Utility class that allows for 6D pose estimation from a set of at least 4 coplanar points. More...

#include <CoplanarPointPoseEstimator.h>

Inheritance diagram for icl::geom::CoplanarPointPoseEstimator:

Classes
struct	RANSACSpec
	Parameter struct that is used to specify optional RANSAC parameters for the internal pose estimation. More...

Public Types
enum	ReferenceFrame { cameraFrame, worldFrame }
	Reference frame enumeration. More...

enum	PoseEstimationAlgorithm { HomographyBasedOnly, SimplexSampling, SamplingCoarse, SamplingMedium, SamplingFine, SamplingCustom }
	Algorithm, that is used for pose-estimation. More...

Public Types inherited from icl::utils::Configurable
typedef Function< void, const Property & >	Callback
	Function type for changed properties. More...

Public Member Functions
	CoplanarPointPoseEstimator (ReferenceFrame returnedPosesReferenceFrame=worldFrame, PoseEstimationAlgorithm a=SimplexSampling, const RANSACSpec &spec=RANSACSpec())
	Default constructor with given reference-frame for the returned poses. More...

	~CoplanarPointPoseEstimator ()
	Destructor. More...

	CoplanarPointPoseEstimator (const CoplanarPointPoseEstimator &other)
	Copy constructor. More...

CoplanarPointPoseEstimator &	operator= (const CoplanarPointPoseEstimator &other)
	Assignment operator. More...

ReferenceFrame	getReferenceFrame () const
	returns the current reference frame value More...

void	setReferenceFrame (ReferenceFrame f)
	sets the refernce-frame property More...

math::FixedMatrix< float, 4, 4 >	getPose (int n, const utils::Point32f modelPoints, const utils::Point32f imagePoints, const Camera &cam)
	main working function that estimates the pose from given model- and image points More...

Public Member Functions inherited from icl::utils::Configurable
virtual	~Configurable ()
	virtual destructor More...

	Configurable (const Configurable &other)
	Copy constructor. More...

Configurable &	operator= (const Configurable &other)
	Assignment operator. More...

void	setConfigurableID (const std::string &ID)
	sets the ID of this configurable More...

const std::string &	getConfigurableID () const
	returns the configurables static ID More...

bool	isOrderedFlagSet () const
	returns whether the ordered flag is set More...

void	deactivateProperty (const std::string &pattern)
	adds an additional deativation pattern More...

void	deleteDeactivationPattern (const std::string &pattern)
	removed a formerly added deactivation pattern More...

std::vector< std::string >	getPropertyListWithoutDeactivated () const
	this returns a filtered list of properties (using all filters added by deactivateProperty) More...

virtual void	adaptProperty (const std::string &name, const std::string &newType, const std::string &newInfo, const std::string &newToolTip)
	this function can be used to adapt a specific property afterwards More...

void	registerCallback (const Callback &cb)
	add a callback for changed properties More...

void	removedCallback (const Callback &cb)
	removes a callback that was registered before More...

void	syncChangesTo (Configurable *others, int num=1)
	this can be used to let this instance also apply property changes to others More...

virtual void	setPropertyValue (const std::string &propertyName, const Any &value)
	sets a property value More...

virtual std::vector< std::string >	getPropertyList () const
	returns a list of All properties, that can be set using setProperty More...

virtual bool	supportsProperty (const std::string &propertyName) const
	base implementation for property check (seaches in the property list) More...

virtual void	saveProperties (const std::string &filename, const std::vector< std::string > &propertiesToSkip=EMPTY_VEC) const
	writes all available properties into a file More...

virtual void	loadProperties (const std::string &filename, const std::vector< std::string > &propertiesToSkip=EMPTY_VEC)
	reads a camera config file from disc More...

virtual std::string	getPropertyType (const std::string &propertyName) const
	get type of property More...

virtual std::string	getPropertyInfo (const std::string &propertyName) const
	get information of a properties valid values More...

virtual Any	getPropertyValue (const std::string &propertyName) const
	returns the current value of a property or a parameter More...

virtual std::string	getPropertyToolTip (const std::string &propertyName) const
	returns the tooltip description for a given property More...

virtual int	getPropertyVolatileness (const std::string &propertyName) const
	Returns whether this property may be changed internally. More...

Private Member Functions
void	propertyChangedCallback (const Property &p)
	Internally used to sync property settings with internal data. More...

void	robustPoseCorrection (int n, const utils::Point32f modelPoints, const utils::Point32f normalizedImagePoints)
	Internally used to correct the first transformation matrix using robust pose estimation algorithm. More...

math::FixedMatrix< float, 4, 4 >	getPoseInternal (PoseEstimationAlgorithm a, int n, const utils::Point32f modelPoints, const utils::Point32f imagePoints, const utils::Point32f *normalizedImagePoints, const Camera &cam)
	internal utility function More...

Private Attributes
Data *	data
	Internally used data pointer. More...

Additional Inherited Members
Static Public Member Functions inherited from icl::utils::Configurable
static std::string	create_default_ID (const std::string &prefix)
	this function can be used in subclasses to create a default ID More...

static Configurable *	get (const std::string &id)
	returns configurable by given ID More...

static void	register_configurable_type (const std::string &classname, Function< Configurable * > creator)
	registers a configurable type More...

static std::vector< std::string >	get_registered_configurables ()
	returns a list of all registered configurable classnames More...

static Configurable *	create_configurable (const std::string &classname)
	creates a configurable by given name More...

Static Public Attributes inherited from icl::utils::Configurable
static const std::vector< std::string >	EMPTY_VEC
	used as shortcut – just an empty vector of std::strings More...

Protected Member Functions inherited from icl::utils::Configurable
void	addProperty (const std::string &name, const std::string &type, const std::string &info, const Any &value=Any(), const int volatileness=0, const std::string &tooltip=std::string())
	This can be used by derived classes to store supported properties in the internal list. More...

void	addChildConfigurable (Configurable *configurable, const std::string &childPrefix="")
	This adds another configurable as child. More...

void	removeChildConfigurable (Configurable *configurable)
	removes the given child configurable More...

Property &	prop (const std::string &propertyName)
	this CAN be used e.g. to store a property value in internal property-list More...

const Property &	prop (const std::string &propertyName) const
	this CAN be used e.g. to store a property value in internal property-list More...

	Configurable (const std::string &ID="", bool ordered=true)
	create this configurable with given ID More...

void	call_callbacks (const std::string &propertyName, const Configurable *caller) const
	calls all registered callbacks More...

Protected Attributes inherited from icl::utils::Configurable
std::vector< Callback >	callbacks
	internally managed list of callbacks More...

Detailed Description

Utility class that allows for 6D pose estimation from a set of at least 4 coplanar points.

General Information

In contrast to the POSIT algorithms (see icl::Posit), this class is able to compute the 6D-pose of an object from coplanar points.

Pose Detection Problem

Given at least 4 model-points (which are 2D because of the fact, that they have to be coplanar), where no subset of 3 points is collinear, and a set of corresponding pixel-locations of these points, the pose-estimation problem can be redefined as homography problem.

The Object Coordinate Frame

As all reference points of the object are coplanar, you can define the objects coordinate in that way that all reference points lie within the z=0 plane. As the algorithm uses this as prior knowledge, the CoplanarPointPoseEstimator::getPose interface does allow to pass 2D object reference points only.

Algorithms

We implemented the algorithm from the paper "Pose estimation based on four coplanar point correspondences" written by Yang et. al. and published 2009. Internally, a 9 by 2N matrix A is created. The solution for the pose detection problem is basically achieved by minimizing |Ax| using SVD. Finally, the resulting x can be used to obtain the transformation matrix. We also added one heuristic to the method described in the paper above. As the projection of a plane is ambiguous (you can project from the front and from the back), we always use always use the solution, where the resulting z-value is in front of the camera (Otherwise, we would not be able to see it). Mathematically, this means, that we do not always use x, but sometimes also -x, which obviously leads to the same error |Ax|.

Reference Frames

CoplanarPointPoseEstimator instances can be set up to return the estimated pose w.r.t. the world frame or with respect to the camera frame. If you obtain the pose w.r.t. the camera frame, you have to multiply it with the inverted camera coordinate system transformation matrix.

Integration with ICL's Scene class

In order to use the CoplanarPointPoseEstimator to estimate an objects pose matrix for visualization using an instance of the icl::Scene class, you can simply define an objects base vertices in the object coordinate frame:
e.g. (1,1,1,1), (1, 1,-1,1), ... for a unity cube. For moving these points to their real location in the 3D scene, you simply have to transform these vectors by the obtained 'w.r.t. world frame' transformation matrix.

Benchmarks:

Simple Pose estimation with 4 points needs about 80 ns on an Intel(R) Xeon(R) E5530 (2.40GHz). If 9 points are used, it needs about 110 ns.

Enabling RANSAC

As a new feature, the pose estimation step can be optimized using RANSAC internally. @TODO perhaps, we need some more text here !

Member Enumeration Documentation

◆ PoseEstimationAlgorithm

enum icl::geom::CoplanarPointPoseEstimator::PoseEstimationAlgorithm

Algorithm, that is used for pose-estimation.

TODO: describe the algorithms

Enumerator
HomographyBasedOnly	uses the above described algorithm (Algorithms) only
SimplexSampling	performs simplex sampling for optimization (very fast and very accurate!
SamplingCoarse	use some predefined sampling parameters for brute force coase sampling (fast)
SamplingMedium	use some predefined sampling parameters for brute force medium sampling (average speed)
SamplingFine	use some predefined sampling parameters for brute force fine sampling (slow)
SamplingCustom	uses custom properties to define sampling parameters for brute force sampling

◆ ReferenceFrame

enum icl::geom::CoplanarPointPoseEstimator::ReferenceFrame

Reference frame enumeration.

Enumerator
cameraFrame	poses are returned w.r.t. the camera frame
worldFrame	poses are returned w.r.t. the world frame

Constructor & Destructor Documentation

◆ CoplanarPointPoseEstimator() [1/2]

icl::geom::CoplanarPointPoseEstimator::CoplanarPointPoseEstimator	(	ReferenceFrame	returnedPosesReferenceFrame = `worldFrame`,
		PoseEstimationAlgorithm	a = `SimplexSampling`,
		const RANSACSpec &	spec = `RANSACSpec()`
	)

Default constructor with given reference-frame for the returned poses.

Please note that the Downhill Simplex based pose optimization is very accurate and very fast. Using other modes does usually slowdown the pose estimation process and also decrease the result quality. Hovever the brute force search is still provided due to 'historic' reasons.

Parameters

spec	Optionally the CoplanarPointPoseEstimator can be set up to use RANSAC to automatically filter out invalid points by means for stochastic sampling.

◆ ~CoplanarPointPoseEstimator()

icl::geom::CoplanarPointPoseEstimator::~CoplanarPointPoseEstimator ( )

Destructor.

◆ CoplanarPointPoseEstimator() [2/2]

icl::geom::CoplanarPointPoseEstimator::CoplanarPointPoseEstimator ( const CoplanarPointPoseEstimator & other )

Copy constructor.

Member Function Documentation

◆ getPose()

math::FixedMatrix<float,4,4> icl::geom::CoplanarPointPoseEstimator::getPose	(	int	n,
		const utils::Point32f *	modelPoints,
		const utils::Point32f *	imagePoints,
		const Camera &	cam
	)

main working function that estimates the pose from given model- and image points

See also: Pose Detection Problem; The Object Coordinate Frame; Algorithms

note: the camera class is only forward-declared for this file

◆ getPoseInternal()

math::FixedMatrix<float,4,4> icl::geom::CoplanarPointPoseEstimator::getPoseInternal	(	PoseEstimationAlgorithm	a,
		int	n,
		const utils::Point32f *	modelPoints,
		const utils::Point32f *	imagePoints,
		const utils::Point32f *	normalizedImagePoints,
		const Camera &	cam
	)

private

internal utility function

◆ getReferenceFrame()

ReferenceFrame icl::geom::CoplanarPointPoseEstimator::getReferenceFrame ( ) const

returns the current reference frame value

◆ operator=()

CoplanarPointPoseEstimator& icl::geom::CoplanarPointPoseEstimator::operator= ( const CoplanarPointPoseEstimator & other )

Assignment operator.

◆ propertyChangedCallback()

void icl::geom::CoplanarPointPoseEstimator::propertyChangedCallback ( const Property & p )

private

Internally used to sync property settings with internal data.

◆ robustPoseCorrection()

void icl::geom::CoplanarPointPoseEstimator::robustPoseCorrection	(	int	n,
		const utils::Point32f *	modelPoints,
		const utils::Point32f *	normalizedImagePoints
	)

private

Internally used to correct the first transformation matrix using robust pose estimation algorithm.

◆ setReferenceFrame()

void icl::geom::CoplanarPointPoseEstimator::setReferenceFrame ( ReferenceFrame f )

sets the refernce-frame property

Member Data Documentation

◆ data

Data* icl::geom::CoplanarPointPoseEstimator::data

private

Internally used data pointer.

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

/Users/alneuman/vm/icl/ICLGeom/src/ICLGeom/CoplanarPointPoseEstimator.h

Classes

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

General Information

Pose Detection Problem

The Object Coordinate Frame

Algorithms

Reference Frames

Integration with ICL's Scene class

Benchmarks:

Enabling RANSAC

Member Enumeration Documentation

◆ PoseEstimationAlgorithm

◆ ReferenceFrame

Constructor & Destructor Documentation

◆ CoplanarPointPoseEstimator() [1/2]

◆ ~CoplanarPointPoseEstimator()

◆ CoplanarPointPoseEstimator() [2/2]

Member Function Documentation

◆ getPose()

◆ getPoseInternal()

◆ getReferenceFrame()

◆ operator=()

◆ propertyChangedCallback()

◆ robustPoseCorrection()

◆ setReferenceFrame()

Member Data Documentation

◆ data