Hi Elisa, it looks like you have a few issues in your code that might be causing the histogram not to be displayed properly. Here are some suggestions and corrections to help you plot the histogram of a series of tomography images effectively:
- Loop through images and plot histograms: Ensure that you are plotting the histogram for the first and the last images correctly.
- Clear previous figures: Use 'clf' to clear the current figure before plotting new images and histograms.
- Figure and subplot management: Make sure you create a new figure for each set of subplots to avoid overwriting.
Here is a modified version of your code:
clear all
close all
clc
a = load('tomo_carota_8bit.mat');
x = a.x_8;
x = double(x);
figure,
for ii = 1:size(x, 3)
I = squeeze(x(:, :, ii));
imshow(I, []);
pause(0.1)
end
figure;
I_first = squeeze(x(:, :, 1));
subplot(3, 2, 1);
imshow(I_first, []);
title('First Grayscale Image', 'FontSize', 15);
subplot(3, 2, 2);
imhist(I_first);
title('Histogram of first image');
subplot(3, 2, 3);
[counts, grayLevels] = imhist(I_first);
bar(grayLevels, counts, 'EdgeColor', 'r', 'FaceColor', 'b', 'BarWidth', 1);
xlim([0, max(I_first(:))]);
title('Histogram of first image zoomed');
I_last = squeeze(x(:, :, end));
subplot(3, 2, 4);
imshow(I_last, []);
title('Last Grayscale Image', 'FontSize', 15);
subplot(3, 2, 5);
imhist(I_last);
title('Histogram of last image');
subplot(3, 2, 6);
[counts, grayLevels] = imhist(I_last);
bar(grayLevels, counts, 'EdgeColor', 'r', 'FaceColor', 'b', 'BarWidth', 1);
xlim([0, max(I_last(:))]);
title('Histogram of last image zoomed');
thresholdValue1 = 60;
thresholdValue2 = 85;
figure;
binaryImage1 = I_first > thresholdValue1;
subplot(2, 2, 1);
imshow(binaryImage1, []);
title('Binary Image threshold 60 (First Image)');
binaryImage2 = I_first > thresholdValue2;
subplot(2, 2, 2);
imshow(binaryImage2, []);
title('Binary Image threshold 85 (First Image)');
binaryImage3 = I_last > thresholdValue1;
subplot(2, 2, 3);
imshow(binaryImage3, []);
title('Binary Image threshold 60 (Last Image)');
binaryImage4 = I_last > thresholdValue2;
subplot(2, 2, 4);
imshow(binaryImage4, []);
title('Binary Image threshold 85 (Last Image)');
By making these changes, you should be able to visualize the histograms of the first and last tomography images and determine the appropriate threshold for extracting cracks.
