% =========================================================================
% Math 336 - Image Processing - Laboratory 4
%
% Image Restoration (Part 1):
% Apply a blurring PSF to peppers. Add noise. Use the function
% l_curve_rtls.m to construct the L-curve of a Tikhonov reconstruction of
% peppers. 
%
% Marty Kandes
% Computational Science Research Center / Department of Physics
% San Diego State University
% Fall 2008
% -------------------------------------------------------------------------
clear all; close all; clc;                  % Clear Matlab workspace.
F = imread('peppers.jpg');                  % Read in peppers image.
F = im2double(F);                           % Convert peppers to double.
F = mat2gray(F);                            % Normalize grayscale image.
[M,N] = size(F);                            % Get dimensions of image.
PSF = fspecial('disk',6);                   % Make disk or circular PSF.
OTF = psf2otf(PSF,[M,N]);                   % Compute the OTF of the PSF.
G = real(ifft2(OTF.*fft2(F)));              % Apply PSF to create blurring.
H = imnoise(G,'gaussian',0,0.01);           % Add gaussian noise.
figure;                                     % Open new figure.
imshow(G);                                  % Display the blurred peppers.
imwrite(F,'peppersblurred.jpg','jpg');      % Write image to file.
figure;                                     % Open new figure.
imshow(H);                                  % Display the blurred+noisy peppers.
imwrite(H,'peppersblurrednoisy.jpg','jpg'); % Write image to file.
% How do you use l_curve_rtls.m correctly? 
L = eye(M,N);                               % Assume zeroth-order regularization operator.