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volrefocus.m
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volrefocus.m
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function volrefocus
% VOLREFOCUS implements the 4-D fan filters for volumetric refocusing of
% LFs.
% The fan filters hxu, hxuth and light field LF are loaded from directory
% and converted to frequency domain using FFT. Filtering is done in 4-D
% frequncy domain to produce outputs lfvf with conventional depth filter
% and lfvfh with hard thresholded depth filter (sparse filter).
% Output images lfvf and lfvfh are saved in .mat format.
%
% Inputs:
% lfnm - Light field name
% hxu - Fan filter impulse response. Loading from saved directory.
% hxuht - Hard thresholded fan filter impulse response. Loading from
% saved directory
%
% Outputs:
% lfvf - Refocused image from conventional depth filter
% lfvfh - Refocused image from hard thresholded depth
% filter (sparse filter)
%
% Author - Chamira Edussooriya
% Edited by - Sanduni U. Premaratne
% Date - Apr 07, 2018
% Last modified - May 24, 2018
clc;
close all;
lfnm = 'Swans_1'; % name of the LF
load([lfnm,'.mat']); % load the LF
LF = LF(3:13,3:13,:,:,1:3); %#ok<NODEF>
LF = im2uint8(LF);
load('hxu.mat'); % load coefficients of conventional fan filter
load('hxuht.mat'); % load coefficients of hardthresholed fan filter
hyv = hxu; % the same filter used for both Hxu and Hyv
hyvht = hxuht; % the same filter used for both Hxuht and Hyvht
[Ny,Nx,Nv,Nu,Nc] = size(LF);
if Nc == 4 % remove the weight channel
Nc = 3;
end
[Mx,Mu] = size(hxu);
[My,Mv] = size(hyv);
Fx = Mx + Nx - 1; % length of the fftn for x dimension
Fy = My + Ny - 1; % length of the fftn for v dimension
Fu = Mu + Nu - 1; % length of the fftn for u dimension
Fv = Mv + Nv - 1; % length of the fftn for v dimension
if max(LF(:))<256 % tesnor to store volumetric focussed LFs
lfvf = zeros(Nv,Nu,Nc,'uint8');
lfvfh = zeros(Nv,Nu,Nc,'uint8');
else
lfvf = zeros(Nv,Nu,Nc,'uint16');
lfvfh = zeros(Nv,Nu,Nc,'uint16');
end
disp('Implement Conventional 4-D Fan Filter');
Hxu = fft2(hxu,Fx,Fu);
Hyv = fft2(hyv,Fy,Fv);
Hxu = permute(repmat(Hxu,[1,1,Ny,Nv]),[3,1,4,2]);
Hyv = repmat(Hyv,[1,1,Nu]);
for c = 1:Nc
disp(['Vol Refocusing, c = ',num2str(c)]);
lfin = squeeze(LF(:,:,:,:,c));
LFIN = fft(fft(lfin,Fx,2),Fu,4);
clear('lfin');
LFOUT = LFIN .* Hxu;
clear('LFIN');
lfout = ifft(ifft(LFOUT,Fx,2),Fu,4);
lfout = squeeze(lfout(:,(Fx+1)/2,:,(Mu+1)/2:end-(Mu-1)/2));
clear('LFOUT');
LFIN = fft(fft(lfout,Fy,1),Fv,2);
clear('lfout');
LFOUT = LFIN .* Hyv;
clear('LFIN');
lfout = ifft(ifft(LFOUT,Fy,1),Fv,2);
clear('LFOUT');
lfvf(:,:,c) = real(squeeze(lfout((Fy+1)/2,(Mv+1)/2:end-(Mv-1)/2,:)));
clear('lfout');
end
save([lfnm,'_VF.mat'],'lfvf');
clear('lfvf');
disp('Implement Hardthresholded 4-D Fan Filter');
Hxu = fft2(hxuht,Fx,Fu);
Hyv = fft2(hyvht,Fy,Fv);
Hxu = permute(repmat(Hxu,[1,1,Ny,Nv]),[3,1,4,2]);
Hyv = repmat(Hyv,[1,1,Nu]);
for c = 1:Nc
disp(['Vol Refocusing, c = ',num2str(c)]);
lfin = squeeze(LF(:,:,:,:,c));
LFIN = fft(fft(lfin,Fx,2),Fu,4);
clear('lfin');
LFOUT = LFIN .* Hxu;
clear('LFIN');
lfout = ifft(ifft(LFOUT,Fx,2),Fu,4);
lfout = squeeze(lfout(:,(Fx+1)/2,:,(Mu+1)/2:end-(Mu-1)/2));
clear('LFOUT');
LFIN = fft(fft(lfout,Fy,1),Fv,2);
clear('lfout');
LFOUT = LFIN .* Hyv;
clear('LFIN');
lfout = ifft(ifft(LFOUT,Fy,1),Fv,2);
clear('LFOUT');
lfvfh(:,:,c) = real(squeeze(lfout((Fy+1)/2,(Mv+1)/2:end-(Mv-1)/2,:)));
clear('lfout');
end
save([lfnm,'_VFHT.mat'],'lfvfh');
clear('lfvf');