Read several images to work with

I am trying to read several images (tomographic - grayscale) of an entire volume so I can make some quantifications.

The name of the data changes according to the number of files, e.g.,

image0001 - image0009

image0010 - image0099

image0100 - image0999

and so on...

I have written this code until now (my N is not bigger than 10000):

if N<10

     for d = 1:N

       s = ['al000' int2str(d) '.bmp'];

     end

elseif N>10 && N<100

     for d = 1:9

       s(d) = ['al000' int2str(d) '.bmp'];

     end 

     for d = 10:N

       s(d) = ['al00' int2str(d) '.bmp'];

     end

elseif N>100 && N<1000

      for d = 1:9

        s(d) = ['al000' int2str(d) '.bmp'];

      end

      for d = 10:99

        s(d) = ['al00' int2str(d) '.bmp'];

      end

      for d = 100:N

        s(d) = ['al0' int2str(d) '.bmp'];

      end

elseif N>1000 && N<10000

      for d = 1:9

        s(d) = ['al000' int2str(d) '.bmp'];

      end

      for d = 10:99

        s(d) = ['al00' int2str(d) '.bmp'];

      end

      for d = 100:999

        s(d) = ['al0' int2str(d) '.bmp'];

      end  

      for d = 1000:N

        s(d) = ['al' int2str(d) '.bmp'];

      end

end

I need to use those names, but there is an error message when I try to use s(d) instead of only s - so I could save all the names I need:

Subscripted assignment dimension mismatch.

Error in teste (line 7) s(d) = ['al000' int2str(d) '.bmp'];

My questions:

1 - How can I save all those names of the images into another variable, which I will need to access all images later?

2 - Is there a easier, faster or, maybe, smarter way to do this if, elseif and for lines? If I had a N even bigger, would I have to write it down for each interval? Or is there a code which would do the same thing I am doing just knowing my N?

Answer 1

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F

for K = 1 : N
  s{d} = sprintf('image%04d.bmp',K);
end

Answer 2

[David Sanchez]

base_name = 'a0000.bmp';
s = cell(999,1); % initialize cell to hold names
for k=1:999
    tmp_str = num2str(k);
    L = length(tmp_str);
    base_name(6-L:5) = tmp_str;
    s{k} = base_name;
end

[Haimon]

This one is a very good solution for what I want but a problem came up.

The base name is usually something like "al0000.bmp" There is around 2000~3000 images.

The thing is, the resulting s starts with 'al0010.bmp' instead of 'al0001.bmp'.

Do you know why?

[Haimon]

I just found out "7-L:6".

Thank you anyway

[Walter Roberson]

The form I used would not have those problems. Just substitute "al" for "image"

[Haimon]

I had the problem that my images not always start from 0.

They could start from, e.g., 1689.