Read, Crop and then Save multiple images - from multiple folders

Hi there, I have working code for reading, cropping and saving an image and now I hope to tackle cropping multiple images in a folder.

I used answers posted on this forum for the same purpose, yet sadly I did not have any luck in getting it working.

The working code I have for reading, cropping and saving just one image is as follows:

imshow('1-01-H PS.jpg');%load image

img = imread('1-01-H PS.jpg');

a = img(250:1565,1480:2370);

a = img(250:1565,1480:2370,:);

imshow(a)

imwrite(a,'Cropped 1-01-H PS.jpg');

imshow('Cropped 1-01-H PS.jpg');

I essentially want to loop this through each folder. Each folder contains 10-40 images, all to be cropped to the same dimensions above.

The advice I saw on this forum was as followed:

images = dir('*.jpg') ; % GEt all images of the folder

N = length(images) ; % number o fimages

I = imread(images(1).name) ; % crop one to get rect

[x, rect] = imcrop(I) ;

for i = 1:N

I = imread(images(i).name) ; % REad image

I = imcrop(I,rect) ; % crop image

fullFileName = fullfile(images(i).folder, images(i).name);

imwrite(I,fullFileName) ; % Save image

end

Unfortunately I could not get the two to marry together. I am using 2019a release. Any advice/suggestions would be much appreciated!

Answer 1

[Ameer Hamza]

Unfortunately, you are overwriting the original files with the cropped images. I hope that you have backed-up all the images. Try this. I have changed the imwrite line.

images = dir('*.jpg') ;  % GEt all images of the folder 
N = length(images) ;     % number o fimages 
I = imread(images(1).name) ;  % crop one to get rect 
[x, rect] = imcrop(I) ;
for i = 1:N
    I = imread(images(i).name) ;   % REad image 
    I = imcrop(I,rect) ;           % crop image 
    fullFileName = fullfile(images(i).folder, ['cropped' images(i).name]);
    imwrite(I,fullFileName);   % Save image
end

To loop through multiple directories:

If your folder structure is like this

filder1:
    image1
    image2
    ..
    imageN
folder2:
    image1
    image2
    ..
    imageN
..
..
folderN:
    image1
    image2
    ..
    imageN

then you can change the first line of the code to

images = dir('*/*.jpg');

and if there are several levels of subfolders and you are at the top-level, then you can get the name of all the files in the current directory and subdirectory with

images = dir('**/*.jpg');

Apply the second options with care. It will recursively search the directories for jpg files.

[Sarah Harrington]

Hi Ameer, thank you very much for your fast response.

Thank you for pointing out that I was overwriting the original files, thankfully I always have a backup because I know what I'm like…

I have tried the code you kindly suggested. Unfortunately I am still getting errors:

Error using fopen

Unable to find file. Ensure file exists and path is valid.

Error in imwrite (line 517)

fid = fopen(filename, 'a');

Error in TESTCropAllImagesInAFolder (line 9)

imwrite(I,['Cropped ' fullFileName]); % Save image

I believe my files and path is correct, would you kindly advise what I am missing/doing incorrectly?

[Ameer Hamza]

I made a mistake in my code. Please try the updated code.

[Image Analyst]

Yes, but she has multiple folders, so you need to show her how to use ** in dir(), or how to use imageDatastore() to recursively go into each folder and process the files.

[Ameer Hamza]

Thanks for pointing out, I missed the part about multiple folders.

[Image Analyst]

You forgot to construct the full input filename in case the image is not in the current folder. Fixed code is below:

clc;    % Clear the command window.
fprintf('Beginning to run %s.m.\n', mfilename);
% Get a list of all images.
folder = pwd; % wherever...  can call uigetdir() if you want.
filePattern = fullfile(folder, '**/*.jpg');
images = dir(filePattern);	% Get all images of the folder
if isempty(images)
	errorMessage = sprintf('No images found in %s', folder);
	uiwait(errordlg(errorMessage));
	return;
end
numberOfImages = length(images) ;     % number of images
thisFileName = fullfile(images(1).folder, images(1).name);
thisImage = imread(thisFileName) ;  % crop one to get rect
imshow(thisImage);
axis('on', 'image');
caption = sprintf('Please click and drag out a cropping rectangle.  Double click inside to accept it');
title(caption, 'FontSize', 15);
uiwait(helpdlg(caption));
[x, rect] = imcrop(thisImage);
for k = 1:numberOfImages
	thisFileName = fullfile(images(k).folder, images(k).name);
	fprintf('Cropping image %d of %d : %s\n', k, numberOfImages, thisFileName);
	thisImage = imread(thisFileName) ;   % Read image
	subplot(1, 2, 1);
	imshow(thisImage);
	axis('on', 'image');
	caption = sprintf('%s, image %d of %d', images(k).name, k, numberOfImages);
	title(caption, 'FontSize', 15, 'Interpreter', 'none');
	croppedImage = imcrop(thisImage, rect) ;   % Crop image
	subplot(1, 2, 2);
	imshow(croppedImage);
	axis('on', 'image');
	drawnow;
	fullOutputFileName = fullfile(images(k).folder, ['cropped' images(k).name]);
	% Save cropped image into source image's folder.
	imwrite(croppedImage, fullOutputFileName);
	pause(0.5); % Delay long enough to see the cropping.
end

[Ameer Hamza]

Ah! I missed that too ?‍♂️. I think you should add this comment as an answer to this question. It is much more detailed than my answer and addresses other issues too.

[Sarah Harrington]

Wow, truly incredible! The code has worked brilliantly.

Thank you both for your time and efforts in assisting me with this issue. It has saved me a great deal of time and it is great to see the code so I can keep learning - I certainly wouldn't have been able to write all of that!

Thank you very much for your inputs :)

[janefrances uba]

Read, imwrite multiple LBP images - from multiple folders....

please "Image Analyst" i need your help am stuck, i want to read and inwrite the LBP multiple image from multiple folder in a folder but am having errors..

below is my code..

function [lbparray] = LBPfun(dir, path)
filesInfor1 = {dir.name};
image_array = [];
var_matrix = [];
 dim = 0;
 im = {};
 TrainingData = {};
 outputFolder = fullfile('C:\Users\uba.janefrances\Desktop\Thesis\All_Faces\LBP_images\LBP Output Images');
if ~exist(outputFolder, 'dir')
	mkdir(outputFolder);
end
for k=1:numel(filesInfor1) 
%      %read image one after the other
        img = imread(strcat(path,'\',filesInfor1{k}))
        img=imresize(img, [64 64]);
        img = rgb2gray(img); 
%         figure(); 
%         imshow(img);
        imgg=LBP2(img);
        lbpImage = (imcomplement(uint8(imgg)));
        imshow( lbpImage);
        cd('C:\Users\uba.janefrances\Desktop\Thesis\All_Faces\LBP_images\LBP Output Images\');
	% Now do the writing
        imwrite(uint8( lbpImage), 'lbpoutputimage.bmp','bmp');
end

[janefrances uba]

AM WORKING ON SIX CLASSES OF IMAGE DATASET ANGER, DISGUST, FEAR,HAPPY,SAD AND SUPRISE AND i want to read and inwrite the LBP multiple image from multiple folder (6) in a folder (6) but am having errors..

 below is my code..
function [lbparray] = LBPfun(dir, path)
filesInfor1 = {dir.name};
image_array = [];
var_matrix = [];
 dim = 0;
 im = {};
 TrainingData = {};
 outputFolder = fullfile('C:\Users\uba.janefrances\Desktop\Thesis\All_Faces\LBP_images\LBP Output Images');
if ~exist(outputFolder, 'dir')
	mkdir(outputFolder);
end
for k=1:numel(filesInfor1) 
%      %read image one after the other
        img = imread(strcat(path,'\',filesInfor1{k}))
        img=imresize(img, [64 64]);
        img = rgb2gray(img); 
%         figure(); 
%         imshow(img);
        imgg=LBP2(img);
        lbpImage = (imcomplement(uint8(imgg)));
        imshow( lbpImage);
        cd('C:\Users\uba.janefrances\Desktop\Thesis\All_Faces\LBP_images\LBP Output Images\');
	% Now do the writing
        imwrite(uint8( lbpImage), 'lbpoutputimage.bmp','bmp');
end