NoveltyFlux

computes the novelty measure per Spectral Flux
> called by ::ComputeNoveltyFunction
>
> @param X: spectrogram (dimension FFTLength X Observations)
> @param f_s: sample rate of audio data (unused)
>
> @retval d_flux novelty measure
 ======================================================================

0001 %computes the novelty measure per Spectral Flux
0002 %> called by ::ComputeNoveltyFunction
0003 %>
0004 %> @param X: spectrogram (dimension FFTLength X Observations)
0005 %> @param f_s: sample rate of audio data (unused)
0006 %>
0007 %> @retval d_flux novelty measure
0008 % ======================================================================
0009 function [d_flux] = NoveltyFlux(X, f_s)
0010 
0011     % difference spectrum (set first diff to zero)
0012     afDeltaX = diff([X(:, 1), X], 1, 2);
0013     
0014     % half-wave rectification
0015     afDeltaX(afDeltaX<0) = 0;
0016     
0017     % flux
0018     d_flux = sqrt(sum(afDeltaX.^2)) / size(X, 1);
0019 end