ENH: better behaviour with the UseConfidenceMap flag

Modules/Applications/AppClassification/app/otbImageClassifier.cxx

@@ -181,6 +181,7 @@ private:
     // output confidence map
     if (IsParameterEnabled("confmap") && HasValue("confmap"))
       {
+      m_ClassificationFilter->SetUseConfidenceMap(true);
       if (m_Model->HasConfidenceIndex())
         {
         SetParameterOutputImage<ConfidenceImageType>("confmap",m_ClassificationFilter->GetOutputConfidence());

Modules/Learning/Supervised/include/otbImageClassificationFilter.h

@@ -80,6 +80,10 @@ public:
   itkSetMacro(DefaultLabel, LabelType);
   itkGetMacro(DefaultLabel, LabelType);
 
+  /** Set/Get the confidence map flag */
+  itkSetMacro(UseConfidenceMap, bool);
+  itkGetMacro(UseConfidenceMap, bool);
+
   /**
    * If set, only pixels within the mask will be classified.
    * All pixels with a value greater than 0 in the mask, will be classified.
@@ -119,7 +123,7 @@ private:
   ModelPointerType m_Model;
   /** Default label for invalid pixels (when using a mask) */
   LabelType m_DefaultLabel;
-  /** Flag to produce the confidence map */
+  /** Flag to produce the confidence map (if the model supports it) */
   bool m_UseConfidenceMap;
 };
 } // End namespace otb

Modules/Learning/Supervised/include/otbImageClassificationFilter.txx

@@ -84,7 +84,6 @@ ImageClassificationFilter<TInputImage, TOutputImage, TMaskImage>
     {
     itkGenericExceptionMacro(<< "No model for classification");
     }
-  m_UseConfidenceMap = m_Model->HasConfidenceIndex();
 }
 
 template <class TInputImage, class TOutputImage, class TMaskImage>
@@ -119,8 +118,9 @@ ImageClassificationFilter<TInputImage, TOutputImage, TMaskImage>
     }
 
   // setup iterator for confidence map
+  bool computeConfidenceMap(m_UseConfidenceMap && m_Model->HasConfidenceIndex());
   ConfidenceMapIteratorType confidenceIt;
-  if (m_UseConfidenceMap)
+  if (computeConfidenceMap)
     {
     confidenceIt = ConfidenceMapIteratorType(confidencePtr,outputRegionForThread);
     confidenceIt.GoToBegin();
@@ -142,7 +142,7 @@ ImageClassificationFilter<TInputImage, TOutputImage, TMaskImage>
     if (validPoint)
       {
       // Classifify
-      if (m_UseConfidenceMap)
+      if (computeConfidenceMap)
         {
         outIt.Set(m_Model->Predict(inIt.Get(),&confidenceIndex)[0]);
         }
@@ -157,7 +157,7 @@ ImageClassificationFilter<TInputImage, TOutputImage, TMaskImage>
       outIt.Set(m_DefaultLabel);
       confidenceIndex = 0.0;
       }
-    if (m_UseConfidenceMap)
+    if (computeConfidenceMap)
       {
       confidenceIt.Set(confidenceIndex);
       ++confidenceIt;