diff mirex2012-matlab/genCQTkernel.m @ 2:8017dd4a650d

Add MIREX 2012 code

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mirex2012-matlab/genCQTkernel.m	Wed Mar 19 09:09:23 2014 +0000
@@ -0,0 +1,135 @@
+function cqtKernel = genCQTkernel(fmax, bins, fs, varargin)
+%Calculating the CQT Kernel for one octave. All atoms are center-stacked.
+%Atoms are placed so that the stacks of lower octaves are centered at the
+%same positions in time, however, their amount is reduced by factor two for
+%each octave down.
+%
+%INPUT:
+%   fmax          ... highest frequency of interest
+%   bins          ... number of bins per octave
+%   fs            ... sampling frequency
+%
+%optional input parameters (parameter name/value pairs):
+%
+%   'q'             ... Q scaling factor. Default: 1.
+%   'atomHopFactor' ... relative hop size corresponding to the shortest
+%                       temporal atom. Default: 0.25.
+%   'thresh'        ... values smaller than 'tresh' in the spectral kernel are rounded to
+%                       zero. Default: 0.0005.
+%   'win'           ... defines which window will be used for the CQT. Valid
+%                       values are: 'blackman','hann' and 'blackmanharris'. To
+%                       use the square root of each window use the prefix 'sqrt_'
+%                      (i.e. 'sqrt_blackman'). Default: 'sqrt_blackmanharris'
+%   'perfRast'      ... if set to 1 the kernel is designed in order to
+%                       enable perfect rasterization using the function
+%                       cqtPerfectRast() (Default: perRast=0). See documentation of
+%                       'cqtPerfectRast' for further information.
+%
+%OUTPUT:
+%   cqtKernel   ... Structure that contains the spectral kernel 'fKernel'
+%                   additional design parameters used in cqt(), cqtPerfectRast() and icqt().
+%
+%Christian Schörkhuber, Anssi Klapuri 2010-06
+
+%% input parameters
+q = 1; %default value
+atomHopFactor = 0.25; %default value
+thresh = 0.0005; %default value
+winFlag = 'sqrt_blackmanharris'; %default value
+perfRast = 0; %default value
+
+for ain = 1:length(varargin)
+    if strcmp(varargin{ain},'q'), q = varargin{ain+1}; end;
+    if strcmp(varargin{ain},'atomHopFactor'), atomHopFactor = varargin{ain+1}; end;
+    if strcmp(varargin{ain},'thresh'), thresh = varargin{ain+1}; end;
+    if strcmp(varargin{ain},'win'), winFlag = varargin{ain+1}; end;
+    if strcmp(varargin{ain},'perfRast'), perfRast = varargin{ain+1}; end;
+end
+
+%% define
+fmin = (fmax/2)*2^(1/bins);
+Q = 1/(2^(1/bins)-1);
+Q = Q*q;
+Nk_max = Q * fs / fmin; 
+Nk_max = round(Nk_max); %length of the largest atom [samples]
+
+
+%% Compute FFT size, FFT hop, atom hop, ...
+Nk_min = round( Q * fs / (fmin*2^((bins-1)/bins)) ); %length of the shortest atom [samples]
+atomHOP = round(Nk_min*atomHopFactor); %atom hop size
+first_center = ceil(Nk_max/2); %first possible center position within the frame
+first_center = atomHOP * ceil(first_center/atomHOP); %lock the first center to an integer multiple of the atom hop size
+FFTLen = 2^nextpow2(first_center+ceil(Nk_max/2)); %use smallest possible FFT size (increase sparsity)
+
+if perfRast
+    winNr = floor((FFTLen-ceil(Nk_max/2)-first_center)/atomHOP); %number of temporal atoms per FFT Frame
+    if winNr == 0
+        FFTLen = FFTLen * 2;
+        winNr = floor((FFTLen-ceil(Nk_max/2)-first_center)/atomHOP);
+    end
+else
+    winNr = floor((FFTLen-ceil(Nk_max/2)-first_center)/atomHOP)+1; %number of temporal atoms per FFT Frame
+end
+
+last_center = first_center + (winNr-1)*atomHOP;
+fftHOP = (last_center + atomHOP) - first_center; % hop size of FFT frames
+fftOLP = (FFTLen-fftHOP/FFTLen)*100; %overlap of FFT frames in percent ***AK:needed?
+
+%% init variables
+tempKernel= zeros(1,FFTLen); 
+sparKernel= []; 
+
+%% Compute kernel
+atomInd = 0;
+for k = 1:bins
+    
+   Nk = round( Q * fs / (fmin*2^((k-1)/bins)) ); %N[k] = (fs/fk)*Q. Rounding will be omitted in future versions
+   
+   switch winFlag
+       case 'sqrt_blackmanharris'
+            winFct = sqrt(blackmanharris(Nk));
+       case 'blackmanharris'
+            winFct = blackmanharris(Nk);
+       case 'sqrt_hann'
+            winFct = sqrt(hann(Nk,'periodic'));
+       case 'hann'
+            winFct = hann(Nk,'periodic');
+       case 'sqrt_blackman'
+            winFct = sqrt(hann(blackman,'periodic'));
+       case 'blackman'
+            winFct = blackman(Nk,'periodic');
+       otherwise
+            winFct = sqrt(blackmanharris(Nk));
+            if k==1, warning('CQT:INPUT','Non-existing window function. Default window is used!'); end;
+   end
+   
+   fk = fmin*2^((k-1)/bins);
+   tempKernelBin = (winFct/Nk) .* exp(2*pi*1i*fk*(0:Nk-1)'/fs);
+   atomOffset = first_center - ceil(Nk/2);
+
+   for i = 1:winNr 
+       shift = atomOffset + ((i-1) * atomHOP);
+       tempKernel(1+shift:Nk+shift) = tempKernelBin; 
+       atomInd = atomInd+1;
+       specKernel= fft(tempKernel);
+       specKernel(abs(specKernel)<=thresh)= 0;   
+       sparKernel= sparse([sparKernel; specKernel]);
+       tempKernel = zeros(1,FFTLen); %reset window     
+   end
+end
+sparKernel = (sparKernel.')/FFTLen;
+
+%% Normalize the magnitudes of the atoms
+[ignore,wx1]=max(sparKernel(:,1));
+[ignore,wx2]=max(sparKernel(:,end));
+wK=sparKernel(wx1:wx2,:);
+wK = diag(wK * wK');
+wK = wK(round(1/q)+1:(end-round(1/q)-2));
+weight = 1./mean(abs(wK));
+weight = weight.*(fftHOP/FFTLen); 
+weight = sqrt(weight); %sqrt because the same weight is applied in icqt again
+sparKernel = weight.*sparKernel;
+
+%% return
+cqtKernel = struct('fKernel',sparKernel,'fftLEN',FFTLen,'fftHOP',fftHOP,'fftOverlap',fftOLP,'perfRast',perfRast,...
+    'bins',bins,'firstcenter',first_center,'atomHOP',atomHOP,'atomNr',winNr,'Nk_max',Nk_max,'Q',Q,'fmin',fmin);