boofcv.alg.geo.calibration

Class CalibrationPlanarGridZhang99

java.lang.Object

boofcv.alg.geo.calibration.CalibrationPlanarGridZhang99

public class CalibrationPlanarGridZhang99
extends java.lang.Object

Full implementation of the Zhang99 camera calibration algorithm using planar calibration targets. First linear approximations of camera parameters are computed, which are then refined using non-linear estimation.

When processing the results be sure to take in account the coordinate system being left or right handed. Calibration works just fine with either coordinate system, but most 3D geometric algorithms assume a right handed coordinate system while most images are left handed.

A listener can be provide that will give status updates and allows requests for early termination. If a request for early termination is made then a RuntimeException will be thrown.

[1] Zhengyou Zhang, "Flexible Camera Calibration By Viewing a Plane From Unknown Orientations,", International Conference on Computer Vision (ICCV'99), Corfu, Greece, pages 666-673, September 1999.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	CalibrationPlanarGridZhang99.Listener

Constructor Summary

Constructors

Constructor and Description
CalibrationPlanarGridZhang99(PlanarCalibrationTarget target, boolean assumeZeroSkew, int numRadialParam) Configures calibration process.

Method Summary

Methods

Modifier and Type	Method and Description
static void	applyDistortion(georegression.struct.point.Point2D_F64 pt, double[] radial) Applies radial distortion to the point.
static Zhang99Parameters	convertIntoZhangParam(java.util.List<georegression.struct.se.Se3_F64> motions, org.ejml.data.DenseMatrix64F K, boolean assumeZeroSkew, double[] distort) Converts results fond in the linear algorithms into Zhang99Parameters
Zhang99Parameters	getOptimized()
protected Zhang99Parameters	initialParam(java.util.List<java.util.List<georegression.struct.point.Point2D_F64>> observations) Find an initial estimate for calibration parameters using linear techniques.
boolean	optimizedParam(java.util.List<java.util.List<georegression.struct.point.Point2D_F64>> observations, java.util.List<georegression.struct.point.Point2D_F64> grid, Zhang99Parameters initial, Zhang99Parameters found, org.ddogleg.optimization.UnconstrainedLeastSquares optimizer) Use non-linear optimization to improve the parameter estimates
boolean	process(java.util.List<java.util.List<georegression.struct.point.Point2D_F64>> observations) Processes observed calibration point coordinates and computes camera intrinsic and extrinsic parameters.
void	setListener(CalibrationPlanarGridZhang99.Listener listener) Used to listen in on progress and request that processing be stopped
void	setOptimizer(org.ddogleg.optimization.UnconstrainedLeastSquares optimizer) Specify which optimization algorithm to use

Methods inherited from class java.lang.Object

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

Constructor Detail

CalibrationPlanarGridZhang99

public CalibrationPlanarGridZhang99(PlanarCalibrationTarget target,
                            boolean assumeZeroSkew,
                            int numRadialParam)

Configures calibration process.

Parameters:

target - Description of the known calibration target

assumeZeroSkew - Should it assumed the camera has zero skew. Typically true.

numRadialParam - Number of radial distortion parameters to consider. Typically 0,1,2.

Method Detail

setListener

public void setListener(CalibrationPlanarGridZhang99.Listener listener)

Used to listen in on progress and request that processing be stopped

Parameters:

listener - The listener

process

public boolean process(java.util.List<java.util.List<georegression.struct.point.Point2D_F64>> observations)

Processes observed calibration point coordinates and computes camera intrinsic and extrinsic parameters.

Parameters:

observations - Set of observed grid locations in pixel coordinates.

Returns:

true if successful and false if it failed

initialParam

protected Zhang99Parameters initialParam(java.util.List<java.util.List<georegression.struct.point.Point2D_F64>> observations)

Find an initial estimate for calibration parameters using linear techniques.

optimizedParam

public boolean optimizedParam(java.util.List<java.util.List<georegression.struct.point.Point2D_F64>> observations,
                     java.util.List<georegression.struct.point.Point2D_F64> grid,
                     Zhang99Parameters initial,
                     Zhang99Parameters found,
                     org.ddogleg.optimization.UnconstrainedLeastSquares optimizer)

Use non-linear optimization to improve the parameter estimates

Parameters:

observations - Observations of calibration points in each image

grid - Location of calibration points on calibration target

initial - Initial estimate of calibration parameters.

found - The refined calibration parameters.

optimizer - Algorithm used to optimize parameters

convertIntoZhangParam

public static Zhang99Parameters convertIntoZhangParam(java.util.List<georegression.struct.se.Se3_F64> motions,
                                      org.ejml.data.DenseMatrix64F K,
                                      boolean assumeZeroSkew,
                                      double[] distort)

Converts results fond in the linear algorithms into Zhang99Parameters

applyDistortion

public static void applyDistortion(georegression.struct.point.Point2D_F64 pt,
                   double[] radial)

Applies radial distortion to the point.

Parameters:

pt - point in calibrated pixel coordinates

radial - radial distortion parameters

setOptimizer

public void setOptimizer(org.ddogleg.optimization.UnconstrainedLeastSquares optimizer)

Specify which optimization algorithm to use

getOptimized

public Zhang99Parameters getOptimized()