comparison mirex2012-matlab/cell2sparse.m @ 2:8017dd4a650d

Add MIREX 2012 code

+function spCQT = cell2sparse(Xcq,octaves,bins,firstcenter,atomHOP,atomNr)
+%Generates a sparse matrix containing the CQT coefficients (rasterized).
+%
+%The sparse matrix representation of the CQT coefficients contains all
+%computed coefficients at the corresponding time-frequency location
+%(similar to a spectrogram). For lower frequencies this means, that
+%each coefficient is followed by zeros stemming from the fact, that the time
+%resolution for lower frequencies decreases as the frequency resolution
+%increases. Due to the design of the CQT kernel, however, the coefficients
+%of different octaves are synchronised, meaning that for the second highest
+%octave each coefficient is followed by one zero, for the next octave down
+%two zeros are inserted, for the next octave four zeros are inserted and so
+%on.
+%
+%INPUT:
+%   Xcq         ... Cell array consisting of all coefficients for all octaves
+%   octaves     ... Number of octaves processed
+%   bins        ... Number of bins per octave
+%   firstcenter ... Location of the leftmost atom-stack in the temporal
+%                   kernel
+%   atomHOP     ... Spacing of two consecutive atom stacks
+%   atomNr      ... Number of atoms per bin within the kernel
+%
+%Christian Schörkhuber, Anssi Klapuri 2010-06
+
+if 0
+%% this version has big memory consumption but is very fast
+    emptyHops = firstcenter/atomHOP;
+    drop = emptyHops*2^(octaves-1)-emptyHops; %distance between first value in highest octave and first value in lowest octave
+    spCQT = zeros(bins*octaves,size(Xcq{1},2)*atomNr-drop);
+
+    for i=1:octaves
+        drop = emptyHops*2^(octaves-i)-emptyHops; %first coefficients of all octaves have to be in synchrony
+        X = Xcq{i}; 
+        if  atomNr > 1 %more than one atom per bin --> reshape
+            Xoct = zeros(bins,atomNr*size(X,2)-drop);
+            for u=1:bins %reshape to continous windows for each bin (for the case of several wins per frame)
+               octX_bin = X((u-1)*atomNr+1:u*atomNr,:);
+               Xcont = reshape(octX_bin,1,size(octX_bin,1)*size(octX_bin,2));
+               Xoct(u,:) = Xcont(1+drop:end);
+            end
+            X = Xoct;
+        else
+            X = X(:,1+drop:end);
+        end
+        binVec = bins*octaves-bins*i+1:bins*octaves-bins*(i-1);
+        spCQT(binVec,1:2^(i-1):size(X,2)*2^(i-1)) = X;
+
+    end
+    spCQT = sparse(spCQT); %storing as sparse matrix at the end is the fastest way. Big memory consumption though!
+
+else
+%% this version uses less memory but is noticable slower
+    emptyHops = firstcenter/atomHOP;
+    drops = emptyHops*2.^(octaves-(1:octaves))-emptyHops;
+    len = max(((atomNr*cellfun('size',Xcq,2)-drops).*2.^(0:octaves-1))); %number of columns of output matrix
+    spCQT = [];
+
+    for i=octaves:-1:1
+        drop = emptyHops*2^(octaves-i)-emptyHops; %first coefficients of all octaves have to be in synchrony
+        X = Xcq{i}; 
+        if  atomNr > 1 %more than one atom per bin --> reshape
+            Xoct = zeros(bins,atomNr*size(X,2)-drop);
+            for u=1:bins %reshape to continous windows for each bin (for the case of several wins per frame)
+               octX_bin = X((u-1)*atomNr+1:u*atomNr,:);
+               Xcont = reshape(octX_bin,1,size(octX_bin,1)*size(octX_bin,2));
+               Xoct(u,:) = Xcont(1+drop:end);
+            end
+            X = Xoct;
+        else
+            X = X(:,1+drop:end);
+        end
+        X = upsample(X.',2^(i-1)).';
+        X = [X zeros(bins,len-size(X,2))];
+        spCQT = sparse([spCQT; X]);  
+    end
+
+end