%==================================================================
% Same code is available as part of Complete Matlab Code and Datasets
% Motion Deblurring Source Code for a Simple Case Shown in Figure 3
% Solves for 1D motion blur assuming object is moving from top to bottom
% Using the 52 element binary sequence for fluttering
 
%==============================================================
m = 52; % Coded Sequence length
CodeSeq=double('1010000111000001010000110011110111010111001001100111')-'0';
% Read input image
InputImage = double(readpfm_color('InputTaxi.pfm')); 
[H,W,CH] = size(InputImage);
k = [235]; % Assume Blur Size in pixels = 235
 
% Resize image height by m/k so that the effective blur is m
InputImage1 = imresize(InputImage,[ceil(H*m/k) W],'bicubic');
 
% Get object size, n, knowing blurredSize = n + m - 1
n = size(InputImage1,1) - m + 1;
 
% Foreground: Get A matrix for foreground which encodes the blurring
Af = ComposeMotionBlurMatrix(CodeSeq, n);
 
% Background: bk is contribution vector of bkgrnd in blurred img for all pix
bk = abs(1 - Af*ones(n,1));
 
% Assume constant background in first m and last m pixels (effective blur is m)
bkLeft = zeros(size(bk)); bkLeft(1:m)=bk(1:m);
bkRite = zeros(size(bk)); bkRite(end-m+1:end)=bk(end-m+1:end);


% Ready to Solve AX=B for each color channel
A = [Af  bkLeft  bkRite];

for colorchannel = 1:CH
    B = InputImage1(:,:,colorchannel); % coded img for channel

        X = A\B; %Least square solution
    
    OutColorImage(:,:,colorchannel) = X(1:end-2,:);
end

% Expand/shrink the deblurred image to match blur size of k 
OutColorImage = imresize(OutColorImage,[H-k+1 W],'bicubic');



%==================================================================

function [A] = ComposeMotionBlurMatrix(CodeSeq,n)
CodeSeq = CodeSeq(:)/sum(CodeSeq);
k = size(CodeSeq,1);
ZeroPaddedCodeSeq = sparse([CodeSeq; zeros(n-1,1)]);
A = gallery('circul',ZeroPaddedCodeSeq)';% Create Circulant Matrix
A = A(:,1:n); % Keep first n columns out of (n+k-1) columns
 
%=================================================================