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lti::blobEM::gaussEllipse

lti::blobEM::gaussEllipse Class Reference

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

#include <ltiBlobEM.h>

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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

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.

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

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.

$ angle - angleTolerance <= newAngle <= angle + angleTolerance $

double lti::blobEM::gaussEllipse::areaTolerance
 

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

$ area/a <= newArea <= area*a $ with $ a = (1+areaTolerance)$

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)

$ dist(newCenter - center) < centerTolerance $

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!

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