Added ground truth factor graph creation. Added OdometryExample3D as a modified version of OdometryExample for reference (can be removed later)

matlab/unstable_examples/+imuSimulator/OdometryExample3D.m

@@ -0,0 +1,68 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% 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 Example of a simple 2D localization example
+% @author Frank Dellaert
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+% Copied Original file. Modified by David Jensen to use Pose3 instead of
+% Pose2. Everything else is the same.
+
+import gtsam.*
+
+%% Assumptions
+%  - Robot poses are facing along the X axis (horizontal, to the right in 2D)
+%  - The robot moves 2 meters each step
+%  - The robot is on a grid, moving 2 meters each step
+
+%% Create the graph (defined in pose2SLAM.h, derived from NonlinearFactorGraph)
+graph = NonlinearFactorGraph;
+
+%% Add a Gaussian prior on pose x_1
+priorMean = Pose3();%Pose3.Expmap([0.0; 0.0; 0.0; 0.0; 0.0; 0.0]); % prior mean is at origin
+priorNoise = noiseModel.Diagonal.Sigmas([0.3; 0.3; 0.3; 0.1; 0.1; 0.1]); % 30cm std on x,y, 0.1 rad on theta
+graph.add(PriorFactorPose3(1, priorMean, priorNoise)); % add directly to graph
+
+%% Add two odometry factors
+odometry = Pose3.Expmap([0.0; 0.0; 0.0; 2.0; 0.0; 0.0]); % create a measurement for both factors (the same in this case)
+odometryNoise = noiseModel.Diagonal.Sigmas([0.2; 0.2; 0.2; 0.1; 0.1; 0.1]); % 20cm std on x,y, 0.1 rad on theta
+graph.add(BetweenFactorPose3(1, 2, odometry, odometryNoise));
+graph.add(BetweenFactorPose3(2, 3, odometry, odometryNoise));
+
+%% print
+graph.print(sprintf('\nFactor graph:\n'));
+
+%% Initialize to noisy points
+initialEstimate = Values;
+%initialEstimate.insert(1, Pose3.Expmap([0.2; 0.1; 0.1; 0.5; 0.0; 0.0]));
+%initialEstimate.insert(2, Pose3.Expmap([-0.2; 0.1; -0.1; 2.3; 0.1; 0.1]));
+%initialEstimate.insert(3, Pose3.Expmap([0.1; -0.1; 0.1; 4.1; 0.1; -0.1]));
+%initialEstimate.print(sprintf('\nInitial estimate:\n  '));
+
+for i=1:3
+  deltaPosition = 0.5*rand(3,1) + [1;0;0]; % create random vector with mean = [1 0 0] and sigma = 0.5
+  deltaRotation = 0.1*rand(3,1) + [0;0;0]; % create random rotation with mean [0 0 0] and sigma = 0.1 (rad)
+  deltaPose = Pose3.Expmap([deltaRotation; deltaPosition]);
+  currentPose = currentPose.compose(deltaPose);
+  initialEstimate.insert(i, currentPose);
+end
+
+%% Optimize using Levenberg-Marquardt optimization with an ordering from colamd
+optimizer = LevenbergMarquardtOptimizer(graph, initialEstimate);
+result = optimizer.optimizeSafely();
+result.print(sprintf('\nFinal result:\n  '));
+
+%% Plot trajectory and covariance ellipses
+cla;
+hold on;
+
+plot3DTrajectory(result, [], Marginals(graph, result));
+
+axis([-0.6 4.8 -1 1])
+axis equal
+view(2)

matlab/unstable_examples/+imuSimulator/covarianceAnalysisBetween.m

@@ -1,3 +1,5 @@
+import gtsam.*;
+
 % Test GTSAM covariances on a graph with betweenFactors
 
 clc
@@ -5,26 +7,56 @@ clear all
 close all
 
 %% Create ground truth trajectory
-trajectoryLength = 100;
+trajectoryLength = 5;
 
 % possibly create random trajectory
 currentPoseKey = symbol('x', 0);
 currentPose = Pose3;
 gtValues = Values;
 gtValues.insert(currentPoseKey, currentPose);
+gtGraph = NonlinearFactorGraph;
+gtNoise = noiseModel.Diagonal.Sigmas([0.1; 0.1; 0.1; 0.05; 0.05; 0.05]); % Noise for GT measurements
 
 for i=1:trajectoryLength
   currentPoseKey = symbol('x', i);
-  deltaPosition = % create random vector with mean [x 0 0]
+  deltaPosition = 0.5*rand(3,1) + [1;0;0]; % create random vector with mean = [1 0 0] and sigma = 0.5
-  deltaRotation = % create random rotation with mean [0 0 0]
+  deltaRotation = 0.1*rand(3,1) + [0;0;0]; % create random rotation with mean [0 0 0] and sigma = 0.1 (rad)
-  deltaPose = Pose3(deltaRotation, Point3(deltaPosition));
+  deltaPose = Pose3.Expmap([deltaRotation; deltaPosition]);
+  deltaPoseNoise = gtNoise;
+  
   % "Deduce" ground truth measurements
   % deltaPose are the gt measurements - save them in some structure
+  gtMeasurementPose(i) = deltaPose;
   currentPose = currentPose.compose(deltaPose);
   gtValues.insert(currentPoseKey, currentPose);
+  
+  % Add the factor to the factor graph
+  if(i == 1)
+      gtGraph.add(PriorFactorPose3(currentPoseKey, deltaPose, deltaPoseNoise));
+  else
+      gtGraph.add(BetweenFactorPose3(previousPoseKey, currentPoseKey, deltaPose, deltaPoseNoise));
+  end
+  previousPoseKey = currentPoseKey;
 end
 
+gtGraph.print(sprintf('\nGround Truth - Factor graph:\n'));
+gtValues.print(sprintf('\nGround Truth - Values:\n'));
+
 %% Create gt graph (using between with ground truth measurements)
+% Optimize using Levenberg-Marquardt
+optimizer = LevenbergMarquardtOptimizer(gtGraph, gtValues);
+gtResult = optimizer.optimizeSafely();
+gtResult.print(sprintf('\nGround Truth - Final Result:\n'));
+
+% Plot trajectory and covariance ellipses
+% Couldn't get this to work in the modified example (OdometryExample3D).
+% Something strange with 3D trajectories?
+cla;
+hold on;
+
+plot3DTrajectory(gtResult, [], Marginals(gtGraph, gtResult));
+axis equal
+
 % Compute covariances using gtGraph and gtValues (for visualization)
 
 % decide measurement covariance