MATLAB: Conversion of 100 jpg images to PGM

faqimage analysisimage processingImage Processing Toolbox

Best Answer

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

Use the second code sample block.

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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: Read images from folder

See the code snippet in the FAQ:

https://matlab.fandom.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

Which you'd adjust like this:

% Specify the folder where the files live.
myFolder = fullfile(pwd, '..\TRAINING SET');
% 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 specify a new folder.', myFolder);
    uiwait(warndlg(errorMessage));
    myFolder = uigetdir(); % Ask for a new one.
    if myFolder == 0
         % User clicked Cancel
         return;
    end
end
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(myFolder, '*.BMP'); % Change to whatever pattern you need.
theFiles = dir(filePattern);
for k = 1 : length(theFiles)
    baseFileName = theFiles(k).name;
    fullFileName = fullfile(theFiles(k).folder, baseFileName);
    fprintf(1, 'Now reading %s\n', fullFileName);
    % Now do whatever you want with this file name,
    % such as reading it in as an image array with imread()
    imageArray = imread(fullFileName);
    imshow(imageArray);  % Display image.
    drawnow; % Force display to update immediately.
end

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Related Solutions

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

MATLAB: Read images from folder

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