1 files changed, 49 insertions, 0 deletions

diff --git a/SD-VBS/common/toolbox/MultiNcut/discretisation.m b/SD-VBS/common/toolbox/MultiNcut/discretisation.m
new file mode 100755
index 0000000..70b5650
--- /dev/null
+++ b/SD-VBS/common/toolbox/MultiNcut/discretisation.m
@@ -0,0 +1,49 @@
+function [SegLabel,EigenVectors]=discretisation(EigenVectors,nr,nc)

+% 

+% EigenvectorsDiscrete=discretisation(EigenVectors)

+% 

+% Input: EigenVectors = continuous Ncut vector, size = ndata x nbEigenvectors 

+% Output EigenvectorsDiscrete = discrete Ncut vector, size = ndata x nbEigenvectors

+%

+% Timothee Cour, Stella Yu, Jianbo Shi, 2004

+

+[n,k]=size(EigenVectors);

+

+vm = sqrt(sum(EigenVectors.*EigenVectors,2));

+EigenVectors = EigenVectors./repmat(vm,1,k);

+

+R=zeros(k);

+R(:,1)=EigenVectors(1+round(rand(1)*(n-1)),:)';

+c=zeros(n,1);

+for j=2:k

+    c=c+abs(EigenVectors*R(:,j-1));

+    [minimum,i]=min(c);

+    R(:,j)=EigenVectors(i,:)';

+end

+

+lastObjectiveValue=0;

+exitLoop=0;

+nbIterationsDiscretisation = 0;

+nbIterationsDiscretisationMax = 20;%voir

+while exitLoop== 0 

+    nbIterationsDiscretisation = nbIterationsDiscretisation + 1 ;   

+    EigenvectorsDiscrete = discretisationEigenVectorData(EigenVectors*R);

+    [U,S,V] = svd(EigenvectorsDiscrete'*EigenVectors,0);    

+    NcutValue=2*(n-trace(S));

+    

+    if abs(NcutValue-lastObjectiveValue) < eps | nbIterationsDiscretisation > nbIterationsDiscretisationMax

+        exitLoop=1;

+    else

+        lastObjectiveValue = NcutValue;

+        R=V*U';

+    end

+end

+

+%%%%

+

+SegLabel = zeros(nr,nc);

+for j=1:size(EigenvectorsDiscrete,2),

+        SegLabel = SegLabel + j*reshape(EigenvectorsDiscrete(:,j),nr,nc);

+end

+EigenVectors = reshape(EigenVectors,nr,nc,size(EigenVectors,2));

+