MATLAB Answers

calculate number of images

Asked by Lalit Patil on 1 Jan 2013
 d = dir('*.bmp');
 n = length(d);

i have a folder and i am calculating number of images in that folder, but it calculates only .bmp images.. Some times there will be png images also.. But whenever there will be images it will be of same extension. So, i want to make general code.. Whatever the images, it should calculate..

so, what should be the change in first line of code, if there are png images..?



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2 Answers

Answer by Walter Roberson
on 1 Jan 2013
 Accepted answer
d = dir('*.bmp')


Walter Roberson
on 1 Jan 2013

Often the easiest way is to read in all filenames from the directory, extract their extensions, and compare the extension to the list of extensions you want.

Lalit Patil on 1 Jan 2013

And there are seven images in folder, but when i am executing

 d = dir('.')
 n = length(d)

I am getting 9, so, why 2 is extra.?

Azzi Abdelmalek
on 1 Jan 2013



to ignore the two



Answer by Image Analyst
on 1 Jan 2013

Here's a snippet of code I use to load just the desired extensions. If you use this you won't have to worry about what file types are in the folder because the code handles all that - it will load just the files you know in advance that you are interested in into the listbox.

	% Get a list of all files in the folder.
	filePattern = fullfile(folder, '/*.*');
	ImageFiles = dir(filePattern);
	% Filter the list to pick out only files of
	% file types that we want (image and video files).
	ListOfImageNames = {}; % Initialize
	for Index = 1:length(ImageFiles)
		% Get the base filename and extension.
		baseFileName = ImageFiles(Index).name;
		[folder, name, extension] = fileparts(baseFileName);
		% Examine extensions for ones we want.
		extension = upper(extension);
		switch lower(extension)
			case {'.png', '.bmp', '.jpg', '.tif'}
				% Keep only PNG, BMP, JPG, TIF image files.
				ListOfImageNames = [ListOfImageNames baseFileName];
	%         otherwise
	% Now we have a list of validated filenames that we want.
	% Send the list of validated filenames to the listbox.
	set(handles.lstImageList, 'string', ListOfImageNames);
	% Need to set this to something smaller than the number it used to be,
	% because if we deleted some files and called this then the old value could be beyond the end of the list
	% and that would cause the listbox to not be displayed.
	set(handles.lstImageList, 'value', []);


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