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OP-1150 Add calibration util class implementing polynomial/ellipsoid fit algorithms

This commit is contained in:
Alessio Morale 2014-01-06 11:11:16 +01:00
parent 82691a9348
commit 46ff4c8bf9
3 changed files with 356 additions and 2 deletions

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/**
******************************************************************************
*
* @file calibrationutils.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2013.
*
* @brief Utilities for calibration using ellipsoid fit algorithm
* @see The GNU Public License (GPL) Version 3
* @defgroup
* @{
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "calibrationutils.h"
using namespace Eigen;
namespace OpenPilot{
CalibrationUtils::CalibrationUtils()
{
NominalRange = 1.0f;
}
/*
* The following code is based on RazorImu calibration samples that can be found here:
* https://github.com/ptrbrtz/razor-9dof-ahrs/tree/master/Matlab/magnetometer_calibration
*/
bool CalibrationUtils::Calibrate(){
Eigen::VectorXf samplesX = Eigen::VectorXf(samples_x);
Eigen::VectorXf samplesY = Eigen::VectorXf(samples_y);
Eigen::VectorXf samplesZ = Eigen::VectorXf(samples_z);
Eigen::VectorXf radii;
Eigen::Vector3f center;
Eigen::MatrixXf evecs;
this->EllipsoidFit(&samplesX, &samplesY, &samplesZ, &center, &radii, &evecs);
Scale.setZero();
Scale << NominalRange / radii.coeff(0),
NominalRange / radii.coeff(1),
NominalRange / radii.coeff(2);
Eigen::Matrix3f tmp;
tmp << Scale.coeff(0), 0, 0,
0, Scale.coeff(1), 0,
0, 0, Scale.coeff(2);
CalibrationMatrix = evecs * tmp * evecs.transpose();
Bias.setZero();
Bias << center.coeff(0), center.coeff(1), center.coeff(2);
return true;
}
/* C++ Implementation of Yury Petrov's ellipsoid fit algorithm
* Following is the origial code and its license from which this implementation is derived
*
Copyright (c) 2009, Yury Petrov
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions 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
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 COPYRIGHT OWNER 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.
function [ center, radii, evecs, v ] = ellipsoid_fit( X, flag, equals )
%
% Fit an ellispoid/sphere to a set of xyz data points:
%
% [center, radii, evecs, pars ] = ellipsoid_fit( X )
% [center, radii, evecs, pars ] = ellipsoid_fit( [x y z] );
% [center, radii, evecs, pars ] = ellipsoid_fit( X, 1 );
% [center, radii, evecs, pars ] = ellipsoid_fit( X, 2, 'xz' );
% [center, radii, evecs, pars ] = ellipsoid_fit( X, 3 );
%
% Parameters:
% * X, [x y z] - Cartesian data, n x 3 matrix or three n x 1 vectors
% * flag - 0 fits an arbitrary ellipsoid (default),
% - 1 fits an ellipsoid with its axes along [x y z] axes
% - 2 followed by, say, 'xy' fits as 1 but also x_rad = y_rad
% - 3 fits a sphere
%
% Output:
% * center - ellispoid center coordinates [xc; yc; zc]
% * ax - ellipsoid radii [a; b; c]
% * evecs - ellipsoid radii directions as columns of the 3x3 matrix
% * v - the 9 parameters describing the ellipsoid algebraically:
% Ax^2 + By^2 + Cz^2 + 2Dxy + 2Exz + 2Fyz + 2Gx + 2Hy + 2Iz = 1
%
% Author:
% Yury Petrov, Northeastern University, Boston, MA
%
error( nargchk( 1, 3, nargin ) ); % check input arguments
if nargin == 1
flag = 0; % default to a free ellipsoid
end
if flag == 2 && nargin == 2
equals = 'xy';
end
if size( X, 2 ) ~= 3
error( 'Input data must have three columns!' );
else
x = X( :, 1 );
y = X( :, 2 );
z = X( :, 3 );
end
% need nine or more data points
if length( x ) < 9 && flag == 0
error( 'Must have at least 9 points to fit a unique ellipsoid' );
end
if length( x ) < 6 && flag == 1
error( 'Must have at least 6 points to fit a unique oriented ellipsoid' );
end
if length( x ) < 5 && flag == 2
error( 'Must have at least 5 points to fit a unique oriented ellipsoid with two axes equal' );
end
if length( x ) < 3 && flag == 3
error( 'Must have at least 4 points to fit a unique sphere' );
end
if flag == 0
% fit ellipsoid in the form Ax^2 + By^2 + Cz^2 + 2Dxy + 2Exz + 2Fyz + 2Gx + 2Hy + 2Iz = 1
D = [ x .* x, ...
y .* y, ...
z .* z, ...
2 * x .* y, ...
2 * x .* z, ...
2 * y .* z, ...
2 * x, ...
2 * y, ...
2 * z ]; % ndatapoints x 9 ellipsoid parameters
elseif flag == 1
% fit ellipsoid in the form Ax^2 + By^2 + Cz^2 + 2Gx + 2Hy + 2Iz = 1
D = [ x .* x, ...
y .* y, ...
z .* z, ...
2 * x, ...
2 * y, ...
2 * z ]; % ndatapoints x 6 ellipsoid parameters
elseif flag == 2
% fit ellipsoid in the form Ax^2 + By^2 + Cz^2 + 2Gx + 2Hy + 2Iz = 1,
% where A = B or B = C or A = C
if strcmp( equals, 'yz' ) || strcmp( equals, 'zy' )
D = [ y .* y + z .* z, ...
x .* x, ...
2 * x, ...
2 * y, ...
2 * z ];
elseif strcmp( equals, 'xz' ) || strcmp( equals, 'zx' )
D = [ x .* x + z .* z, ...
y .* y, ...
2 * x, ...
2 * y, ...
2 * z ];
else
D = [ x .* x + y .* y, ...
z .* z, ...
2 * x, ...
2 * y, ...
2 * z ];
end
else
% fit sphere in the form A(x^2 + y^2 + z^2) + 2Gx + 2Hy + 2Iz = 1
D = [ x .* x + y .* y + z .* z, ...
2 * x, ...
2 * y, ...
2 * z ]; % ndatapoints x 4 sphere parameters
end
% solve the normal system of equations
v = ( D' * D ) \ ( D' * ones( size( x, 1 ), 1 ) );
% find the ellipsoid parameters
if flag == 0
% form the algebraic form of the ellipsoid
A = [ v(1) v(4) v(5) v(7); ...
v(4) v(2) v(6) v(8); ...
v(5) v(6) v(3) v(9); ...
v(7) v(8) v(9) -1 ];
% find the center of the ellipsoid
center = -A( 1:3, 1:3 ) \ [ v(7); v(8); v(9) ];
% form the corresponding translation matrix
T = eye( 4 );
T( 4, 1:3 ) = center';
% translate to the center
R = T * A * T';
% solve the eigenproblem
[ evecs evals ] = eig( R( 1:3, 1:3 ) / -R( 4, 4 ) );
radii = sqrt( 1 ./ diag( evals ) );
else
if flag == 1
v = [ v(1) v(2) v(3) 0 0 0 v(4) v(5) v(6) ];
elseif flag == 2
if strcmp( equals, 'xz' ) || strcmp( equals, 'zx' )
v = [ v(1) v(2) v(1) 0 0 0 v(3) v(4) v(5) ];
elseif strcmp( equals, 'yz' ) || strcmp( equals, 'zy' )
v = [ v(2) v(1) v(1) 0 0 0 v(3) v(4) v(5) ];
else % xy
v = [ v(1) v(1) v(2) 0 0 0 v(3) v(4) v(5) ];
end
else
v = [ v(1) v(1) v(1) 0 0 0 v(2) v(3) v(4) ];
end
center = ( -v( 7:9 ) ./ v( 1:3 ) )';
gam = 1 + ( v(7)^2 / v(1) + v(8)^2 / v(2) + v(9)^2 / v(3) );
radii = ( sqrt( gam ./ v( 1:3 ) ) )';
evecs = eye( 3 );
end
*/
void CalibrationUtils::EllipsoidFit(Eigen::VectorXf *samplesX, Eigen::VectorXf *samplesY, Eigen::VectorXf *samplesZ,
Eigen::Vector3f *center,
Eigen::VectorXf *radii,
Eigen::MatrixXf *evecs)
{
int numSamples = (*samplesX).rows();
Eigen::MatrixXf D(numSamples,9);
D.setZero();
D.col(0) = (*samplesX).cwiseProduct(*samplesX);
D.col(1) = (*samplesY).cwiseProduct(*samplesY);
D.col(2) = (*samplesZ).cwiseProduct(*samplesZ);
D.col(3) = (*samplesX).cwiseProduct(*samplesY) * 2;
D.col(4) = (*samplesX).cwiseProduct(*samplesZ) * 2;
D.col(5) = (*samplesY).cwiseProduct(*samplesZ) * 2;
D.col(6) = 2 * (*samplesX);
D.col(7) = 2 * (*samplesY);
D.col(8) = 2 * (*samplesZ);
Eigen::VectorXf ones(numSamples);
ones.setOnes(numSamples);
Eigen::MatrixXf dt1 = (D.transpose() * D);
Eigen::MatrixXf dt2 = (D.transpose() * ones);
Eigen::VectorXf v = dt1.inverse() * dt2;
Eigen::Matrix4f A;
A << v.coeff(0), v.coeff(3), v.coeff(4), v.coeff(6),
v.coeff(3), v.coeff(1), v.coeff(5), v.coeff(7),
v.coeff(4), v.coeff(5), v.coeff(2), v.coeff(8),
v.coeff(6), v.coeff(7), v.coeff(8), -1;
(*center) = -1 * A.block(0,0,3,3).inverse() * v.segment(6,3);
Eigen::Matrix4f t = Eigen::Matrix4f::Identity();
t.block(3,0,1,3) = center->transpose();
Eigen::Matrix4f r = t * A * t.transpose();
Eigen::Matrix3f tmp2 = r.block(0,0,3,3) * -1 / r.coeff(3,3);
Eigen::EigenSolver<Eigen::Matrix3f> es(tmp2);
Eigen::VectorXf evals = es.eigenvalues().real();
(*evecs) = es.eigenvectors().real();
radii->setZero(3);
(*radii) = (evals.segment(0,3)).cwiseInverse().cwiseSqrt();
}
}

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/**
******************************************************************************
*
* @file calibrationutils.h
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2013.
*
* @brief Utilities for calibration using ellipsoid fit algorithm
* @see The GNU Public License (GPL) Version 3
* @defgroup
* @{
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef CALIBRATIONUTILS_H
#define CALIBRATIONUTILS_H
#include <Eigen/Core>
#include <Eigen/Eigenvalues>
#include <Eigen/Dense>
#include <iostream>
namespace OpenPilot{
class CalibrationUtils
{
public:
CalibrationUtils();
bool Calibrate();
Eigen::VectorXf samples_x;
Eigen::VectorXf samples_y;
Eigen::VectorXf samples_z;
Eigen::Matrix3f CalibrationMatrix;
Eigen::Vector3f Scale;
Eigen::Vector3f Bias;
float NominalRange;
private:
void EllipsoidFit(Eigen::VectorXf *samplesX, Eigen::VectorXf *samplesY, Eigen::VectorXf *samplesZ,
Eigen::Vector3f *center,
Eigen::VectorXf *radii,
Eigen::MatrixXf *evecs);
};
}
#endif // CALIBRATIONUTILS_H

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@ -39,7 +39,8 @@ HEADERS += configplugin.h \
config_global.h \
mixercurve.h \
dblspindelegate.h \
configrevohwwidget.h
configrevohwwidget.h \
calibration/calibrationutils.h \
SOURCES += configplugin.cpp \
configgadgetwidget.cpp \
@ -72,7 +73,8 @@ SOURCES += configplugin.cpp \
outputchannelform.cpp \
mixercurve.cpp \
dblspindelegate.cpp \
configrevohwwidget.cpp
configrevohwwidget.cpp \
calibration/calibrationutils.cpp \
FORMS += airframe.ui \
airframe_ccpm.ui \