MATLAB: Hello, I was hoping if i could get the code for getting images from a folder and storing them in an array and how to perform sift on those images.

digital image processingsift

myFolder=('C:\Users\Paul\Documents\MATLAB\SignatureDataset'); if ~isdir(myFolder) errorMessage = sprintf('Error: The following folder does not exist: \n%s', myFolder); uiwait(warndlg(errorMessage)); return; end filePattern = fullfile(myFolder, '*.pgm'); pngFiles = dir(filePattern); for k = 1:length(pngFiles) baseFileName = pngFiles(k).name; fullFileName = fullfile(myFolder, baseFileName); fprintf(1, 'Now readng %s\n', fullFileName); imageArray = imread(fullFileName); imshow(imageArray); %Display image. drawnow; %Force display to update immediately. end

Best Answer

You are "getting images from a folder and storing them in an array" in this line:

imageArray = imread(fullFileName);

so not sure why you asked.

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MATLAB: Hello! I was hoping if you could help tell me how to read images from a subfolder and store them in an array. I have this code but it doesnt read the subfolder images

That code would appear to be appropriate for png files that are directly in C:\Users\Paul\Documents\MATLAB\SignatureDataset .

If you want to look inside all folders inside C:\Users\Paul\Documents\MATLAB\SignatureDataset then you will need to either program finding the folders yourself, or you will need to use a tool such as rdir() from the File Exchange. Or, if you are using R2017a or later you can use the new behavior of dir():

%the below is R2017a or later only
myFolder=('C:\Users\Paul\Documents\MATLAB\SignatureDataset);
if ~isdir(myFolder)
    errorMessage = sprintf('Error: The following folder does not exist: \n%s', myFolder);
    uiwait(warndlg(errorMessage));
    return;
end
filePattern = fullfile(myFolder, '**', '*.png');   %needs R2017a or later

pngFiles = dir(filePattern);
for k = 1:length(pngFiles)
    folderName = pngFiles(k).folder;    %needs R2017a or later
    baseFileName = pngFiles(k).name;
    fullFileName = fullfile(folderName, baseFileName);
    fprintf(1, 'Now reading %s\n', fullFileName);
    imageArray = imread(fullFileName);
    imshow(imageArray); 
    drawnow; %Force display to update immediately.
end

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

Best Answer

Related Solutions

MATLAB: Hello! I was hoping if you could help tell me how to read images from a subfolder and store them in an array. I have this code but it doesnt read the subfolder images

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

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