NonDecomposedPointCorrespondencePinholeCameraRefiner.java
/*
* Copyright (C) 2017 Alberto Irurueta Carro (alberto@irurueta.com)
*
* 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.geometry.refiners;
import com.irurueta.algebra.Matrix;
import com.irurueta.geometry.CoordinatesType;
import com.irurueta.geometry.PinholeCamera;
import com.irurueta.geometry.Point2D;
import com.irurueta.geometry.Point3D;
import com.irurueta.geometry.estimators.LockedException;
import com.irurueta.geometry.estimators.NotReadyException;
import com.irurueta.numerical.EvaluationException;
import com.irurueta.numerical.GradientEstimator;
import com.irurueta.numerical.fitting.LevenbergMarquardtMultiDimensionFitter;
import com.irurueta.numerical.fitting.LevenbergMarquardtMultiDimensionFunctionEvaluator;
import com.irurueta.numerical.robust.InliersData;
import java.util.BitSet;
import java.util.List;
/**
* A pinhole camera refiner using point correspondences and the
* Levenberg-Marquardt algorithm to try to decrease overall error in LMSE terms
* among inlier samples by taking the pinhole camera matrix as a whole without
* decomposition.
* Typically, this refiner is used by a robust estimator, however it can also be
* useful in some other situations.
*/
@SuppressWarnings("DuplicatedCode")
public class NonDecomposedPointCorrespondencePinholeCameraRefiner extends PointCorrespondencePinholeCameraRefiner {
/**
* Default value for the weight applied to errors related to suggested
* camera parameters during computation of projection residuals.
*/
public static final double DEFAULT_SUGGESTION_ERROR_WEIGHT = 2.0;
/**
* Dimensions for refinement.
*/
private static final int REFINE_DIMS = 12;
/**
* Suggestion error weight. This weight is applied to errors related to
* suggested camera parameters during computation of projection residuals.
*/
private double suggestionErrorWeight = DEFAULT_SUGGESTION_ERROR_WEIGHT;
/**
* Constructor.
*/
public NonDecomposedPointCorrespondencePinholeCameraRefiner() {
}
/**
* Constructor.
*
* @param initialEstimation initial estimation to be set.
* @param keepCovariance true if covariance of estimation must be kept after
* refinement, false otherwise.
* @param inliers set indicating which of the provided matches are inliers.
* @param residuals residuals for matched samples.
* @param numInliers number of inliers on initial estimation.
* @param samples1 1st set of paired samples.
* @param samples2 2nd set of paired samples.
* @param refinementStandardDeviation standard deviation used for
* Levenberg-Marquardt fitting.
*/
public NonDecomposedPointCorrespondencePinholeCameraRefiner(
final PinholeCamera initialEstimation, final boolean keepCovariance, final BitSet inliers,
final double[] residuals, final int numInliers, final List<Point3D> samples1, final List<Point2D> samples2,
final double refinementStandardDeviation) {
super(initialEstimation, keepCovariance, inliers, residuals, numInliers, samples1, samples2,
refinementStandardDeviation);
}
/**
* Constructor.
*
* @param initialEstimation initial estimation to be set.
* @param keepCovariance true if covariance of estimation must be kept after
* refinement, false otherwise.
* @param inliersData inlier data, typically obtained from a robust
* estimator.
* @param samples1 1st set of paired samples.
* @param samples2 2nd set of paired samples.
* @param refinementStandardDeviation standard deviation used for
* Levenberg-Marquardt fitting.
*/
public NonDecomposedPointCorrespondencePinholeCameraRefiner(
final PinholeCamera initialEstimation, final boolean keepCovariance, final InliersData inliersData,
final List<Point3D> samples1, final List<Point2D> samples2, final double refinementStandardDeviation) {
super(initialEstimation, keepCovariance, inliersData, samples1, samples2, refinementStandardDeviation);
}
/**
* Gets suggestion error weight. This weight is applied to errors related to
* suggested camera parameters during computation of projection residuals.
*
* @return suggestion error weight.
*/
public double getSuggestionErrorWeight() {
return suggestionErrorWeight;
}
/**
* Sets suggestion error weight. This weight is applied to errors related to
* suggested camera parameters during computation of projection residuals.
*
* @param suggestionErrorWeight suggestion error weight.
* @throws LockedException if estimator is locked.
*/
public void setSuggestionErrorWeight(final double suggestionErrorWeight) throws LockedException {
if (isLocked()) {
throw new LockedException();
}
this.suggestionErrorWeight = suggestionErrorWeight;
}
/**
* Refines provided initial estimation.
* This method always sets a value into provided result instance regardless
* of the fact that error has actually improved in LMSE terms or not.
*
* @param result instance where refined estimation will be stored.
* @return true if result improves (decreases) in LMSE terms respect to
* initial estimation, false if no improvement has been achieved.
* @throws NotReadyException if not enough input data has been provided.
* @throws LockedException if estimator is locked because refinement is
* already in progress.
* @throws RefinerException if refinement fails for some reason (e.g. unable
* to converge to a result).
*/
@Override
public boolean refine(final PinholeCamera result) throws NotReadyException, LockedException, RefinerException {
if (isLocked()) {
throw new LockedException();
}
if (!isReady()) {
throw new NotReadyException();
}
locked = true;
if (listener != null) {
listener.onRefineStart(this, initialEstimation);
}
try {
initialEstimation.normalize();
// output values to be fitted/optimized will contain residuals
final var y = new double[numInliers];
// input values will contain 3D point and 2D point to compute
// residuals
final var nDims = Point2D.POINT2D_HOMOGENEOUS_COORDINATES_LENGTH
+ Point3D.POINT3D_HOMOGENEOUS_COORDINATES_LENGTH;
final var x = new Matrix(numInliers, nDims);
final var nSamples = inliers.length();
var pos = 0;
final var initParams = new double[REFINE_DIMS];
cameraToParameters(initialEstimation, initParams);
final var initResidual = residualPowell(initialEstimation, initParams, suggestionErrorWeight);
final var suggestionResidual = hasSuggestions() ? suggestionResidual(initParams, suggestionErrorWeight)
: 0.0;
for (var i = 0; i < nSamples; i++) {
if (inliers.get(i)) {
// sample is inlier
final var point2D = samples2.get(i);
final var point3D = samples1.get(i);
point2D.normalize();
point3D.normalize();
x.setElementAt(pos, 0, point2D.getHomX());
x.setElementAt(pos, 1, point2D.getHomY());
x.setElementAt(pos, 2, point2D.getHomW());
x.setElementAt(pos, 3, point3D.getHomX());
x.setElementAt(pos, 4, point3D.getHomY());
x.setElementAt(pos, 5, point3D.getHomZ());
x.setElementAt(pos, 6, point3D.getHomW());
y[pos] = Math.pow(residuals[i], 2.0) + suggestionResidual;
pos++;
}
}
final var evaluator = new LevenbergMarquardtMultiDimensionFunctionEvaluator() {
private final Point2D point2D = Point2D.create(CoordinatesType.HOMOGENEOUS_COORDINATES);
private final Point3D point3D = Point3D.create(CoordinatesType.HOMOGENEOUS_COORDINATES);
private final PinholeCamera pinholeCamera = new PinholeCamera();
private final GradientEstimator gradientEstimator = new GradientEstimator(params -> {
parametersToCamera(params, pinholeCamera);
return residualLevenbergMarquardt(pinholeCamera, point3D, point2D, params, suggestionErrorWeight);
});
@Override
public int getNumberOfDimensions() {
return nDims;
}
@Override
public double[] createInitialParametersArray() {
return initParams;
}
@Override
public double evaluate(
final int i, final double[] point, final double[] params, final double[] derivatives)
throws EvaluationException {
point2D.setHomogeneousCoordinates(point[0], point[1], point[2]);
point3D.setHomogeneousCoordinates(point[3], point[4], point[5], point[6]);
point2D.normalize();
point3D.normalize();
parametersToCamera(params, pinholeCamera);
final var y = residualLevenbergMarquardt(pinholeCamera, point3D, point2D, params,
suggestionErrorWeight);
gradientEstimator.gradient(params, derivatives);
return y;
}
};
final var fitter = new LevenbergMarquardtMultiDimensionFitter(evaluator, x, y, refinementStandardDeviation);
fitter.fit();
final var finalParams = fitter.getA();
parametersToCamera(finalParams, result);
if (keepCovariance) {
covariance = fitter.getCovar();
}
final var finalResidual = residualPowell(result, finalParams, suggestionErrorWeight);
final var errorDecreased = finalResidual < initResidual;
if (listener != null) {
listener.onRefineEnd(this, initialEstimation, result,
errorDecreased);
}
return errorDecreased;
} catch (final Exception e) {
throw new RefinerException(e);
} finally {
locked = false;
}
}
}