Signal-to-noise ratio program based on matlab

% Calculate the signal-to-noise ratio function
% I :original signal
% In:noisy signal(ie. original signal + noise signal)
% The definition of signal-to-noise ratio is:
% SNR=signal energy/noise energy=(pure signal)^2/( Noisy signal - pure signal)^2
snr=0;
Ps=sum(sum((I-mean(mean(I))).^2));%signal power
Pn=sum(sum((I-In) .^2)); %noise power

snr=10*log10(Ps/Pn); % where I is the pure signal, In is the noisy signal, and snr is the signal-to-noise ratio