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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
% Parametrizador MEL cepstrum | |
% Par�metros: | |
% Nombre del fichero de entrada: n_fichero | |
% Longitud de la ventana: l_v | |
% Desplazamiento: desplaza | |
% N�mero de bandas: n_bandas | |
% Filtrado de preenfasis: preen | |
% Salida gr�fica: dibuja | |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
function [matr_param, n_trozos, matr_dparam, matr_fft, matr_bandas] = ... | |
mel_param(n_fichero, n_bandas, l_v, desplaza, preen, dibuja) | |
[x,fs]=audioread(n_fichero); | |
if (size(x,2) == 2) % estéreo | |
x = x(:, 1); | |
end | |
%descartamos las muestras finales | |
descarta = ceil(l_v/desplaza)-1; | |
n_trozos = floor(length(x)/desplaza) -descarta; %trozos sobre los que evaluar el espectro | |
% funci�n de ventana sobre la que calcular la fft | |
ventana = hamming(l_v); | |
% filtrado de preenfasis | |
if (preen==1) | |
a = 1; | |
cero=0.95; | |
b = [1,-cero]; | |
x_fil = filter(b,a,x); | |
x=x_fil; | |
end | |
Matriz_bandas=[]; | |
Matriz_fft=[]; | |
Matriz_cepstrum=[]; | |
Matriz_dcepstrum=[]; | |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
% C�lculo de las bandas MEL | |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
% Frecuencia m�xima representable | |
fmax=fs/2; | |
% Valor m�ximo en escala mel | |
mmax=1127.01048*(log(1+fmax/700)); | |
% Valores equiespaciados en escala mel | |
f_mels=0:mmax/(n_bandas+1):mmax; | |
% Valores en Hz equivalentes a los mel calculados | |
f_frecs=700*(exp(f_mels/1127.01048)-1); | |
for i=1:n_bandas | |
f_ini(i)=f_frecs(i); | |
f_fin(i)=f_frecs(i+2); | |
end | |
% muestras de inicio y fin | |
m_ini=floor(f_ini*(l_v/2)/fmax)+1; | |
m_fin=floor(f_fin*(l_v/2)/fmax)+1; | |
% filtros en las bandas mel | |
filtro=zeros(l_v,n_bandas); | |
for i=1:n_bandas | |
filtro(m_ini(i):m_fin(i),i)=bartlett(m_fin(i)-m_ini(i)+1); | |
end | |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
%Bucle principal para el c�lculo de los par�metros MEL cepstrum | |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
for i=1:n_trozos | |
trozo=x((i-1)*desplaza+1 : (i-1)*desplaza+l_v); % Corte del trozo | |
trozo_e = trozo.*ventana; % Enventanado | |
TROZO_E = fft(trozo_e); % fft | |
TROZO_E2= (abs(TROZO_E)).^2; % abs()^2 | |
% Rellenamos una matriz con todos los valores | |
Matriz_fft(:,i)=TROZO_E2; | |
% Filtrado con las bandas MEL | |
for j=1:n_bandas | |
banda(j)=sum(filtro(:,j).*TROZO_E2); | |
end | |
Matriz_bandas(:,i)=banda'; % Energ�a en bandas | |
Matriz_cepstrum(:,i)=dct(log(banda))'; % DCT | |
end | |
a=1; | |
b=[2,1,0,-1,-2]; | |
for(i=1:n_bandas) | |
Matriz_dcepstrum(i,:)=filter(b,a,Matriz_cepstrum(i,:)); | |
end | |
matr_param = Matriz_cepstrum'; | |
matr_dparam = Matriz_dcepstrum; | |
matr_fft = Matriz_fft; | |
matr_bandas = Matriz_bandas; | |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
% Representaci�n gr�fica | |
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
if (dibuja==1) | |
figure; | |
plot(filtro); | |
title('Filtros para MEL cepstrum'); | |
xlabel('Muestras'); | |
ylabel('Amplitud'); | |
figure; | |
surf(log(Matriz_bandas)); | |
title('Energía en bandas'); | |
xlabel('Trama'); | |
ylabel('Banda'); | |
zlabel('Amplitud'); | |
figure; | |
plot(Matriz_cepstrum'); | |
title('Parámetros MEL cepstrum'); | |
xlabel('Trama'); | |
ylabel('Valor del Cepstrum'); | |
grid; | |
figure; | |
surf(log(Matriz_fft(1:l_v/2+1,:))); | |
title('Espectrograma'); | |
xlabel('Trama'); | |
ylabel('Banda en frecuencia'); | |
zlabel('Amplitud'); | |
shading interp; | |
figure; | |
plot3(Matriz_cepstrum(1,:), Matriz_cepstrum(2,:),Matriz_cepstrum(3,:), 'marker', '*', 'color', 'r'); | |
title('Parámetros MEL cesptrum de las observaciones'); | |
xlabel('Primer Componente'); | |
ylabel('Segundo Componente'); | |
zlabel('Tercer Componente'); | |
grid; | |
figure; | |
title('Parámetros Delta cepstrum'); | |
plot(Matriz_dcepstrum'); | |
xlabel('Trama'); | |
ylabel('Valor del Delta Cepstrum'); | |
grid; | |
end | |
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