gramods::gmMisc::EFFOAW Class Reference

This is an end-fitting first-order adaptive window estimator of velocity from samples allowing jittering. More...

#include <EFFOAW.hh>

Classes
struct	Impl

Public Member Functions
	EFFOAW ()
	Creates a new end-fitting first-order adaptive window estimator using the default parameters.
void	setHistoryLength (size_t N)
	Set how many samples should be saved to be used when estimating the velocity.
size_t	getHistoryLength () const
	Get the number of samples that are saved to be used when estimating the velocity.
void	setHistoryDuration (double t)
	Set how old samples should be saved to be used when estimating the velocity.
double	getHistoryDuration () const
	Get how old samples are saved to be used when estimating the velocity.
double	getLastSampleTime (size_t id, size_t N=0)
	Returns the time associated with the last sample associated with the specified id, or -1 if there is no last sample available.
void	addSample (size_t id, Eigen::Vector3d position, double time)
	Add a position sample.
void	removeLastSample (size_t id)
	Remove the last sample for the specified id.
Eigen::Vector3d	estimateVelocity (size_t id, double error, size_t *samples=nullptr) const
	Estimate and return the velocity using samples associated to id.
Eigen::Vector3d	estimatePosition (size_t id, double error, double time, size_t *samples=nullptr) const
	Estimate and return the position using samples associated to id.
void	cleanup (double time=-1)
	Clean-up old samples and unused ids.

Detailed Description

This is an end-fitting first-order adaptive window estimator of velocity from samples allowing jittering.

Units of both length and time can be arbitrarily chosen and the velocity will be estimated as distance over time in the same units.

The class uses std::valarray<double> to represent both position and velocity.

Constructor & Destructor Documentation

EFFOAW()

gramods::gmMisc::EFFOAW::EFFOAW

(

)

Creates a new end-fitting first-order adaptive window estimator using the default parameters.

Member Function Documentation

addSample()

void gramods::gmMisc::EFFOAW::addSample	(	size_t	id,
		Eigen::Vector3d	position,
		double	time
	)

Add a position sample.

Each sample is associated to an id and a time. If a new sample is provided with the same id and time as a previously added sample, this new sample will replace the old.

Parameters

[in]	id	The id to add position sample to.
[in]	position	The position value to use as sample.
[in]	time	The time at which the sample was taken.

cleanup()

void gramods::gmMisc::EFFOAW::cleanup

(

double

time = -1

)

Clean-up old samples and unused ids.

This function should be called from time to time, for example after calling addSample, to avoid too much unnecessary memory usage.

Parameters

time	The current time, to use when estimating if samples are too old, or -1 to use the samples' time.

estimatePosition()

Eigen::Vector3d gramods::gmMisc::EFFOAW::estimatePosition	(	size_t	id,
		double	error,
		double	time,
		size_t *	samples = nullptr
	)		const

Estimate and return the position using samples associated to id.

This is not really a functionality of EFFOAW, but uses the EFFOAW estimated velocity as a means to estimate a position in the immediate future. It is assumed that the specified time occurs after or at the time of the last sample.

Parameters

[in]	id	The id to estimate position for.
[in]	error	An estimate of the position tracking error, used to determine how many samples to include in the averaging.
[in]	time	The time to estimate the position for.
[out]	samples	The number of history samples used in the estimation.

estimateVelocity()

Eigen::Vector3d gramods::gmMisc::EFFOAW::estimateVelocity	(	size_t	id,
		double	error,
		size_t *	samples = nullptr
	)		const

Estimate and return the velocity using samples associated to id.

The velocity will be expressed in chosen units per second.

Parameters

[in]	id	The id to estimate velocity for.
[in]	error	An estimate of the position tracking error, used to determine how many samples to include in the averaging.
[out]	samples	The number of history samples used in the estimation.

getHistoryDuration()

double gramods::gmMisc::EFFOAW::getHistoryDuration

(

)

const

Get how old samples are saved to be used when estimating the velocity.

getHistoryLength()

size_t gramods::gmMisc::EFFOAW::getHistoryLength

(

)

const

Get the number of samples that are saved to be used when estimating the velocity.

getLastSampleTime()

double gramods::gmMisc::EFFOAW::getLastSampleTime	(	size_t	id,
		size_t	N = 0
	)

Returns the time associated with the last sample associated with the specified id, or -1 if there is no last sample available.

Parameters

[in]	id	The id to read off the last sample for.
[in]	N	Read off the Nth last sample, 0 (default) being the last sample.

removeLastSample()

void gramods::gmMisc::EFFOAW::removeLastSample

(

size_t

id

)

Remove the last sample for the specified id.

This will remove the last sample what was actually added to the id; it will not restore a sample that was overwritten by another with the same time.

Parameters

[in]

id

The id to remove the last sample for.

setHistoryDuration()

void gramods::gmMisc::EFFOAW::setHistoryDuration

(

double

t

)

Set how old samples should be saved to be used when estimating the velocity.

setHistoryLength()

void gramods::gmMisc::EFFOAW::setHistoryLength

(

size_t

N

)

Set how many samples should be saved to be used when estimating the velocity.

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

• /home/karlu/private/program/gramods/modules/gmMisc/include/gmMisc/EFFOAW.hh
• /home/karlu/private/program/gramods/modules/gmMisc/src/EFFOAW.cpp