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Augmented Reality and 3D reconstruction library
/*
* Copyright (C) 2017 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.estimators;
import com.irurueta.ar.calibration.ImageOfAbsoluteConic;
import com.irurueta.geometry.HomogeneousPoint3D;
import com.irurueta.geometry.MatrixRotation3D;
import com.irurueta.geometry.PinholeCamera;
import com.irurueta.geometry.PinholeCameraIntrinsicParameters;
import com.irurueta.geometry.ProjectiveTransformation2D;
import com.irurueta.geometry.Transformation2D;
import com.irurueta.geometry.estimators.LockedException;
import com.irurueta.geometry.estimators.NotReadyException;
import java.util.ArrayList;
import java.util.List;
/**
* This class estimate intrinsic and extrinsic (rotation and camera center)
* parameters of a camera by using provided homography.
* For intrinsic parameters estimation it is assumed that skewness and principal
* point are zero and that aspect ratio are known.
* This class can be used in planar scenes where projected points of two views
* are related by an homography.
*/
public class SingleHomographyPinholeCameraEstimator {
/**
* Default aspect ratio value.
*/
public static final double DEFAULT_ASPECT_RATIO = 1.0;
/**
* Aspect ratio of intrinsic parameters.
*/
private double mFocalDistanceAspectRatio = DEFAULT_ASPECT_RATIO;
/**
* Homography relating two views.
*/
private Transformation2D mHomography;
/**
* True when estimation is in progress.
*/
private boolean mLocked = false;
/**
* Listener to be notified of events such as when estimation starts or ends.
*/
private SingleHomographyPinholeCameraEstimatorListener mListener;
/**
* Constructor.
*/
public SingleHomographyPinholeCameraEstimator() {
}
/**
* Constructor with listener.
*
* @param listener listener to be notified of events such as when estimation
* starts or ends.
*/
public SingleHomographyPinholeCameraEstimator(
final SingleHomographyPinholeCameraEstimatorListener listener) {
mListener = listener;
}
/**
* Constructor with homography.
*
* @param homography homography to estimate canera and intrinsic parameters.
* @throws NullPointerException if provided homography is null.
*/
public SingleHomographyPinholeCameraEstimator(final Transformation2D homography) {
internalSetHomography(homography);
}
/**
* Constructor with listener and homography.
*
* @param homography homography to estimate camera and intrinsic parameters.
* @param listener listener to be notified of events such as when estimation
* starts or ends.
*/
public SingleHomographyPinholeCameraEstimator(final Transformation2D homography,
final SingleHomographyPinholeCameraEstimatorListener listener) {
internalSetHomography(homography);
mListener = listener;
}
/**
* Gets aspect ratio of intrinsic parameters.
*
* @return aspect ratio of intrinsic parameters.
*/
public double getFocalDistanceAspectRatio() {
return mFocalDistanceAspectRatio;
}
/**
* Sets aspect ratio of intrinsic parameters.
*
* @param focalDistanceAspectRatio aspect ratio of intrinsic parameters.
* @throws LockedException if estimator is locked.
*/
public void setFocalDistanceAspectRatio(final double focalDistanceAspectRatio)
throws LockedException {
if (mLocked) {
throw new LockedException();
}
mFocalDistanceAspectRatio = focalDistanceAspectRatio;
}
/**
* Gets homography relating two views.
*
* @return homography relating two views.
*/
public Transformation2D getHomography() {
return mHomography;
}
/**
* Sets homography relating two views.
*
* @param homography homography relating two views.
* @throws LockedException if estimator is locked.
*/
public void setHomography(final Transformation2D homography)
throws LockedException {
if (mLocked) {
throw new LockedException();
}
mHomography = homography;
}
/**
* Indicates whether this instance is locked.
*
* @return true if this estimator is busy doing the estimation, false
* otherwise.
*/
public boolean isReady() {
return mHomography != null;
}
/**
* Gets listener to be notified of events such as when estimation starts or
* ends.
*
* @return listener to be notified of events.
*/
public SingleHomographyPinholeCameraEstimatorListener getListener() {
return mListener;
}
/**
* Sets listener to be notified of events such as when estimation starts or
* ends.
*
* @param listener listener to be notified of events.
* @throws LockedException if estimator is locked.
*/
public void setListener(
final SingleHomographyPinholeCameraEstimatorListener listener)
throws LockedException {
if (mLocked) {
throw new LockedException();
}
mListener = listener;
}
/**
* Indicates whether this instance is locked or not.
*
* @return true if instance is locked, false otherwise.
*/
public boolean isLocked() {
return mLocked;
}
/**
* Estimates a pinhole camera.
*
* @return estimated pinhole camera.
* @throws LockedException if estimator is locked.
* @throws NotReadyException if no homography has been provided yet.
* @throws SingleHomographyPinholeCameraEstimatorException if estimation
* fails.
*/
public PinholeCamera estimate() throws LockedException, NotReadyException,
SingleHomographyPinholeCameraEstimatorException {
final PinholeCamera result = new PinholeCamera();
estimate(result);
return result;
}
/**
* Estimates a pinhole camera.
*
* @param result instance where estimated camera will be stored.
* @throws LockedException if estimator is locked.
* @throws NotReadyException if no homography has been provided yet.
* @throws SingleHomographyPinholeCameraEstimatorException if estimation
* fails.
*/
public void estimate(PinholeCamera result) throws LockedException,
NotReadyException, SingleHomographyPinholeCameraEstimatorException {
if (mLocked) {
throw new LockedException();
}
if (!isReady()) {
throw new NotReadyException();
}
try {
mLocked = true;
if (mListener != null) {
mListener.onEstimateStart(this);
}
// estimate intrinsic parameters
final List homographies =
new ArrayList<>();
homographies.add(mHomography);
// also add its inverse
homographies.add(
((ProjectiveTransformation2D) mHomography).inverseAndReturnNew());
final LMSEImageOfAbsoluteConicEstimator intrinsicEstimator =
new LMSEImageOfAbsoluteConicEstimator(homographies);
intrinsicEstimator.setPrincipalPointAtOrigin(true);
intrinsicEstimator.setFocalDistanceAspectRatioKnown(true);
intrinsicEstimator.setFocalDistanceAspectRatio(
mFocalDistanceAspectRatio);
ImageOfAbsoluteConic iac = intrinsicEstimator.estimate();
iac.normalize();
final PinholeCameraIntrinsicParameters intrinsic =
iac.getIntrinsicParameters();
// estimate camera pose
final MatrixRotation3D rotation = new MatrixRotation3D();
final HomogeneousPoint3D center = new HomogeneousPoint3D();
CameraPoseEstimator.estimate(intrinsic, mHomography, rotation,
center, result);
if (mListener != null) {
mListener.onEstimateEnd(this);
}
} catch (final Exception e) {
throw new SingleHomographyPinholeCameraEstimatorException(e);
} finally {
mLocked = false;
}
}
/**
* Sets homography to estimate camera and intrinsic parameters.
*
* @param homography homography to be set.
* @throws NullPointerException if provided homography is null.
*/
private void internalSetHomography(final Transformation2D homography) {
if (homography == null) {
throw new NullPointerException();
}
mHomography = homography;
}
}
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