frc::AprilTagPoseEstimator Class Reference

Pose estimators for AprilTag tags. More...

#include <frc/apriltag/AprilTagPoseEstimator.h>

Classes
struct	Config
	Configuration for the pose estimator. More...

Public Member Functions
	AprilTagPoseEstimator (const Config &config)
	Creates estimator. More...
void	SetConfig (const Config &config)
	Sets estimator configuration. More...
const Config &	GetConfig () const
	Gets estimator configuration. More...
Transform3d	EstimateHomography (const AprilTagDetection &detection) const
	Estimates the pose of the tag using the homography method described in [1]. More...
Transform3d	EstimateHomography (std::span< const double, 9 > homography) const
	Estimates the pose of the tag using the homography method described in [1]. More...
AprilTagPoseEstimate	EstimateOrthogonalIteration (const AprilTagDetection &detection, int nIters) const
	Estimates the pose of the tag. More...
AprilTagPoseEstimate	EstimateOrthogonalIteration (std::span< const double, 9 > homography, std::span< const double, 8 > corners, int nIters) const
	Estimates the pose of the tag. More...
Transform3d	Estimate (const AprilTagDetection &detection) const
	Estimates tag pose. More...
Transform3d	Estimate (std::span< const double, 9 > homography, std::span< const double, 8 > corners) const
	Estimates tag pose. More...

Detailed Description

Pose estimators for AprilTag tags.

Constructor & Destructor Documentation

AprilTagPoseEstimator()

frc::AprilTagPoseEstimator::AprilTagPoseEstimator ( const Config &  config )

inlineexplicit

Creates estimator.

Parameters

config

Configuration

Member Function Documentation

Estimate() [1/2]

Transform3d frc::AprilTagPoseEstimator::Estimate

(

const AprilTagDetection &

detection

)

const

Estimates tag pose.

This method is an easier to use interface to EstimatePoseOrthogonalIteration(), running 50 iterations and returning the pose with the lower object-space error.

Parameters

detection

Tag detection

Returns

Pose estimate

Estimate() [2/2]

Transform3d frc::AprilTagPoseEstimator::Estimate	(	std::span< const double, 9 >	homography,
		std::span< const double, 8 >	corners
	)		const

Estimates tag pose.

This method is an easier to use interface to EstimatePoseOrthogonalIteration(), running 50 iterations and returning the pose with the lower object-space error.

Parameters

homography	Homography 3x3 matrix data
corners	Corner point array (X and Y for each corner in order)

Returns

Pose estimate

EstimateHomography() [1/2]

Transform3d frc::AprilTagPoseEstimator::EstimateHomography

(

const AprilTagDetection &

detection

)

const

Estimates the pose of the tag using the homography method described in [1].

Parameters

detection

Tag detection

Returns

Pose estimate

EstimateHomography() [2/2]

Transform3d frc::AprilTagPoseEstimator::EstimateHomography

(

std::span< const double, 9 >

homography

)

const

Estimates the pose of the tag using the homography method described in [1].

Parameters

homography

Homography 3x3 matrix data

Returns

Pose estimate

EstimateOrthogonalIteration() [1/2]

AprilTagPoseEstimate frc::AprilTagPoseEstimator::EstimateOrthogonalIteration	(	const AprilTagDetection &	detection,
		int	nIters
	)		const

Estimates the pose of the tag.

This returns one or two possible poses for the tag, along with the object-space error of each.

This uses the homography method described in [1] for the initial estimate. Then Orthogonal Iteration [2] is used to refine this estimate. Then [3] is used to find a potential second local minima and Orthogonal Iteration is used to refine this second estimate.

[1]: E. Olson, “Apriltag: A robust and flexible visual fiducial system,” in 2011 IEEE International Conference on Robotics and Automation, May 2011, pp. 3400–3407. [2]: Lu, G. D. Hager and E. Mjolsness, "Fast and globally convergent pose estimation from video images," in IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 22, no. 6, pp. 610-622, June 2000. doi: 10.1109/34.862199 [3]: Schweighofer and A. Pinz, "Robust Pose Estimation from a Planar Target," in IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 28, no. 12, pp. 2024-2030, Dec. 2006. doi: 10.1109/TPAMI.2006.252

Parameters

detection	Tag detection
nIters	Number of iterations

Returns

Initial and (possibly) second pose estimates

EstimateOrthogonalIteration() [2/2]

AprilTagPoseEstimate frc::AprilTagPoseEstimator::EstimateOrthogonalIteration	(	std::span< const double, 9 >	homography,
		std::span< const double, 8 >	corners,
		int	nIters
	)		const

Estimates the pose of the tag.

This returns one or two possible poses for the tag, along with the object-space error of each.

Parameters

homography	Homography 3x3 matrix data
corners	Corner point array (X and Y for each corner in order)
nIters	Number of iterations

Returns

Initial and (possibly) second pose estimates

GetConfig()

const Config & frc::AprilTagPoseEstimator::GetConfig ( ) const

inline

Gets estimator configuration.

Returns

Configuration

SetConfig()

void frc::AprilTagPoseEstimator::SetConfig ( const Config &  config )

inline

Sets estimator configuration.

Parameters

config

Configuration

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

• frc/apriltag/AprilTagPoseEstimator.h