for i=1:numImages
So far we can expect to run numImages times. We can work backwards to find that numImages = 5 in the current code.
for font_size = num_fonts(i)
num_fonts is a vector, not a function, so num_fonts(i) is a scalar. There is not much point using a for loop for a single iteration; it would be clearer to have written that flow as just font_size = num_fonts(i); without using for . Anyhow, as this is a scalar, the number of times executing loops so far is numImages*1 which is numImages
figure('Name','Sauvola thresholding with %f font size,%f percent ','NumberTitle','off');
for IntDiff_no=1:each_intensityDifference
Okay, so now we are at numImages*1*each_intensityDifference loop iterations, which is 5*1*5 = 25 when you work backwards to find out what each_intensityDifference is.
for IntDiff_percentage= intensityDifference(IntDiff_no)
Again, no point using a for loop for a scalar; just use IntDiff_percentage = intensityDifference(IntDiff_no);
for Noise_no =1:each_noise
We can work backwards to see that each_noise = 5. So now we are at numImages*1*each_IntensityDifference*1*each_noise = 5*1*5*1*5 = 125 loop iterations
for noise= num_noiseimg(Noise_no)
Again, no point using a for loop for a scalar; just use noise = num_noiseimg(Noise_no); without a loop structure. So we are now at numImages*1*each_IntensityDifference*1*each_noise*1 = 5*1*5*1*5*1 = 125 loop iterations
subplot(5,1,Noise_no)
5 subplots possible, a Noise_no has a maximum value of 5, so the for Noise_no loop is filling each of the 5 subplots in turn
imshow(alphabetSauvImage_collection{i,IntDiff_no,Noise_no});
title(sprintf('Image with %f font size %f intensity difference %f noise',font_size,IntDiff_percentage,noise));
No drawnow(), no pause(), no axes() or figure() -- the actual drawing of the images will be postponed for later
end
That ends the for noise loop that has only one iteration. Nothing is present here to trigger drawing yet
end
That ends the for Noise_no loop that does all 5 noises. Nothing is present here to trigger drawing yet.
end
That ends the for IntDiff_precentage loop that has only one iteration. Nothing is present here to trigger drawing yet.
end
That ends the for IntDiff_no loop that has 5 iterations. But nothing was present anywhere in here to trigger drawing, so each of the IntDiff_no iterations triggers drawing 5 images, but the next IntDiff_no iteration draws on top of the same subplots. If you had had a drawnow() or pause() in the loops, they might at least have shown up temporarily before being replaced, but as it is the earlier ones will not be displayed at all.
end
end
... and that happens 5 times more. All you are going to see is the 5 images drawn by the last iteration of for i and the last iteration of for IntDiff_no .
