How to read all types images from the folder regardless of file extension ?

The below is my code

clear all
close all
clc
Directory = 'Images_folder\'; 
% Read images from Images folder
Imgs = dir(fullfile(Directory,'*.bmp'));
for j=1:length(Imgs)
    Img = imread(fullfile(Directory,Imgs(j).name));  % Read image
    Im = Img(:,:,1);
    figure    
    imshow(Im)
end

From this code I can read only .bmp images.But I want to read all types of images from the folder regardless of the file extension.

[pavani]

Hi i need how to read all types of images from directory like jpg, jpeg.

[Image Analyst]

@pavani Did you try imread? It should work if you pass it a valid filename for an image type it recognizes.

[pavani]

img_dir = '\New folder (2)\';
File_list = [...
    dir('*.jpg');
    dir('*.jpeg');
    dir('*.png');
    dir('*.bmp');
    dir('*.tif');
    dir('*.dcm');
    ];
fileNames = sort({File_list.name}');
for i = 1:length(file_list)
    % get the file name
    filename = [img_dir File_list(i).name];
    % read the image
    img = imread(filename);
    Y = rgb2gray(img); 
end

i tried this. but it didn't worked for me. In my folder i am having png, jpg,jpeg images. I want to read all these images using for loop. but it is getting error like

Error using imread>get_full_filename

File "\New folder (2)\II.jpg" does not exist.

Error in imread (line 372)

fullname = get_full_filename(filename);

[Stephen23]

@pavani: you are telling IMREAD to look in a specific directory, but you are not telling DIR to look in the same directory... so by default it will look in the current directory. Most likely the filenames differ between those two directories, thus the error.

The solution is to give both DIR and IMREAD the same directory path. You should also use FULLFILE rather than concatenating strings together:

P = '\New folder (2)';
S = [... You need to give DIR the same directory path:
    dir(fullfile(P,'*.jpg'));
    dir(fullfile(P,'*.jpeg'));
    dir(fullfile(P,'*.png'));
    dir(fullfile(P,'*.bmp'));
    dir(fullfile(P,'*.tif'));
    dir(fullfile(P,'*.dcm'));
    ];
for k = 1:numel(S)
    F = fullfile(S(k).folder,S(k).name);
    I = imread(F);
    Y = rgb2gray(I);
end

[Walter Roberson]

img_dir = '\New folder (2)\';

That is an absolute directory name relative to the "current" drive (probably C:) .

It is likely that C:\New folder (2) does not exist.

[pavani]

Thank you. This code is working.

Answer 1

[Walter Roberson]

Directory = 'Images_folder'; 
% Read images from Images folder
Imgs = dir(Directory);
for j=1:length(Imgs)
    thisname = Imgs(j).name;
    thisfile = fullfile(Directory, thisname);
    try
      Img = imread(thisfile);  % try to read image
      Im = Img(:,:,1);
      figure    
      imshow(Im)
      title(thisname);
   catch
   end
end

Remember, image files are defined by their content, not by their extension, so the only sure way to determine if any given file can be read as an image is to try reading it as an image.

Myself, I would at the very least filter out directories before making the attempt, but I do not know Windows well enough to be certain that it would refuse to read a directory as an image.

This code is deficient in that it can only read the image types handled by MATLAB, not all types of images as you had asked for.

[Renjith V Ravi]

Thank you.it is workig

[narin karabulut]

Thank you so much. I used this code for MR images in different folders and it worked. You use it separately for each folder.

[Walter Roberson]

For multiple folders you can use

Directory = 'Images_parent_folder'; 
% Read images from Images parent folder
Imgs = dir( fullfile(Directory, '*') );
for j=1:length(Imgs)
    thisname = Imgs(j).name;
    thisfile = fullfile(Imgs(folder), thisname);
    try
      Img = imread(thisfile);  % try to read image
      Im = Img(:,:,1);         % was so in original code
      figure    
      imshow(Im)
      title(thisname);
   catch
   end
end

[Image Analyst]

Try this for multiple files and multiple folders under a top level folder.

topLevelFolder = pwd; %'C:\Images_parent_folder';
% Read images from top level folder and also subfolders of it.
Imgs = dir( fullfile(topLevelFolder, '**\*') ); % Use ** - special wildcard added a few years ago.
fprintf('Found %d files.\n', length(Imgs))
% Throw out directories
itsAFolder = [Imgs.isdir];
Imgs(itsAFolder) = [];
fprintf('After throwing out folders, there are now %d files.\n', length(Imgs))
for k = 1 : length(Imgs)	
	thisBaseFileName = Imgs(k).name;
	thisFolder = Imgs(k).folder;
	fullFileName = fullfile(thisFolder, thisBaseFileName);
	try
		fprintf('Reading %s\n', fullFileName)
% 		Img = imread(thisfile);  % try to read image
% 		Im = Img(:,:,1);         % was so in original code
% 		figure
% 		imshow(Im)
% 		title(thisname);
% 		drawnow;
	catch
	end
end

Answer 2

[KSSV]

Files=[dir('*.jpg');dir('*.png')]

specify all possible image extensions.

[Thilak Babu Sayila]

it's not working!

[KSSV]

It is working in my case...what you have tried?

[Thilak Babu Sayila]

only jpeg images are reading, png images are not reading

[Thilak Babu Sayila]

if you dont mind, can you give me full code?

[Walter Roberson]

what happened when you tried the code in my answer ?

[Thilak Babu Sayila]

actually, total 20 images are in my folder, after executing the code 'Imgs' contains 22 contents and extra two are dummy (nothing is present). but i need exactly 20 images of various formats.

[Walter Roberson]

In my code, Imgs (capital I) will contain directory information for everything in the folder, including the . and .. folders. It is the loop with the try/catch that determines whether each entry is an image file that MATLAB is able to deal with, so you should record the filename information for those cases.

It is easier when there are a list of specific extensions you want to be able to handle, instead of wanting "everything that MATLAB turns out to be able to process" no matter how obscure.

Answer 3

[Image Analyst]

For multiple file extensions in a single folder, try this:

fileList = [...
    dir('*.jpg');
    dir('*.jpeg');
    dir('*.png');
    dir('*.bmp');
    dir('*.tif');
    dir('*.dcm');
    ]
fileNames = sort({fileList.name}')

Answer 4

[DGM]

If you just want to read everything into memory at once, then MIMT mimread() makes it simple.

% read all the images in my giant pile of forum garbage
% includes JPG, GIF, TIFF, PNG, BMP, ICO, MPO
% amongst hundreds of non-image files
% includes I, IA, RGB, RGBA, logical, indexed, and multiframe images
ST = mimread('forum_junk/*','quiet'); % one line

ST is a cell array containing all of the images.

• If a JPG image has EXIF orientation data, it will be rectified.
• Multiframe GIFs will be read as a multiframe 4D RGB image
• Multi-image TIFF/CUR/ICO files will also be read in whole
• If an image is indexed color, it is converted to RGB.
• If an image has transparent content, it will have an attached alpha channel (IA/RGBA).

Is it a good idea to blindly load perhaps hundreds of images into memory simultaneously? Possibly not, but since the original question is about how to create an unmanageable forest of figure windows, I figured that good ideas weren't a requirement.

Jokes aside, mimread() isn't the most flexible thing to use if you want to have a lot of control over managing the path expression or if you have a bunch of elaborate TIFFs or something. It's also not useful if you want to incrementally process the files one at a time. It's intended to be a simple-to-use tool for ad-hoc use. You just point it at a directory or a bunch of easily-isolated filenames and grab them.