Numerical Analysis of changes happening in subsequent image difference

Suppose I have 25 images. Next, I subtract the 1st image from subsequent images. It means now I have (2nd-1st), (3rd-1st), (4th-1st).....(24th-1st) and (25th-1st) images. Suppose I name these differences asas T21, T31, T41,....,T241 and T251 respectively. I want to analyze the changes happening between these i.e. between T21 and T31, between T31 and T41 and so on. I am able to see these changes as an image but how can I visualize it numerically and quantitatively?

Can anyone please suggest some methods to analyze and visualize these changes?

In case my query is not clear, feel free to write.

Answer 1

[Image Analyst]

Try this:

% Specify the folder where the files live.
myFolder = 'C:\Users\yourUserName\Documents\My Pictures';
% Check to make sure that folder actually exists.  Warn user if it doesn't.
if ~isfolder(myFolder)
    errorMessage = sprintf('Error: The following folder does not exist:\n%s\nPlease specify a new folder.', myFolder);
    uiwait(warndlg(errorMessage));
    myFolder = uigetdir(); % Ask for a new one.
    if myFolder == 0
        % User clicked Cancel
        return;
    end
end
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.png'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
% Read in first file
baseFileName = theFiles(k).name;
fullFileName = fullfile(theFiles(k).folder, baseFileName);
image1 = imread(fullFileName);
subplot(2, 2, 1);
imshow(imageArray);  % Display image.
title(baseFileName);
theDifference = zeros(1, numel(theFiles));
for k = 2 : length(theFiles)
    baseFileName = theFiles(k).name;
    fullFileName = fullfile(theFiles(k).folder, baseFileName);
    fprintf(1, 'Now reading %s\n', fullFileName);
    % Now read it in as an image array with imread()
    imageArray = imread(fullFileName);
    subplot(2, 2, 2);
    imshow(imageArray);  % Display image.
    title(baseFileName);
    % Now subtract first image from it
    diffImage = imabsdiff(imageArray, image1);
    theDifference(k) = mean(diffImage, 'all');
    subplot(2, 2, 3);
    imshow(diffImage, []);
    caption = sprintf('Image #%d out of %d', k, numel(theFiles));
    title(caption);
    
    % Plot the difference
    subplot(2, 2, 4);
    plot(theDifference, 'b.', 'LineWidth', 2, 'MarkerSize', 15);
    drawnow; % Force display to update immediately.
end

[NAVNEET NAYAN]

Thank You for answering the question and solving my query.

Answer 2

[Avinash]

As per my understanding , you are trying to subtract one image from many other images, and want to see the difference between the images in the form of numeric data

1. First, you can read images using “imread” function
2. Then using a for loop, you can subtract one image from other images using “imsubtract” function
3. The output result of “imsubtract” function is a numeric value.

You can refer to the following links to know more about “imread” & “imsubtract” functions

• imread
• imsubtract

Thanks

Avinash

[NAVNEET NAYAN]

Thank You for your answer but this doesnot solve my problem. The points that you mentioned in the answer have been already done by me as mentioned in the question. I want to visualize and quantify those changes.

[Avinash]

Can you elaborate your query,

[NAVNEET NAYAN]

I have already subtracted the 1st image from subsequent images. I wanted to visualize that differences of each current image and 1st image. Also, I wanted to compare these differences.