function M = load_image(type, n, options)
% load_image - load benchmark images.
%
% M = load_image(name, n, options);
%
% name can be:
% Synthetic images:
% 'chessboard1', 'chessboard', 'square', 'squareregular', 'disk', 'diskregular', 'quaterdisk', '3contours', 'line',
% 'line_vertical', 'line_horizontal', 'line_diagonal', 'line_circle',
% 'parabola', 'sin', 'phantom', 'circ_oscil',
% 'fnoise' (1/f^alpha noise).
% Natural images:
% 'boat', 'lena', 'goldhill', 'mandrill', 'maurice', 'polygons_blurred', or your own.
%
% Copyright (c) 2004 Gabriel Peyre
if nargin<2
n = 512;
end
options.null = 0;
type = lower(type);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% parameters for geometric objects
eta = 0.1; % translation
gamma = 1/sqrt(2); % slope
if isfield( options, 'eta' )
eta = options.eta;
end
if isfield( options, 'gamma' )
eta = options.gamma;
end
if isfield( options, 'radius' )
radius = options.radius;
end
if isfield( options, 'center' )
center = options.center;
end
if isfield( options, 'center1' )
center1 = options.center1;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% for the line, can be vertical / horizontal / diagonal / any
if strcmp(type, 'line_vertical')
eta = 0.5; % translation
gamma = 0; % slope
elseif strcmp(type, 'line_horizontal')
eta = 0.5; % translation
gamma = Inf; % slope
elseif strcmp(type, 'line_diagonal')
eta = 0; % translation
gamma = 1; % slope
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% for some blurring
sigma = 0;
if isfield(options, 'sigma')
sigma = options.sigma;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
switch lower(type)
case {'letter-x' 'letter-v' 'letter-z' 'letter-y'}
if isfield(options, 'radius')
r = options.radius;
else
r = 10;
end
M = create_letter(type(8), r, n);
case 'l'
r1 = [.1 .1 .3 .9];
r2 = [.1 .1 .9 .4];
M = double( draw_rectangle(r1,n) | draw_rectangle(r2,n) );
case 'ellipse'
c1 = [0.15 0.5];
c2 = [0.85 0.5];
if isfield(options, 'eccentricity')
eccentricity = options.eccentricity;
else
eccentricity = 1.3;
end
x = linspace(0,1,n);
[Y,X] = meshgrid(x,x);
d = sqrt((X-c1(1)).^2 + (Y-c1(2)).^2) + sqrt((X-c2(1)).^2 + (Y-c2(2)).^2);
M = double( d<=eccentricity*sqrt( sum((c1-c2).^2) ) );
case 'ellipse-thin'
options.eccentricity = 1.06;
M = load_image('ellipse', n, options);
case 'ellipse-fat'
options.eccentricity = 1.3;
M = load_image('ellipse', n, options);
case 'square-tube'
if isfield(options, 'tube_width')
w = options.tube_width;
else
w = 0.06;
end
c1 = [.25 .5];
c2 = [.75 .5];
r1 = [c1 c1] + .18*[-1 -1 1 1];
r2 = [c2 c2] + .18*[-1 -1 1 1];
r3 = [c1(1)-w c1(2)-w c2(1)+w c2(2)+w];
M = double( draw_rectangle(r1,n) | draw_rectangle(r2,n) | draw_rectangle(r3,n) );
case 'square-tube-1'
options.tube_width = 0.03;
M = load_image('square-tube', n, options);
case 'square-tube-2'
options.tube_width = 0.06;
M = load_image('square-tube', n, options);
case 'square-tube-3'
options.tube_width = 0.09;
M = load_image('square-tube', n, options);
case 'polygon'
if isfield(options, 'nb_points')
nb_points = options.nb_points;
else
nb_points = 9;
end
if isfield(options, 'scaling')
scaling = options.scaling;
else
scaling = 1;
end
theta = sort( rand(nb_points,1)*2*pi );
radius = scaling*rescale(rand(nb_points,1), 0.1, 0.93);
points = [cos(theta) sin(theta)] .* repmat(radius, 1,2);
points = (points+1)/2*(n-1)+1; points(end+1,:) = points(1,:);
M = draw_polygons(zeros(n),0.8,{points'});
[x,y] = ind2sub(size(M),find(M));
p = 100; m = length(x);
lambda = linspace(0,1,p);
X = n/2 + repmat(x-n/2, [1 p]) .* repmat(lambda, [m 1]);
Y = n/2 + repmat(y-n/2, [1 p]) .* repmat(lambda, [m 1]);
I = round(X) + (round(Y)-1)*n;
M = zeros(n); M(I) = 1;
case 'polygon-8'
options.nb_points = 8;
M = load_image('polygon', n, options);
case 'polygon-10'
options.nb_points = 8;
M = load_image('polygon', n, options);
case 'polygon-12'
options.nb_points = 8;
M = load_image('polygon', n, options);
case 'pacman'
if isfield(options, 'theta')
theta = options.theta;
else
theta = 30 * 2*pi/360;
end
options.radius = 0.45;
M = load_image('disk', n, options);
x = linspace(-1,1,n);
[Y,X] = meshgrid(x,x);
T =atan2(Y,X);
M = M .* (1-(abs(T)<theta/2));
case 'square-hole'
options.radius = 0.45;
M = load_image('disk', n, options);
options.scaling = 0.5;
M = M - load_image('polygon-10', n, options);
case 'grid-circles'
if isempty(n)
n = 256;
end
if isfield(options, 'frequency')
f = options.frequency;
else
f = 30;
end
if isfield(options, 'width')
eta = options.width;
else
eta = 0.3;
end
x = linspace(-n/2,n/2,n) - round(n*0.03);
y = linspace(0,n,n);
[Y,X] = meshgrid(y,x);
R = sqrt(X.^2+Y.^2);
theta = 0.05*pi/2;
X1 = cos(theta)*X+sin(theta)*Y;
Y1 = -sin(theta)*X+cos(theta)*Y;
A1 = abs(cos(2*pi*R/f))<eta;
A2 = max( abs(cos(2*pi*X1/f))<eta, abs(cos(2*pi*Y1/f))<eta );
M = A1;
M(X1>0) = A2(X1>0);
case 'chessboard1'
x = -1:2/(n-1):1;
[Y,X] = meshgrid(x,x);
M = (2*(Y>=0)-1).*(2*(X>=0)-1);
case 'chessboard'
if ~isfield( options, 'width' )
width = round(n/16);
else
width = options.width;
end
[Y,X] = meshgrid(0:n-1,0:n-1);
M = mod( floor(X/width)+floor(Y/width), 2 ) == 0;
case 'square'
if ~isfield( options, 'radius' )
radius = 0.6;
end
x = -1:2/(n-1):1;
[Y,X] = meshgrid(x,x);
M = max( abs(X),abs(Y) )<radius;
case 'squareregular'
M = rescale(load_image('square',n,options));
if not(isfield(options, 'alpha'))
options.alpha = 3;
end
S = load_image('fnoise',n,options);
M = M + rescale(S,-0.3,0.3);
case 'regular1'
options.alpha = 1;
M = load_image('fnoise',n,options);
case 'regular2'
options.alpha = 2;
M = load_image('fnoise',n,options);
case 'regular3'
options.alpha = 3;
M = load_image('fnoise',n,options);
case 'sparsecurves'
options.alpha = 3;
M = load_image('fnoise',n,options);
M = rescale(M);
ncurves = 3;
M = cos(2*pi*ncurves);
case 'square_texture'
M = load_image('square',n);
M = rescale(M);
% make a texture patch
x = linspace(0,1,n);
[Y,X] = meshgrid(x,x);
theta = pi/3;
x = cos(theta)*X + sin(theta)*Y;
c = [0.3,0.4]; r = 0.2;
I = find( (X-c(1)).^2 + (Y-c(2)).^2 < r^2 );
eta = 3/n; lambda = 0.3;
M(I) = M(I) + lambda * sin( x(I) * 2*pi / eta );
case 'oscillatory_texture'
x = linspace(0,1,n);
[Y,X] = meshgrid(x,x);
theta = pi/3;
x = cos(theta)*X + sin(theta)*Y;
c = [0.3,0.4]; r = 0.2;
I = find( (X-c(1)).^2 + (Y-c(2)).^2 < r^2 );
eta = 3/n; lambda = 0.3;
M = sin( x * 2*pi / eta );
case {'line', 'line_vertical', 'line_horizontal', 'line_diagonal'}
x = 0:1/(n-1):1;
[Y,X] = meshgrid(x,x);
if gamma~=Inf
M = (X-eta) - gamma*Y < 0;
else
M = (Y-eta) < 0;
end
case 'grating'
x = linspace(-1,1,n);
[Y,X] = meshgrid(x,x);
if isfield(options, 'theta')
theta = options.theta;
else
theta = 0.2;
end
if isfield(options, 'freq')
freq = options.freq;
else
freq = 0.2;
end
X = cos(theta)*X + sin(theta)*Y;
M = sin(2*pi*X/freq);
case 'disk'
if ~isfield( options, 'radius' )
radius = 0.35;
end
if ~isfield( options, 'center' )
center = [0.5, 0.5]; % center of the circle
end
x = 0:1/(n-1):1;
[Y,X] = meshgrid(x,x);
M = (X-center(1)).^2 + (Y-center(2)).^2 < radius^2;
case 'diskregular'
M = rescale(load_image('disk',n,options));
if not(isfield(options, 'alpha'))
options.alpha = 3;
end
S = load_image('fnoise',n,options);
M = M + rescale(S,-0.3,0.3);
case 'quarterdisk'
if ~isfield( options, 'radius' )
radius = 0.95;
end
if ~isfield( options, 'center' )
center = -[0.1, 0.1]; % center of the circle
end
x = 0:1/(n-1):1;
[Y,X] = meshgrid(x,x);
M = (X-center(1)).^2 + (Y-center(2)).^2 < radius^2;
case 'fading_contour'
if ~isfield( options, 'radius' )
radius = 0.95;
end
if ~isfield( options, 'center' )
center = -[0.1, 0.1]; % center of the circle
end
x = 0:1/(n-1):1;
[Y,X] = meshgrid(x,x);
M = (X-center(1)).^2 + (Y-center(2)).^2 < radius^2;
theta = 2/pi*atan2(Y,X);
h = 0.5;
M = exp(-(1-theta).^2/h^2).*M;
case '3contours'
radius = 1.3;
center = [-1, 1];
radius1 = 0.8;
center1 = [0, 0];
x = 0:1/(n-1):1;
[Y,X] = meshgrid(x,x);
f1 = (X-center(1)).^2 + (Y-center(2)).^2 < radius^2;
f2 = (X-center1(1)).^2 + (Y-center1(2)).^2 < radius1^2;
M = f1 + 0.5*f2.*(1-f1);
case 'line_circle'
gamma = 1/sqrt(2);
x = linspace(-1,1,n);
[Y,X] = meshgrid(x,x);
M1 = double( X>gamma*Y+0.25 );
M2 = X.^2 + Y.^2 < 0.6^2;
M = 20 + max(0.5*M1,M2) * 216;
case 'fnoise'
% generate an image M whose Fourier spectrum amplitude is
% |M^(omega)| = 1/f^{omega}
if isfield(options, 'alpha')
alpha = options.alpha;
else
alpha = 1;
end
M = gen_noisy_image(n,alpha);
case 'gaussiannoise'
% generate an image of filtered noise with gaussian
if isfield(options, 'sigma')
sigma = options.sigma;
else
sigma = 10;
end
M = randn(n);
m = 51;
h = compute_gaussian_filter([m m],sigma/(4*n),[n n]);
M = perform_convolution(M,h);
return;
case {'bwhorizontal','bwvertical','bwcircle'}
[Y,X] = meshgrid(0:n-1,0:n-1);
if strcmp(type, 'bwhorizontal')
d = X;
elseif strcmp(type, 'bwvertical')
d = Y;
elseif strcmp(type, 'bwcircle')
d = sqrt( (X-(n-1)/2).^2 + (Y-(n-1)/2).^2 );
end
if isfield(options, 'stripe_width')
stripe_width = options.stripe_width;
else
stripe_width = 5;
end
if isfield(options, 'black_prop')
black_prop = options.black_prop;
else
black_prop = 0.5;
end
M = double( mod( d/(2*stripe_width),1 )>=black_prop );
case 'parabola'
% curvature
if isfield(options, 'c')
c = options.c;
else
c = 0.1;
end
% angle
if isfield(options, 'theta');
theta = options.theta;
else
theta = pi/sqrt(2);
end
x = -0.5:1/(n-1):0.5;
[Y,X] = meshgrid(x,x);
Xs = X*cos(theta) + Y*sin(theta);
Y =-X*sin(theta) + Y*cos(theta); X = Xs;
M = Y>c*X.^2;
case 'sin'
[Y,X] = meshgrid(-1:2/(n-1):1, -1:2/(n-1):1);
M = Y >= 0.6*cos(pi*X);
M = double(M);
case 'circ_oscil'
x = linspace(-1,1,n);
[Y,X] = meshgrid(x,x);
R = sqrt(X.^2+Y.^2);
M = cos(R.^3*50);
case 'phantom'
M = phantom(n);
case 'periodic_bumps'
if isfield(options, 'nbr_periods')
nbr_periods = options.nbr_periods;
else
nbr_periods = 8;
end
if isfield(options, 'theta')
theta = options.theta;
else
theta = 1/sqrt(2);
end
if isfield(options, 'skew')
skew = options.skew;
else
skew = 1/sqrt(2);
end
A = [cos(theta), -sin(theta); sin(theta), cos(theta)];
B = [1 skew; 0 1];
T = B*A;
x = (0:n-1)*2*pi*nbr_periods/(n-1);
[Y,X] = meshgrid(x,x);
pos = [X(:)'; Y(:)'];
pos = T*pos;
X = reshape(pos(1,:), n,n);
Y = reshape(pos(2,:), n,n);
M = cos(X).*sin(Y);
case 'noise'
if isfield(options, 'sigma')
sigma = options.sigma;
else
sigma = 1;
end
M = randn(n);
otherwise
ext = {'gif', 'png', 'jpg', 'bmp', 'tiff', 'pgm', 'ppm'};
for i=1:length(ext)
name = [type '.' ext{i}];
if( exist(name) )
M = imread( name );
M = double(M);
if not(isempty(n)) && (n~=size(M, 1) || n~=size(M, 2)) && nargin>=2
M = image_resize(M,n,n);
end
return;
end
end
error( ['Image ' type ' does not exists.'] );
end
M = double(M);
if sigma>0
h = compute_gaussian_filter( [9 9], sigma/(2*n), [n n]);
M = perform_convolution(M,h);
end
M = rescale(M) * 256;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function M = create_letter(a, r, n)
c = 0.2;
p1 = [c;c];
p2 = [c; 1-c];
p3 = [1-c; 1-c];
p4 = [1-c; c];
p4 = [1-c; c];
pc = [0.5;0.5];
pu = [0.5; c];
switch a
case 'x'
point_list = { [p1 p3] [p2 p4] };
case 'z'
point_list = { [p2 p3 p1 p4] };
case 'v'
point_list = { [p2 pu p3] };
case 'y'
point_list = { [p2 pc pu] [pc p3] };
end
% fit image
for i=1:length(point_list)
a = point_list{i}(2:-1:1,:);
a(1,:) = 1-a(1,:);
point_list{i} = round( a*(n-1)+1 );
end
M = draw_polygons(zeros(n),r,point_list);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function sk = draw_polygons(mask,r,point_list)
sk = mask*0;
for i=1:length(point_list)
pl = point_list{i};
for k=2:length(pl)
sk = draw_line(sk,pl(1,k-1),pl(2,k-1),pl(1,k),pl(2,k),r);
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function sk = draw_line(sk,x1,y1,x2,y2,r)
n = size(sk,1);
[Y,X] = meshgrid(1:n,1:n);
q = 100;
t = linspace(0,1,q);
x = x1*t+x2*(1-t); y = y1*t+y2*(1-t);
if r==0
x = round( x ); y = round( y );
sk( x+(y-1)*n ) = 1;
else
for k=1:q
I = find((X-x(k)).^2 + (Y-y(k)).^2 <= r^2 );
sk(I) = 1;
end
end
function M = gen_noisy_image(n,alpha)
% gen_noisy_image - generate a noisy cloud-like image.
%
% M = gen_noisy_image(n,alpha);
%
% generate an image M whose Fourier spectrum amplitude is
% |M^(omega)| = 1/f^{omega}
%
% Copyright (c) 2004 Gabriel Peyr?
if nargin<1
n = 128;
end
if nargin<2
alpha = 1.5;
end
if mod(n(1),2)==0
x = -n/2:n/2-1;
else
x = -(n-1)/2:(n-1)/2;
end
[Y,X] = meshgrid(x,x);
d = sqrt(X.^2 + Y.^2) + 0.1;
f = rand(n)*2*pi;
M = (d.^(-alpha)) .* exp(f*1i);
% M = real(ifft2(fftshift(M)));
M = ifftshift(M);
M = real( ifft2(M) );
function y = gen_signal_2d(n,alpha)
% gen_signal_2d - generate a 2D C^\alpha signal of length n x n.
% gen_signal_2d(n,alpha) generate a 2D signal C^alpha.
%
% The signal is scale in [0,1].
%
% Copyright (c) 2003 Gabriel Peyr?
% new new method
[Y,X] = meshgrid(0:n-1, 0:n-1);
A = X+Y+1;
B = X-Y+n+1;
a = gen_signal(2*n+1, alpha);
b = gen_signal(2*n+1, alpha);
y = a(A).*b(B);
% M = a(1:n)*b(1:n)';
return;
% new method
h = (-n/2+1):(n/2); h(n/2)=1;
[X,Y] = meshgrid(h,h);
h = sqrt(X.^2+Y.^2+1).^(-alpha-1/2);
h = h .* exp( 2i*pi*rand(n,n) );
h = fftshift(h);
y = real( ifft2(h) );
m1 = min(min(y));
m2 = max(max(y));
y = (y-m1)/(m2-m1);
return;
%% old code
y = rand(n,n);
y = y - mean(mean(y));
for i=1:alpha
y = cumsum(cumsum(y)')';
y = y - mean(mean(y));
end
m1 = min(min(y));
m2 = max(max(y));
y = (y-m1)/(m2-m1);
function newimg = image_resize(img,p1,q1,r1)
% image_resize - resize an image using bicubic interpolation
%
% newimg = image_resize(img,nx,ny,nz);
% or
% newimg = image_resize(img,newsize);
%
% Works for 2D, 2D 2 or 3 channels, 3D images.
%
% Copyright (c) 2004 Gabriel Peyr?
if nargin==2
% size specified as an array
q1 = p1(2);
if length(p1)>2
r1 = p1(3);
else
r1 = size(img,3);
end
p1 = p1(1);
end
if nargin<4
r1 = size(img,3);
end
if ndims(img)<2 || ndims(img)>3
error('Works only for grayscale or color images');
end
if ndims(img)==3 && size(img,3)<4
% RVB image
newimg = zeros(p1,q1, size(img,3));
for m=1:size(img,3)
newimg(:,:,m) = image_resize(img(:,:,m), p1, q1);
end
return;
elseif ndims(img)==3
p = size(img,1);
q = size(img,2);
r = size(img,3);
[Y,X,Z] = meshgrid( (0:q-1)/(q-1), (0:p-1)/(p-1), (0:r-1)/(r-1) );
[YI,XI,ZI] = meshgrid( (0:q1-1)/(q1-1), (0:p1-1)/(p1-1), (0:r1-1)/(r1-1) );
newimg = interp3( Y,X,Z, img, YI,XI,ZI ,'cubic');
return;
end
p = size(img,1);
q = size(img,2);
[Y,X] = meshgrid( (0:q-1)/(q-1), (0:p-1)/(p-1) );
[YI,XI] = meshgrid( (0:q1-1)/(q1-1), (0:p1-1)/(p1-1) );
newimg = interp2( Y,X, img, YI,XI ,'cubic');
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function M = draw_rectangle(r,n)
x = linspace(0,1,n);
[Y,X] = meshgrid(x,x);
M = double( (X>=r(1)) & (X<=r(3)) & (Y>=r(2)) & (Y<=r(4)) ) ;
