How to save all the data after processing all the images

Hallo everyone,

I would like to ask you a question about how to save all the datas after processing all the images.

The code is shown as follow,

% Specify the folder where the files live.
myFolder = '';
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.bmp'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
for k = 1 : length(theFiles)
    baseFileName = theFiles(k).name;
    fullFileName = fullfile(theFiles(k).folder, baseFileName);
    fprintf(1, 'Now reading %s\n', fullFileName);
    figure
    drawnow; % Force display to update immediately.
end

Use this code to process all the images, however the data will get overwritten each time, in the workspace only show the last image data. there are totally 8 images, I would like to save all the datas of 8 images, and make histogram of the datas(such as, area, premieter....)

Thanks in advance

JL

Answer 1

[Image Analyst]

Didn't I answer that in your duplicate question? https://www.mathworks.com/matlabcentral/answers/1938859-how-to-save-all-the-images-data-in-workplace-after-processing-all-the-images#answer_1206859

You have to get the values and index them, for example:

% Specify the folder where the files live.
myFolder = pwd;
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.bmp'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
allAreas = []; % Array to store all the areas from all the images.
allMeans = [];
for k = 1 : length(theFiles)
    baseFileName = theFiles(k).name;
    fullFileName = fullfile(theFiles(k).folder, baseFileName);
    fprintf(1, 'Now reading %s\n', fullFileName);
    % Read in grayscale image
    grayImage = imread(fullFileName);
    % Threshold image
    mask = imbinarize(grayImage);
    % Compute areas for k'th image
    props = regionprops(mask);
    % Get all areas.
    theseAreas = [props.Area]; % Areas of blobs in only this particular image.
    % Append to our growing list of areas for all images.
    allAreas = [allAreas, theseAreas];
    % Get the mean for this image.
    allMeans(k) = mean(thisImage, 'all');
end
% Show histogram of all the areas for all the images.
figure;
subplot(1, 2, 1);
histogram(allAreas);
title('Area Histogram')
grid on;
% Show histogram of all the means for all the images.
subplot(1, 2, 2);
histogram(allMeans);
title('Mean Gray Level Histogram')
grid on;

See my Image Segmentation Tutorial in my File Exchange:

Image Analyst's File Exchange

It's a generic, general purpose demo of how to threshold an image to find blobs, and then measure things about the blobs, and extract certain blobs based on their areas or diameters.

[JM]

Hallo Image Analyst,

Thanks so much for your reply. That is help me a lot. I just feel that last question what I post is not exactly clear, therefore I made this question again, I have already try to use your following method before, however it does not work for me. I investigate so long time and still not find solution.

for k = 1 : numImages

data(k) = whatever;

end

I will try to learn what you tell me.

Thousands Thanks.

JL

[Image Analyst]

So, just to be clear, is everything working now?

[JM]

Hallo Image Analyst,

Thanks so much for your help, finally it works. I am soooooooo happy.

Anoter question is about to evaluate the time of run the code, I use tic and toc,

when i put tic in the beginning, and toc in the end, it shows only the total time after processing all the images automatically, but if i would like to know how long it takes for each image, what I should do?

Best regards

JL

[Image Analyst]

Count up the number of images and divide the overall time by that number

startTime = tic
numImageAnalyzed = 0;
for k = 1 : numImages
    if maybeSomeCondition
        numImageAnalyzed = numImageAnalyzed + 1;
    end
    elapsedSeconds = toc(startTime);
    fprintf('Elapsed seconds so far = %.1f', elapsedSeconds)
end
elapsedSeconds = toc(startTime);
secondsPerImage = elapsedSeconds / numImageAnalyzed
fprintf('Yay! All done analyzing %d images!\nElapsed seconds = %.1f.\nSeconds per image = %.2f\n', ...
    numImageAnalyzed, elapsedSeconds, secondsPerImage)

[JM]

Hallo Image Analyst,

I sincerely appreciate your help, That helps me really a lot.

I would like to ask you, which book you could advice me to read about the code and image analysis.

Thousnad Thans

JL

[Image Analyst]

Steve Eddins has one, with Gonzales I think, on image processing using MATLAB. Also a book by John Russ "The Image Processing Handbook" is a very good book. Wide variety of examples and not heavy on math.

[JM]

Hallo Image Analyst,

I am extremely grateful for your help.

That means a lot to me.

I hope one day to become an expert in image processing like you.

Have a nice day

JL