ENH: the norm of the input is now also a parameter of SpectralAngleDetails:ComputeSpectralAngle

Modules/Filtering/ImageManipulation/include/otbBinarySpectralAngleFunctor.h

@@ -30,6 +30,9 @@ namespace otb
 /** \class BinarySpectralAngleFunctor
  *  \brief This functor computes the spectral angle between two pixels.
  *
+ *  If the pixels have different sizes, only the first components of the 
+ *  largest pixel will be considered.
+ *
  *  It can be used as a functor in a BinaryFunctorImageFilter to
  *  compute the pixel-by-pixel spectral angles.
  *
@@ -46,9 +49,18 @@ public:
   virtual ~BinarySpectralAngleFunctor() = default;
 
   // Binary operator
-  inline TOutputValue operator()(const TInput1& a, const TInput2& b) const
+  inline TOutputValue operator()(const TInput1& in1, const TInput2& in2) const
   {
-    return SpectralAngleDetails::ComputeSpectralAngle<TInput1, TInput2, TOutputValue>(a, b, b.GetNorm());
+    // Compute norms.
+    auto in1Norm = 0;
+    auto in2Norm = 0;
+    for (unsigned int i = 0; i < std::min(in1.Size(), in2.Size()); ++i)
+    {
+      in1Norm += in1[i] * in1[i];
+      in2Norm += in2[i] * in2[i];
+    }
+    
+    return SpectralAngleDetails::ComputeSpectralAngle<TInput1, TInput2, TOutputValue>(in1, in1Norm, in2, in2Norm);
   }
 };
 

Modules/Filtering/ImageManipulation/include/otbSpectralAngleFunctor.h

@@ -33,18 +33,16 @@ namespace SpectralAngleDetails
 {
 
 template <class TInput, class TReference, class TOutput>
-TOutput ComputeSpectralAngle(TInput const & input, TReference const & reference, 
-                              typename TReference::ValueType refNorm)
+TOutput ComputeSpectralAngle(TInput const & input, typename TInput ::ValueType const & inputNorm, 
+                              TReference const & reference, typename TReference::ValueType refNorm)
 {
-  // Compute norm and scalar product.
+  // Compute scalar product.
   double scalarProduct   = 0.0;
-  double squaredNormInput  = 0.0;
   for (unsigned int i = 0; i < std::min(input.Size(), reference.Size()); ++i)
   {
     scalarProduct += input[i] * reference[i];
-    squaredNormInput += input[i] * input[i];
   }
-  auto normProd = std::sqrt(squaredNormInput) * refNorm;
+  auto normProd = inputNorm * refNorm;
   if ((normProd == 0.0) || (scalarProduct / normProd > 1))
   {
     return static_cast<TOutput>(0.0);
@@ -77,7 +75,7 @@ public:
   // Binary operator
   inline TOutputValue operator()(TInput const & inPix) const
   {
-    return SpectralAngleDetails::ComputeSpectralAngle<TInput, TInput, TOutputValue>(inPix, m_ReferencePixel, m_RefNorm);
+    return SpectralAngleDetails::ComputeSpectralAngle<TInput, TInput, TOutputValue>(inPix, inPix.GetNorm(), m_ReferencePixel, m_RefNorm);
   }
 
   void SetReferencePixel(TInput const & ref)
@@ -109,10 +107,12 @@ public:
     TOutput res;
     res.SetSize(m_ReferencePixels.size());
     
+    auto inputNorm = inPix.GetNorm();
+    
     for (unsigned int i = 0; i< m_ReferencePixels.size(); i++)
     {
       res[i] = SpectralAngleDetails::ComputeSpectralAngle<TInput, TInput, typename TOutput::ValueType>
-                                      (inPix, m_ReferencePixels[i], m_ReferenceNorm[i]);
+                                      (inPix, inputNorm, m_ReferencePixels[i], m_ReferenceNorm[i]);
     }
 
     return res;

Modules/Filtering/ImageManipulation/include/otbSqrtSpectralAngleFunctor.h

@@ -56,7 +56,7 @@ public:
   // Binary operator
   inline TOutputValue operator()(TInput const & inPix) const
   {
-    return std::sqrt(SpectralAngleDetails::ComputeSpectralAngle<TInput, TInput, TOutputValue>(inPix, m_ReferencePixel, m_RefNorm));
+    return std::sqrt(SpectralAngleDetails::ComputeSpectralAngle<TInput, TInput, TOutputValue>(inPix, inPix.GetNorm(), m_ReferencePixel, m_RefNorm));
   }
 
   void SetReferencePixel(TInput const & ref)

Modules/Radiometry/Indices/include/otbWaterSqrtSpectralAngleImageFilter.h

@@ -82,9 +82,8 @@ public:
     pix[3] = this->Value(CommonBandNames::NIR, inPix);
 
     return std::sqrt(SpectralAngleDetails::ComputeSpectralAngle<PixelType, PixelType, TOutput>
-                                                                  (pix,
-                                                                    m_ReferencePixel, 
-                                                                    m_RefNorm));
+                                                                  (pix, pix.GetNorm(),
+                                                                   m_ReferencePixel, m_RefNorm));
   }
 
   /**@{*/ 

Modules/Segmentation/CCOBIA/include/otbConnectedComponentMuParserFunctor.h

@@ -25,7 +25,7 @@
 
 #include "otbParser.h"
 #include "otbMacro.h"
-#include "otbSpectralAngleFunctor.h"
+#include "otbBinarySpectralAngleFunctor.h"
 
 #include <vnl/algo/vnl_lsqr.h>
 #include <vnl/vnl_sparse_matrix_linear_system.h>
@@ -115,8 +115,9 @@ public:
     m_IntensityP2 = m_IntensityP2 / (static_cast<double>(m_NbOfBands));
 
     m_Distance = std::sqrt(m_Distance);
-
-    m_SpectralAngle = SpectralAngleDetails::ComputeSpectralAngle<TInput, TInput, double>(p1, p2, p2.GetNorm());
+    
+    BinarySpectralAngleFunctor<TInput, TInput, double> spectralAngleFunctor;
+    m_SpectralAngle = spectralAngleFunctor(p1, p2);
 
     value = m_Parser->Eval();