vectorizing 150 images, reshaping them and concatenating in computer vision

I have 150 images in png format (161x261 pixels), named image001.png to image 150.png .

If I want to convert all these 150 images into data 150 data matrices, reshape them such that each image gives me a 42021x1 matrix and concatenate all 150 matrices into a 42021x150 matrix, is there a code to achieve this loop process? I am not sure how to do this as my knowledge of basic is pretty basic. Thanks.

Answer 1

[Dima Lisin]

You can read an image using the imread function. You can convert an image into a 1D array using the : operator.

% Pre-allocate the giant matrix. Use uint8 to save memory
output = zeros(161*261, 150, 'uint8');

% The main loop

for i = 1:15
    % Read an image
    im = imread(sprintf('image%00d.png', i));

    % Convert to grayscale, assuming the image is RGB
    im = rgb2gray(im);

    % Copy into the giant matrix
    output(i, :) = im(:);
end