Added function decomposeHomographyMat. New files added are homography_decomp.cpp and test_homography_decomp.cpp.

Modified files calib3d.hpp and camera_calibration_and_3d_reconstruction.rst.
pull/2671/head
Samson Yilma 11 years ago
parent 32b25de583
commit e6420bde73
  1. 23
      modules/calib3d/doc/camera_calibration_and_3d_reconstruction.rst
  2. 5
      modules/calib3d/include/opencv2/calib3d.hpp
  3. 480
      modules/calib3d/src/homography_decomp.cpp
  4. 138
      modules/calib3d/test/test_homography_decomp.cpp

@ -758,6 +758,27 @@ They are
:math:`[R_2, -t]`.
By decomposing ``E``, you can only get the direction of the translation, so the function returns unit ``t``.
decomposeHomographyMat
--------------------------
Decompose a homography matrix to rotation(s), translation(s) and plane normal(s).
.. ocv:function:: int decomposeHomographyMat( InputArray H, InputArray K, OutputArrayOfArrays rotations, OutputArrayOfArrays translations, OutputArrayOfArrays normals)
:param H: The input homography matrix.
:param K: The input intrinsic camera calibration matrix.
:param rotations: Array of rotation matrices.
:param translations: Array of translation matrices.
:param normals: Array of plane normal matrices.
This function extracts relative camera motion between two views observing a planar object from the homography ``H`` induced by the plane.
The intrinsic camera matrix ``K`` must also be provided. The function may return up to four mathematical solution sets. At least two of the
solutions may further be invalidated if point correspondences are available by applying positive depth constraint (all points must be in front of the camera).
The decomposition method is described in detail in [Malis]_.
recoverPose
---------------
@ -1512,3 +1533,5 @@ The function reconstructs 3-dimensional points (in homogeneous coordinates) by u
.. [Slabaugh] Slabaugh, G.G. Computing Euler angles from a rotation matrix. http://www.soi.city.ac.uk/~sbbh653/publications/euler.pdf (verified: 2013-04-15)
.. [Zhang2000] Z. Zhang. A Flexible New Technique for Camera Calibration. IEEE Transactions on Pattern Analysis and Machine Intelligence, 22(11):1330-1334, 2000.
.. [Malis] Malis, E. and Vargas, M. Deeper understanding of the homography decomposition for vision-based control, Research Report 6303, INRIA (2007)

@ -314,6 +314,11 @@ CV_EXPORTS_W int estimateAffine3D(InputArray src, InputArray dst,
double ransacThreshold = 3, double confidence = 0.99);
CV_EXPORTS_W int decomposeHomographyMat(InputArray _H,
InputArray _K,
OutputArrayOfArrays _rotations,
OutputArrayOfArrays _translations,
OutputArrayOfArrays _normals);
class CV_EXPORTS_W StereoMatcher : public Algorithm
{

@ -0,0 +1,480 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// This is a homography decomposition implementation contributed to OpenCV
// by Samson Yilma. It implements the homography decomposition algorithm
// descriped in the research report:
// Malis, E and Vargas, M, "Deeper understanding of the homography decomposition
// for vision-based control", Research Report 6303, INRIA (2007)
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2014, Samson Yilma¸ (samson_yilma@yahoo.com), all rights reserved.
//
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of the copyright holders may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
//M*/
#include "precomp.hpp"
namespace cv
{
namespace HomographyDecomposition
{
//struct to hold solutions of homography decomposition
typedef struct _CameraMotion {
cv::Matx33d R; //!< rotation matrix
cv::Vec3d n; //!< normal of the plane the camera is looking at
cv::Vec3d t; //!< translation vector
} CameraMotion;
inline int signd(const double x)
{
return ( x >= 0 ? 1 : -1 );
}
class HomographyDecomp {
public:
HomographyDecomp() {}
virtual ~HomographyDecomp() {}
virtual void decomposeHomography(const cv::Matx33d& H, const cv::Matx33d& K,
std::vector<CameraMotion>& camMotions);
bool isRotationValid(const cv::Matx33d& R, const double epsilon=0.01);
protected:
bool passesSameSideOfPlaneConstraint(CameraMotion& motion);
virtual void decompose(std::vector<CameraMotion>& camMotions) = 0;
const cv::Matx33d& getHnorm() const {
return _Hnorm;
}
private:
cv::Matx33d normalize(const cv::Matx33d& H, const cv::Matx33d& K);
void removeScale();
cv::Matx33d _Hnorm;
};
class HomographyDecompZhang : public HomographyDecomp {
public:
HomographyDecompZhang():HomographyDecomp() {}
virtual ~HomographyDecompZhang() {}
private:
virtual void decompose(std::vector<CameraMotion>& camMotions);
bool findMotionFrom_tstar_n(const cv::Vec3d& tstar, const cv::Vec3d& n, CameraMotion& motion);
};
class HomographyDecompInria : public HomographyDecomp {
public:
HomographyDecompInria():HomographyDecomp() {}
virtual ~HomographyDecompInria() {}
private:
virtual void decompose(std::vector<CameraMotion>& camMotions);
double oppositeOfMinor(const cv::Matx33d& M, const int row, const int col);
void findRmatFrom_tstar_n(const cv::Vec3d& tstar, const cv::Vec3d& n, const double v, cv::Matx33d& R);
};
// normalizes homography with intrinsic camera parameters
Matx33d HomographyDecomp::normalize(const Matx33d& H, const Matx33d& K)
{
return K.inv() * H * K;
}
void HomographyDecomp::removeScale()
{
Mat W;
SVD::compute(_Hnorm, W);
_Hnorm = _Hnorm * (1.0/W.at<double>(1));
}
/*! This checks that the input is a pure rotation matrix 'm'.
* The conditions for this are: R' * R = I and det(R) = 1 (proper rotation matrix)
*/
bool HomographyDecomp::isRotationValid(const Matx33d& R, const double epsilon)
{
Matx33d RtR = R.t() * R;
Matx33d I(1,0,0, 0,1,0, 0,0,1);
if (norm(RtR, I, NORM_INF) > epsilon)
return false;
return (fabs(determinant(R) - 1.0) < epsilon);
}
bool HomographyDecomp::passesSameSideOfPlaneConstraint(CameraMotion& motion)
{
typedef Matx<double, 1, 1> Matx11d;
Matx31d t = Matx31d(motion.t);
Matx31d n = Matx31d(motion.n);
Matx11d proj = n.t() * motion.R.t() * t;
if ( (1 + proj(0, 0) ) <= 0 )
return false;
return true;
}
//!main routine to decompose homography
void HomographyDecomp::decomposeHomography(const Matx33d& H, const cv::Matx33d& K,
std::vector<CameraMotion>& camMotions)
{
//normalize homography matrix with intrinsic camera matrix
_Hnorm = normalize(H, K);
//remove scale of the normalized homography
removeScale();
//apply decomposition
decompose(camMotions);
}
/* function computes R&t from tstar, and plane normal(n) using
R = H * inv(I + tstar*transpose(n) );
t = R * tstar;
returns true if computed R&t is a valid solution
*/
bool HomographyDecompZhang::findMotionFrom_tstar_n(const cv::Vec3d& tstar, const cv::Vec3d& n, CameraMotion& motion)
{
Matx31d tstar_m = Mat(tstar);
Matx31d n_m = Mat(n);
Matx33d temp = tstar_m * n_m.t();
temp(0, 0) += 1.0;
temp(1, 1) += 1.0;
temp(2, 2) += 1.0;
motion.R = getHnorm() * temp.inv();
motion.t = motion.R * tstar;
motion.n = n;
return passesSameSideOfPlaneConstraint(motion);
}
void HomographyDecompZhang::decompose(std::vector<CameraMotion>& camMotions)
{
Mat W, U, Vt;
SVD::compute(getHnorm(), W, U, Vt);
double lambda1=W.at<double>(0);
double lambda3=W.at<double>(2);
double lambda1m3 = (lambda1-lambda3);
double lambda1m3_2 = lambda1m3*lambda1m3;
double lambda1t3 = lambda1*lambda3;
double t1 = 1.0/(2.0*lambda1t3);
double t2 = sqrtf(1.0+4.0*lambda1t3/lambda1m3_2);
double t12 = t1*t2;
double e1 = -t1 + t12; //t1*(-1.0f + t2 );
double e3 = -t1 - t12; //t1*(-1.0f - t2);
double e1_2 = e1*e1;
double e3_2 = e3*e3;
double nv1p = sqrtf(e1_2*lambda1m3_2 + 2*e1*(lambda1t3-1) + 1.0);
double nv3p = sqrtf(e3_2*lambda1m3_2 + 2*e3*(lambda1t3-1) + 1.0);
double v1p[3], v3p[3];
v1p[0]=Vt.at<double>(0)*nv1p, v1p[1]=Vt.at<double>(1)*nv1p, v1p[2]=Vt.at<double>(2)*nv1p;
v3p[0]=Vt.at<double>(6)*nv3p, v3p[1]=Vt.at<double>(7)*nv3p, v3p[2]=Vt.at<double>(8)*nv3p;
/*The eight solutions are
(A): tstar = +- (v1p - v3p)/(e1 -e3), n = +- (e1*v3p - e3*v1p)/(e1-e3)
(B): tstar = +- (v1p + v3p)/(e1 -e3), n = +- (e1*v3p + e3*v1p)/(e1-e3)
*/
double v1pmv3p[3], v1ppv3p[3];
double e1v3me3v1[3], e1v3pe3v1[3];
double inv_e1me3 = 1.0/(e1-e3);
for(int kk=0;kk<3;++kk){
v1pmv3p[kk] = v1p[kk]-v3p[kk];
v1ppv3p[kk] = v1p[kk]+v3p[kk];
}
for(int kk=0; kk<3; ++kk){
double e1v3 = e1*v3p[kk];
double e3v1=e3*v1p[kk];
e1v3me3v1[kk] = e1v3-e3v1;
e1v3pe3v1[kk] = e1v3+e3v1;
}
Vec3d tstar_p, tstar_n;
Vec3d n_p, n_n;
///Solution group A
for(int kk=0; kk<3; ++kk) {
tstar_p[kk] = v1pmv3p[kk]*inv_e1me3;
tstar_n[kk] = -tstar_p[kk];
n_p[kk] = e1v3me3v1[kk]*inv_e1me3;
n_n[kk] = -n_p[kk];
}
CameraMotion cmotion;
//(A) Four different combinations for solution A
// (i) (+, +)
if (findMotionFrom_tstar_n(tstar_p, n_p, cmotion))
camMotions.push_back(cmotion);
// (ii) (+, -)
if (findMotionFrom_tstar_n(tstar_p, n_n, cmotion))
camMotions.push_back(cmotion);
// (iii) (-, +)
if (findMotionFrom_tstar_n(tstar_n, n_p, cmotion))
camMotions.push_back(cmotion);
// (iv) (-, -)
if (findMotionFrom_tstar_n(tstar_n, n_n, cmotion))
camMotions.push_back(cmotion);
//////////////////////////////////////////////////////////////////
///Solution group B
for(int kk=0;kk<3;++kk){
tstar_p[kk] = v1ppv3p[kk]*inv_e1me3;
tstar_n[kk] = -tstar_p[kk];
n_p[kk] = e1v3pe3v1[kk]*inv_e1me3;
n_n[kk] = -n_p[kk];
}
//(B) Four different combinations for solution B
// (i) (+, +)
if (findMotionFrom_tstar_n(tstar_p, n_p, cmotion))
camMotions.push_back(cmotion);
// (ii) (+, -)
if (findMotionFrom_tstar_n(tstar_p, n_n, cmotion))
camMotions.push_back(cmotion);
// (iii) (-, +)
if (findMotionFrom_tstar_n(tstar_n, n_p, cmotion))
camMotions.push_back(cmotion);
// (iv) (-, -)
if (findMotionFrom_tstar_n(tstar_n, n_n, cmotion))
camMotions.push_back(cmotion);
}
double HomographyDecompInria::oppositeOfMinor(const Matx33d& M, const int row, const int col)
{
int x1 = col == 0 ? 1 : 0;
int x2 = col == 2 ? 1 : 2;
int y1 = row == 0 ? 1 : 0;
int y2 = row == 2 ? 1 : 2;
return (M(y1, x2) * M(y2, x1) - M(y1, x1) * M(y2, x2));
}
//computes R = H( I - (2/v)*te_star*ne_t )
void HomographyDecompInria::findRmatFrom_tstar_n(const cv::Vec3d& tstar, const cv::Vec3d& n, const double v, cv::Matx33d& R)
{
Matx31d tstar_m = Matx31d(tstar);
Matx31d n_m = Matx31d(n);
Matx33d I(1.0, 0.0, 0.0,
0.0, 1.0, 0.0,
0.0, 0.0, 1.0);
R = getHnorm() * (I - (2/v) * tstar_m * n_m.t() );
}
void HomographyDecompInria::decompose(std::vector<CameraMotion>& camMotions)
{
const double epsilon = 0.001;
Matx33d S;
//S = H'H - I
S = getHnorm().t() * getHnorm();
S(0, 0) -= 1.0;
S(1, 1) -= 1.0;
S(2, 2) -= 1.0;
//check if H is rotation matrix
if( norm(S, NORM_INF) < epsilon) {
CameraMotion motion;
motion.R = Matx33d(getHnorm());
motion.t = Vec3d(0, 0, 0);
motion.n = Vec3d(0, 0, 0);
camMotions.push_back(motion);
return;
}
//! Compute nvectors
Vec3d npa, npb;
double M00 = oppositeOfMinor(S, 0, 0);
double M11 = oppositeOfMinor(S, 1, 1);
double M22 = oppositeOfMinor(S, 2, 2);
double rtM00 = sqrt(M00);
double rtM11 = sqrt(M11);
double rtM22 = sqrt(M22);
double M01 = oppositeOfMinor(S, 0, 1);
double M12 = oppositeOfMinor(S, 1, 2);
double M02 = oppositeOfMinor(S, 0, 2);
int e12 = signd(M12);
int e02 = signd(M02);
int e01 = signd(M01);
double nS00 = abs(S(0, 0));
double nS11 = abs(S(1, 1));
double nS22 = abs(S(2, 2));
//find max( |Sii| ), i=0, 1, 2
int indx = 0;
if(nS00 < nS11){
indx = 1;
if( nS11 < nS22 )
indx = 2;
}
else {
if(nS00 < nS22 )
indx = 2;
}
switch (indx) {
case 0:
npa[0] = S(0, 0), npb[0] = S(0, 0);
npa[1] = S(0, 1) + rtM22, npb[1] = S(0, 1) - rtM22;
npa[2] = S(0, 2) + e12 * rtM11, npb[2] = S(0, 2) - e12 * rtM11;
break;
case 1:
npa[0] = S(0, 1) + rtM22, npb[0] = S(0, 1) - rtM22;
npa[1] = S(1, 1), npb[1] = S(1, 1);
npa[2] = S(1, 2) - e02 * rtM00, npb[2] = S(1, 2) + e02 * rtM00;
break;
case 2:
npa[0] = S(0, 2) + e01 * rtM11, npb[0] = S(0, 2) - e01 * rtM11;
npa[1] = S(1, 2) + rtM00, npb[1] = S(1, 2) - rtM00;
npa[2] = S(2, 2), npb[2] = S(2, 2);
break;
default:
break;
}
double traceS = S(0, 0) + S(1, 1) + S(2, 2);
double v = 2.0 * sqrtf(1 + traceS - M00 - M11 - M22);
double ESii = signd(S(indx, indx)) ;
double r_2 = 2 + traceS + v;
double nt_2 = 2 + traceS - v;
double r = sqrt(r_2);
double n_t = sqrt(nt_2);
Vec3d na = npa / norm(npa);
Vec3d nb = npb / norm(npb);
double half_nt = 0.5 * n_t;
double esii_t_r = ESii * r;
Vec3d ta_star = half_nt * (esii_t_r * nb - n_t * na);
Vec3d tb_star = half_nt * (esii_t_r * na - n_t * nb);
camMotions.resize(4);
Matx33d Ra, Rb;
Vec3d ta, tb;
//Ra, ta, na
findRmatFrom_tstar_n(ta_star, na, v, Ra);
ta = Ra * ta_star;
camMotions[0].R = Ra;
camMotions[0].t = ta;
camMotions[0].n = na;
//Ra, -ta, -na
camMotions[1].R = Ra;
camMotions[1].t = -ta;
camMotions[1].n = -na;
//Rb, tb, nb
findRmatFrom_tstar_n(tb_star, nb, v, Rb);
tb = Rb * tb_star;
camMotions[2].R = Rb;
camMotions[2].t = tb;
camMotions[2].n = nb;
//Rb, -tb, -nb
camMotions[3].R = Rb;
camMotions[3].t = -tb;
camMotions[3].n = -nb;
}
} //namespace HomographyDecomposition
int decomposeHomographyMat(InputArray _H,
InputArray _K,
OutputArrayOfArrays _rotations,
OutputArrayOfArrays _translations,
OutputArrayOfArrays _normals)
{
using namespace std;
using namespace HomographyDecomposition;
Mat H = _H.getMat().reshape(1, 3);
CV_Assert(H.cols == 3 && H.rows == 3);
Mat K = _K.getMat().reshape(1, 3);
CV_Assert(K.cols == 3 && K.rows == 3);
auto_ptr<HomographyDecomp> hdecomp(new HomographyDecompInria);
vector<CameraMotion> motions;
hdecomp->decomposeHomography(H, K, motions);
int nsols = static_cast<int>(motions.size());
int depth = CV_64F; //double precision matrices used in CameraMotion struct
if (_rotations.needed()) {
_rotations.create(nsols, 1, depth);
for (int k = 0; k < nsols; ++k ) {
_rotations.getMatRef(k) = Mat(motions[k].R);
}
}
if (_translations.needed()) {
_translations.create(nsols, 1, depth);
for (int k = 0; k < nsols; ++k ) {
_translations.getMatRef(k) = Mat(motions[k].t);
}
}
if (_normals.needed()) {
_normals.create(nsols, 1, depth);
for (int k = 0; k < nsols; ++k ) {
_normals.getMatRef(k) = Mat(motions[k].n);
}
}
return nsols;
}
} //namespace cv

@ -0,0 +1,138 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// This is a test file for the function decomposeHomography contributed to OpenCV
// by Samson Yilma.
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2014, Samson Yilma¸ (samson_yilma@yahoo.com), all rights reserved.
//
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of the copyright holders may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
//M*/
#include "test_precomp.hpp"
#include "opencv2/calib3d.hpp"
#include <vector>
using namespace cv;
using namespace std;
class CV_HomographyDecompTest: public cvtest::BaseTest {
public:
CV_HomographyDecompTest()
{
buildTestDataSet();
}
protected:
void run(int)
{
vector<Mat> rotations;
vector<Mat> translations;
vector<Mat> normals;
decomposeHomographyMat(_H, _K, rotations, translations, normals);
//there should be at least 1 solution
ASSERT_GT(rotations.size(), 0);
ASSERT_GT(translations.size(), 0);
ASSERT_GT(normals.size(), 0);
ASSERT_EQ(rotations.size(), normals.size());
ASSERT_EQ(translations.size(), normals.size());
ASSERT_TRUE(containsValidMotion(rotations, translations, normals));
decomposeHomographyMat(_H, _K, rotations, noArray(), noArray());
ASSERT_GT(rotations.size(), 0);
}
private:
void buildTestDataSet()
{
_K = Matx33d(640, 0.0, 320,
0, 640, 240,
0, 0, 1);
_H = Matx33d(2.649157564634028, 4.583875997496426, 70.694447785121326,
-1.072756858861583, 3.533262150437228, 1513.656999614321649,
0.001303887589576, 0.003042206876298, 1.000000000000000
);
//expected solution for the given homography and intrinsic matrices
_R = Matx33d(0.43307983549125, 0.545749113549648, -0.717356090899523,
-0.85630229674426, 0.497582023798831, -0.138414255706431,
0.281404038139784, 0.67421809131173, 0.682818960388909);
_t = Vec3d(1.826751712278038, 1.264718492450820, 0.195080809998819);
_n = Vec3d(0.244875830334816, 0.480857890778889, 0.841909446789566);
}
bool containsValidMotion(std::vector<Mat>& rotations,
std::vector<Mat>& translations,
std::vector<Mat>& normals
)
{
double max_error = 1.0e-3;
vector<Mat>::iterator riter = rotations.begin();
vector<Mat>::iterator titer = translations.begin();
vector<Mat>::iterator niter = normals.begin();
for (;
riter != rotations.end() && titer != translations.end() && niter != normals.end();
++riter, ++titer, ++niter) {
double rdist = norm(*riter, _R, NORM_INF);
double tdist = norm(*titer, _t, NORM_INF);
double ndist = norm(*niter, _n, NORM_INF);
if ( rdist < max_error
&& tdist < max_error
&& ndist < max_error )
return true;
}
return false;
}
Matx33d _R, _K, _H;
Vec3d _t, _n;
};
TEST(Calib3d_DecomposeHomography, regression) { CV_HomographyDecompTest test; test.safe_run(); }
Loading…
Cancel
Save