gtsam/matlab/+gtsam/points2DTrackMonocular.m

91 lines
2.6 KiB
Matlab

function pts2dTracksMono = points2DTrackMonocular(cameras, imageSize, cylinders)
% Assess how accurately we can reconstruct points from a particular monocular camera setup.
% After creation of the factor graph for each track, linearize it around ground truth.
% There is no optimization
% @author: Zhaoyang Lv
import gtsam.*
%% create graph
graph = NonlinearFactorGraph;
%% create the noise factors
pointNoiseSigma = 0.1;
poseNoiseSigmas = [0.001 0.001 0.001 0.1 0.1 0.1]';
measurementNoiseSigma = 1.0;
posePriorNoise = noiseModel.Diagonal.Sigmas(poseNoiseSigmas);
pointPriorNoise = noiseModel.Isotropic.Sigma(3, pointNoiseSigma);
measurementNoise = noiseModel.Isotropic.Sigma(2, measurementNoiseSigma);
cameraPosesNum = length(cameras);
%% add measurements and initial camera & points values
pointsNum = 0;
cylinderNum = length(cylinders);
for i = 1:cylinderNum
pointsNum = pointsNum + length(cylinders{i}.Points);
end
pts3d = {};
initialEstimate = Values;
initialized = false;
for i = 1:cameraPosesNum
% add a constraint on the starting pose
camera = cameras{i};
pts3d.pts{i} = cylinderSampleProjection(camera, imageSize, cylinders);
pts3d.camera{i} = camera;
if ~initialized
graph.add(PriorFactorPose3(symbol('x', 1), camera.pose, posePriorNoise));
k = 0;
if ~isempty(pts3d.pts{i}.data{1+k})
graph.add(PriorFactorPoint3(symbol('p', 1), ...
pts3d.pts{i}.data{1+k}, pointPriorNoise));
else
k = k+1;
end
initialized = true;
end
for j = 1:length(pts3d.pts{i}.Z)
if isempty(pts3d.pts{i}.Z{j})
continue;
end
graph.add(GenericProjectionFactorCal3_S2(pts3d.pts{i}.Z{j}, ...
measurementNoise, symbol('x', i), symbol('p', j), camera.calibration) );
end
end
%% initialize cameras and points close to ground truth
for i = 1:cameraPosesNum
pose_i = camera.pose.retract(0.1*randn(6,1));
initialEstimate.insert(symbol('x', i), pose_i);
end
ptsIdx = 0;
for i = 1:length(cylinders)
for j = 1:length(cylinders{i}.Points)
ptsIdx = ptsIdx + 1;
point_j = cylinders{i}.Points{j}.retract(0.1*randn(3,1));
initialEstimate.insert(symbol('p', ptsIdx), point_j);
end
end
%% Print the graph
graph.print(sprintf('\nFactor graph:\n'));
marginals = Marginals(graph, initialEstimate);
%% get all the 2d points track information
% currently throws the Indeterminant linear system exception
ptIdx = 0;
for i = 1:pointsNum
if isempty(pts3d.pts{i})
continue;
end
pts2dTracksMono.cov{ptIdx} = marginals.marginalCovariance(symbol('p',i));
end
end