Question

I just want to iterate through an image array one by one but I can’t get it working, I get the errors below. I can show single images via imshow (a), but not iterate through an array.

Error using getImageFromFile (line 12)
Cannot find the specified file: “a”.

Error in imageDisplayParseInputs (line 74)
[common_args.CData,common_args.Map] = …

Error in imshow (line 198)
[common_args,specific_args] = …

Code

% Images
a = 'redsquare.bmp';
b = 'bluesquare.bmp';
c = 'greysquare.bmp';
d = 'yellowsquare.bmp';

% Array to display
t = [a b c d];

% Loop to display    
for n=1:length(t)
 imshow(t(n))
end

Thanks.

Answer 1

You have several bugs in the code as it is.
First, verify that the directory where the images are located is in Matlab’s path , or try adding the full path of the images locations.
I’d recommend to use a cell array to contain all the file names. The way you’ve done it in the question is to concatenate all strings to one long one, that is

t =

redsquare.bmpbluesquare.bmpgreysquare.bmpyellowsquare.bmp

So in the code change t to:

t = {a, b, c, d}; % note the curly brackets

In the loop, you need first to read the image to an array before showing it, therefor add an imread line. After reading the file onto an array (lets called that array im), you can use imshow to plot it. All in all, the code in the loop should be:

for n=1:numel(t)
   im=imread(t{n}); 
   imshow(im);
end

Again, note that I used curly brackets {} for the imread line, that is the way to extract the cell element content.