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% Columns modulation
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out = (1+cos(2*pi*(Nc- floor((unmodsize-1)/2) )/(outputdim+1-unmodsize)))/2;
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if floor((unmodsize-1)/2)>0,
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out(:,1:floor((unmodsize-1)/2)) = 1;
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end
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out(:,floor((unmodsize-1)/2) + outputdim+3-unmodsize:length(N)) = 1;
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% Row modulation
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out2 = (1+cos(2*pi*(Nr- floor((unmodsize-1)/2) )/(outputdim+1-unmodsize)))/2;
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if floor((unmodsize-1)/2)>0,
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out2(1:floor((unmodsize-1)/2),:) = 1;
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end
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out2(floor((unmodsize-1)/2) + outputdim+3-unmodsize:length(N),:) = 1;
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out = out.*out2;
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end
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% out = ifftshift(out);
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% one-edge at Nc = floor((unmodsize-1)/2)
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% other-edge at Nc = floor((unmodsize-1)/2) + (outputdim+1-unmodsize)
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%%% FINISH UP THIS CODE TO DO THE LOW PASS RECONSTRUCTION
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return; |