get error while creating nl filter

I'm trying to create an nl filter with for loops. The coefficient values and dimension ​​of the filter must be entered by the user. I can understand the part up to here. But I get an error when applying the filter to the image, with the dimension data I get from the user. The code I wrote for the filter and the error image are attached. I would be very happy if you help.

Answer 1

[prabhat kumar sharma]

Hi Enes,

I understand that you are facing some error in line 44:

fun2 = im(i:i+1,j:j+1).*filtre;

I understand that here you're extracting a sub-matrix of size 2x2 from im because i:i+1 and j:j+1 define a range that selects a 2x2 area.

However, filtre is created based on user input for its dimensions, which means its size can vary and does not necessarily match the 2x2 size of the sub-matrix from im.

To resolve this issue, you need to ensure that the size of the sub-matrix of im matches the size of filtre. This can be done by adjusting the range of indices used to extract the sub-matrix from im so that it matches the dimensions of filtre. Assuming filtre has dimensions r x c (which you've initially set to 11 x 11 but then later allow the user to define), you should modify the line as follows:

1. Ensure filtre has the dimensions as intended by the user input or your initial setup.
2. Adjust the sub-matrix extraction from im to match the dimensions of filtre.

Here's how you can adjust the problematic line,

% Correctly extracting a sub-matrix of im that matches the size of filtre
for i=1:size(im,1)-size(filtre,1)+1
    for j=1:size(im,2)-size(filtre,2)+1
        subMatrix = im(i:i+size(filtre,1)-1, j:j+size(filtre,2)-1);
        fun2 = subMatrix .* filtre;
        yi(i,j) = sum(fun2(:));
    end
end

I hope it helps!