This class implements the possibility to find local maximum in a 2D array by applying a non-maximum-suppression search. More...

#include <NonMaximumSuppression.h>

Inheritance diagram for Ocean::CV::NonMaximumSuppressionT< T >:

Data Structures
class	StrengthCandidate
	This class holds the horizontal position and strength parameter of an interest pixel. More...

Public Types
template<typename TCoordinate , typename TStrength >
using	PositionCallback = std::function< bool(const unsigned int x, const unsigned int y, const TStrength strength, TCoordinate &preciseX, TCoordinate &preciseY, TStrength &preciseStrength)>
	Definition of a callback function used to determine the precise sub-pixel position of a specific point.

Public Types inherited from Ocean::CV::NonMaximumSuppression
enum	SuppressionMode : uint32_t { SM_MAXIMUM , SM_MINIMUM , SM_MAXIMUM_POSITIVE_ONLY , SM_MINIMUM_NEGATIVE_ONLY }
	Definition of individual suppression modes for extremum search. More...

enum	RefinementStatus : uint32_t { RS_INVALID = 0u , RS_DIVERGED , RS_BORDER , RS_MAX_ITERATIONS , RS_CONVERGED }
	Definition of individual refinement status values for iterative sub-pixel peak refinement. More...

template<typename TCoordinate , typename TStrength >
using	StrengthPositions = std::vector< StrengthPosition< TCoordinate, TStrength > >
	Definition of a vector holding strength pixel positions.

Public Member Functions
	NonMaximumSuppressionT (NonMaximumSuppressionT< T > &&nonMaximumSuppression) noexcept
	Move constructor.

	NonMaximumSuppressionT (const NonMaximumSuppressionT< T > &nonMaximumSuppression) noexcept
	Copy constructor.

	NonMaximumSuppressionT (const unsigned int width, const unsigned int height, const unsigned int yOffset=0u) noexcept
	Creates a new maximum suppression object with a predefined size.

unsigned int	width () const
	Returns the width of this object.

unsigned int	height () const
	Returns the height of this object.

unsigned int	yOffset () const
	Returns the optional offset in the vertical direction.

void	addCandidate (const unsigned int x, const unsigned int y, const T &strength)
	Adds a new candidate to this object.

void	addCandidates (const T values, const unsigned int valuesPaddingElements, const unsigned int firstColumn, const unsigned int numberColumns, const unsigned int firstRow, const unsigned int numberRows, const T &minimalThreshold, Worker worker)
	Adds new candidates to this object from a given buffer providing one value for each bin/pixel of this object.

void	removeCandidatesRightFrom (const unsigned int x, const unsigned int y)
	Removes all candidates from a specified row having a horizontal location equal or larger than a specified coordinate.

bool	candidate (const unsigned int x, const unsigned int y, T &strength) const
	Returns the strength value of a candidate at a specified position.

void	candidates (const unsigned int firstColumn, const unsigned int numberColumns, const unsigned int firstRow, const unsigned int numberRows, StrengthPositions< unsigned int, T > &strengthPositions) const
	Returns all gathered candidates of this object.

template<typename TCoordinate , typename TStrength , bool tStrictMaximum = true, NonMaximumSuppression::SuppressionMode tSuppressionMode = NonMaximumSuppression::SM_MAXIMUM>
bool	suppressNonMaximum (const unsigned int firstColumn, const unsigned int numberColumns, const unsigned int firstRow, const unsigned int numberRows, StrengthPositions< TCoordinate, TStrength > &strengthPositions, Worker worker=nullptr, const PositionCallback< TCoordinate, TStrength > positionCallback=nullptr) const
	Applies a non-maximum-suppression search on a given 2D frame in a 3x3 neighborhood (eight neighbors).

void	reset ()
	Removes the gathered non-maximum suppression information so that this object can be reused again (for the same task with same resolution etc.).

NonMaximumSuppressionT< T > &	operator= (NonMaximumSuppressionT< T > &&nonMaximumSuppression)
	Move operator.

NonMaximumSuppressionT< T > &	operator= (const NonMaximumSuppressionT< T > &nonMaximumSuppression)
	Copy operator.

template<typename TCoordinate , typename TStrength , bool tStrictMaximum>
NonMaximumSuppressionT< T >::template StrengthPositions< TCoordinate, TStrength >	suppressNonMaximum (const unsigned int width, const unsigned int height, const StrengthPositions< TCoordinate, TStrength > &strengthPositions, const TCoordinate radius, Indices32 *validIndices)

Static Public Member Functions
template<typename TCoordinate , typename TStrength , bool tStrictMaximum>
static StrengthPositions< TCoordinate, TStrength >	suppressNonMaximum (const unsigned int width, const unsigned int height, const StrengthPositions< TCoordinate, TStrength > &strengthPositions, const TCoordinate radius, Indices32 *validIndices=nullptr)
	Applies a non-maximum-suppression based on already existing strength positions (just with a custom suppression radius) e.g., as a post-processing step.

template<typename TFloat >
static bool	determinePrecisePeakLocation1 (const T &leftValue, const T &middleValue, const T &rightValue, TFloat &location)
	Determines the precise peak location in 1D space for three discrete neighboring measurements at location x == 0.

template<typename TFloat >
static bool	determinePrecisePeakLocation2 (const T const topValues, const T const centerValues, const T *const bottomValues, VectorT2< TFloat > &location)
	Determines the precise peak location in 2D space for nine discrete neighboring measurements at location x == 0, y == 0.

template<typename TFloat , unsigned int tSize, bool tFindMaximum = true>
static bool	determinePrecisePeakLocationNxN (const TFloat *values, const size_t valuesStrideElements, TFloat &offsetX, TFloat &offsetY)
	Determines the precise peak location in 2D space by fitting a quadratic surface via least-squares to a tSize x tSize grid of values.

template<typename TFloat , unsigned int tSize, bool tFindMaximum = true, PixelCenter tPixelCenter = PC_TOP_LEFT>
static NonMaximumSuppression::RefinementStatus	determinePrecisePeakLocationIterativeNxN (const uint8_t *frame, const unsigned int width, const unsigned int height, const unsigned int framePaddingElements, const TFloat x, const TFloat y, TFloat &preciseX, TFloat &preciseY, const unsigned int maxIterations=5u, const TFloat stepSize=TFloat(0.75), const TFloat convergenceThreshold=TFloat(0.01))
	Determines the precise sub-pixel peak location by iteratively sampling image intensity values at sub-pixel positions.

Protected Types
using	StrengthCandidateRow = std::vector< StrengthCandidate >
	Definition of a vector holding strength candidate objects.

using	StrengthCandidateRows = ShiftVector< StrengthCandidateRow >
	Definition of a vector holding a vector of strength candidates.

Private Member Functions
void	addCandidatesSubset (const T values, const unsigned int valuesStrideElements, const unsigned int firstColumn, const unsigned int numberColumns, const T minimalThreshold, const unsigned int firstRow, const unsigned int numberRows)
	Adds new candidates to this object from a subset of a given buffer providing one value for each bin/pixel of this object.

template<typename TCoordinate , typename TStrength , bool tStrictMaximum, bool tOnlyPositive = false>
void	suppressNonMaximumSubset (StrengthPositions< TCoordinate, TStrength > strengthPositions, const unsigned int firstColumn, const unsigned int numberColumns, Lock lock, const PositionCallback< TCoordinate, TStrength > *positionCallback, const unsigned int firstRow, const unsigned int numberRows) const
	Applies a non-maximum-suppression search on a subset of a given 2D frame in a 3x3 neighborhood (eight neighbors).

template<typename TCoordinate , typename TStrength , bool tStrictMaximum, bool tOnlyNegative = false>
void	suppressNonMinimumSubset (StrengthPositions< TCoordinate, TStrength > strengthPositions, const unsigned int firstColumn, const unsigned int numberColumns, Lock lock, const PositionCallback< TCoordinate, TStrength > *positionCallback, const unsigned int firstRow, const unsigned int numberRows) const
	Applies a non-minimum-suppression search on a subset of a given 2D frame in a 3x3 neighborhood (eight neighbors).

Private Attributes
unsigned int	width_ = 0u
	Width of this object.

StrengthCandidateRows	rows_
	All candidate rows.

Detailed Description

template<typename T>
class Ocean::CV::NonMaximumSuppressionT< T >

This class implements the possibility to find local maximum in a 2D array by applying a non-maximum-suppression search.

The search is done within a 3x3 neighborhood (centered around the point of interest).
Use this class to determine e.g. reliable feature points.
The class supports bin accuracy (pixel accuracy) and sub-bin accuracy (sub-pixel accuracy).

The non-maximum-suppression search is implemented by a vertical list holding maps of horizontal array elements.
The performance depends on the number of elements inserted into the individual maps.
Thus, do not add data elements with negligible value.

It should be mentioned that the application of this class should be restricted to situations in which the entire filter response values do not exist already.
The performance boost comes with a simultaneous determination of filter responses and the insertion of possible candidates for maximum locations.

Template Parameters

T	The data type of the individual elements that are applied for the non-maximum-suppression search.

Member Typedef Documentation

◆ PositionCallback

template<typename T >

template<typename TCoordinate , typename TStrength >

using Ocean::CV::NonMaximumSuppressionT< T >::PositionCallback = std::function<bool(const unsigned int x, const unsigned int y, const TStrength strength, TCoordinate& preciseX, TCoordinate& preciseY, TStrength& preciseStrength)>

Definition of a callback function used to determine the precise sub-pixel position of a specific point.

Parameters

x	The horizontal position of the point, with range [0, width - 1]
y	The vertical position of the point, with range [0, height - 1]
strength	The strength parameter already known for the position of the point
preciseX	The resulting precise horizontal position of the point, with range (x - 1, x + 1)
preciseY	The resulting precise vertical position of the point, with range (y - 1, y + 1)
preciseStrength	The resulting precise strength parameter of the precise point

Returns: True, if the precise position could be determined

Template Parameters

TCoordinate	The data type of a scalar coordinate
TStrength	The data type of the strength parameter

◆ StrengthCandidateRow

template<typename T >

using Ocean::CV::NonMaximumSuppressionT< T >::StrengthCandidateRow = std::vector<StrengthCandidate>

protected

Definition of a vector holding strength candidate objects.

◆ StrengthCandidateRows

template<typename T >

using Ocean::CV::NonMaximumSuppressionT< T >::StrengthCandidateRows = ShiftVector<StrengthCandidateRow>

protected

Definition of a vector holding a vector of strength candidates.

Constructor & Destructor Documentation

◆ NonMaximumSuppressionT() [1/3]

template<typename T >

Ocean::CV::NonMaximumSuppressionT< T >::NonMaximumSuppressionT ( NonMaximumSuppressionT< T > && nonMaximumSuppression )

noexcept

Move constructor.

Parameters

nonMaximumSuppression The object to be moved

◆ NonMaximumSuppressionT() [2/3]

template<typename T >

Ocean::CV::NonMaximumSuppressionT< T >::NonMaximumSuppressionT ( const NonMaximumSuppressionT< T > & nonMaximumSuppression )

noexcept

Copy constructor.

Parameters

nonMaximumSuppression The object to be moved

◆ NonMaximumSuppressionT() [3/3]

template<typename T >

Ocean::CV::NonMaximumSuppressionT< T >::NonMaximumSuppressionT	(	const unsigned int	width,
		const unsigned int	height,
		const unsigned int	yOffset = `0u`
	)

noexcept

Creates a new maximum suppression object with a predefined size.

Parameters

width	The width of this object in pixel, with range [3, infinity)
height	The height of this object in pixel, with range [3, infinity)
yOffset	Optional offset in the vertical direction moving the suppression region by the specified number of rows, with range [0, infinity)

Member Function Documentation

◆ addCandidate()

template<typename T >

void Ocean::CV::NonMaximumSuppressionT< T >::addCandidate	(	const unsigned int	x,
		const unsigned int	y,
		const T &	strength
	)

inline

Adds a new candidate to this object.

Beware: Due to performance issues do no add candidates with negligible strength parameter.

Parameters

x	Horizontal position in pixel, with range [0, width() - 1]
y	Vertical position in pixel, with range [yOffset(), yOffset() + height() - 1]
strength	The strength parameter

See also: addCandidates(), removeCandidatesFromRight().

◆ addCandidates()

template<typename T >

void Ocean::CV::NonMaximumSuppressionT< T >::addCandidates	(	const T *	values,
		const unsigned int	valuesPaddingElements,
		const unsigned int	firstColumn,
		const unsigned int	numberColumns,
		const unsigned int	firstRow,
		const unsigned int	numberRows,
		const T &	minimalThreshold,
		Worker *	worker
	)

Adds new candidates to this object from a given buffer providing one value for each bin/pixel of this object.

Beware: Due to performance reasons, you should use the addCandidate() function to add one single new candidate in the moment the filter response is larger than a specific threshold.

Parameters

values	The from which candidates will be added, must be width() * height() elements
valuesPaddingElements	The number of padding elements at the end of each values row, in elements, with range [0, infinity)
firstColumn	First column to be handled, with range [0, width() - 1]
numberColumns	Number of columns to be handled, with range [1, width() - firstColumn]
firstRow	First row to be handled, with range [yOffset(), height() - 1]
numberRows	Number of rows to be handled, with range [1, height() - firstRow]
minimalThreshold	The minimal threshold so that a value counts as candidate
worker	Optional worker object to distribute the computation

See also: addCandidate(), removeCandidatesFromRight().

◆ addCandidatesSubset()

template<typename T >

void Ocean::CV::NonMaximumSuppressionT< T >::addCandidatesSubset	(	const T *	values,
		const unsigned int	valuesStrideElements,
		const unsigned int	firstColumn,
		const unsigned int	numberColumns,
		const T *	minimalThreshold,
		const unsigned int	firstRow,
		const unsigned int	numberRows
	)

private

Adds new candidates to this object from a subset of a given buffer providing one value for each bin/pixel of this object.

Parameters

values	The from which candidates will be added, must be width() * height() elements
valuesStrideElements	The number of elements between two values rows, in elements, with range [0, infinity)
minimalThreshold	The minimal threshold so that a value counts as candidate
firstColumn	First column to be handled, with range [0, width() - 1]
numberColumns	Number of columns to be handled, with range [1, width() - firstColumn]
firstRow	The first row in the buffer from which the candidates will be added, with range [yOffset(), height())
numberRows	The number of rows to be handled, with range [1, height() - firstRow]

See also: addCandidates().

◆ candidate()

template<typename T >

bool Ocean::CV::NonMaximumSuppressionT< T >::candidate	(	const unsigned int	x,
		const unsigned int	y,
		T &	strength
	)		const

Returns the strength value of a candidate at a specified position.

The function uses binary search on the x-coordinate within the specified row, as candidates are sorted by horizontal position.

Parameters

x	The horizontal position to look up, with range [0, width() - 1]
y	The vertical position (row) to look up, with range [yOffset(), yOffset() + height() - 1]
strength	The resulting strength value if a candidate exists at the specified position

Returns: True, if a candidate exists at the specified position; False, if no candidate was found

◆ candidates()

template<typename T >

void Ocean::CV::NonMaximumSuppressionT< T >::candidates	(	const unsigned int	firstColumn,
		const unsigned int	numberColumns,
		const unsigned int	firstRow,
		const unsigned int	numberRows,
		StrengthPositions< unsigned int, T > &	strengthPositions
	)		const

Returns all gathered candidates of this object.

The resulting candidates are raw candidates without any suppression.

Parameters

firstColumn	The first column from which candidates will be returned, with range [0, width() - 1]
numberColumns	The number of columns for which candidates will be returned, with range [1, width() - firstColumn]
firstRow	The first row from which candidates will be returned, with range [yOffset(), height() - 1]
numberRows	The number of rows for which candidates will be returned, with range [1, height() - firstRow]
strengthPositions	The resulting strength positions

◆ determinePrecisePeakLocation1()

template<typename T >

template<typename TFloat >

bool Ocean::CV::NonMaximumSuppressionT< T >::determinePrecisePeakLocation1	(	const T &	leftValue,
		const T &	middleValue,
		const T &	rightValue,
		TFloat &	location
	)

static

Determines the precise peak location in 1D space for three discrete neighboring measurements at location x == 0.

The precise peak is determined based on the first and second derivatives of the measurement values.

Parameters

leftValue	The left discrete value, e.g., at location x - 1, with range (-infinity, middleValue]
middleValue	The middle discrete value, e.g., at location x, with range (-infinity, infinity)
rightValue	The discrete value, e.g., at location x + 1, with range (-infinity, middleValue]
location	The location of the precise peak of all values, with range (-1, 1)

Returns: True, if succeeded

Template Parameters

TFloat The floating point data type to be used for calculation, either 'float' or 'double'

◆ determinePrecisePeakLocation2()

template<typename T >

template<typename TFloat >

bool Ocean::CV::NonMaximumSuppressionT< T >::determinePrecisePeakLocation2	(	const T *const	topValues,
		const T *const	centerValues,
		const T *const	bottomValues,
		VectorT2< TFloat > &	location
	)

static

Determines the precise peak location in 2D space for nine discrete neighboring measurements at location x == 0, y == 0.

The precise peak is determined based on the first and second derivatives of the measurement values.

Parameters

topValues	The three discrete values in the top row, must be valid
centerValues	The three discrete values in the center row, must be valid
bottomValues	The three discrete values in the bottom row, must be valid
location	The location of the precise peak of all values, with range (-1, 1)

Returns: True, if succeeded

Template Parameters

TFloat The floating point data type to be used for calculation, either 'float' or 'double'

◆ determinePrecisePeakLocationIterativeNxN()

template<typename T >

template<typename TFloat , unsigned int tSize, bool tFindMaximum, PixelCenter tPixelCenter>

NonMaximumSuppression::RefinementStatus Ocean::CV::NonMaximumSuppressionT< T >::determinePrecisePeakLocationIterativeNxN	(	const uint8_t *	frame,
		const unsigned int	width,
		const unsigned int	height,
		const unsigned int	framePaddingElements,
		const TFloat	x,
		const TFloat	y,
		TFloat &	preciseX,
		TFloat &	preciseY,
		const unsigned int	maxIterations = `5u`,
		const TFloat	stepSize = `TFloat(0.75)`,
		const TFloat	convergenceThreshold = `TFloat(0.01)`
	)

static

Determines the precise sub-pixel peak location by iteratively sampling image intensity values at sub-pixel positions.

The function uses bilinear interpolation to sample a tSize x tSize grid of intensity values around the current estimate, calls determinePrecisePeakLocationNxN() to find the sub-pixel offset, and iterates with decreasing step size until convergence.
The valid sampling range is [0, width - 1]x[0, height - 1] for PC_TOP_LEFT or [0, width]x[0, height] for PC_CENTER.

Parameters

frame	Pointer to the first pixel of the grayscale frame (single channel, uint8_t), must be valid
width	The width of the frame in pixels, with range [tSize, infinity)
height	The height of the frame in pixels, with range [tSize, infinity)
framePaddingElements	The number of padding elements at the end of each frame row, in elements, with range [0, infinity)
x	The horizontal position of the initial peak estimate, in the coordinate system defined by tPixelCenter
y	The vertical position of the initial peak estimate, in the coordinate system defined by tPixelCenter
preciseX	The resulting precise horizontal position, in the coordinate system defined by tPixelCenter
preciseY	The resulting precise vertical position, in the coordinate system defined by tPixelCenter
maxIterations	The maximum number of refinement iterations, with range [1, infinity)
stepSize	The initial step size for the sampling grid, with range (0, 1]
convergenceThreshold	The threshold for the pixel offset magnitude below which convergence is declared, with range (0, infinity)

Returns: The refinement status

Template Parameters

TFloat	The floating point data type to be used for calculation, either 'float' or 'double'
tSize	The size of the sampling grid, must be odd and >= 3
tFindMaximum	True, to find the intensity maximum; False, to find the intensity minimum
tPixelCenter	The pixel center to be used during interpolation, either 'PC_TOP_LEFT' or 'PC_CENTER'

◆ determinePrecisePeakLocationNxN()

template<typename T >

template<typename TFloat , unsigned int tSize, bool tFindMaximum>

bool Ocean::CV::NonMaximumSuppressionT< T >::determinePrecisePeakLocationNxN	(	const TFloat *	values,
		const size_t	valuesStrideElements,
		TFloat &	offsetX,
		TFloat &	offsetY
	)

static

Determines the precise peak location in 2D space by fitting a quadratic surface via least-squares to a tSize x tSize grid of values.

Uses all tSize * tSize samples to fit F(x,y) = a + bx + cy + dx^2 + exy + fy^2 and solves for the peak of the fitted surface.
For a 3x3 grid this reduces to central differences; for larger grids the least-squares fit uses all samples for a more robust estimate.
The function validates that the fitted surface has the correct curvature (negative-definite Hessian for maximum, positive-definite for minimum).

Parameters

values	The grid values in row-major order, must have at least (tSize - 1) * valuesStrideElements + tSize elements
valuesStrideElements	The number of elements between the start of two consecutive rows, with range [tSize, infinity)
offsetX	The resulting horizontal offset of the peak from the grid center, in range (-1, 1)
offsetY	The resulting vertical offset of the peak from the grid center, in range (-1, 1)

Returns: True, if the fit succeeded, the curvature is correct, and the offset is within range; False, if the surface is degenerate, has wrong curvature, or the offset is out of range

Template Parameters

TFloat	The floating point data type to be used for calculation, either 'float' or 'double'
tSize	The size of the sampling grid, must be odd and >= 3
tFindMaximum	True, to find the maximum of the fitted surface; False, to find the minimum

◆ height()

template<typename T >

unsigned int Ocean::CV::NonMaximumSuppressionT< T >::height ( ) const

inline

Returns the height of this object.

Returns: Height in pixel

◆ operator=() [1/2]

template<typename T >

NonMaximumSuppressionT< T > & Ocean::CV::NonMaximumSuppressionT< T >::operator= ( const NonMaximumSuppressionT< T > & nonMaximumSuppression )

Copy operator.

Parameters

nonMaximumSuppression The object to be copied

Returns: Reference to this object

◆ operator=() [2/2]

template<typename T >

NonMaximumSuppressionT< T > & Ocean::CV::NonMaximumSuppressionT< T >::operator= ( NonMaximumSuppressionT< T > && nonMaximumSuppression )

Move operator.

Parameters

nonMaximumSuppression Object to be moved

Returns: Reference to this object

◆ removeCandidatesRightFrom()

template<typename T >

void Ocean::CV::NonMaximumSuppressionT< T >::removeCandidatesRightFrom	(	const unsigned int	x,
		const unsigned int	y
	)

inline

Removes all candidates from a specified row having a horizontal location equal or larger than a specified coordinate.

Parameters

x	The horizontal coordinate specifying which candidates will be removed, all candidates with horizontal location >= x will be removed, with range [0, infinity)
y	The index of the row in which the candidates will be removed, with range [yOffset(), yOffset() + height() - 1]

◆ reset()

template<typename T >

void Ocean::CV::NonMaximumSuppressionT< T >::reset ( )

Removes the gathered non-maximum suppression information so that this object can be reused again (for the same task with same resolution etc.).

The allocated memory will remain so that reusing this object may improve performance.

◆ suppressNonMaximum() [1/3]

template<typename T >

template<typename TCoordinate , typename TStrength , bool tStrictMaximum, NonMaximumSuppression::SuppressionMode tSuppressionMode>

bool Ocean::CV::NonMaximumSuppressionT< T >::suppressNonMaximum	(	const unsigned int	firstColumn,
		const unsigned int	numberColumns,
		const unsigned int	firstRow,
		const unsigned int	numberRows,
		StrengthPositions< TCoordinate, TStrength > &	strengthPositions,
		Worker *	worker = `nullptr`,
		const PositionCallback< TCoordinate, TStrength > *	positionCallback = `nullptr`
	)		const

Applies a non-maximum-suppression search on a given 2D frame in a 3x3 neighborhood (eight neighbors).

This function allows to determine the precise position of the individual maximum value positions by application of a callback function determining the individual positions.

Parameters

firstColumn	First column to be handled, with range [1, width() - 1)
numberColumns	Number of columns to be handled
firstRow	First row to be handled, with range [yOffset() + 1, height() - 1)
numberRows	Number of rows to be handled
strengthPositions	The resulting non maximum suppressed positions including the strength parameters, will be appended
worker	Optional worker object to distribute the computation
positionCallback	Optional callback function allowing to determine the precise position of the individual maximum value positions

Returns: True, if succeeded

Template Parameters

TCoordinate	The data type of a scalar coordinate
TStrength	The data type of the strength parameter
tStrictMaximum	True, to search for a strict maximum (larger than all eight neighbors); False, to allow equal values in the upper left neighborhood
tSuppressionMode	The suppression mode defining whether to find maximum/minimum and whether to enforce sign constraints

◆ suppressNonMaximum() [2/3]

template<typename T >

template<typename TCoordinate , typename TStrength , bool tStrictMaximum>

NonMaximumSuppressionT< T >::template StrengthPositions< TCoordinate, TStrength > Ocean::CV::NonMaximumSuppressionT< T >::suppressNonMaximum	(	const unsigned int	width,
		const unsigned int	height,
		const StrengthPositions< TCoordinate, TStrength > &	strengthPositions,
		const TCoordinate	radius,
		Indices32 *	validIndices
	)

◆ suppressNonMaximum() [3/3]

template<typename T >

template<typename TCoordinate , typename TStrength , bool tStrictMaximum>

static StrengthPositions< TCoordinate, TStrength > Ocean::CV::NonMaximumSuppressionT< T >::suppressNonMaximum	(	const unsigned int	width,
		const unsigned int	height,
		const StrengthPositions< TCoordinate, TStrength > &	strengthPositions,
		const TCoordinate	radius,
		Indices32 *	validIndices = `nullptr`
	)

static

Applies a non-maximum-suppression based on already existing strength positions (just with a custom suppression radius) e.g., as a post-processing step.

Parameters

width	The width of the image/domain in which the strength positions are located, e.g., in pixel, with range [1, infinity)
height	The height of the image/domain in which the strength positions are located, e.g., in pixel, with range [1, infinity)
strengthPositions	The strength positions for which a custom suppression-radius will be applied
radius	The suppression radius to be applied, with range [1, infinity)
validIndices	Optional resulting indices of all strength positions which remain after suppression

Returns: The resulting strength positions

Template Parameters

TCoordinate	The data type of a scalar coordinate
TStrength	The data type of the strength parameter
tStrictMaximum	True, to search for a strict maximum (larger than all eight neighbors); False, to allow equal values in the upper left neighborhood

◆ suppressNonMaximumSubset()

template<typename T >

template<typename TCoordinate , typename TStrength , bool tStrictMaximum, bool tOnlyPositive>

void Ocean::CV::NonMaximumSuppressionT< T >::suppressNonMaximumSubset	(	StrengthPositions< TCoordinate, TStrength > *	strengthPositions,
		const unsigned int	firstColumn,
		const unsigned int	numberColumns,
		Lock *	lock,
		const PositionCallback< TCoordinate, TStrength > *	positionCallback,
		const unsigned int	firstRow,
		const unsigned int	numberRows
	)		const

private

Applies a non-maximum-suppression search on a subset of a given 2D frame in a 3x3 neighborhood (eight neighbors).

This function allows to determine the precise position of the individual maximum value positions by application of a callback function determining the individual positions.

Parameters

strengthPositions	Resulting non maximum suppressed positions including the strength parameters
firstColumn	First column to be handled
numberColumns	Number of columns to be handled
lock	Optional lock when executed in parallel
positionCallback	Optional callback function allowing to determine the precise position of the individual maximum value positions
firstRow	First row to be handled
numberRows	Number of rows to be handled

Template Parameters

TCoordinate	The data type of a scalar coordinate
TStrength	The data type of the strength parameter
tStrictMaximum	True, to search for a strict maximum (larger than all eight neighbors); False, to allow equal values in the upper left neighborhood
tOnlyPositive	True, to only consider positive values (> 0); False, to consider all values

◆ suppressNonMinimumSubset()

template<typename T >

template<typename TCoordinate , typename TStrength , bool tStrictMaximum, bool tOnlyNegative>

void Ocean::CV::NonMaximumSuppressionT< T >::suppressNonMinimumSubset	(	StrengthPositions< TCoordinate, TStrength > *	strengthPositions,
		const unsigned int	firstColumn,
		const unsigned int	numberColumns,
		Lock *	lock,
		const PositionCallback< TCoordinate, TStrength > *	positionCallback,
		const unsigned int	firstRow,
		const unsigned int	numberRows
	)		const

private

Applies a non-minimum-suppression search on a subset of a given 2D frame in a 3x3 neighborhood (eight neighbors).

This function allows to determine the precise position of the individual minimum value positions by application of a callback function determining the individual positions.

Parameters

strengthPositions	Resulting non minimum suppressed positions including the strength parameters
firstColumn	First column to be handled
numberColumns	Number of columns to be handled
lock	Optional lock when executed in parallel
positionCallback	Optional callback function allowing to determine the precise position of the individual minimum value positions
firstRow	First row to be handled
numberRows	Number of rows to be handled

Template Parameters

TCoordinate	The data type of a scalar coordinate
TStrength	The data type of the strength parameter
tStrictMaximum	True, to search for a strict minimum (smaller than all eight neighbors); False, to allow equal values in the upper left neighborhood
tOnlyNegative	True, to only consider negative values (< 0); False, to consider all values

◆ width()

template<typename T >

unsigned int Ocean::CV::NonMaximumSuppressionT< T >::width ( ) const

inline

Returns the width of this object.

Returns: Width in pixel

◆ yOffset()

template<typename T >

unsigned int Ocean::CV::NonMaximumSuppressionT< T >::yOffset ( ) const

inline

Returns the optional offset in the vertical direction.

Returns: Optional vertical direction offset, 0 by default

Field Documentation

◆ rows_

template<typename T >

StrengthCandidateRows Ocean::CV::NonMaximumSuppressionT< T >::rows_

private

All candidate rows.

◆ width_

template<typename T >

unsigned int Ocean::CV::NonMaximumSuppressionT< T >::width_ = 0u

private

Width of this object.

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

NonMaximumSuppression.h

Data Structures

Public Types

Public Member Functions

Static Public Member Functions

Protected Types

Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ PositionCallback

◆ StrengthCandidateRow

◆ StrengthCandidateRows

Constructor & Destructor Documentation

◆ NonMaximumSuppressionT() [1/3]

◆ NonMaximumSuppressionT() [2/3]

◆ NonMaximumSuppressionT() [3/3]

Member Function Documentation

◆ addCandidate()

◆ addCandidates()

◆ addCandidatesSubset()

◆ candidate()

◆ candidates()

◆ determinePrecisePeakLocation1()

◆ determinePrecisePeakLocation2()

◆ determinePrecisePeakLocationIterativeNxN()

◆ determinePrecisePeakLocationNxN()

◆ height()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ removeCandidatesRightFrom()

◆ reset()

◆ suppressNonMaximum() [1/3]

◆ suppressNonMaximum() [2/3]

◆ suppressNonMaximum() [3/3]

◆ suppressNonMaximumSubset()

◆ suppressNonMinimumSubset()

◆ width()

◆ yOffset()

Field Documentation

◆ rows_

◆ width_