[features] Use aligned memory for features & descriptors. #511

- Enable usage of Eigen function on descriptor arrays.

src/openMVG/features/akaze/msurf_descriptor.hpp

@@ -133,10 +133,7 @@ namespace features {
     }
 
     // convert to unit vector (L2 norm)
-    typedef Eigen::Matrix<Real, Eigen::Dynamic, 1> VecReal;
-    Eigen::Map< VecReal > dataMap( &desc[0], 64);
-    dataMap.normalize();
-    //std::cout << dataMap.transpose() << std::endl << std::endl;
+    desc.normalize();
   }
 
   template<typename ImageT>

src/openMVG/features/descriptor.hpp

@@ -21,30 +21,18 @@ namespace features {
 /**
  * Class that handle descriptor (a data container of N values of type T).
  * SiftDescriptor => <uchar,128> or <float,128>
-
  * Surf 64 => <float,64>
+ * Brief 512 bits => <unsigned char,512/sizeof(unsigned char)>
  */
 template <typename T, std::size_t N>
-class Descriptor
+class Descriptor : public Eigen::Matrix<T, N, 1>
 {
 public:
+  EIGEN_MAKE_ALIGNED_OPERATOR_NEW
   typedef T bin_type;
-  typedef std::size_t size_type;
 
   /// Compile-time length of the descriptor
-  static const size_type static_size = N;
-
-  /// Constructor
-  inline Descriptor() {}
-
-  /// capacity
-  inline size_type size() const { return N; }
-
-  /// Mutable and non-mutable bin getters
-  inline bin_type& operator[](std::size_t i) { return data[i]; }
-  inline bin_type operator[](std::size_t i) const { return data[i]; }
-
-  inline bin_type* getData() const {return (bin_type* ) (&data[0]);}
+  static const std::size_t static_size = N;
 
   /// Ostream interface
   std::ostream& print(std::ostream& os) const;
@@ -54,7 +42,7 @@ class Descriptor
   template<class Archive>
   void save(Archive & archive) const
   {
-    std::vector<T> array(data,data+N);
+    const std::vector<T> array(this->data(), this->data()+N);
     archive( array );
   }
 
@@ -63,11 +51,8 @@ class Descriptor
   {
     std::vector<T> array(N);
     archive( array );
-    std::memcpy(data, array.data(), sizeof(T)*N);
+    std::memcpy(this->data(), array.data(), sizeof(T)*N);
   }
-
-private:
-  bin_type data[N];
 };
 
 // Output stream definition
@@ -122,13 +107,13 @@ inline std::istream& readT<unsigned char>(std::istream& is, unsigned char *tab,
 template<typename T, std::size_t N>
 std::ostream& Descriptor<T,N>::print(std::ostream& os) const
 {
-  return printT<T>(os, (T*) &data[0], N);
+  return printT<T>(os, (T*) this->data(), N);
 }
 
 template<typename T, std::size_t N>
 std::istream& Descriptor<T,N>::read(std::istream& in)
 {
-  return readT<T>(in, (T*) &data[0], N);
+  return readT<T>(in, (T*) this->data(), N);
 }
 
 /// Read descriptors from file
@@ -187,7 +172,7 @@ static bool loadDescsFromBinFile(
   vec_desc.resize(cardDesc);
   for (typename DescriptorsT::const_iterator iter = vec_desc.begin();
     iter != vec_desc.end(); ++iter) {
-    fileIn.read((char*) (*iter).getData(),
+    fileIn.read((char*) (*iter).data(),
       VALUE::static_size*sizeof(typename VALUE::bin_type));
   }
   const bool bOk = !fileIn.bad();
@@ -211,7 +196,7 @@ static bool saveDescsToBinFile(
   file.write((const char*) &cardDesc,  sizeof(std::size_t));
   for (typename DescriptorsT::const_iterator iter = vec_desc.begin();
     iter != vec_desc.end(); ++iter) {
-    file.write((const char*) (*iter).getData(),
+    file.write((const char*) (*iter).data(),
       VALUE::static_size*sizeof(typename VALUE::bin_type));
   }
   const bool bOk = file.good();

src/openMVG/features/feature.hpp

@@ -28,6 +28,8 @@ class PointFeature {
   friend std::istream& operator>>(std::istream& in, PointFeature& obj);
 
 public:
+  EIGEN_MAKE_ALIGNED_OPERATOR_NEW
+
   PointFeature(float x=0.0f, float y=0.0f)
    : coords_(x, y) {}
 

src/openMVG/features/image_describer_akaze.hpp

@@ -224,8 +224,8 @@ class AKAZE_Image_describer : public Image_describer
             SIOPointFeature(ptAkaze.x, ptAkaze.y, ptAkaze.size, ptAkaze.angle);
 
           // Compute MLDB descriptor
-		      Descriptor<bool,486> desc;
-      		ComputeMLDBDescriptor(cur_slice.cur, cur_slice.Lx, cur_slice.Ly,
+          Descriptor<bool,486> desc;
+          ComputeMLDBDescriptor(cur_slice.cur, cur_slice.Lx, cur_slice.Ly,
             ptAkaze.octave, regionsCasted->Features()[i], desc);
           // convert the bool vector to the binary unsigned char array
           unsigned char * ptr = reinterpret_cast<unsigned char*>(&regionsCasted->Descriptors()[i]);

src/openMVG/features/regions.hpp

@@ -66,8 +66,8 @@ class Regions
 
   /// Return the squared distance between two descriptors
   // A default metric is used according the descriptor type:
-  // - Scalar: L2,
-  // - Binary: Hamming
+  // - Scalar: SquaredL2,
+  // - Binary: SquaredHamming
   virtual double SquaredDescriptorDistance(size_t i, const Regions *, size_t j) const = 0;
 
   /// Add the Inth region to another Region container
@@ -159,7 +159,7 @@ class Scalar_Regions : public Regions
 
   Regions * EmptyClone() const
   {
-    return new Scalar_Regions();
+    return new Scalar_Regions;
   }
 
   // Return the L2 distance between two descriptors
@@ -171,7 +171,7 @@ class Scalar_Regions : public Regions
 
     const Scalar_Regions<FeatT, T, L> * regionsT = dynamic_cast<const Scalar_Regions<FeatT, T, L> *>(regions);
     static matching::L2_Vectorized<T> metric;
-    return metric(vec_descs_[i].getData(), regionsT->vec_descs_[j].getData(), DescriptorT::static_size);
+    return metric(vec_descs_[i].data(), regionsT->vec_descs_[j].data(), DescriptorT::static_size);
   }
 
   /// Add the Inth region to another Region container
@@ -273,7 +273,7 @@ class Binary_Regions : public Regions
 
   Regions * EmptyClone() const
   {
-    return new Binary_Regions();
+    return new Binary_Regions;
   }
 
   // Return the squared Hamming distance between two descriptors
@@ -286,7 +286,7 @@ class Binary_Regions : public Regions
     const Binary_Regions<FeatT, L> * regionsT = dynamic_cast<const Binary_Regions<FeatT, L> *>(regions);
     static matching::Hamming<unsigned char> metric;
     const typename matching::Hamming<unsigned char>::ResultType descDist =
-      metric(vec_descs_[i].getData(), regionsT->vec_descs_[j].getData(), DescriptorT::static_size);
+      metric(vec_descs_[i].data(), regionsT->vec_descs_[j].data(), DescriptorT::static_size);
     return descDist * descDist;
   }
 

src/software/SfM/main_ComputeFeatures_OpenCV.cpp

@@ -107,7 +107,7 @@ class AKAZE_OCV_Image_describer : public Image_describer
         SIOPointFeature feat((*i_keypoint).pt.x, (*i_keypoint).pt.y, (*i_keypoint).size, (*i_keypoint).angle);
         regionsCasted->Features().push_back(feat);
 
-        memcpy(descriptor.getData(),
+        memcpy(descriptor.data(),
                m_desc.ptr<typename DescriptorT::bin_type>(cpt),
                DescriptorT::static_size*sizeof(DescriptorT::bin_type));
         regionsCasted->Descriptors().push_back(descriptor);