Image processing code Help
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NEED help to use imread for 20 images together. This code can work on 1 image at a time i want to use this code for all 20 images at once and want to save all images in one new folder after processing .Please can anyone help me to modify this code.
RGB=imread('1.jpg');
% input 768*576 pixel uint8 type true color image.
R=RGB(:,:,1);
% red surface image extraction
G=RGB(:,:,2);
B=RGB(:,:,3);
figure;
imshow(RGB)
title('original image');
% create a new empty graphics window
% view images
figure,
imshow(R)
title('red face version');
figure,
imshow(G)
title('green face version');
figure,
imshow(B)
3 Comments
Geoff Hayes
on 16 Apr 2020
Anas - are all 20 files in the same folder? Which new image do you want to save to file - the extracted red, green or blue images? Where should the new files be saved to and what should their new names be?
Anas Bilal
on 16 Apr 2020
Anas Bilal
on 16 Apr 2020
Accepted Answer
Ameer Hamza
on 16 Apr 2020
Edited: Ameer Hamza
on 16 Apr 2020
See my answer here related to batch processing of csv files: https://www.mathworks.com/matlabcentral/answers/509790-read-and-manipulate-multiple-csv-files
Here is a general structure of the code
files = dir('*.jpg'); % get name of all files with jpg extension
for i=1:numel(files) % run the for loop over all images
name = files(i).name; % get name of i-th image file
img = imread(name); % load the image
R=RGB(:,:,1);
% red surface image extraction
G=RGB(:,:,2);
B=RGB(:,:,3);
imwrite(R, ['img' num2str(i) ' red.jpg']);
imwrite(G, ['img' num2str(i) ' green.jpg']);
imwrite(B, ['img' num2str(i) ' blue.jpg']);
end
This link also provide helpful information: https://matlab.fandom.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F
20 Comments
Anas Bilal
on 16 Apr 2020
Ameer Hamza
on 16 Apr 2020
Check the updated code. It will save each channel in a separate file. Since you are saving a single channel, the actual image will appear gray.
Anas Bilal
on 16 Apr 2020
Ameer Hamza
on 16 Apr 2020
What is the error?
Anas Bilal
on 16 Apr 2020
Ameer Hamza
on 16 Apr 2020
Glad to be of help.
Anas Bilal
on 17 Apr 2020
Anas Bilal
on 17 Apr 2020
Ameer Hamza
on 17 Apr 2020
Can you paste your code?
Anas Bilal
on 17 Apr 2020
Anas Bilal
on 17 Apr 2020
Ameer Hamza
on 17 Apr 2020
I couldn't find an issue in the for loop. Can you add a breakpoint in your code and see if the loop is running once or 400 times for each image?
Anas Bilal
on 17 Apr 2020
Ameer Hamza
on 17 Apr 2020
What is the value of variable 'name' in each iteration? Does it get changed or remain same?
Anas Bilal
on 17 Apr 2020
Image Analyst
on 17 Apr 2020
Anas, it can't run 400 times on one image without using a loop, unless you had the cope copied 400 times, which I very much doubt. Most likely what happened is you didn't properly get the filename at the top of the loop. You didn't use the index and just got the same filename over and over again.
Anas Bilal
on 17 Apr 2020
Ameer Hamza
on 17 Apr 2020
Anas, your code is correct. Can you show us the output after running these two lines?
files = dir('*.ppm');
numel(files)
Image Analyst
on 17 Apr 2020
Anas: I've corrected your code. This works. Just uncomment the imwrite() lines:
folder = pwd; % Whever you want...
filePattern = fullfile(folder, '*.ppm');
files = dir(filePattern); % get name of all files with jpg extension
if numel(files) == 0
warningMessage = sprintf('No files found in folder\n%s.\n', folder);
fprintf('%s\n', warningMessage);
beep;
uiwait(errordlg(warningMessage));
return;
end
numberOfImageFiles = length(files)
for k = 1 : numberOfImageFiles % run the for loop over all images
baseFileName = files(k).name; % get name of i-th image file
fullFileName = fullfile(folder, baseFileName);
fprintf('Reading in file %d of %d : %s\n', k, numberOfImageFiles, fullFileName);
img = imread(fullFileName); % load the image
subplot(1, 2, 1);
imshow(img);
caption = sprintf('Original Image :\n%s', baseFileName);
title(caption, 'FontSize', 15, 'Interpreter', 'none');
[rows, columns, numberOfColorChannels] = size(img);
if numberOfColorChannels == 3
R = img(:, :, 1); % Red channel image extraction
G = img(:, :, 2);
B = img(:, :, 3);
% Write out RGB image as TIFF format.
outputBaseFileName = sprintf('img %d RGB.tif', k);
outputFullFileName = fullfile(folder, outputBaseFileName);
fprintf(' Writing file %s\n', outputFullFileName);
% imwrite(R, outputFullFileName);
% Write out red image as TIFF format.
outputBaseFileName = sprintf('img %d red.tif', k);
outputFullFileName = fullfile(folder, outputBaseFileName);
fprintf(' Writing file %s\n', outputFullFileName);
% imwrite(R, outputFullFileName);
% Write out green image as TIFF format.
outputBaseFileName = sprintf('img %d green.tif', k);
outputFullFileName = fullfile(folder, outputBaseFileName);
fprintf(' Writing file %s\n', outputFullFileName);
% imwrite(R, outputFullFileName);
% Write out blue image as TIFF format.
outputBaseFileName = sprintf('img %d blue.tif', k);
outputFullFileName = fullfile(folder, outputBaseFileName);
fprintf(' Writing file %s\n', outputFullFileName);
% imwrite(R, outputFullFileName);
else
% img is already a gray scale image.
G = img;
end
% Histogram equivilzation of Green Channel
b=adapthisteq(G);
% Two times limited contrast adaptive direct equalization
ba=adapthisteq(b);
% adjusts contrast in grayscale images.
subplot(1, 2, 2);
imshow(ba)
title('Enhanced contrast', 'FontSize', 15, 'Interpreter', 'none');
outputBaseFileName = sprintf('img %d enhanced.tif', k);
outputFullFileName = fullfile(folder, outputBaseFileName);
fprintf(' Writing file %s\n', outputFullFileName);
% imwrite(ba, outputFullFileName);
drawnow;
pause(0.5);
end
Anas Bilal
on 17 Apr 2020
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