Package com.irurueta.ar.sfm

Class LMedSRobustSinglePoint3DTriangulator

java.lang.Object

com.irurueta.ar.sfm.RobustSinglePoint3DTriangulator

com.irurueta.ar.sfm.LMedSRobustSinglePoint3DTriangulator

public class LMedSRobustSinglePoint3DTriangulator
extends RobustSinglePoint3DTriangulator

Robustly triangulates 3D points from matched 2D points and their corresponding cameras on several views using LMedS algorithm.

Field Summary

Fields

Modifier and Type	Field	Description
static final double	DEFAULT_STOP_THRESHOLD	Default value to be used for stop threshold.
static final double	MIN_STOP_THRESHOLD	Minimum allowed stop threshold value.
private double	stopThreshold	Threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough.

Fields inherited from class com.irurueta.ar.sfm.RobustSinglePoint3DTriangulator

cameras, confidence, DEFAULT_CONFIDENCE, DEFAULT_MAX_ITERATIONS, DEFAULT_PROGRESS_DELTA, DEFAULT_ROBUST_METHOD, DEFAULT_USE_HOMOGENEOUS_SOLUTION, listener, locked, MAX_CONFIDENCE, MAX_PROGRESS_DELTA, maxIterations, MIN_CONFIDENCE, MIN_ITERATIONS, MIN_PROGRESS_DELTA, MIN_REQUIRED_VIEWS, points2D, progressDelta, useHomogeneousSolution

Constructor Summary

Constructors

Constructor	Description
LMedSRobustSinglePoint3DTriangulator()	Constructor.
LMedSRobustSinglePoint3DTriangulator(RobustSinglePoint3DTriangulatorListener listener)	Constructor.
LMedSRobustSinglePoint3DTriangulator(List<com.irurueta.geometry.Point2D> points, List<com.irurueta.geometry.PinholeCamera> cameras)	Constructor.
LMedSRobustSinglePoint3DTriangulator(List<com.irurueta.geometry.Point2D> points, List<com.irurueta.geometry.PinholeCamera> cameras, RobustSinglePoint3DTriangulatorListener listener)	Constructor.

Method Summary

Modifier and Type	Method	Description
com.irurueta.numerical.robust.RobustEstimatorMethod	getMethod()	Returns method being used for robust estimation.
double	getStopThreshold()	Returns threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough.
void	setStopThreshold(double stopThreshold)	Sets threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough.
com.irurueta.geometry.Point3D	triangulate()	Triangulates provided matched 2D points being projected by each corresponding camera into a single 3D point.

Methods inherited from class com.irurueta.ar.sfm.RobustSinglePoint3DTriangulator

create, create, create, create, create, create, getCameras, getConfidence, getListener, getMaxIterations, getPoints2D, getProgressDelta, getQualityScores, isListenerAvailable, isLocked, isReady, isUseHomogeneousSolution, setConfidence, setListener, setMaxIterations, setPointsAndCameras, setProgressDelta, setQualityScores, setUseHomogeneousSolution

Methods inherited from class java.lang.Object

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

Field Details

DEFAULT_STOP_THRESHOLD

public static final double DEFAULT_STOP_THRESHOLD

Default value to be used for stop threshold. Stop threshold can be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm iterating too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.

See Also:

• Constant Field Values

MIN_STOP_THRESHOLD

public static final double MIN_STOP_THRESHOLD

Minimum allowed stop threshold value.

See Also:

• Constant Field Values

stopThreshold

private double stopThreshold

Threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm iterating too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.

Constructor Details

LMedSRobustSinglePoint3DTriangulator

public LMedSRobustSinglePoint3DTriangulator()

Constructor.

LMedSRobustSinglePoint3DTriangulator

public LMedSRobustSinglePoint3DTriangulator(RobustSinglePoint3DTriangulatorListener listener)

Constructor.

Parameters:

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

LMedSRobustSinglePoint3DTriangulator

public LMedSRobustSinglePoint3DTriangulator(List<com.irurueta.geometry.Point2D> points,
 List<com.irurueta.geometry.PinholeCamera> cameras)

Constructor.

Parameters:

points - Matched 2D points. Each point in the list is assumed to be projected by the corresponding camera in the list.

cameras - List of cameras associated to the matched 2D point on the same position as the camera on the list.

Throws:

IllegalArgumentException - if provided lists don't have the same length or their length is less than 2 views, which is the minimum required to compute triangulation.

LMedSRobustSinglePoint3DTriangulator

public LMedSRobustSinglePoint3DTriangulator(List<com.irurueta.geometry.Point2D> points,
 List<com.irurueta.geometry.PinholeCamera> cameras,
 RobustSinglePoint3DTriangulatorListener listener)

Constructor.

Parameters:

points - Matched 2D points. Each point in the list is assumed to be projected by the corresponding camera in the list.

cameras - List of cameras associated to the matched 2D point on the same position as the camera on the list.

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

Throws:

IllegalArgumentException - if provided lists don't have the same length or their length is less than 2 views, which is the minimum required to compute triangulation.

Method Details

getStopThreshold

public double getStopThreshold()

Returns threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm iterating too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.

Returns:

stop threshold to stop the algorithm prematurely when a certain accuracy has been reached.

setStopThreshold

public void setStopThreshold(double stopThreshold)
                      throws com.irurueta.geometry.estimators.LockedException

Sets threshold to be used to keep the algorithm iterating in case that best estimated threshold using median of residuals is not small enough. Once a solution is found that generates a threshold below this value, the algorithm will stop. The stop threshold can be used to prevent the LMedS algorithm iterating too many times in cases where samples have a very similar accuracy. For instance, in cases where proportion of outliers is very small (close to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would iterate for a long time trying to find the best solution when indeed there is no need to do that if a reasonable threshold has already been reached. Because of this behaviour the stop threshold can be set to a value much lower than the one typically used in RANSAC, and yet the algorithm could still produce even smaller thresholds in estimated results.

Parameters:

stopThreshold - stop threshold to stop the algorithm prematurely when a certain accuracy has been reached.

Throws:

IllegalArgumentException - if provided value is zero or negative.

com.irurueta.geometry.estimators.LockedException - if robust estimator is locked because an estimation is already in progress.

triangulate

public com.irurueta.geometry.Point3D triangulate()
                                          throws com.irurueta.geometry.estimators.LockedException,
com.irurueta.geometry.estimators.NotReadyException,
com.irurueta.numerical.robust.RobustEstimatorException

Triangulates provided matched 2D points being projected by each corresponding camera into a single 3D point. At least 2 matched 2D points and their corresponding 2 cameras are required to compute triangulation. If more views are provided, an averaged solution can be found.

Specified by:

triangulate in class RobustSinglePoint3DTriangulator

Returns:

computed triangulated 3D point.

Throws:

com.irurueta.geometry.estimators.LockedException - if this instance is locked.

com.irurueta.geometry.estimators.NotReadyException - if lists of points and cameras don't have the same length or less than 2 views are provided.

com.irurueta.numerical.robust.RobustEstimatorException - if estimation fails for any reason (i.e. numerical instability, no solution available, etc).

getMethod

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

Returns method being used for robust estimation.

Specified by:

getMethod in class RobustSinglePoint3DTriangulator

Returns:

method being used for robust estimation.