How to run all the image with format jpg in folder? and save into folder?

Hello. Anyone know how to run a folder with thousand images instead of run one by one the image? and save into folder?

I=imread('11_285.jpg');
imshow(I)
magnificationFactor = 1.2;
J=imresize(I,magnificationFactor, 'bilinear');
imshowpair(I,J,method="montage")
imwrite(J,'11_285_rescale.jpg');

Answer 1

[Walter Roberson]

dinfo = dir('*.jpg');
filenames = fullfile({dinfo.folder}, {dinfo.name});
nfiles = length(filenames);
magnificationFactor = 1.2;
for K = 1 : nfiles
    thisfile = filenames{K};
    [folder, basename, ext] = fileparts(thisfile);
    outfile = fullfile(folder, basename + "_rescale" + ext);
    I = imread(thisfile);
    J = imresize(I, magnificationFactor, 'bilinear');
    imwrite(J, outfile);
end

[Dayangku Nur Faizah Pengiran Mohamad]

hello sir. thanks for your fast responded.

i'm using linux. so this is the parent file.

/home/motmot/Downloads/All data/285/Ground truth/Original image

where can i put this file name? can you teach me?

[Dayangku Nur Faizah Pengiran Mohamad]

dinfo = dir('*.jpg');
filenames = fullfile('home/motmot/Downloads/All data/285/Ground truth/Original image', '*.jpg');
nfiles = length(filenames);
magnificationFactor = 1.2;
for K = 1 : nfiles
    thisfile = filenames(K);
    [folder, basename, ext] = fileparts(thisfile);
    outfile = fullfile(folder, basename + "_rescale" + ext);
    I = imread(thisfile);
    J = imresize(I, magnificationFactor, 'bilinear');
    imwrite(J, outfile);
end

I got error when run this code.

Here's the error said:

Error using imread>get_full_filename (line 570)

File "h" does not exist.

Error in imread (line 377)

fullname = get_full_filename(filename);

Error in rescale3 (line 9)

I = imread(thisfile);

[Stephen23]

In your code replace

dinfo = dir('*.jpg');
filenames = fullfile('home/motmot/Downloads/All data/285/Ground truth/Original image', '*.jpg');

with

mypath = 'home/motmot/Downloads/All data/285/Ground truth/Original image';
dinfo = dir(fullfile(mypath,'*.jpg'));
filenames = fullfile({dinfo.folder}, {dinfo.name});

and of course revert to using curly braces to access the content of FILENAMES, i.e.:

thisfile = filenames{K};

not with parentheses like you tried.

Explanation: You completely ignore the output from DIR which is required for iterating over the filenames. Instead you defined FILENAMES to be a character vector, which you then used parentheses to index into, giving you exactly the first character from that character vector: 'h'. But 'h' is not the name of an existing file, thus the error.

Avoid LENGTH, use NUMEL instead.

[Dayangku Nur Faizah Pengiran Mohamad]

ok thanks sir. I get it now. But now I want to crop my image. Here's my codes:

mypath = '/home/motmot/Downloads/All data/275/Ground truth/Rescale image/';
dinfo = dir(fullfile(mypath,'*_275.jpg'));
filenames = fullfile({dinfo.folder}, {dinfo.name});
nfiles = length(filenames);
for K = 1 : nfiles
    thisfile = filenames{K};
    [folder, basename, ext] = fileparts(thisfile);
    outfile = fullfile(folder, basename + "_crop" + ext);
    x_cent= 450;
    y_cent= 260;
    size_of_cropped_img=511;
    centroide=[x_cent y_cent];
    I3=imread(thisfile);
    xmin=x_cent-size_of_cropped_img/2;
    ymin=y_cent-size_of_cropped_img/2;
    I4=imcrop(I3,[xmin ymin size_of_cropped_img size_of_cropped_img]);
    imshow(I4)
    imwrite(I4, outfile);
end

The image for outfile for cropping image did not save in the folder. How can I save the crop image?

[Dayangku Nur Faizah Pengiran Mohamad]

OK sir. I get the idea. I forgot to put 'rescale' at back the code

from this,

dinfo = dir(fullfile(mypath,'*_275.jpg'));

into this,

dinfo = dir(fullfile(mypath,'*_275_rescale.jpg'));