Index exceeds the number of array elements (0)

Hi, I have made a script to analyze image data. However, each time I run the script I get the following error message

Index exceeds the number of array elements (0).

Error in NewNormalScript (line 16)
    FinalArray (q) = [aux(1)];

The script that i have made:

clear 
clc 

directory = 'C:\Users\anask\Desktop\New\CameraPhotos\';
b = zeros(3000,291);
FinalArray = zeros(1,291);

files = dir([directory '/*.jpg']);
[~,index] = sortrows({files.date}.'); files = files(index); clear index;
for q = 1:1:291
    A= imread([directory '/' files(q).name]);
    b(:,q) = A(:,2500,1);
    aux = (find(b(:,q) >= 255));
    FinalArray (q) = [aux(1)];
    
    
    clear aux;
    clc
end

I pretty confused with this problem. Can someone tell me what to do please?

Answer 1

[Chunru]

aux = (find(b(:,q) >= 255));    % This could be empty
if ~isempty(aux)
    FinalArray (q) = [aux(1)];
end

[ennes mulla]

% it worked perfectly! Thank you so much!!!