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Augmented Reality and 3D reconstruction library
/*
* Copyright (C) 2015 Alberto Irurueta Carro ([email protected])
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.irurueta.ar.calibration;
import com.irurueta.algebra.AlgebraException;
import com.irurueta.algebra.CholeskyDecomposer;
import com.irurueta.algebra.Matrix;
import com.irurueta.algebra.WrongSizeException;
import com.irurueta.geometry.Conic;
import com.irurueta.geometry.ConicNotAvailableException;
import com.irurueta.geometry.DualConic;
import com.irurueta.geometry.DualQuadric;
import com.irurueta.geometry.InvalidPinholeCameraIntrinsicParametersException;
import com.irurueta.geometry.NonSymmetricMatrixException;
import com.irurueta.geometry.PinholeCamera;
import com.irurueta.geometry.PinholeCameraIntrinsicParameters;
import java.io.Serializable;
/**
* The dual image of the absolute conic (DIAC), is the projection of the
* dual absolute quadric using a given pinhole camera.
* In an ideal metric stratum, the dual absolute quadric is equal to the
* identity matrix, except for the bottom-right element, which is zero. In those
* cases the dual image of the absolute conic only depends on the pinhole camera
* intrinsic parameters, and for that reason the DIAC is typically used for
* camera calibration purposes.
*/
public class DualImageOfAbsoluteConic extends DualConic implements Serializable {
/**
* Constructor.
* When working on a metric stratum, the DIAC is directly related by the
* pinhole camera intrinsic parameters as C^-1=K*K'
*
* @param k pinhole camera intrinsic parameters.
*/
public DualImageOfAbsoluteConic(final PinholeCameraIntrinsicParameters k) {
super();
setFromPinholeCameraIntrinsicParameters(k);
}
/**
* Constructor.
* When not working on a metric stratum, the DIAC can be obtained as the
* projection of provided dual absolute quadric using provided camera
*
* @param camera a pinhole camera.
* @param dualAbsoluteQuadric the dual absolute quadric.
*/
public DualImageOfAbsoluteConic(final PinholeCamera camera,
final DualQuadric dualAbsoluteQuadric) {
super();
setFromCameraAndDualAbsoluteQuadric(camera, dualAbsoluteQuadric);
}
/**
* Constructor of this class. This constructor accepts every parameter
* describing a dual conic (parameters a, b, c, d, e, f).
*
* @param a Parameter A of the conic.
* @param b Parameter B of the conic.
* @param c Parameter C of the conic.
* @param d Parameter D of the conic.
* @param e Parameter E of the conic.
* @param f Parameter F of the conic.
*/
public DualImageOfAbsoluteConic(
final double a, final double b, final double c, final double d,
final double e, final double f) {
super(a, b, c, d, e, f);
}
/**
* This method sets the matrix used to describe a dual conic.
* This matrix must be 3x3 and symmetric.
*
* @param m 3x3 Matrix describing the conic.
* @throws IllegalArgumentException Raised when the size of the matrix is
* not 3x3.
* @throws NonSymmetricMatrixException Raised when the conic matrix is not
* symmetric.
*/
public DualImageOfAbsoluteConic(final Matrix m) throws NonSymmetricMatrixException {
super(m);
}
/**
* Constructor without arguments.
*/
protected DualImageOfAbsoluteConic() {
super();
}
/**
* Computes the conic corresponding to this dual conic.
*
* @return A new conic instance of this dual conic.
* @throws ConicNotAvailableException Raised if the rank of the dual conic
* matrix is not complete due to wrong parameters or numerical instability.
*/
@Override
public Conic getConic() throws ConicNotAvailableException {
final ImageOfAbsoluteConic c = new ImageOfAbsoluteConic();
conic(c);
return c;
}
/**
* Sets DIAC parameters from pinhole camera intrinsic parameters when we
* are working in a metric stratum, which is equal to C^-1=K*K'.
*
* @param k pinhole camera intrinsic parameters.
*/
public final void setFromPinholeCameraIntrinsicParameters(
final PinholeCameraIntrinsicParameters k) {
final Matrix kMatrix = k.getInternalMatrix();
try {
setParameters(kMatrix.multiplyAndReturnNew(
kMatrix.transposeAndReturnNew()));
} catch (final WrongSizeException | NonSymmetricMatrixException ignore) {
// never happens
}
}
/**
* Sets DIAC parameters by projecting provided dual absolute quadric using
* provided pinhole camera. This method can be used when not working in a
* metric stratum. The projection is equal to C^-1=P*Q^-1*P'.
*
* @param camera a pinhole camera.
* @param dualAbsoluteQuadric the dual absolute quadric.
*/
public final void setFromCameraAndDualAbsoluteQuadric(final PinholeCamera camera,
final DualQuadric dualAbsoluteQuadric) {
camera.project(dualAbsoluteQuadric, this);
}
/**
* Assuming that we are working in a metric stratum this method obtains the
* internal parameters of a pinhole camera by means of Cholesky
* decomposition.
* To avoid numerical instabilities it is preferred to obtain the
* ImageOfAbsoluteConic corresponding to this instance (using #getConic()
* method), and from there using
* ImageOfAbsoluteConic#getIntrinsicParameters() method, since it is more
* reliable than using cholesky decomposition.
*
* @return the internal parameters of a pinhole camera.
* @throws InvalidPinholeCameraIntrinsicParametersException if pinhole
* camera intrinsic parameters cannot be obtained from this conic instance.
*/
public PinholeCameraIntrinsicParameters getIntrinsicParameters()
throws InvalidPinholeCameraIntrinsicParametersException {
try {
normalize();
// the DIAC is a dual conic, and hence it is symmetric, hence:
// C^-1=K*K'=(K*K')'=(C^-1)'
// C=(K*K')^-1 = K'^-1*K^-1 = (K^-1)'*(K^-1), where K^-1 is still
// upper triangular
final Matrix m = asMatrix();
final Matrix invM = com.irurueta.algebra.Utils.inverse(m);
final CholeskyDecomposer decomposer = new CholeskyDecomposer(invM);
decomposer.decompose();
final Matrix inverseInternalParamsMatrix = decomposer.getR();
final Matrix internalParamsMatrix = com.irurueta.algebra.Utils.inverse(
inverseInternalParamsMatrix);
return new PinholeCameraIntrinsicParameters(internalParamsMatrix);
} catch (final AlgebraException e) {
throw new InvalidPinholeCameraIntrinsicParametersException(e);
}
}
}
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