COLOR IMAGE ERROR IN SPECAL NOISE REDUCTION

I am trying to run the specal noise reduction code. It is working completely fine with the balck and white specal noise image but when I run the code with a color specal noise image it is showing the following error. I feel it is due to the matrix dimension mismatch while calculating the y. Reason may be balck white image of a*a dimension but where as color image is of a*a*b dimension. Kindly share your suggestion to resolve this, It would be really a great help. I am attaching the reference image below.

Answer 1

[Riya]

Hi Nethala,

I understand that you are encountering an error while processing a color image in your speckle noise reduction code. The main reason for this error is a dimension mismatch, as the code is designed for grayscale images (2D matrices), while a color image is a 3D matrix (height × width × channels).

The “.*” operation requires matching dimensions, so using a color image directly leads to an error. To solve this issue, you can either convert the image to grayscale or process each color channel separately before applying the filtering and Poisson noise.

Solution 1: Convert to Grayscale (if color is not required):

You can modify this part of your code as follows:

% Convert to grayscale if the image has multiple channels 
if size(xy, 3) == 3 
    xy = rgb2gray(xy);   
end 

Solution 2: Process Each Color Channel Separately:

If you want to preserve the color information, process each channel independently. Replace the single-channel processing with:

[yN, xN, numChannels] = size(xy);  
y_blur = zeros(yN, xN, numChannels);   
for c = 1:numChannels   
    y_channel = xy(:, :, c);   
    y_blur(:, :, c) = real(ifft2(V .* fft2(y_channel)));   
end 

This will ensure that the operation works without dimension mismatch errors.

For more details on MATLAB matrix operations, please refer to the official documentation:

https://www.mathworks.com/help/matlab/learn_matlab/matrices-and-arrays.html

Thanks!