How to read images in a folder

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Nilushi Dissanayake
Nilushi Dissanayake on 25 Jan 2011
Answered: DGM on 24 Jun 2023
I am a student and I need to find the code to read the images in a file in order to do cropping. In here I named my images as
user001-01.bmp
user001-02.bmp etc.
I need help for this because I'm a beginner to MATLAB.
  7 Comments
naila
naila on 24 Jun 2023
hi,
i have some jpeg images in a folder (saved in C drive),using imread command in matlab 2018 but its not working.
please help me out.
Image Analyst
Image Analyst on 24 Jun 2023
If you have any more questions, then attach your image and code to read it in with the paperclip icon after you read this:
Do it in your own new question rather than here in @Nilushi Dissanayake's question. And "not working" is so vauge as to be unanswerable. Explain what that means, like give us ALL the red text.

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Accepted Answer

Michelle Hirsch
Michelle Hirsch on 25 Jan 2011
Nilushi -
We won't be able to hand you a complete answer, but can give some pointers. Here's a code snippet that shows common patterns for reading data from files. There are a bunch of concepts you are going to want to learn about to understand this code:
  • Working with structures. When you get a list of image files, their names will be stored inside of a structure.
  • Working with cell arrays. We'll use a cell array to store the data coming from the different images, since it allows for each image to be a different size. If you happen to know that all of your images are exactly the same size you can use a regular numeric array instead.
% Get list of all BMP files in this directory
% DIR returns as a structure array. You will need to use () and . to get
% the file names.
imagefiles = dir('*.bmp');
nfiles = length(imagefiles); % Number of files found
for ii=1:nfiles
currentfilename = imagefiles(ii).name;
currentimage = imread(currentfilename);
images{ii} = currentimage;
end
Best of luck! - scott
  10 Comments
Hasaan Ijaz
Hasaan Ijaz on 12 Sep 2020
Worked for me as well. Thank you!

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More Answers (4)

Sebastian
Sebastian on 25 Jan 2011
There might be different ways to do this. An easy one is
for a = 1:10
filename = ['user001-' num2str(a,'%02d') '.bmp'];
img = imread(filename);
% do something with img
end
  4 Comments
artprakasa
artprakasa on 13 Mar 2017
yeaayy.. thanks, good idea.
Liu Sam
Liu Sam on 4 Mar 2018
Thank you! This is the exact answer I want!

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Walter Roberson
Walter Roberson on 25 Jan 2011
Please check the FAQ on this topic

George
George on 24 Sep 2016
You can try ImageDatastore
  3 Comments
Walter Roberson
Walter Roberson on 11 Sep 2017
To be slightly more accurate, the imageDatastore function needs R2016a or later, but the imageDatastore class was introduced in R2015b and objects could be created by calls to datastore.
Walter Roberson
Walter Roberson on 11 Sep 2017
Before R2015a, the closest equivalent was the dataset array from the Statistics toolbox.

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DGM
DGM on 24 Jun 2023
There are already many examples that I don't need to repeat, but I have my own ways of doing things. I'm only throwing this here because this is a defacto reference question.
Pay particular note to the latter part of the answer.

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