Provided by: mrpt-apps_1.5.8-1_amd64 
NAME
graphslam-engine - Construct and solve robot pose graphs from .rawlog dataset files
Note:As the graphslam-engine application still under development, current manpage may be
outdated. Refer to the MRPT doxygen class documentation and the corresponding application
documentation for the latest features and usage instructions
SYNOPSIS
The available command line arguments are listed below:
graphslam-engine [--disable-visuals] [--list-optimizers]
[--list-regs] [--list-edge-regs]
[--list-node-regs][-o <CLevMarqGSO>][-e
<CICPCriteriaERD>][-n <CICPCriteriaNRD>][-g
<contents.rawlog.GT.txt>][-r <contents.rawlog>] [-i
<config.ini>] [--][--version] [-h]
Alternatively run graphslam-engine -h for the full arguments list
DESCRIPTION
Aim of the app is to perform 2D graph-slam: Robot localizes itself in the environment
while, at the same time builds a map of that environment. App currently executes SLAM
using MRPT rawlog files (both MRPT rawlog formats are supported) as input which should
contain (some of) the following observation types:
· CObservationOdometry
· CObservation2DRangeScan
· CObservation3DRangeScan
Working with 3DRangeScan is currently in an experimental phase.
The majority of the graphslam-engine parameters in each case should be specified in an
external .ini file which is to be given as a command-line argument. The following
parameters can also be specified as command-line arguments:
· .ini-file [REQUIRED]
Specify the .ini configuration file using the -i, --ini-file flags. Configuration
file parameters are read by the main CGraphSlamEngine class as well as the node/edge
registration schemes, and the optimization scheme.
· rawlog-file [REQUIRED]
Specify the rawlog dataset file using the -r, --rawlog flags.
· ground-truth
Specify a ground truth file with -g, --ground-truth flags. Ground truth has to be
specified if user has set visualize_slam_metric or visualize_ground_truth to true in
the .ini file, otherwise an exception is raised.
· Node/Edge registration decider classes to be used.
Specify the node registration or/and edge registration decider classes to be used
using -n, --node-reg, -e --edge-reg flags.
If not specified the default CFixedIntervalsNRD, CICPCriteriaERD are used as node and
edge registration decider schemes respectively.
· Optimizer class to be used
Specify the class to be used for the optimization of the pose-graph using the -o
--optimizer flags. Currently the only supported optimization scheme is Levenberg-
Marquardt non-linear graph optimization defined in optimize_graph_spa_levmarq
(http://reference.mrpt.org/devel/group__mrpt__graphslam__grp.html#ga022f4a70be5ec7c432f46374e4bb9d66)
If not specified, the default CLevMarqGSO is used.
OPTIONS
--disable-visuals
Disable Visualization - Overrides related visualize* directives of the
.ini file
--list-optimizers
List (all) available graphslam optimizer classes
--list-regs
List (all) available registration decider classes
--list-edge-regs
List available edge registration decider classes
--list-node-regs
List available node registration decider classes
-o <CLevMarqGSO>, --optimizer <CLevMarqGSO>
Specify GraphSlam Optimizer
-e <CICPCriteriaERD>, --edge-reg <CICPCriteriaERD>
Specify Edge registration decider
-n <CICPCriteriaNRD>, --node-reg <CICPCriteriaNRD>
Specify Node registration decider
-g <contents.rawlog.GT.txt>, --ground-truth <contents.rawlog.GT.txt>
Ground-truth textfile
-r <contents.rawlog>, --rawlog <contents.rawlog>
Rawlog dataset file
-i <config.ini>, --ini_file <config.ini>
.ini configuration file
--, --ignore_rest
Ignores the rest of the labeled arguments following this flag.
--version
Displays version information and exits.
-h, --help
Displays usage information and exits.
PROGRAM INPUT/OUTPUT
By default graphslam-engine execution generates an output directory by the name
"graphslam-results" within the current working directory. The output directory contains
the following files:
· CGraphSlamEngine.log
Logfile containing the activity of the CGraphSlamEngine class instance. Activity
involves output logger messages, time statistics for critical parts of the
application, and summary statistics about the constructed graph (e.g. number of
registered nodes, edges).
· node_registrar.log, edge_registrar.log, optimizer.log
Logfiles containing the activity of the corresponding class instances. File contents
depend on the implementation of the corresponding classes but in most cases they
contain output logger messages, time statistics for critical parts of the class
execution.
· output_graph.graph
File contains the constructed graph in the VERTEX/EDGE format. The latter can be
visualized using the MRPT graph-slam application for verification reasons.
For more information on this, see: http://www.mrpt.org/Graph-SLAM_maps
http://www.mrpt.org/list-of-mrpt-apps/application-graph-slam/
· output_scene.3DScene
File contains the 3DScene that was generated in the end of the graphslam-engine
execution. The latter can be visualized using the MRPT SceneViewer3D tool.
For more information on this, see
http://www.mrpt.org/list-of-mrpt-apps/application-sceneviewer3d/
Note: File is generated only when the visualization of the graph construction is
enabled in the .ini configuration file. See .ini parameters as well as the --disable
flag for more on this.
· SLAM_evaluation_metric.log
File contains the differences between the estimated trajectory increments and the
corresponding ground-truth increments and can be used to verify and evaluate the
performance of the SLAM algorithm. For more information on the metric, see "A
Comparison of SLAM Algorithms Based on a Graph of Relations - Burgard, Wolfram et al."
Note: File is generated only when the ground-truth of the corresponding dataset is
given.
Note: In case a directory named graphslam-results, generated during a previous execution,
already exists it is, by default, overwritten. If this is not the desired behavior, user
can set the user_decides_about_output_dir .ini parameter to true so that they are asked
about this naming conflict during program execution.
EXAMPLES
Sample calls to the graphslam-engine application are given below:
graphslam-engine --list-regs
graphslam-engine --list-regs --list-optimizers
graphslam-engine -i $mrpt/share/mrpt/config_files/graphslam-engine/odometry_2DRangeScans.ini -r $mrpt/share//mrpt/datasets/graphslam-engine-demos/action_observations_map/range_030_bearing_015.rawlog -g $mrpt/share//mrpt/datasets/graphslam-engine-demos/action_observations_map/range_030_bearing_015.rawlog.GT.txt
graphslam-engine -i $mrpt/share//mrpt/config_files/graphslam-engine/odometry_2DRangeScans_LC_version.ini -r $mrpt/share//mrpt/datasets/graphslam-engine-demos/action_observations_map/range_030_bearing_015.rawlog -g $mrpt/share//mrpt/datasets/graphslam-engine-demos/action_observations_map/range_030_bearing_015.rawlog.GT.txt --node-reg CFixedIntervalsNRD --edge-reg CLoopCloserERD --optimizer CLevMarqGSO
graphslam-engine -i $mrpt/share//mrpt/config_files/graphslam-engine/laser_odometry.ini -r $mrpt/share//mrpt/datasets/graphslam-engine-demos/action_observations_map/range_030_bearing_015.rawlog -g $mrpt/share//mrpt/datasets/graphslam-engine-demos/action_observations_map/range_030_bearing_015.rawlog.GT.txt -n CFixedIntervalsNRD -e CICPCriteriaERD
APPLICATION DESIGN
In this section insight into the graphslam-engine application - and corresponding library
- is provided.
CGraphSlamEngine is the main class executing graphslam. CGraphSlamEngine delegates most of
the graph manipulation tasks to node/edge registration deciders and optimizer classes.
This makes up for independence between the different tasks as well as for a reconfigurable
setup, as the user can select to use different decider/optimizer classes depending on the
situation. Users can also write their own decider/optimizer classes by inheriting from one
of the CNodeRegistrationDecider, CEdgeRegistrationDecider, CGraphSlamOptimizer interfaces
depending on what part they want to implement.
REGISTRATION DECIDERS
The registration decider classes are divided into node and edge registration deciders. The
former are responsible of adding new nodes in the graph while the latter add additional
edges between already added graph nodes. These nodes can be consecutive or non-
consecutive.
NODE REGISTRATION DECIDERS
Node registration decider schemes add nodes to the graph according to a specific
criterion. Node deciders should implement the methods defined in the
CNodeRegistrationDecider abstract class. CNodeRegistrationDecider provides the basic
methods that have to exist in every node registration decider class. For an example of
inheriting from this class see CFixedIntervalsNRD. As a naming convention, all the
implemented node registration deciders are suffixed with the NRD acronym.
Currently two specific node registration schemes have been implemented:
· CFixedIntervalsNRD
Decider registers a new node in the graph if the distance or the angle difference with
regards to the previous registered node surpasses a corresponding fixed threshold.
Decider makes use only of the CObservationOdometry instances in the rawlog file.
· CICPCriteriaNRD
Decider registers a new node in the graph if the distance or the angle difference with
regards to the previous registered node surpasses a corresponding fixed threshold.
Decider measures the distance from the current position to the previous registered
node using ICP (i.e. matches the current range scan against the range scan of the
previous node). In case of noisy 2D laser scans, decider can also use odometry
information to locally correct and smoothen the robot trajectory. Decider makes use of
2DRangeScans or 3DRangeScans.
For more information on this see
http://reference.mrpt.org/devel/classmrpt_1_1graphslam_1_1deciders_1_1_c_node_registration_decider.html
EDGE REGISTRATION DECIDERS
Edge registration decider schemes add edges between already added nodes in the graph
according to a specific criterion. Edge deciders should implement the methods defined in
CEdgeRegistrationDecider abstract class. CEdgeRegistrationDecider provides the basic
methods that have to exist in every edge registration decider class. For an example of
inheriting from this class see CICPCriteriaERD. As a naming convention, all the
implemented edge registration deciders are suffixed with the ERD acronym.
Currently two specific edge registration schemes have been implemented:
· CICPCriteriaERD
Register new edges in the graph with the last inserted node. Criterion for adding new
edges should be the goodness of the candidate ICP edge. The nodes for ICP are picked
based on the distance from the last inserted node. Decider makes use of 2DRangeScans
or 3DRangeScans.
· CLoopCloserERD
Evaluate sets of potential loop closure edges in the graph based on their pairwise
consistency matrix.
Decider first splits the graph into partitions based on the 2D laser scans of the
nodes and then searches for potential loop closure edges within the partitions. Goal
is to register only a subset of the potential loop closure edges that maximally agree
with each other. Decider is implemented based on the following two papers:
[1] Consistent Observation Grouping for Generating Metric-Topological Maps that
Improves Robot Localization - J. Blanco, J. Gonzalez, J. Antonio Fernandez Madrigal,
2006 [2] Recognizing places using spectrally clustered local matches - E. Olson, 2009
For more information on this see
http://reference.mrpt.org/devel/classmrpt_1_1graphslam_1_1deciders_1_1_c_edge_registration_decider.html
OPTIMIZERS
Optimizer schemes optimize an already constructed graph so that the registered edges
maximally agree with each other. Optimizer schemes should implement the methods defined in
CGraphSlamOptimizer abstract class. For an example of inheriting from this class see
CLevMarqGSO.
As a naming convention, all the implemented graphslam optimizer classes are suffixed with
the GSO acronym.
For more information on this see
http://reference.mrpt.org/devel/classmrpt_1_1graphslam_1_1optimizers_1_1_c_graph_slam_optimizer.html
BUGS
Please report bugs at https://github.com/MRPT/mrpt/issues
SEE ALSO
· Application wiki page - http://www.mrpt.org/Applications
· mrpt::graphslam lib documentation page -
http://reference.mrpt.org/devel/namespacemrpt_1_1graphslam.html
· Application demo video - https://www.youtube.com/watch?v=Pv0yvlzrcXk
· .ini Example files:
For examples of .ini configuration files see the
$mrpt/share/mrpt/config_files/graphslam-engine directory. Modify $mrpt according to
the path of MRPT source code.
· Example datasets
For a list of datasets used during the application testing see the
$mrpt/share/mrpt/datasets/graphslam-engine directory. Modify $mrpt according to the
path of MRPT source code.
AUTHORS
graphslam-engine is part of the Mobile Robot Programming Toolkit (MRPT), It was originally
written by Nikos Koukis during the Google Summer of Code (GSOC) 2016 program.
This manual page was written by Nikos Koukis <nickkouk@gmail.com>.
COPYRIGHT
This program is free software; you can redistribute it and/or modify it under the terms of
the BSD License.
On Debian GNU/Linux systems, the complete text of the BSD License can be found in
`/usr/share/common-licenses/BSD'.