gtsam/matlab/examples/Pose2SLAMExample_graph.m

40 lines
1.4 KiB
Matlab

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% GTSAM Copyright 2010, Georgia Tech Research Corporation,
% Atlanta, Georgia 30332-0415
% All Rights Reserved
% Authors: Frank Dellaert, et al. (see THANKS for the full author list)
%
% See LICENSE for the license information
%
% @brief Read graph from file and perform GraphSLAM
% @author Frank Dellaert
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Initialize graph, initial estimate, and odometry noise
model = gtsamnoiseModelDiagonal_Sigmas([0.05; 0.05; 5*pi/180]);
[graph,initial]=load2D('../../examples/Data/w100-odom.graph',model);
initial.print(sprintf('Initial estimate:\n'));
%% Add a Gaussian prior on pose x_1
priorMean = gtsamPose2(0.0, 0.0, 0.0); % prior mean is at origin
priorNoise = gtsamnoiseModelDiagonal_Sigmas([0.01; 0.01; 0.01]);
graph.addPrior(0, priorMean, priorNoise); % add directly to graph
%% Plot Initial Estimate
figure(1);clf
plot(initial.xs(),initial.ys(),'g-*'); axis equal
%% Optimize using Levenberg-Marquardt optimization with an ordering from colamd
result = graph.optimize(initial);
hold on; plot(result.xs(),result.ys(),'b-*')
result.print(sprintf('\nFinal result:\n'));
%% Plot Covariance Ellipses
marginals = graph.marginals(result);
P={};
for i=1:result.size()-1
pose_i = result.pose(i);
P{i}=marginals.marginalCovariance(i);
plotPose2(pose_i,'b',P{i})
end
fprintf(1,'%.5f %.5f %.5f\n',P{99})