68 lines
2.6 KiB
Matlab
68 lines
2.6 KiB
Matlab
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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% GTSAM Copyright 2010, Georgia Tech Research Corporation,
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% Atlanta, Georgia 30332-0415
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% All Rights Reserved
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% Authors: Frank Dellaert, et al. (see THANKS for the full author list)
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%
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% See LICENSE for the license information
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%
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% @brief Basic VO Example with 3 landmarks and two cameras
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% @author Chris Beall
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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import gtsam.*
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%% Assumptions
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% - For simplicity this example is in the camera's coordinate frame
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% - X: right, Y: down, Z: forward
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% - Pose x1 is at the origin, Pose 2 is 1 meter forward (along Z-axis)
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% - x1 is fixed with a constraint, x2 is initialized with noisy values
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% - No noise on measurements
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%% Create keys for variables
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x1 = symbol('x',1); x2 = symbol('x',2);
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l1 = symbol('l',1); l2 = symbol('l',2); l3 = symbol('l',3);
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%% Create graph container and add factors to it
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graph = NonlinearFactorGraph;
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%% add a constraint on the starting pose
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first_pose = Pose3();
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graph.add(NonlinearEqualityPose3(x1, first_pose));
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%% Create realistic calibration and measurement noise model
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% format: fx fy skew cx cy baseline
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K = Cal3_S2Stereo(1000, 1000, 0, 320, 240, 0.2);
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stereo_model = noiseModel.Diagonal.Sigmas([1.0; 1.0; 1.0]);
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%% Add measurements
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% pose 1
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graph.add(GenericStereoFactor3D(StereoPoint2(520, 480, 440), stereo_model, x1, l1, K));
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graph.add(GenericStereoFactor3D(StereoPoint2(120, 80, 440), stereo_model, x1, l2, K));
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graph.add(GenericStereoFactor3D(StereoPoint2(320, 280, 140), stereo_model, x1, l3, K));
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%pose 2
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graph.add(GenericStereoFactor3D(StereoPoint2(570, 520, 490), stereo_model, x2, l1, K));
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graph.add(GenericStereoFactor3D(StereoPoint2( 70, 20, 490), stereo_model, x2, l2, K));
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graph.add(GenericStereoFactor3D(StereoPoint2(320, 270, 115), stereo_model, x2, l3, K));
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%% Create initial estimate for camera poses and landmarks
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initialEstimate = Values;
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initialEstimate.insert(x1, first_pose);
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% noisy estimate for pose 2
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initialEstimate.insert(x2, Pose3(Rot3(), Point3(0.1,-.1,1.1)));
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expected_l1 = Point3( 1, 1, 5);
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initialEstimate.insert(l1, expected_l1);
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initialEstimate.insert(l2, Point3(-1, 1, 5));
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initialEstimate.insert(l3, Point3( 0,-.5, 5));
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%% optimize
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optimizer = LevenbergMarquardtOptimizer(graph, initialEstimate);
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result = optimizer.optimize();
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%% check equality for the first pose and point
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pose_x1 = result.atPose3(x1);
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CHECK('pose_x1.equals(first_pose,1e-4)',pose_x1.equals(first_pose,1e-4));
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point_l1 = result.atPoint3(l1);
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CHECK('point_1.equals(expected_l1,1e-4)',point_l1.equals(expected_l1,1e-4)); |