%% This file demonstrates the Split Bregman method for Total Variation denoising
%
%   SB_ATV.m  Split Bregman Anisotropic Total Variation Denoising
%   SB_ITV.m  Split Bregman Isotropic Total Variation Denoising
%
% Benjamin Trémoulhéac
% University College London
% b.tremoulheac@cs.ucl.ac.uk
% April 2012

clc; clear all;
close all;

N = 512; n = N^2;
f = double(imread('Lena512','png'));
g = f(:) + 0.09*max(f(:))*randn(n,1);

mu = 20;

g_denoise_atv = SB_ATV(g,mu);
g_denoise_itv = SB_ITV(g,mu);

fprintf('ATV Rel.Err = %g\n',norm(g_denoise_atv(:) - f(:)) / norm(f(:)));
fprintf('ITV Rel.Err = %g\n',norm(g_denoise_itv(:) - f(:)) / norm(f(:)));

figure; colormap gray;
subplot(221); imagesc(f); axis image; title('Original');
subplot(222); imagesc(reshape(g,N,N)); axis image; title('Noisy');
subplot(223); imagesc(reshape(g_denoise_atv,N,N)); axis image; 
title('Anisotropic TV denoising');
subplot(224); imagesc(reshape(g_denoise_itv,N,N)); axis image; 
title('Isotropic TV denoising');