imbase = ['../text/images/'];


% Segmentation by histograsm thresholding
f = imread([imbase,'coins.tif']);     
f1 = double(f);
[N1 X1] = hist(f1(:),256);

f = imread([imbase,'bacteria.tif']);     
f2 = double(f);
[N2 X2] = hist(f2(:),256);

figure(1);clf;
subplot(221);imagesc(f1);colormap gray;axis image
subplot(222);imagesc(f2);colormap gray;axis image
subplot(223);plot(X1,N1);
subplot(224);plot(X2,N2);

figure(2);clf;
subplot(221);imagesc(f1);colormap gray;axis image
subplot(222);imagesc(f2);colormap gray;axis image
subplot(223);imagesc(f1>150);colormap gray;axis image
subplot(224);imagesc(f2>100);colormap gray;axis image

% Variance as a measure of similarity

g = fspecial('gaussian',15,4);
f1 = filter2(g,5*randn(256));
f2 = filter2(g,.5*randn(256));
[n1 x1] = hist(f1(:),256);
[n2 x2] = hist(f2(:),256);

close all;figure(1);clf; colormap gray
subplot(221);imagesc(f1);caxis([-1.5 1.5]);
subplot(222);imagesc(f2);caxis([-1.5 1.5]);
subplot(223);plot(x1,n1);a1 = axis;
subplot(224);plot(x2,n2);
a2 = axis; axis([a1(1) a1(2) a2(3) a2(4)]);
print -djpeg ~/Desktop/var.jpg

var(f1(:));var(f2(:))

% Plot some histograms
a = lognrnd(1*ones(1e4,1),.3*ones(1e4,1));
[N,X] = hist(a,50);
figure(1);clf;colormap default
bar(X,N/length(a),1);
[mean(a) var(a)]

f = imread([imbase,'bacteria.tif']);     
f2 = double(f);
[N2 X2] = hist(f2(:),256); N2 = N2(:);
plot(X2,N2);
print -djpeg ~/Desktop/histex.jpg

% Otsu
% Segmentation by histograsm thresholding
f = imread([imbase,'coins.tif']);     
f1 = double(f);
[N1 X1] = hist(f1(:),256);
sigw1 = otsu(N1);
[v1 t1] = min(sigw1);

f = imread([imbase,'bacteria.tif']);     
f2 = double(f);
[N2 X2] = hist(f2(:),256);
sigw2 = otsu(N2);
[v2 t2] = min(sigw2);

figure(1);clf;
subplot(221);imagesc(f1);colormap gray;axis image
subplot(222);imagesc(f2);colormap gray;axis image
subplot(223);plot(X1,sigw1);
subplot(224);plot(X2,sigw2);
print -djpeg ~/Desktop/otsu1.jpg

figure(2);clf;
subplot(221);imagesc(f1);colormap gray;axis image
subplot(222);imagesc(f2);colormap gray;axis image
subplot(223);imagesc(f1>t1);colormap gray;axis image
subplot(224);imagesc(f2>t2);colormap gray;axis image
print -djpeg ~/Desktop/otsu2.jpg

figure(2);clf;
subplot(221);imagesc(f1);colormap gray;axis image
subplot(222);imagesc(f2);colormap gray;axis image
subplot(223);imagesc((f1>t1)-(f1>150));colormap gray;axis image
subplot(224);imagesc((f2>t2)-(f2>100));colormap gray;axis image
print -djpeg ~/Desktop/otsu3.jpg