wrote brief, added cepstrum, added formant freqs
This commit is contained in:
aj
parent
5eb36e7af8
commit
438f25c7ca
22
func/autocorr.m
Normal file
22
func/autocorr.m
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@ -0,0 +1,22 @@
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function [cep_autocorr, cep_lags] = autocorr(signal, max_lags, time, Fs)
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[cep_autocorr, cep_lags] = xcorr(signal, max_lags, 'coeff');
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% [cep_autocorr, cep_lags] = xcorr(signal, 'coeff');
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if time
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cep_lags = 1000*cep_lags/Fs; % turn samples into ms
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end
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plot(cep_lags, cep_autocorr)
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grid
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if time
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xlabel('Delay (ms)')
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else
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xlabel('Delay (samples)')
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end
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ylabel('Normalized Autocorrelation')
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title('Autocorrelation')
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xlim([min(cep_lags) max(cep_lags)]);
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end
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16
func/clip_segment.m
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16
func/clip_segment.m
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@ -0,0 +1,16 @@
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function output = clip_segment(signal, Fs, seg_length, offset)
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signal_length_samples = length(signal);
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seg_length_samples = min(ms_to_samples(seg_length, Fs), signal_length_samples);
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offset_samples = max(ms_to_samples(offset, Fs), 1);
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seg_length_samples = min(seg_length_samples, signal_length_samples - 1);
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if signal_length_samples < seg_length_samples + offset_samples
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offset_samples = signal_length_samples - seg_length_samples;
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end
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output = signal(offset_samples:offset_samples + seg_length_samples);
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end
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@ -5,7 +5,7 @@ L=length(signal);
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Y = fft(signal);
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P2 = abs(Y); % two-sided spectrum
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% P2 = abs(Y/L); % two-sided spectrum
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P1 = P2(1:L/2+1); % single-sided spectrum
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P1 = P2(1:floor(L/2+1)); % single-sided spectrum
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P1(2:end-1) = 2*P1(2:end-1);
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frequencies = sample_frequency*(0:(L/2))/L;
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values = P1;
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3
func/ms_to_samples.m
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3
func/ms_to_samples.m
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@ -0,0 +1,3 @@
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function samples = ms_to_samples(time_in, sample_freq)
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samples = (time_in / 1000) * sample_freq;
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end
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@ -1,6 +1,6 @@
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function spectro(signal, sample_frequency, windows, overlap_interval)
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sample_overlap = (overlap_interval / 1000) * sample_frequency;
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sample_overlap = ms_to_samples(overlap_interval, sample_frequency);
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sample_size = size(signal);
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%window_size = round(sample_size(1) / ((windows + 1)/2))
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167
lpss.m
167
lpss.m
@ -4,80 +4,159 @@
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close all;clear all;clc;
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LPC_ORDER = 8;
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DISPLAY_SAMPLES = 1000;
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SEGMENT_LENGTH = 100; % ms
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SEGMENT_OFFSET = 0; % ms from start
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LPC_ORDER = 20;
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AC_DISP_SAMPLES = 1000; % autocorrelation display samples
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WINDOW_NUMBER = 10;
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WINDOW_OVERLAP = 5; % ms
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% READ SIGNAL
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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[y, Fs] = audioread('samples/hood_m.wav');
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L = length(y) % number of samples
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DISPLAY_SAMPLES = min([DISPLAY_SAMPLES L]);
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F0 = 60; % low-pitched male speech
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% F0 = 600; % children
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% flags for selective running
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FREQ_RESPONSE = ~false;
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AUTOCORRELATION = false;
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CEPSTRUM_PLOT = false;
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CEPSTRUM_ONE_SIDED = true;
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ORIG_LPC_T_COMPARE = false;
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ORIG_SPECTROGRAM = false;
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PLAY = false;
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% LPC
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%% READ SIGNAL
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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a = aryule(y, LPC_ORDER) % signal, filter order
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[y, Fs] = audioread('samples/hood_m.wav');
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y = clip_segment(y, Fs, SEGMENT_LENGTH, SEGMENT_OFFSET);
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L = length(y) % number of samples
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max_lag = Fs/ F0;
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%% LPC
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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a = lpc(y, LPC_ORDER) % signal, filter order
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est_y = filter(0.02, a, y);
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% PREDICTION ERROR
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%% COMPARE ORIGINAL SIGNAL WITH LPC (T DOMAIN)
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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e = y - est_y;
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[acs, lags] = xcorr(e,'coeff');
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if ORIG_LPC_T_COMPARE
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x = 1:AC_DISP_SAMPLES;
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AC_DISP_SAMPLES = min([AC_DISP_SAMPLES L]);
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% COMPARE TWO SIGNALS
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% x = 1:DISPLAY_SAMPLES;
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% figure(1)
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% plot(x, y(end-DISPLAY_SAMPLES+1:end), x, est_y(end-DISPLAY_SAMPLES+1:end), '--')
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figure(1)
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plot(x, y(end-AC_DISP_SAMPLES+1:end), x, est_y(end-AC_DISP_SAMPLES+1:end), '--')
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% plot(x, y(end-DISPLAY_SAMPLES+1:end))
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% plot(x, est_y(end-DISPLAY_SAMPLES+1:end))
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% grid
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% xlabel('Sample Number')
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% ylabel('Amplitude')
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% legend('Original signal','LPC estimate')
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grid
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xlabel('Sample Number')
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ylabel('Amplitude')
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legend('Original signal','LPC estimate')
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end
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% PLOT AUTOCORRELATION
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%% T DOMAIN PREDICTION ERROR
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% figure(2)
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% plot(lags, acs)
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% grid
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% xlabel('Lags')
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% ylabel('Normalized Autocorrelation')
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%ylim([-0.1 1.1])
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t_domain_err = y - est_y;
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if AUTOCORRELATION
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figure(2)
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[acs, lags] = autocorr(t_domain_err, max_lag, true, Fs);
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title('Autocorrelation for error in Time domain')
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end
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% PLOT FREQUENCY RESPONSE
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%% FREQUENCY RESPONSE
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% CALCULATE FFT
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if FREQ_RESPONSE
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figure(3)
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%% ORIGINAL FFT
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[freq_dom_freqs, freq_dom_vals] = fft_(y, Fs);
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% GET FILTER RESPONSE
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[h, filter_freqs] = freqz(1, a, length(freq_dom_freqs), Fs);
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orig_freq_plot = plot(freq_dom_freqs, 20*log10(abs(freq_dom_vals)), 'black');
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orig_freq_plot.Color(4) = 0.25;
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orig_freq_plot.LineWidth = 1;
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hold on
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figure(3)
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plot(freq_dom_freqs, 20*log10(freq_dom_vals), 'r', filter_freqs, 20*log10(abs(h)), 'b')
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% plot(w/pi, 20*log10(abs(h)))
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%% LPC FILTER RESPONSE
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[filter_vals, filter_freqs] = freqz(1, a, length(freq_dom_freqs), Fs);
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filter_vals_db = 20*log10(abs(filter_vals));
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lpc_freq_plot = plot(filter_freqs, filter_vals_db, 'b');
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lpc_freq_plot.LineWidth = 2;
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% MAXIMA
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maxima = islocalmax(filter_vals_db);
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maxima_freqs = filter_freqs(maxima)
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maxima_db = filter_vals_db(maxima)
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maxima_plot = plot(maxima_freqs, maxima_db, 'rx');
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maxima_plot.MarkerSize = 12;
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maxima_plot.LineWidth = 2;
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%% PLOT
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hold off
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grid
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xlabel('Frequency (Hz)')
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ylabel('Magnitude (dB)')
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legend('Original Signal', 'LPC Filter')
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legend('Original Signal', 'LPC Filter', 'LPC Maxima')
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title('Frequency Response For Speech Signal and LPC Filter')
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end
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% PLOT ORIGINAL SPECTROGRAM
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%% CEPSTRUM
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% figure(4)
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% spectro(y, Fs, WINDOW_NUMBER, WINDOW_OVERLAP);
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% colormap bone
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cep = rceps(y);
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% cep = cceps(y);
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if CEPSTRUM_PLOT
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ceps_t = (0:L - 1);
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figure(4)
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if CEPSTRUM_ONE_SIDED
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plot(ceps_t(1:L / 2), cep(1:L / 2))
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else
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plot(ceps_t(1:L), cep(1:L))
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end
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grid
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xlabel('Quefrency')
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ylabel('ceps(x[n])')
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if CEPSTRUM_ONE_SIDED
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xlim([0 L / 2])
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title('One-sided Speech Signal Cepstrum')
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else
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xlim([0 L])
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title('Speech Signal Cepstrum')
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end
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end
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%% AUTOCORRELATION
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if AUTOCORRELATION
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figure(5)
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[cep_autocorr, cep_lags] = autocorr(cep(1:L/2), max_lag, true, Fs);
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title('One-sided Cepstrum Autocorrelation')
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end
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% PLAY
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%% PLOT ORIGINAL SPECTROGRAM
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%sound(y, Fs);
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if ORIG_SPECTROGRAM
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figure(6)
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spectro(y, Fs, WINDOW_NUMBER, WINDOW_OVERLAP);
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colormap bone
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title('Speech Signal Spectrogram')
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end
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%% PLAY
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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if PLAY
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sound(y, Fs);
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end
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@ -4,11 +4,34 @@
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close all;clear all;clc;
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CEPSTRUM_COEFFS = 100;
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% READ SIGNAL
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[y, Fs] = audioread('samples/hood_m.wav');
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sample_length = length(y);
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half = sample_length / 2;
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t = (0:length(y) - 1);
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t = (0:sample_length - 1);
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c = rceps(y);
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% c = cceps(y);
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plot(t, c)
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% plot(t(1:sample_length), c(1:sample_length))
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plot(t(1:half), c(1:half))
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xlabel('Quefrency')
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ylabel('ceps(x[n])')
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% xlim([0 sample_length])
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xlim([0 half])
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%% PLOT FFT
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c = cceps(y);
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c(CEPSTRUM_COEFFS:end) = 0;
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% [cep_freqs, cep_vals] = fft_(c, Fs);
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cep_vals = fft(c);
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cep_vals = cep_vals(1:floor(sample_length/2+1));
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cep_freqs = Fs*(0:(sample_length/2))/sample_length;
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figure(2)
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cep_plot = plot(cep_freqs, 20*log10(abs(cep_vals)), 'g');
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cep_plot.LineWidth = 2;
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hold off
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@ -9,6 +9,10 @@
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\def\changemargin#1#2{\list{}{\rightmargin#2\leftmargin#1}\item[]}
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\let\endchangemargin=\endlist
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\pagenumbering{roman}
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\usepackage{color}
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\definecolor{commentgreen}{RGB}{0,94,11}
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\end_preamble
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\use_default_options true
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\begin_modules
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@ -257,6 +261,53 @@ setcounter{page}{1}
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Introduction
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\end_layout
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\begin_layout Section
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Brief
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\end_layout
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\begin_layout Standard
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The aim of this report is to demonstrate how digital signal processing technique
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s can be used to analyse, model and synthesise speech.
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The task will take will be considered as two areas of concern, that of
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modelling and synthesis.
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\end_layout
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\begin_layout Standard
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The modelling stage will utilise Linear Predictive Coding and the source-filter
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model of speech to construct a filter that acts similarly to the vocal
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tract's effect on sound produced by the vocal chords.
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Comparisons of the frequency response for both the estimated filter and
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the original sound will be presented, the effect of different filter orders
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will also be demonstrated.
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Relevant parameters of the original vowel speech segment will be presented
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including the fundamental frequency and further formant frequencies.
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\end_layout
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\begin_layout Standard
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The synthesis stage will complete the source-filter model of speech by creating
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a suitable periodic sound source to be modulated by the previous filter.
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With a complete source-filter model, artificial vowel sounds will be synthesise
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d and analysed.
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Subjective assessments will be made as to the differences between the original
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sound and the final product of the model when system parameters are varied.
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\end_layout
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\begin_layout Section
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Implementation
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\end_layout
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\begin_layout Section
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Results
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\end_layout
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\begin_layout Section
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Discussion
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\end_layout
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\begin_layout Section
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Conclusion
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\end_layout
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\begin_layout Standard
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\begin_inset Newpage newpage
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\end_inset
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@ -285,7 +336,7 @@ options "bibtotoc"
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\begin_layout Section
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\start_of_appendix
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Code
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Source Code
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\begin_inset CommandInset label
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LatexCommand label
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name "sec:Code"
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@ -293,6 +344,72 @@ name "sec:Code"
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\end_inset
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\end_layout
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\begin_layout Standard
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\begin_inset CommandInset include
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LatexCommand lstinputlisting
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filename "../lpss.m"
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lstparams "breaklines=true,frame=tb,language=Matlab,basicstyle={\\ttfamily},commentstyle={\\color{commentgreen}\\itshape},keywordstyle={\\color{blue}},emphstyle={\\color{red}},stringstyle={\\color{red}},identifierstyle={\\color{cyan}},morekeywords={audioread, aryule, xcorr, freqz, spectrogram, mfcc, spectro, fft_, autocorr, clip_segment, islocalmax, ms_to_samples},caption={Main script},label={main_script}"
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\end_inset
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\end_layout
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\begin_layout Standard
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\begin_inset CommandInset include
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LatexCommand lstinputlisting
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filename "../func/spectro.m"
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lstparams "breaklines=true,frame=tb,language=Matlab,basicstyle={\\ttfamily},commentstyle={\\color{commentgreen}\\itshape},keywordstyle={\\color{blue}},emphstyle={\\color{red}},stringstyle={\\color{red}},identifierstyle={\\color{cyan}},morekeywords={audioread, aryule, xcorr, freqz, spectrogram, ms_to_samples},caption={Spectrogram plotting wrapper function},label={spectrogram_function}"
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\end_inset
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\end_layout
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\begin_layout Standard
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\begin_inset CommandInset include
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LatexCommand lstinputlisting
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filename "../func/fft_.m"
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lstparams "breaklines=true,frame=tb,language=Matlab,basicstyle={\\ttfamily},commentstyle={\\color{commentgreen}\\itshape},keywordstyle={\\color{blue}},emphstyle={\\color{red}},stringstyle={\\color{red}},identifierstyle={\\color{cyan}},morekeywords={audioread, aryule, xcorr, freqz, spectrogram},caption={Fast Fourier transform wrapper function},label={fft_function}"
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\end_inset
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\end_layout
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\begin_layout Standard
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\begin_inset CommandInset include
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LatexCommand lstinputlisting
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filename "../func/autocorr.m"
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lstparams "breaklines=true,frame=tb,language=Matlab,basicstyle={\\ttfamily},commentstyle={\\color{commentgreen}\\itshape},keywordstyle={\\color{blue}},emphstyle={\\color{red}},stringstyle={\\color{red}},identifierstyle={\\color{cyan}},morekeywords={audioread, aryule, xcorr, freqz, spectrogram},caption={Autocorrelation plotting wrapper function},label={autocorr_function}"
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\end_inset
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\end_layout
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\begin_layout Standard
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\begin_inset CommandInset include
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LatexCommand lstinputlisting
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filename "../func/clip_segment.m"
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lstparams "breaklines=true,frame=tb,language=Matlab,basicstyle={\\ttfamily},commentstyle={\\color{commentgreen}\\itshape},keywordstyle={\\color{blue}},emphstyle={\\color{red}},stringstyle={\\color{red}},identifierstyle={\\color{cyan}},morekeywords={audioread, aryule, xcorr, freqz, spectrogram},caption={Retrieve a segment of the original speech signal},label={clip_segment_function}"
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\end_inset
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\end_layout
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\begin_layout Standard
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\begin_inset CommandInset include
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LatexCommand lstinputlisting
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filename "../func/ms_to_samples.m"
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lstparams "breaklines=true,frame=tb,language=Matlab,basicstyle={\\ttfamily},commentstyle={\\color{commentgreen}\\itshape},keywordstyle={\\color{blue}},emphstyle={\\color{red}},stringstyle={\\color{red}},identifierstyle={\\color{cyan}},morekeywords={audioread, aryule, xcorr, freqz, spectrogram},caption={Transform time in milliseconds into the respective number of samples},label={clip_segment_function-1}"
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\end_inset
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\end_layout
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\end_body
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