[ITK-dev] expectationmaximizationMixtureModelEstimator bug

[Wei Liu]

Dear ITK developers,

I've found that the filter does not work even on the example code [1]. In
this example, there are two Gaussian components defined, but the parameters
of the second component is never updated. The reason is in the
iktExpectationMaximizationMixtureModelEstimator.hxx, the
UpdateComponentParameters function stops early. Here is the code that need
to be changted.

_______________________________
template< typename TSample >
bool
ExpectationMaximizationMixtureModelEstimator< TSample >
::UpdateComponentParameters()
{
  bool           updated = false;
  ComponentType *component;

  for ( size_t componentIndex = 0; componentIndex <
m_ComponentVector.size();
        ++componentIndex )
    {
    component = m_ComponentVector[componentIndex];
    component->Update();
    if ( component->AreParametersModified() )
      {
      // return true;
   updated = true;
      }
    }

  return updated;
}

_____________________________________________

We need to change the variable 'updated' instead of 'return true',
otherwise, the remaining components can not get the parameters updated.
After fixed, the example program works.


[1]
http://www.itk.org/Wiki/ITK/Examples/Statistics/ExpectationMaximizationMixtureModelEstimator_2D
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