Reducing the size of images by a loop

Here I reduced the size of an image. But I want to reduce the size of all the images of my folder. Images are : abc_20190304_0001 to abc_20190304_0095. How can I make the loop?

I=imread('abc_20190304_0001.png');

imshow abc_20190304_0001.png

L = imresize(I,.25,'bilinear');

figure, imshow(L);

Answer 1

[KSSV]

imgNames = dir('*.png') ;   % give your exntenion of images in the folder 
N = length(imgNames) ;      % toal number of images 
% loop for each image
for i = 1:N
    thisImg = imgNames(i).name ; 
    I=imread(thisImg);
    figure(1)
    imshow(I) ;
    L = imresize(I,.25,'bilinear');    
    figure(2)
    imshow(L);
end

[Joydeb Saha]

Can I save the new reduced images by the same name or 1.png, 2.png.. etc in a separate folder?

[KSSV]

Yes, you can. Read about imwrite.

thepath = '';  % give path of the folder here 
for i = 1:N
    thisImg = imgNames(i).name ; 
    I=imread(thisImg);
    figure(1)
    imshow(I) ;
    L = imresize(I,.25,'bilinear');    
    figure(2)
    imshow(L);
    % WRite image into a folder 
    name = [thepath,filesep,num2str(i),'.png'] ;
    imwrite(L,name)
end

[Joydeb Saha]

Yes its working. The names of the files are like abc_20190304_0001,abc_20190304_0002, abc_20190304_0003 etc. Can we save the files in that way? Or in the 4digit format like.. 0001.png,0002.png etc

[Joydeb Saha]

actually when the code read the files, it reads as 0001,0002....0011..0095 etc, but when it saves the files it saves as 1.png,2.png....22.png etc.

so when i make the video of the files .. the continuation of the files gets scattered. so i want to save the files in 4digit format

[KSSV]

imgNames = dir('*.png') ;   % give your exntenion of images in the folder 
N = length(imgNames) ;      % toal number of images 
thepath = '';  % give path of the folder here 
% loop for each image
for i = 1:N
    thisImg = imgNames(i).name ; 
    I=imread(thisImg);
    figure(1)
    imshow(I) ;
    L = imresize(I,.25,'bilinear');    
    figure(2)
    imshow(L);
    % WRite image into a folder 
    [filepath,name,ext] = fileparts(thisImg) ; 
    name = [thepath,filesep,name,'.png'] ;
    imwrite(L,name)
end

[Joydeb Saha]

Can you just make me understand the last two lines...

consider my path name is : E:\MW\Channel

and I want to save it in the same folder as : abc_20190304_0001, abc_20190304_0002 ....abc_20190304_0095 etc

[Image Analyst]

You can use sprintf()

baseFileName = sprintf('%4.4d.png', i); % 0001.png for example.
fullOutputFileName = fullfile(outputFolder, baseFileName);
imwrite(L, fullOutputFileName);

Answer 2

[Joydeb Saha]

well the problem is solved