diff toolboxes/AudioInpaintingToolbox/Utils/makeClippedSignal.m @ 138:56d719a5fd31 ivand_dev

Audio Inpaintin Toolbox

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolboxes/AudioInpaintingToolbox/Utils/makeClippedSignal.m	Thu Jul 21 14:27:47 2011 +0100
@@ -0,0 +1,110 @@
+function [xClipped, IClipped, xClean, clipSizes] = makeClippedSignal(x,clippingLevel,GR)
+% Normalize and clip a signal.
+%
+% Usage:
+%   [xClipped, IClipped, xClean, clipSizes] = makeClippedSignal(x,clippingLevel,GR)
+%
+% Inputs:
+%   - x: input signal (may be multichannel)
+%   - clippingLevel: clipping level, between 0 and 1
+%   - GR (default: false): flag to generate an optional graphical display
+%
+% Outputs:
+%   - xClipped: clipped signal
+%   - IClipped: boolean vector (same size as xClipped) that indexes clipped
+%   samples
+%   - xClean: clean signal
+%   - clipSizes: size of the clipped segments
+%
+% Note that the input signal is normalized to 0.9999 (-1 is not allowed in
+% wav files) to provide xClipped and xClean.
+%
+% -------------------
+%
+% Audio Inpainting toolbox
+% Date: June 28, 2011
+% By Valentin Emiya, Amir Adler, Maria Jafari
+% This code is distributed under the terms of the GNU Public License version 3 (http://www.gnu.org/licenses/gpl.txt).
+
+if nargin<3 || isempty(GR)
+    GR = false;
+end
+
+%% Normalization
+xMax = 0.9999;
+xClean = x/max(abs(x(:)))*xMax;
+clippingLevel = clippingLevel*xMax;
+
+%% DISABLED - Ramp to produce a clipping level that linearly increases
+if 0
+    xClean = xClean.*(1:length(xClean))'/length(xClean);
+end
+
+%% Clipping (hard threshold)
+xClipped = min(max(xClean,-clippingLevel),clippingLevel);
+IClipped = abs(xClipped)>=clippingLevel; % related indices
+
+%% Size of the clipped segments
+if nargout>3 || GR
+   %     clipSizes = diff(find(diff(~IClipped)));
+   %     clipSizes = clipSizes(2-(IClipped(1)==0):2:end);
+   clipSizes = diff(IClipped);
+   if clipSizes(find(clipSizes,1,'first'))==-1,clipSizes = [1;clipSizes]; end
+   if clipSizes(find(clipSizes,1,'last'))==1,clipSizes = [clipSizes;-1]; end
+   clipSizes = diff(find(clipSizes));
+   clipSizes = clipSizes(1:2:end);
+end
+
+%% Optional graphical display
+if GR
+    
+    % Plot histogram of the sizes of the clipped segments
+    if ~isempty(clipSizes)
+        figure
+        hist(clipSizes,1:max(clipSizes))
+        title('Size of missing segments')
+        xlabel('Size'),ylabel('# of segments')
+    end
+    
+    t = (0:length(xClean)-1); % time scale in samples
+    
+    % Plot original and clipped signals
+    figure
+    plot(t,xClean,'',t,xClipped,'')
+    legend('original','clipped')
+    
+    % Scatter plot between original and clipped signals
+    figure
+    plot(xClean,xClipped,'.')
+    xlabel('Original signal'),ylabel('Clipped signal')
+    
+    % Spectrograms
+    N = 512;
+    w = hann(N);
+    fs = 1;
+    NOverlap = round(.8*N);
+    nfft = 2^nextpow2(N)*2*2;
+    figure
+    subplot(3,3,[1,4])
+    spectrogram(xClean,w,NOverlap,nfft,fs,'yaxis')
+    title('Original')
+    xlim(t([1,end]))
+    cl = get(gca,'clim');
+    set(gca,'clim',cl);
+    subplot(3,3,[1,4]+1)
+    spectrogram(xClipped,w,NOverlap,nfft,fs,'yaxis')
+    title('Clipped')
+    set(gca,'clim',cl);
+    subplot(3,3,[1,4]+2)
+    spectrogram(xClean-xClipped,w,NOverlap,nfft,fs,'yaxis')
+    title('Error (=original-clipped)')
+    set(gca,'clim',cl);
+    subplot(3,3,7)
+    plot(t,xClean,'');xlim(t([1,end]))
+    subplot(3,3,8)
+    plot(t,xClean,'',t,xClipped,'');xlim(t([1,end]))
+    subplot(3,3,9)
+    plot(t,xClean-xClipped,'');xlim(t([1,end]))
+end
+
+return