Generic implementation for standard M-estimators. More...

#include <rrel_m_est_obj.h>

Inheritance diagram for rrel_m_est_obj:

Public Types
typedef vcl_vector< double > ::const_iterator	vect_const_iter
	The iterators used to pass in values.
typedef vcl_vector< double > ::iterator	vect_iter
	The iterators used to pass out values.
Public Member Functions
	rrel_m_est_obj ()
	Constructor.
virtual	~rrel_m_est_obj ()
	Destructor.
virtual double	fcn (vect_const_iter res_begin, vect_const_iter res_end, vect_const_iter scale_begin, vnl_vector< double > *=0) const
	Evaluate the objective function on heteroscedastic residuals.
virtual double	fcn (vect_const_iter begin, vect_const_iter end, double scale, vnl_vector< double > *=0) const
	Evaluate the objective function on homoscedastic residuals.
virtual void	wgt (vect_const_iter res_begin, vect_const_iter res_end, vect_const_iter scale_begin, vect_iter wgt_begin) const
	Evaluate the objective function on heteroscedastic residuals.
virtual void	wgt (vect_const_iter begin, vect_const_iter end, double scale, vect_iter wgt_begin) const
	Computes the weights for homoscedastic residuals.
virtual double	rho (double u) const =0
	The robust loss function for the M-estimator.
double	rho (double r, double s) const
	The robust loss function for the M-estimator.
virtual double	wgt (double u) const =0
	The weight of the residual.
double	wgt (double r, double s) const
	The weight of the residual.
virtual bool	requires_prior_scale () const
	False.
virtual bool	can_estimate_scale () const
	True if the objective function can estimate scale.
virtual double	scale (vect_const_iter, vect_const_iter) const
	Scale estimate.

Detailed Description

Generic implementation for standard M-estimators.

Most standard M-estimators are defined by a rho and psi functions on a normalised residual. This class allows derived classes to merely implement those two functions, and implements the fcn() and wgt() functions based on rho() and psi(). (See Stewart, "Robust Parameter Estimation in Computer Vision", SIAM Reviews 41, Sept 1999.)

Definition at line 19 of file rrel_m_est_obj.h.

Member Typedef Documentation

typedef vcl_vector<double>::const_iterator rrel_objective::vect_const_iter [inherited]

The iterators used to pass in values.

Since we don't allow member templates, we have to fix on a particular type of container for residuals. Using this typedef will allow things to easily change when member templates are allowed.

Definition at line 27 of file rrel_objective.h.

typedef vcl_vector<double>::iterator rrel_objective::vect_iter [inherited]

The iterators used to pass out values.

Definition at line 30 of file rrel_objective.h.

Constructor & Destructor Documentation

rrel_m_est_obj::rrel_m_est_obj ( ) [inline]

Constructor.

Definition at line 22 of file rrel_m_est_obj.h.

virtual rrel_m_est_obj::~rrel_m_est_obj ( ) [inline, virtual]

Destructor.

Definition at line 25 of file rrel_m_est_obj.h.

Member Function Documentation

virtual bool rrel_objective::can_estimate_scale ( ) const [inline, virtual, inherited]

True if the objective function can estimate scale.

Some objective functions, such as MUSE, can provide an accurate inlier scale estimate.

Reimplemented in rrel_muset_obj, and rrel_lms_obj.

Definition at line 72 of file rrel_objective.h.

double rrel_m_est_obj::fcn	(	vect_const_iter	res_begin,
		vect_const_iter	res_end,
		vect_const_iter	scale_begin,
		vnl_vector< double > *	= `0`
	)		const `[virtual]`

Evaluate the objective function on heteroscedastic residuals.

See also:: rrel_objective::fcn.

Implements rrel_objective.

Definition at line 5 of file rrel_m_est_obj.cxx.

double rrel_m_est_obj::fcn	(	vect_const_iter	begin,
		vect_const_iter	end,
		double	scale,
		vnl_vector< double > *	= `0`
	)		const `[virtual]`

Evaluate the objective function on homoscedastic residuals.

See also:: rrel_objective::fcn.

Implements rrel_objective.

Definition at line 19 of file rrel_m_est_obj.cxx.

virtual bool rrel_m_est_obj::requires_prior_scale ( ) const [inline, virtual]

False.

In general, most M-estimators work quite well with an estimated scale. The scale estimate should be robust, but not necessarily efficient (e.g. MAD scale estimate.)

Implements rrel_objective.

Definition at line 73 of file rrel_m_est_obj.h.

virtual double rrel_m_est_obj::rho ( double u ) const [pure virtual]

The robust loss function for the M-estimator.

u is a normalised residual (i.e. u=r/scale).

Implemented in rrel_tukey_obj, rrel_trunc_quad_obj, and rrel_cauchy_obj.