Image Approximation: Signal-to-Noise Ratio

can someone help me with this question please ?

 (SNR) in decibels (dB): -20*log10(|f-fapp|/f)

The norm is the Frobenius norm (l2 norm of the Matrix reshaped as a column vector). Follow the instructions below to complete the compute_snr function.

this is the steps and info that the question shows in my matlab fun :

function snr = compute_snr(I, Id)

      % Input:
      % I: the original image
      % Id: the approximated (noisy) image
      % Output:
      % snr: signal-to-noise ratio

      % Please follow the instructions in the comments to fill in the missing commands.    

      % 1) Compute the noise image (original image minus the approximation)

      % 2) Compute the Frobenius norm of the noise image

      % 3) Compute the Frobenius norm of the original image

      % 4) Compute SNR

end

Answer 1

[Matt J]

You can compute the Frobenius norm using Matlab's norm command

   norm(yourImage,'fro')

The other steps in your question are just simple arithmetic.