bsfm::DistanceMetric Class Reference

#include <distance_metric.h>

Public Types
enum	Metric { SCALED_L2, HAMMING }

Public Member Functions
void	SetMetric (const Metric &metric=Metric::SCALED_L2)
void	SetMaximumDistance (double maximum_distance)
double	Max () const
double	operator() (const Descriptor &descriptor1, const Descriptor &descriptor2)
bool	MaybeNormalizeDescriptors (std::vector< Descriptor > &descriptors) const

Static Public Member Functions
static DistanceMetric &	Instance ()

Private Member Functions
	DistanceMetric ()
double	GetScaledL2Distance (const Descriptor &descriptor1, const Descriptor &descriptor2) const
double	GetHammingDistance (const Descriptor &descriptor1, const Descriptor &descriptor2) const
void	NormalizeDescriptors (std::vector< Descriptor > &descriptors) const

Private Attributes
Metric	metric_
double	maximum_distance_

Detailed Description

Definition at line 58 of file distance_metric.h.

Member Enumeration Documentation

enum bsfm::DistanceMetric::Metric

Enumerator
SCALED_L2
HAMMING

Definition at line 61 of file distance_metric.h.

              {
    SCALED_L2,
    HAMMING
  };

Constructor & Destructor Documentation

bsfm::DistanceMetric::DistanceMetric ( )

private

Definition at line 91 of file distance_metric.cpp.

    : maximum_distance_(std::numeric_limits<double>::max()) {
  // Set metric to the default argument of SetMetric(), defined in the header.
  SetMetric();
}

Member Function Documentation

double bsfm::DistanceMetric::GetHammingDistance ( const Descriptor &  descriptor1, const Descriptor &  descriptor2  ) const

private

Definition at line 103 of file distance_metric.cpp.

                                                                               {
  CHECK_EQ(descriptor1.size(), descriptor2.size());
  int sum = 0;
  for (size_t ii = 0; ii < descriptor1.size(); ++ii) {
    unsigned char d1 = static_cast<unsigned char>(descriptor1(ii));
    unsigned char d2 = static_cast<unsigned char>(descriptor2(ii));
    sum += d1 ^ d2;
  }
  return static_cast<double>(sum);
}

double bsfm::DistanceMetric::GetScaledL2Distance ( const Descriptor &  descriptor1, const Descriptor &  descriptor2  ) const

private

Definition at line 97 of file distance_metric.cpp.

                                                                        {
  CHECK_EQ(descriptor1.size(), descriptor2.size());
  return 1.0 - descriptor1.dot(descriptor2);
}

DistanceMetric & bsfm::DistanceMetric::Instance ( )

static

Definition at line 42 of file distance_metric.cpp.

                                         {
  static DistanceMetric instance;
  return instance;
}

double bsfm::DistanceMetric::Max

(

)

const

Definition at line 55 of file distance_metric.cpp.

                                 {
  return maximum_distance_;
}

bool bsfm::DistanceMetric::MaybeNormalizeDescriptors

(

std::vector< Descriptor > &

descriptors

)

const

Definition at line 74 of file distance_metric.cpp.

                                              {
  bool normalized = false;
  switch (metric_) {
    case SCALED_L2:
      NormalizeDescriptors(descriptors);
      normalized = true;
      break;
    case HAMMING:
      break;
    // No default to catch incompatible types at compile time.
  }

  return normalized;
}

void bsfm::DistanceMetric::NormalizeDescriptors ( std::vector< Descriptor > &  descriptors ) const

private

Definition at line 115 of file distance_metric.cpp.

                                              {
  for (auto& descriptor : descriptors) {
    descriptor.normalize();
  }
}

double bsfm::DistanceMetric::operator()	(	const Descriptor &	descriptor1,
		const Descriptor &	descriptor2
	)

Definition at line 59 of file distance_metric.cpp.

                                                                 {
  double distance = 0.0;
  switch (metric_) {
    case SCALED_L2:
      distance = GetScaledL2Distance(descriptor1, descriptor2);
      break;
    case HAMMING:
      distance = GetHammingDistance(descriptor1, descriptor2);
      break;
    // No default to catch incompatible types at compile time.
  }
  return distance;
}

void bsfm::DistanceMetric::SetMaximumDistance

(

double

maximum_distance

)

Definition at line 51 of file distance_metric.cpp.

                                                               {
  maximum_distance_ = maximum_distance;
}

void bsfm::DistanceMetric::SetMetric

(

const Metric &

metric = Metric::SCALED_L2

)

Definition at line 47 of file distance_metric.cpp.

                                                   {
  metric_ = metric;
}

Member Data Documentation

double bsfm::DistanceMetric::maximum_distance_

private

Definition at line 122 of file distance_metric.h.

Metric bsfm::DistanceMetric::metric_

private

Definition at line 117 of file distance_metric.h.

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The documentation for this class was generated from the following files:

• /Users/eanelson/Git/berkeley_sfm/src/cpp/matching/distance_metric.h
• /Users/eanelson/Git/berkeley_sfm/src/cpp/matching/distance_metric.cpp