MATLAB: How to read and store greyscaleimage into single matrix

image processingImage Processing Toolbox

i have 2429 images in pgm format. each is in 19*19 size. Now i need to read all the images one by one and store in single matrix. With the help of previous mathworks available examples i read my file. now how to store in single matrix.

myFolder = 'C:\Users\smanohar\Documents\MATLAB\RBMimplementation\Gaussian    RBM\gdrbm\greyscsalegdrbm\face';
if ~isdir(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
uiwait(warndlg(errorMessage));
return;
end
filePattern = fullfile(myFolder, '*.pgm');
jpegFiles = dir(filePattern);
for k = 1:length(jpegFiles)
baseFileName = jpegFiles(k).name;
fullFileName = fullfile(myFolder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
imageArray = imread(fullFileName);
end

Best Answer

Subha - if all images are of the same dimension, 19x19, then you can save all of them to a single array of size 19x19x2429. Try something like the following

 % pre-size the image array
 imageArray = zeros(19,19,2429);
 filePattern = fullfile(myFolder, '*.pgm');
 pgmFiles = dir(filePattern);
 for k = 1:length(pgmFiles)
     baseFileName = pgmFiles(k).name;
     fullFileName = fullfile(myFolder, baseFileName);
     fprintf(1, 'Now reading %s\n', fullFileName);
     imageArray(:,:,k) = imread(fullFileName);
 end

Note how the kth image is stored in the imageArray. You may want to cast the imageArray to the appropriate data type before or after you have copied the images into it. (The appropriate data type being that of the pgm images.)

Related Solutions

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

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.

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.

Best Answer

Related Solutions

MATLAB: Read images from folder

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.

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