Thermography Camera Image Color Scale cropping

6 views (last 30 days)
Hello, I am currently doing a project using Thermography Camera Images. I managed to find a code by @Image Analyst which would allow for me to use these images. I am relatively new to the use of Matlab/Mathworks and am not sure how to properly crop to reach the color bar. Is there a basic code/program I can use that would allow auto-cropping of the photo that would allow me to properly crop the colorbar. I attached the code to the description.Thanks for any assistance
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
clear; % Erase all existing variables. Or clearvars if you want.
workspace; % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 15;
%===============================================================================
% Get the name of the image the user wants to use.
baseFileName = 'Trial1.png'; % Assign the one on the button that they clicked on.
% Get the full filename, with path prepended.
folder = pwd
fullFileName = fullfile(folder, baseFileName);
%===============================================================================
% Read in a demo image.
originalRGBImage = imread(fullFileName);
% Display the image.
subplot(2, 3, 1);
imshow(originalRGBImage, []);
axis on;
caption = sprintf('Original Pseudocolor Image, %s', baseFileName);
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
xlabel('Column', 'FontSize', fontSize, 'Interpreter', 'None');
ylabel('Row', 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
grayImage = min(originalRGBImage, [], 3); % Useful for finding image and color map regions of image.
% Get the dimensions of the image. numberOfColorChannels should be = 3.
[rows, columns, numberOfColorChannels] = size(originalRGBImage);
% Crop off the surrounding clutter to get the colorbar.
colorBarImage = imcrop(originalRGBImage, [1, 20, 17, rows]);
b = colorBarImage(:,:,3);
% Crop off the surrounding clutter to get the RGB image.
rgbImage = imcrop(originalRGBImage, [81, 1, columns-20, rows]);
% Get the dimensions of the image.
% numberOfColorBands should be = 3.
[rows, columns, numberOfColorChannels] = size(rgbImage);
% Display the image.
subplot(2, 3, 2);
imshow(rgbImage, []);
axis on;
caption = sprintf('Cropped Pseudocolor Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
xlabel('Column', 'FontSize', fontSize, 'Interpreter', 'None');
ylabel('Row', 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
hp = impixelinfo();
% Display the colorbar image.
subplot(2, 3, 3);
imshow(colorBarImage, []);
axis on;
caption = sprintf('Cropped Colorbar Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
xlabel('Column', 'FontSize', fontSize, 'Interpreter', 'None');
ylabel('Row', 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0.05 1 0.95]);
% Get rid of tool bar and pulldown menus that are along top of figure.
% set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')
% Get the color map.
storedColorMap = colorBarImage(:,1,:);
% Need to call squeeze to get it from a 3D matrix to a 2-D matrix.
% Also need to divide by 255 since colormap values must be between 0 and 1.
storedColorMap = double(squeeze(storedColorMap)) / 255
% Need to flip up/down because the low rows are the high temperatures, not the low temperatures.
storedColorMap = flipud(storedColorMap);
% Convert from an RGB image to a grayscale, indexed, thermal image.
indexedImage = rgb2ind(rgbImage, storedColorMap);
% Display the thermal image.
subplot(2, 3, 4);
imshow(indexedImage, []);
axis on;
caption = sprintf('Indexed Image (Gray Scale Image)');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
% Define the temperature at the top end of the scale
% This will probably be the high temperature.
highTemp = 28.9;
% Define the temperature at the dark end of the scale
% This will probably be the low temperature.
lowTemp = 0.9;
% Scale the image so that it's actual temperatures
thermalImage = lowTemp + (highTemp - lowTemp) * mat2gray(indexedImage);
subplot(2, 3, 5);
imshow(thermalImage, []);
axis on;
colorbar;
title('Floating Point Thermal (Temperature) Image', 'FontSize', fontSize, 'Interpreter', 'None');
hp = impixelinfo(); % Let user mouse around and see temperatures.
hp.Units = 'normalized';
hp.Position = [0.45, 0.03, 0.25, 0.05];
% Get the histogram of the indexed image
subplot(2, 3, 6);
histogram(thermalImage, 'Normalization', 'probability');
axis on;
grid on;
caption = sprintf('Histogram of Thermal Temperature Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
xlabel('Temperature', 'FontSize', fontSize, 'Interpreter', 'None');
ylabel('Frequency', 'FontSize', fontSize, 'Interpreter', 'None');
  4 Comments

Sign in to comment.

Accepted Answer

Image Analyst
Image Analyst on 20 Jun 2022
If you want you can ask the user to specify the colorbar and image by dragging out a box around them. You can use imcrop or drawrectangle.
  15 Comments
Image Analyst
Image Analyst on 28 Jul 2022
Yes. Use mean() and std() on the region of interest, or the whole image.

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!