This class implements a point tracker able to track points between concurrent frames and stores previous points in a database. More...

Public Types
enum	TrackingMode : uint32_t { TM_SSD_7 , TM_SSD_15 , TM_SSD_31 , TM_ZM_SSD_7 , TM_ZM_SSD_15 , TM_ZM_SSD_31 , TM_END }
	Definition of individual tracking modes. More...

typedef std::vector< Vectors2 >	PointTracks
	Definition of a vector holding 2D vectors. More...

Public Member Functions
	PointTracker ()
	Creates a new point tracker. More...

	PointTracker (PointTracker &&pointTracker) noexcept
	Move constructor. More...

	PointTracker (const PointTracker &pointTracker)
	Copy constructor. More...

void	setTrackingMode (const TrackingMode trackingMode)
	Sets or changes the tracking mode. More...

TrackingMode	trackingMode () const
	Returns the current tracking mode. More...

Index32	newFrame (const Frame &yFrame, Worker *worker=nullptr)
	Tracks object points (feature points) in a new frame. More...

PointTracks	pointTracks (const Index32 imageIndex, const unsigned int maximalLength=(unsigned int)(-1))
	Returns the point tracks for all object points. More...

void	clearUpTo (const unsigned int frameIndex)
	Removes all entries from the tracking database older than a specified frame index. More...

void	clear ()
	Clears the database containing the object points and their corresponding image points. More...

Database &	database ()
	Returns the internal database storing the topology of the tracked points. More...

PointTracker &	operator= (PointTracker &&pointTracker) noexcept
	Move operator. More...

PointTracker &	operator= (const PointTracker &pointTracker)
	Assign operator. More...

Static Public Attributes
static constexpr Index32	invalidFrameIndex = Index32(-1)
	Definition of an invalid frame index. More...

Protected Member Functions
void	detectNewFeaturePoints (const Frame &yFrame, Geometry::SpatialDistribution::OccupancyArray &occupancyArray, Vectors2 &newFeaturePoints, Worker *worker=nullptr)
	Detects new feature points in empty regions of the provided frame. More...

Static Protected Member Functions
static bool	trackFeaturePoints (const TrackingMode trackingMode, const CV::FramePyramid &previousFramePyramid, const CV::FramePyramid &currentFramePyramid, Vectors2 &previousImagePoints, Vectors2 &currentImagePoints, Indices32 &validIndices, Worker *worker)
	Tracks feature points from one frame (pyramid) to another frame (pyramid). More...

Protected Attributes
TrackingMode	trackingMode_ = TM_ZM_SSD_7
	The tracking mode to be used. More...

Database	database_
	The database storing the object points (feature points) and their corresponding image points. More...

CV::FramePyramid	previousFramePyramid_
	The frame pyramid of the previous frame. More...

CV::FramePyramid	currentFramePyramid_
	The frame pyramid of the current frame. More...

Index32	previousFrameIndex_ = invalidFrameIndex
	The index of the previous frame. More...

unsigned int	featurePointStrengthThreshold_ = 15u
	Threshold for strengths of feature points, with range [1, 255]. More...

unsigned int	binSize_ = 40u
	The size of each bin (edge length) in pixel controlling whether new feature points will be added in an empty region. More...

Lock	lock_
	The lock for this tracker. More...

Detailed Description

This class implements a point tracker able to track points between concurrent frames and stores previous points in a database.

The tracker determines feature points in the very first frame - and stored as object points (feature points).
Those points are tracked from one frame to another frame as long as possible.
All points are tracked from the previous frame to the current frame (and not from a common reference frame to the current frame).
Whenever an object point (feature point) is lost the tracker will add a new feature point in the empty region - so that the tracker is always tracking a high number of feature points.
Tracking is based on matches between small image patches around the image points.

Member Typedef Documentation

◆ PointTracks

typedef std::vector<Vectors2> Ocean::Tracking::Point::PointTracker::PointTracks

Definition of a vector holding 2D vectors.

Member Enumeration Documentation

◆ TrackingMode

enum Ocean::Tracking::Point::PointTracker::TrackingMode : uint32_t

Definition of individual tracking modes.

Enumerator
TM_SSD_7	Sum square differences tracking with 7 pixel image patch.
TM_SSD_15	Sum square differences tracking with 15 pixel image patch.
TM_SSD_31	Sum square differences tracking with 31 pixel image patch.
TM_ZM_SSD_7	Zero-mean sum square differences tracking with 7 pixel image patch.
TM_ZM_SSD_15	Zero-mean sum square differences tracking with 15 pixel image patch.
TM_ZM_SSD_31	Zero-mean sum square differences tracking with 31 pixel image patch.
TM_END	End mode.

Constructor & Destructor Documentation

◆ PointTracker() [1/3]

Ocean::Tracking::Point::PointTracker::PointTracker ( )

Creates a new point tracker.

◆ PointTracker() [2/3]

Ocean::Tracking::Point::PointTracker::PointTracker ( PointTracker && pointTracker )

noexcept

Move constructor.

Parameters

pointTracker The tracker object to be moved

◆ PointTracker() [3/3]

Ocean::Tracking::Point::PointTracker::PointTracker ( const PointTracker & pointTracker )

Copy constructor.

Parameters

pointTracker The tracker object to be copied

Member Function Documentation

◆ clear()

void Ocean::Tracking::Point::PointTracker::clear ( )

inline

Clears the database containing the object points and their corresponding image points.

See also: clearUpTo().

◆ clearUpTo()

void Ocean::Tracking::Point::PointTracker::clearUpTo ( const unsigned int frameIndex )

Removes all entries from the tracking database older than a specified frame index.

Parameters

frameIndex The index of the frame which will be the first frame in the database for which data exists

See also: clear().

◆ database()

Database & Ocean::Tracking::Point::PointTracker::database ( )

inline

Returns the internal database storing the topology of the tracked points.

Beware: This function is not thread-safe.

Returns: The tracker's database

◆ detectNewFeaturePoints()

void Ocean::Tracking::Point::PointTracker::detectNewFeaturePoints	(	const Frame &	yFrame,
		Geometry::SpatialDistribution::OccupancyArray &	occupancyArray,
		Vectors2 &	newFeaturePoints,
		Worker *	worker = `nullptr`
	)

protected

Detects new feature points in empty regions of the provided frame.

Parameters

yFrame	The provided frame in which new feature points will be detected, must have pixel format FORMAT_Y8, must be valid
occupancyArray	The occupancy array specifying empty and non-empty regions in the frame, must be valid
newFeaturePoints	The resulting new feature points
worker	Optional worker object to distribute the computation

◆ newFrame()

Index32 Ocean::Tracking::Point::PointTracker::newFrame	(	const Frame &	yFrame,
		Worker *	worker = `nullptr`
	)

Tracks object points (feature points) in a new frame.

Parameters

yFrame	The new frame in which the points will be tracked, must have pixel format FORMAT_Y8, must be valid
worker	Optional worker object to distribute the computation

Returns: The index of the new frame, 'invalidFrameIndex' if something went wrong

◆ operator=() [1/2]

PointTracker& Ocean::Tracking::Point::PointTracker::operator= ( const PointTracker & pointTracker )

Assign operator.

Parameters

pointTracker The tracker object to be moved

Returns: Reference to this object

◆ operator=() [2/2]

PointTracker& Ocean::Tracking::Point::PointTracker::operator= ( PointTracker && pointTracker )

noexcept

Move operator.

Parameters

pointTracker The tracker object to be moved

Returns: Reference to this object

◆ pointTracks()

PointTracks Ocean::Tracking::Point::PointTracker::pointTracks	(	const Index32	imageIndex,
		const unsigned int	maximalLength = `(unsigned int)(-1)`
	)

Returns the point tracks for all object points.

One track is a connected path of images points belonging to one object point (feature point).

Parameters

imageIndex	The index of the frame for which the tracks will be provided
maximalLength	The maximal length of each track (the maximal number of image points for each object point), with range [1, infinity)

Returns: The tracks of tracked object points starting at the specified frame (and going into the past)

◆ setTrackingMode()

void Ocean::Tracking::Point::PointTracker::setTrackingMode ( const TrackingMode trackingMode )

inline

Sets or changes the tracking mode.

Parameters

trackingMode The new tracking mode

◆ trackFeaturePoints()

static bool Ocean::Tracking::Point::PointTracker::trackFeaturePoints	(	const TrackingMode	trackingMode,
		const CV::FramePyramid &	previousFramePyramid,
		const CV::FramePyramid &	currentFramePyramid,
		Vectors2 &	previousImagePoints,
		Vectors2 &	currentImagePoints,
		Indices32 &	validIndices,
		Worker *	worker
	)

staticprotected

Tracks feature points from one frame (pyramid) to another frame (pyramid).

Parameters

trackingMode	The tracking mode to be used, must be valid
previousFramePyramid	The frame pyramid of the previous frame, must be valid
currentFramePyramid	The frame pyramid of the current frame, must be valid
previousImagePoints	The image points located in the previous frame which will be tracked to the current frame, at least one point
currentImagePoints	The resulting image points located in the current image, one for each previous image points
validIndices	The indices of all point correspondences that could be tracked reliably (all other correspondences are invalid)
worker	Optional worker object to distribute the computation

Returns: True, if succeeded

◆ trackingMode()

PointTracker::TrackingMode Ocean::Tracking::Point::PointTracker::trackingMode ( ) const

inline

Returns the current tracking mode.

Returns: The point tracker's tracking mode

Field Documentation

◆ binSize_

unsigned int Ocean::Tracking::Point::PointTracker::binSize_ = 40u

protected

The size of each bin (edge length) in pixel controlling whether new feature points will be added in an empty region.

◆ currentFramePyramid_

CV::FramePyramid Ocean::Tracking::Point::PointTracker::currentFramePyramid_

protected

The frame pyramid of the current frame.

◆ database_

Database Ocean::Tracking::Point::PointTracker::database_

protected

The database storing the object points (feature points) and their corresponding image points.

◆ featurePointStrengthThreshold_

unsigned int Ocean::Tracking::Point::PointTracker::featurePointStrengthThreshold_ = 15u

protected

Threshold for strengths of feature points, with range [1, 255].

◆ invalidFrameIndex

constexpr Index32 Ocean::Tracking::Point::PointTracker::invalidFrameIndex = Index32(-1)

staticconstexpr

Definition of an invalid frame index.

◆ lock_

Lock Ocean::Tracking::Point::PointTracker::lock_

mutableprotected

The lock for this tracker.

◆ previousFrameIndex_

Index32 Ocean::Tracking::Point::PointTracker::previousFrameIndex_ = invalidFrameIndex

protected

The index of the previous frame.

◆ previousFramePyramid_

CV::FramePyramid Ocean::Tracking::Point::PointTracker::previousFramePyramid_

protected

The frame pyramid of the previous frame.

◆ trackingMode_

TrackingMode Ocean::Tracking::Point::PointTracker::trackingMode_ = TM_ZM_SSD_7

protected

The tracking mode to be used.

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

PointTracker.h

Public Types

Public Member Functions

Static Public Attributes

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Detailed Description

Member Typedef Documentation

◆ PointTracks

Member Enumeration Documentation

◆ TrackingMode

Constructor & Destructor Documentation

◆ PointTracker() [1/3]

◆ PointTracker() [2/3]

◆ PointTracker() [3/3]

Member Function Documentation

◆ clear()

◆ clearUpTo()

◆ database()

◆ detectNewFeaturePoints()

◆ newFrame()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ pointTracks()

◆ setTrackingMode()

◆ trackFeaturePoints()

◆ trackingMode()

Field Documentation

◆ binSize_

◆ currentFramePyramid_

◆ database_

◆ featurePointStrengthThreshold_

◆ invalidFrameIndex

◆ lock_

◆ previousFrameIndex_

◆ previousFramePyramid_

◆ trackingMode_