How to create a single .mat file from multiple images?

Hi all,

Assume that I have 5 images as following: 1.bmp, 2.bmp, 3.bmp, 4.bmp, 5.bmp. I want to combine those 5 images into a single .mat file. Anyone knows how to solve this issue, please help me!!

Thanks in advance!!

[naila]

Hi I have the same problem with images: 01.dcm, 02.dcm, 03.dcm ... 22.dcm;

%d isn't working for 01.dcm. what should I do Please

[Azzi Abdelmalek]

What is the error message?

Answer 1

[Azzi Abdelmalek]

for k=1:5
h{k}=imread(sprintf('%d.bmp',k));
end
save file h

[Le Nguyen]

Thanks Azzi!! your solution found me well!!

However, how to modify your solution in order to achieve a 3d .mat file where the 3rd dimension is the frame sequence and the first two dimensions are of the size of the LR image!!

Thanks in advance!!

[Matt Kindig]

a = imread('1.bmp');   %read in first image to get size
[r,c]= size(a);
h = NaN(r,c,5);  %pre-allocate memory
h(:,:,1) = a;
for k=2:5,
   h(:,:,k) = imread(sprintf('%d.bmp',k))
end
save file h

[Le Nguyen]

Hi Matt,

Your solution didnt work at all!! At the line 4, there was an error as following: "Subscripted assignment dimension mismatch."

Please double check it!!

[Matt J]

Le Nguyen, you double check it. You're supposed to be studying the code people suggest to you and understanding why they work or don't work.

In this case, I suspect that your bitmap files are not 2D, but rather have color channels. Thus they cannot be treated as the slices of a 3D array, as Matt Kindig's code attempts to do.

[Image Analyst]

Matt J is probably right. Here are some code snippets that may help you:

% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);

Alternatively,

% Get a weighted sum of the Red, Green, and Blue channels.
grayImage = rgb2gray(rgbImage);

[Le Nguyen]

Hi all,

After taking a look around Matlab for a while, I seem to know how to solve this issue!! You are right, Matt J!! My bitmap files are all 3D as well as colourful!! That's why Matt Kindig's solution didnt work at all!! Here is my modification and it really works well!!

img = rgb2gray(imread('1.bmp'));

[r,c]= size(img);

h = NaN(r,c,5); %pre-allocate memory

h(:,:,1) = img;

for k=2:5

   h(:,:,k) = rgb2gray(imread(sprintf('%d.bmp',k)));

end

save filename h

I am totally a newbie to Matlab, thus, all of your suggestions are always helpful to me and I am really in debt of it!!

Again, thanks a lot!! :)

PS: if there are any modifications for better performance as well as optimization, please let me know!!

[Jan]

@Le: Please be careful with the exclamation marks. The have a lot of power in English, e.g. much more than in German.

Your solution looks fine and efficient. Disk access like imread has the benefit, that it is such slow, that improvements in other parts of the code are usually not significant.

Answer 2

[mona]

how to deal with images in a single .mat file?

[Shourya]

Hi,

Have you figured out how to display multiple images stored in a single .mat file? Please help.