Package com.irurueta.navigation.inertial.calibration.magnetometer

Class RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

java.lang.Object

com.irurueta.navigation.inertial.calibration.magnetometer.RobustKnownHardIronAndFrameMagnetometerCalibrator

com.irurueta.navigation.inertial.calibration.magnetometer.RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

All Implemented Interfaces:

KnownHardIronMagnetometerCalibrator, MagnetometerCalibrator, MagnetometerNonLinearCalibrator, OrderedStandardDeviationFrameBodyMagneticFluxDensityMagnetometerCalibrator, QualityScoredMagnetometerCalibrator

public class RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator
extends RobustKnownHardIronAndFrameMagnetometerCalibrator

Robustly estimates magnetometer soft-iron cross couplings and scaling factors using RANSAC algorithm.

To use this calibrator at least 4 measurements at different known frames must be provided. In other words, magnetometer samples must be obtained at 4 different positions or orientations. Notice that frame velocities are ignored by this calibrator.

Measured magnetic flux density is assumed to follow the model shown below:

     mBmeas = bm + (I + Mm) * mBtrue + w
 

Where: - mBmeas is the measured magnetic flux density. This is a 3x1 vector. - bm is magnetometer hard-iron bias. Ideally, on a perfect magnetometer, this should be a 3x1 zero vector. - I is the 3x3 identity matrix. - Mm is the 3x3 soft-iron matrix containing cross-couplings and scaling factors. Ideally, on a perfect magnetometer, this should be a 3x3 zero matrix. - mBtrue is ground-truth magnetic flux density. This is a 3x1 vector. - w is measurement noise. This is a 3x1 vector.

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	computeAndKeepInliers	Indicates whether inliers must be computed and kept.
private boolean	computeAndKeepResiduals	Indicates whether residuals must be computed and kept.
static final boolean	DEFAULT_COMPUTE_AND_KEEP_INLIERS	Indicates that by default inliers will only be computed but not kept.
static final boolean	DEFAULT_COMPUTE_AND_KEEP_RESIDUALS	Indicates that by default residuals will only be computed but not kept.
static final double	DEFAULT_THRESHOLD	Constant defining default threshold to determine whether samples are inliers or not.
static final double	MIN_THRESHOLD	Minimum value that can be set as threshold.
private double	threshold	Threshold to determine whether samples are inliers or not when testing possible solutions.

Fields inherited from class com.irurueta.navigation.inertial.calibration.magnetometer.RobustKnownHardIronAndFrameMagnetometerCalibrator

confidence, DEFAULT_CONFIDENCE, DEFAULT_KEEP_COVARIANCE, DEFAULT_MAX_ITERATIONS, DEFAULT_PROGRESS_DELTA, DEFAULT_REFINE_PRELIMINARY_SOLUTIONS, DEFAULT_REFINE_RESULT, DEFAULT_ROBUST_METHOD, DEFAULT_USE_COMMON_Z_AXIS, DEFAULT_USE_LINEAR_CALIBRATOR, inliersData, listener, MAX_CONFIDENCE, MAX_PROGRESS_DELTA, maxIterations, measurements, MIN_CONFIDENCE, MIN_ITERATIONS, MIN_PROGRESS_DELTA, MINIMUM_MEASUREMENTS, preliminarySubsetSize, progressDelta, refineResult, running

Constructor Summary

Constructors

Constructor	Description
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator()	Constructor.
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(boolean commonAxisUsed)	Constructor.
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(boolean commonAxisUsed, RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)	Constructor.
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)	Constructor.
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements)	Constructor.
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements, boolean commonAxisUsed)	Constructor.
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements, boolean commonAxisUsed, RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)	Constructor.
RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements, RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	calibrate()	Estimates magnetometer calibration parameters containing soft-iron scale factors and cross-coupling errors.
com.irurueta.numerical.robust.RobustEstimatorMethod	getMethod()	Returns method being used for robust estimation.
double	getThreshold()	Gets threshold to determine whether samples are inliers or not when testing possible solutions.
boolean	isComputeAndKeepInliersEnabled()	Indicates whether inliers must be computed and kept.
boolean	isComputeAndKeepResiduals()	Indicates whether residuals must be computed and kept.
boolean	isQualityScoresRequired()	Indicates whether this calibrator requires quality scores for each measurement or not.
void	setComputeAndKeepInliersEnabled(boolean computeAndKeepInliers)	Specifies whether inliers must be computed and kept.
void	setComputeAndKeepResidualsEnabled(boolean computeAndKeepResiduals)	Specifies whether residuals must be computed and kept.
void	setThreshold(double threshold)	Sets threshold to determine whether samples are inliers or not when testing possible solutions.

Methods inherited from class com.irurueta.navigation.inertial.calibration.magnetometer.RobustKnownHardIronAndFrameMagnetometerCalibrator

attemptRefine, computeError, computePreliminarySolutions, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, create, getConfidence, getEstimatedChiSq, getEstimatedCovariance, getEstimatedMm, getEstimatedMse, getEstimatedMxy, getEstimatedMxz, getEstimatedMyx, getEstimatedMyz, getEstimatedMzx, getEstimatedMzy, getEstimatedSx, getEstimatedSy, getEstimatedSz, getHardIron, getHardIron, getHardIronAsTriad, getHardIronAsTriad, getHardIronMatrix, getHardIronMatrix, getHardIronX, getHardIronXAsMagneticFluxDensity, getHardIronXAsMagneticFluxDensity, getHardIronY, getHardIronYAsMagneticFluxDensity, getHardIronYAsMagneticFluxDensity, getHardIronZ, getHardIronZAsMagneticFluxDensity, getHardIronZAsMagneticFluxDensity, getInitialMm, getInitialMm, getInitialMxy, getInitialMxz, getInitialMyx, getInitialMyz, getInitialMzx, getInitialMzy, getInitialSx, getInitialSy, getInitialSz, getInliersData, getListener, getMagneticModel, getMaxIterations, getMeasurements, getMeasurementType, getMinimumRequiredMeasurements, getPreliminarySubsetSize, getProgressDelta, getQualityScores, isCommonAxisUsed, isCovarianceKept, isLinearCalibratorUsed, isOrderedMeasurementsRequired, isPreliminarySolutionRefined, isReady, isResultRefined, isRunning, setCommonAxisUsed, setConfidence, setCovarianceKept, setHardIron, setHardIron, setHardIron, setHardIronCoordinates, setHardIronCoordinates, setHardIronX, setHardIronX, setHardIronY, setHardIronY, setHardIronZ, setHardIronZ, setInitialCrossCouplingErrors, setInitialMm, setInitialMxy, setInitialMxz, setInitialMyx, setInitialMyz, setInitialMzx, setInitialMzy, setInitialScalingFactors, setInitialScalingFactorsAndCrossCouplingErrors, setInitialSx, setInitialSy, setInitialSz, setLinearCalibratorUsed, setListener, setMagneticModel, setMaxIterations, setMeasurements, setPreliminarySolutionRefined, setPreliminarySubsetSize, setProgressDelta, setQualityScores, setResultRefined, setupWmmEstimator

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

DEFAULT_THRESHOLD

public static final double DEFAULT_THRESHOLD

Constant defining default threshold to determine whether samples are inliers or not.

See Also:

• Constant Field Values

MIN_THRESHOLD

public static final double MIN_THRESHOLD

Minimum value that can be set as threshold. Threshold must be strictly greater than 0.0.

See Also:

• Constant Field Values

DEFAULT_COMPUTE_AND_KEEP_INLIERS

public static final boolean DEFAULT_COMPUTE_AND_KEEP_INLIERS

Indicates that by default inliers will only be computed but not kept.

See Also:

• Constant Field Values

DEFAULT_COMPUTE_AND_KEEP_RESIDUALS

public static final boolean DEFAULT_COMPUTE_AND_KEEP_RESIDUALS

Indicates that by default residuals will only be computed but not kept.

See Also:

• Constant Field Values

threshold

private double threshold

Threshold to determine whether samples are inliers or not when testing possible solutions. The threshold refers to the amount of error on distance between estimated position and distances provided for each sample.

computeAndKeepInliers

private boolean computeAndKeepInliers

Indicates whether inliers must be computed and kept.

computeAndKeepResiduals

private boolean computeAndKeepResiduals

Indicates whether residuals must be computed and kept.

Constructor Details

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator()

Constructor.

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)

Constructor.

Parameters:

listener - listener to be notified of events such as when estimation starts, ends or its progress significantly changes.

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements)

Constructor.

Parameters:

measurements - list of body magnetic flux density measurements with standard deviations taken at different frames (positions and orientations).

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements,
 RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)

Constructor.

Parameters:

measurements - list of body magnetic flux density measurements with standard deviations taken at different frames (positions and orientations).

listener - listener to handle events raised by this calibrator.

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(boolean commonAxisUsed)

Constructor.

Parameters:

commonAxisUsed - indicates whether z-axis is assumed to be common for the accelerometer, gyroscope and magnetometer.

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(boolean commonAxisUsed,
 RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)

Constructor.

Parameters:

commonAxisUsed - indicates whether z-axis is assumed to be common for the accelerometer, gyroscope and magnetometer.

listener - listener to handle events raised by this calibrator.

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements,
 boolean commonAxisUsed)

Constructor.

Parameters:

measurements - list of body magnetic flux density measurements with standard deviations taken at different frames (positions and orientations).

commonAxisUsed - indicates whether z-axis is assumed to be common for the accelerometer, gyroscope and magnetometer.

RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator

public RANSACRobustKnownHardIronAndFrameMagnetometerCalibrator(List<StandardDeviationFrameBodyMagneticFluxDensity> measurements,
 boolean commonAxisUsed,
 RobustKnownHardIronAndFrameMagnetometerCalibratorListener listener)

Constructor.

Parameters:

measurements - list of body magnetic flux density measurements with standard deviations taken at different frames (positions and orientations).

commonAxisUsed - indicates whether z-axis is assumed to be common for the accelerometer, gyroscope and magnetometer.

listener - listener to handle events raised by this calibrator.

Method Details

getThreshold

public double getThreshold()

Gets threshold to determine whether samples are inliers or not when testing possible solutions. The threshold refers to the amount of error on norm between measured specific forces and the ones generated with estimated calibration parameters provided for each sample.

Returns:

threshold to determine whether samples are inliers or not.

setThreshold

public void setThreshold(double threshold)
                  throws com.irurueta.navigation.LockedException

Sets threshold to determine whether samples are inliers or not when testing possible solutions. The threshold refers to the amount of error on norm between measured specific forces and the ones generated with estimated calibration parameters provided for each sample.

Parameters:

threshold - threshold to determine whether samples are inliers or not.

Throws:

IllegalArgumentException - if provided value is equal or less than zero.

com.irurueta.navigation.LockedException - if calibrator is currently running.

isComputeAndKeepInliersEnabled

public boolean isComputeAndKeepInliersEnabled()

Indicates whether inliers must be computed and kept.

Returns:

true if inliers must be computed and kept, false if inliers only need to be computed but not kept.

setComputeAndKeepInliersEnabled

public void setComputeAndKeepInliersEnabled(boolean computeAndKeepInliers)
                                     throws com.irurueta.navigation.LockedException

Specifies whether inliers must be computed and kept.

Parameters:

computeAndKeepInliers - true if inliers must be computed and kept, false if inliers only need to be computed but not kept.

Throws:

com.irurueta.navigation.LockedException - if calibrator is currently running.

isComputeAndKeepResiduals

public boolean isComputeAndKeepResiduals()

Indicates whether residuals must be computed and kept.

Returns:

true if residuals must be computed and kept, false if residuals only need to be computed but not kept.

setComputeAndKeepResidualsEnabled

public void setComputeAndKeepResidualsEnabled(boolean computeAndKeepResiduals)
                                       throws com.irurueta.navigation.LockedException

Specifies whether residuals must be computed and kept.

Parameters:

computeAndKeepResiduals - true if residuals must be computed and kept, false if residuals only need to be computed but not kept.

Throws:

com.irurueta.navigation.LockedException - if calibrator is currently running.

calibrate

public void calibrate()
               throws com.irurueta.navigation.LockedException,
com.irurueta.navigation.NotReadyException,
CalibrationException

Estimates magnetometer calibration parameters containing soft-iron scale factors and cross-coupling errors.

Throws:

com.irurueta.navigation.LockedException - if calibrator is currently running.

com.irurueta.navigation.NotReadyException - if calibrator is not ready.

CalibrationException - if estimation fails for numerical reasons.

getMethod

public com.irurueta.numerical.robust.RobustEstimatorMethod getMethod()

Returns method being used for robust estimation.

Specified by:

getMethod in class RobustKnownHardIronAndFrameMagnetometerCalibrator

Returns:

method being used for robust estimation.

isQualityScoresRequired

public boolean isQualityScoresRequired()

Indicates whether this calibrator requires quality scores for each measurement or not.

Returns:

true if quality scores are required, false otherwise.