Resizing and saving images on a new directory - image

Question

I am writing a simple function that reads a sequence of images, re-sizes them and then saves each set of re-sized images to a new folder. Here is my code:
function [ image ] = FrameResize(Folder, ImgType)
Frames = dir([Folder '/' ImgType]);
NumFrames = size(Frames,1);
new_size = 2;
for i = 1 : NumFrames,
image = double(imread([Folder '/' Frames(i).name]));
for j = 2 : 10,
new_size = power(new_size, j);
% Creating a new folder called 'Low-Resolution' on the
% previous directory
mkdir ('.. Low-Resolution');
image = imresize(image, [new_size new_size]);
imwrite(image, 'Low-Resolution');
end
end
end
I have mainly two doubts:
How can I save those images with specific names, like im_1_64, im_2_64, etc. according to the iteration and to the resolution?
How can I make the name of the folder being created change with each iteration so that I save images with the same resolution on the same folder?

Answer 1

Since you know the resolution will be: new_size x new_size, you can use this in the imwrite function:
imwrite(image, ['im_' num2str(i) '_' num2str(new_size) '.' ImgType]);
Assuming that ImgType holds the extension.
To setup the folders you can do something like this:
mkdir(num2str(new_size))
cd(num2str(new_size))
imwrite(image, ['im_' num2str(i) '_' num2str(new_size) '.' ImgType]);
cd ..

Answer 2

You have an answer you are satisfied with, but I strongly suggest doing two things differently:
Use fullfile to create/concatenate file and path names.
For example, instead of:
imread([Folder '/' Frames(i).name])
do
imread(fullfile(Folder,Frames(i).name))
It's good for relative paths too:
fullfile('..','Low-Resolution')
ans =
..\Low-Resolution
Use sprintf to create strings containing numerical data from variables. Instead of:
['im_' num2str(i) '_' num2str(new_size) '.' ImgType]
do
sprintf('im_%d_%d.%s', i, new_size, ImgType)
You can even specify how many digits you want per integer. Compare:
K>> sprintf('im_%d_%d.%s', i, new_size, ImgType)
ans =
im_2_64.png
K>> sprintf('im_%02d_%d.%s', i, new_size, ImgType)
ans =
im_02_64.png