MATLAB: How to read images one by one

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There is multiple images in a folder, but the name is not in order, for example, 01.jpg, 21.jpg, 41.jpg,……101.jpg. How to read these images successively? Thanks very much.

Best Answer

If you have a cell array of the names, then use that. If you don't know the names, then use dir to read the names from the directory where they are saved. The MATLAB Wiki gives an complete working example of how to do this:

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

(Just scroll down a little to find the example using dir.)

Related Solutions

MATLAB: I have a folder of .tif images that need to be converted to a different format for downstream analysis

Hi,

I think your input tif files are in single format whereas your output file format which is jpeg doesn't support single format while using imwrite (you can find using help imwrite in the 'fmt' of the file output section)

You can do this instead. either save them in a different file format let us say 'bmp', 'jp2' or 'png'. Else you can do the following thing by converting your input image from single format to unsigned integer 8 (uint8).

% Specify the folder where the files live.
myFolder = '/Users/masonlien/Desktop/PhD/Drone/2020/test';
% Check to make sure that folder actually exists.  Warn user if it doesn't.
if ~isfolder(myFolder)
	errorMessage = sprintf('Error: The following folder does not exist:\n%s\nPlease select another folder.', myFolder);
	uiwait(warndlg(errorMessage));
	myFolder = uigetdir();
end
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.tif'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
numFiles = length(theFiles);
if numFiles == 0
	warningMessage = sprintf('Warning: no TIFF images found in the folder:\n%s', myFolder);
	uiwait(warnuser(warningMessage));
	return;
end
for k = 1 : numFiles
	baseFileName = theFiles(k).name;
	fullFileName = fullfile(myFolder, baseFileName);
	fprintf('Now reading %s (#%d of %d).\n', fullFileName, k, numFiles);
    % such as reading it in as an image array with imread()
    
    % Change made here 
	imageArray = uint8(imread((fullFileName)));
	imshow(imageArray);  % Display image.
	caption = sprintf('%s (#%d of %d)', fullFileName, k, numFiles);
	title(caption, 'FontSize', 14, 'Interpreter', 'none');
	drawnow; % Force display to update immediately.
	% Write it out as a PNG file.
	baseFileName = strrep(lower(baseFileName), '.tif', '.jpg');
	outputFileName = fullfile(myFolder, baseFileName);
	fprintf(1, 'Now writing %s\n', outputFileName);
 	imwrite(imageArray, outputFileName);
end

MATLAB: Applying Function to Structure

In terms of your existing code, you would just add a readSPE(fullFileName) after your fprintf().

If you want to use more compact code then

filePattern = fullfile(myFolder, '*.spe'); 
dinfo = dir(filePattern);
filenames = fullfile(myFolder, {dinfo.name});
output = arrayfun(@readSPE, filenames, 'uniform', 0);

Best Answer

Related Solutions

MATLAB: I have a folder of .tif images that need to be converted to a different format for downstream analysis

MATLAB: Applying Function to Structure

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