220 lines
4.4 KiB
Matlab
220 lines
4.4 KiB
Matlab
function [out,dout]=rodrigues(in)
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% RODRIGUES Transform rotation matrix into rotation vector and viceversa.
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%
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% Sintax: [OUT]=RODRIGUES(IN)
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% If IN is a 3x3 rotation matrix then OUT is the
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% corresponding 3x1 rotation vector
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% if IN is a rotation 3-vector then OUT is the
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% corresponding 3x3 rotation matrix
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%
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%%
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%% Copyright (c) March 1993 -- Pietro Perona
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%% California Institute of Technology
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%%
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%% ALL CHECKED BY JEAN-YVES BOUGUET, October 1995.
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%% FOR ALL JACOBIAN MATRICES !!! LOOK AT THE TEST AT THE END !!
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%% BUG when norm(om)=pi fixed -- April 6th, 1997;
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%% Jean-Yves Bouguet
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%% Add projection of the 3x3 matrix onto the set of special ortogonal matrices SO(3) by SVD -- February 7th, 2003;
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%% Jean-Yves Bouguet
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[m,n] = size(in);
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%bigeps = 10e+4*eps;
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bigeps = 10e+20*eps;
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if ((m==1) & (n==3)) | ((m==3) & (n==1)) %% it is a rotation vector
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theta = norm(in);
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if theta < eps
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R = eye(3);
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%if nargout > 1,
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dRdin = [0 0 0;
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0 0 1;
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0 -1 0;
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0 0 -1;
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0 0 0;
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1 0 0;
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0 1 0;
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-1 0 0;
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0 0 0];
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%end;
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else
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if n==length(in) in=in'; end; %% make it a column vec. if necess.
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%m3 = [in,theta]
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dm3din = [eye(3);in'/theta];
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omega = in/theta;
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%m2 = [omega;theta]
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dm2dm3 = [eye(3)/theta -in/theta^2; zeros(1,3) 1];
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alpha = cos(theta);
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beta = sin(theta);
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gamma = 1-cos(theta);
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omegav=[[0 -omega(3) omega(2)];[omega(3) 0 -omega(1)];[-omega(2) omega(1) 0 ]];
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A = omega*omega';
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%m1 = [alpha;beta;gamma;omegav;A];
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dm1dm2 = zeros(21,4);
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dm1dm2(1,4) = -sin(theta);
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dm1dm2(2,4) = cos(theta);
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dm1dm2(3,4) = sin(theta);
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dm1dm2(4:12,1:3) = [0 0 0 0 0 1 0 -1 0;
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0 0 -1 0 0 0 1 0 0;
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0 1 0 -1 0 0 0 0 0]';
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w1 = omega(1);
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w2 = omega(2);
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w3 = omega(3);
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dm1dm2(13:21,1) = [2*w1;w2;w3;w2;0;0;w3;0;0];
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dm1dm2(13: 21,2) = [0;w1;0;w1;2*w2;w3;0;w3;0];
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dm1dm2(13:21,3) = [0;0;w1;0;0;w2;w1;w2;2*w3];
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R = eye(3)*alpha + omegav*beta + A*gamma;
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dRdm1 = zeros(9,21);
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dRdm1([1 5 9],1) = ones(3,1);
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dRdm1(:,2) = omegav(:);
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dRdm1(:,4:12) = beta*eye(9);
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dRdm1(:,3) = A(:);
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dRdm1(:,13:21) = gamma*eye(9);
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dRdin = dRdm1 * dm1dm2 * dm2dm3 * dm3din;
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end;
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out = R;
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dout = dRdin;
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%% it is prob. a rot matr.
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elseif ((m==n) & (m==3) & (norm(in' * in - eye(3)) < bigeps)...
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& (abs(det(in)-1) < bigeps))
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R = in;
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% project the rotation matrix to SO(3);
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[U,S,V] = svd(R);
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R = U*V';
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tr = (trace(R)-1)/2;
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dtrdR = [1 0 0 0 1 0 0 0 1]/2;
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theta = real(acos(tr));
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if sin(theta) >= 1e-5,
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dthetadtr = -1/sqrt(1-tr^2);
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dthetadR = dthetadtr * dtrdR;
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% var1 = [vth;theta];
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vth = 1/(2*sin(theta));
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dvthdtheta = -vth*cos(theta)/sin(theta);
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dvar1dtheta = [dvthdtheta;1];
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dvar1dR = dvar1dtheta * dthetadR;
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om1 = [R(3,2)-R(2,3), R(1,3)-R(3,1), R(2,1)-R(1,2)]';
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dom1dR = [0 0 0 0 0 1 0 -1 0;
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0 0 -1 0 0 0 1 0 0;
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0 1 0 -1 0 0 0 0 0];
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% var = [om1;vth;theta];
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dvardR = [dom1dR;dvar1dR];
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% var2 = [om;theta];
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om = vth*om1;
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domdvar = [vth*eye(3) om1 zeros(3,1)];
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dthetadvar = [0 0 0 0 1];
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dvar2dvar = [domdvar;dthetadvar];
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out = om*theta;
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domegadvar2 = [theta*eye(3) om];
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dout = domegadvar2 * dvar2dvar * dvardR;
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else
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if tr > 0; % case norm(om)=0;
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out = [0 0 0]';
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dout = [0 0 0 0 0 1/2 0 -1/2 0;
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0 0 -1/2 0 0 0 1/2 0 0;
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0 1/2 0 -1/2 0 0 0 0 0];
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else % case norm(om)=pi; %% fixed April 6th
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out = theta * (sqrt((diag(R)+1)/2).*[1;2*(R(1,2:3)>=0)'-1]);
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%keyboard;
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if nargout > 1,
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fprintf(1,'WARNING!!!! Jacobian domdR undefined!!!\n');
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dout = NaN*ones(3,9);
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end;
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end;
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end;
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else
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error('Neither a rotation matrix nor a rotation vector were provided');
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end;
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return;
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%% test of the Jacobians:
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%%%% TEST OF dRdom:
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om = randn(3,1);
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dom = randn(3,1)/1000000;
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[R1,dR1] = rodrigues(om);
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R2 = rodrigues(om+dom);
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R2a = R1 + reshape(dR1 * dom,3,3);
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gain = norm(R2 - R1)/norm(R2 - R2a)
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%%% TEST OF dOmdR:
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om = randn(3,1);
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R = rodrigues(om);
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dom = randn(3,1)/10000;
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dR = rodrigues(om+dom) - R;
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[omc,domdR] = rodrigues(R);
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[om2] = rodrigues(R+dR);
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om_app = omc + domdR*dR(:);
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gain = norm(om2 - omc)/norm(om2 - om_app)
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%%% OTHER BUG: (FIXED NOW!!!)
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omu = randn(3,1);
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omu = omu/norm(omu)
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om = pi*omu;
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[R,dR]= rodrigues(om);
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[om2] = rodrigues(R);
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[om om2]
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%%% NORMAL OPERATION
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om = randn(3,1);
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[R,dR]= rodrigues(om);
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[om2] = rodrigues(R);
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[om om2] |