gtsam/matlab/unstable_examples/+imuSimulator/+lib/rotatePoints.m

83 lines
3.3 KiB
Matlab

function rotatedData = rotatePoints(alignmentVector, originalData)
% rotatedData = rotatePoints(alignmentVector, originalData) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Rotate the 'originalData' in the form of Nx2 or Nx3 about the origin by aligning the x-axis with the alignment vector
%
% Rdata = rotatePoints([1,2,-1], [Xpts(:), Ypts(:), Zpts(:)]) - rotate the (X,Y,Z)pts in 3D with respect to the vector [1,2,-1]
%
% Rotating using spherical components can be done by first converting using [dX,dY,dZ] = cart2sph(theta, phi, rho); alignmentVector = [dX,dY,dZ];
%
% Example:
% %% Rotate the point [3,4,-7] with respect to the following:
% %%%% Original associated vector is always [1,0,0]
% %%%% Calculate the appropriate rotation requested with respect to the x-axis. For example, if only a rotation about the z-axis is
% %%%% sought, alignmentVector = [2,1,0] %% Note that the z-component is zero
% rotData = rotatePoints(alignmentVector, [3,4,-7]);
%
% Author: Shawn Arseneau
% Created: Feb.2, 2006
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
alignmentDim = numel(alignmentVector);
DOF = size(originalData,2); %---- DOF = Degrees of Freedom (i.e. 2 for two dimensional and 3 for three dimensional data)
if alignmentDim~=DOF
error('Alignment vector does not agree with originalData dimensions');
end
if DOF<2 || DOF>3
error('rotatePoints only does rotation in two or three dimensions');
end
if DOF==2 % 2D rotation...
[rad_theta, rho] = cart2pol(alignmentVector(1), alignmentVector(2));
deg_theta = -1 * rad_theta * (180/pi);
ctheta = cosd(deg_theta); stheta = sind(deg_theta);
Rmatrix = [ctheta, -1.*stheta;...
stheta, ctheta];
rotatedData = originalData*Rmatrix;
else % 3D rotation...
[rad_theta, rad_phi, rho] = cart2sph(alignmentVector(1), alignmentVector(2), alignmentVector(3));
rad_theta = rad_theta * -1;
deg_theta = rad_theta * (180/pi);
deg_phi = rad_phi * (180/pi);
ctheta = cosd(deg_theta); stheta = sind(deg_theta);
Rz = [ctheta, -1.*stheta, 0;...
stheta, ctheta, 0;...
0, 0, 1]; %% First rotate as per theta around the Z axis
rotatedData = originalData*Rz;
[rotX, rotY, rotZ] = sph2cart(-1* (rad_theta+(pi/2)), 0, 1); %% Second rotation corresponding to phi
rotationAxis = [rotX, rotY, rotZ];
u = rotationAxis(:)/norm(rotationAxis); %% Code extract from rotate.m from MATLAB
cosPhi = cosd(deg_phi);
sinPhi = sind(deg_phi);
invCosPhi = 1 - cosPhi;
x = u(1);
y = u(2);
z = u(3);
Rmatrix = [cosPhi+x^2*invCosPhi x*y*invCosPhi-z*sinPhi x*z*invCosPhi+y*sinPhi; ...
x*y*invCosPhi+z*sinPhi cosPhi+y^2*invCosPhi y*z*invCosPhi-x*sinPhi; ...
x*z*invCosPhi-y*sinPhi y*z*invCosPhi+x*sinPhi cosPhi+z^2*invCosPhi]';
rotatedData = rotatedData*Rmatrix;
end