lti::blobEM::gaussEllipse Class Reference

An internal class of lti::blobEM for handling 2D gaussian ellipses. More...

#include <ltiBlobEM.h>

Collaboration diagram for lti::blobEM::gaussEllipse:

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List of all members.

Public Member Functions
bool	from2x2Covariance (const lti::matrix< double > &cov, const bool &constraints=true)
bool	fromEllipse (const gaussEllipse &other, const bool &constraints=true)
bool	to2x2Covariance (lti::matrix< double > &cov) const
Public Attributes
Ellipse properties
lti::tpoint< double >	center
double	lambda1
double	lambda2
double	angle
Ellipse constraints
Use these to indicate constraints for the properties of an ellipse. NOTE: constraining properties can make it impossible for the EM-Algorithm to converge. Use with caution, preferably only for one component amongst several!
bool	constrainCenter
bool	constrainShape
bool	constrainArea
bool	constrainAngle
Constraint tolerances
Setting these to values > 0 (default) relaxes the constraint conditions.
double	centerTolerance
double	shapeTolerance
double	areaTolerance
double	angleTolerance

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Detailed Description

An internal class of lti::blobEM for handling 2D gaussian ellipses.

The properties can be set manually.

Another possibility is to obtain the properties from a 2x2 covariance matrix (except center) or another ellipse, either considering constraints or not.

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Member Function Documentation

bool lti::blobEM::gaussEllipse::from2x2Covariance	(	const lti::matrix< double > &	cov,
		const bool &	constraints = true
	)

Get Ellipse properties lambda and angle from a 2x2 covariance matrix considering shape, size, and/or angle constraints, if desired.

Note: center can NOT be obtained from covariance.

Returns false, if not possible

bool lti::blobEM::gaussEllipse::fromEllipse	(	const gaussEllipse &	other,
		const bool &	constraints = true
	)

Get all ellipse properties (center, lambda, angle) from another ellipse considering center, shape, size, and/or angle constraints, if desired.

THIS IS NOT A COPY METHOD!!!

Returns false, if not possible.

bool lti::blobEM::gaussEllipse::to2x2Covariance

(

lti::matrix< double > &

cov

)

const

Generate 2x2 covariance matrix with ellipse params lambda and angle.

Returns false, if not possible

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Member Data Documentation

double lti::blobEM::gaussEllipse::angle

Angle of main axis (-Pi/2 to +Pi/2).

Second axis is perpendicular to main axis.

double lti::blobEM::gaussEllipse::angleTolerance

The (+/-) angle tolerance (default = 0).

Reasonable range is from 0 to Pi/2, since this is Pi/2 cyclic.

double lti::blobEM::gaussEllipse::areaTolerance

The relative size tolerance (default = 0), which means Ellipse area may change in range.

with

lti::tpoint<double> lti::blobEM::gaussEllipse::center

Center of ellipse.

double lti::blobEM::gaussEllipse::centerTolerance

The center tolerance as maximum Euclidean distance in pixel.

(default = 0)

bool lti::blobEM::gaussEllipse::constrainAngle

keep orientation angle within angleTolerance (default = false)

bool lti::blobEM::gaussEllipse::constrainArea

keep area size (lambda1*lambda2) within areaTolerance (default = false)

bool lti::blobEM::gaussEllipse::constrainCenter

keep center within centerTolerance (default = false)

bool lti::blobEM::gaussEllipse::constrainShape

keep shape (lambda1/lambda2) within shapeTolerance (default = false)

double lti::blobEM::gaussEllipse::lambda1

Variance along main axis (eigenvalue 1).

Ensure lambda1 to be > lambda2 for plausibility.

Note: This is not the standard deviation! For visualization of an ellipse use std dev.

double lti::blobEM::gaussEllipse::lambda2

Variance along second axis (eigenvalue 2).

Note: This is not the standard deviation! For visualization of an ellipse use std dev.

double lti::blobEM::gaussEllipse::shapeTolerance

The relative shape tolerance (default = 0).

NOT CONSIDERED YET!!! Development in Progress!

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

• ltiBlobEM.h