How do I make a loop for multiple identical actions?

I need to read some images in matlab like:

>> A1=dicomread('IM-0001.dcm');

>> A2=dicomread('IM-0002.dcm');

>> A3=dicomread('IM-0003.dcm');

>> A4=dicomread('IM-0004.dcm');

>> A5=dicomread('IM-0005.dcm');

I have 180 of those images. Is there a way to do it automatically so the first image is stored as A1 and the last as A180?

Cheers.

Answer 1

[Sean de Wolski]

You don't need the cell at all then! So here are both ways:

1) Rather than preallocating img as a cell, preallocate it as a three d array:

img = zeros(128,128,170,'uint8');
for ii = 1:170
  img(:,:,ii) = dicomread(etc)
end

2) Or you could take the cell and concatenate the elements along the third dimension using the comma-separated list expansion:

img = cat(3,img{:});

Welcome to MATLAB Answers!

[Tomislav]

Great answer.

In addition: just remember to put ';' after 'end' otherwise matlab will keep showing you numbers of matrix for like 10 minutes :))

[Sean de Wolski]

A mistake we all make very frequently :)

It gets me the worst when I miss the ';' once; it hangs around when I use the up arrow to pull up recent lines to run the same semicolon missing line again...

Answer 2

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_create_variables_A1.2C_A2.2C....2CA10_in_a_loop.3F

[Tomislav]

I couldn't get it to work: I have tried the code:

for i=1:170

    s1=int2str(i);

    s2=strcat(s1,'.jpg');

    img=dicomread('C:\Users\Tomek\Documents\MATLAB\dicoms\IM-0002-0001.dcm');

end

but got only empty tables.

Please more help about this.

Thanks.

[Sean de Wolski]

Preallocate img as a cell array or 3d array (3d array only if all images the same size)

Then:

img = cell(170,1);
for ii = 1:170
  img{ii} = dicomread(['C:\Users\Tomek\Documents\MATLAB\dicoms\IM-0002-' num2str(ii,'%04i') '.dcm'])
end

Now each element of img is the corresponding image:

imshow(img{120})

[Tomislav]

ok, so i have made the 3d array like:

img=zeros(128,128,170); %images are 128x128 pixels

and then the code you provided, and it works.

Now i have a 170x1 cell with all the images inside.

How can I transform this into a 128x128x170 unit8 matrix?

Cheers.