Parameters (Gflags)
Maplab uses gflags (gflags_catkin) to pass parameters to executables and commands inside the maplab console. If you have never used gflags before, it might help you to take a look at the gflags documentation.
Special gflags and flag files
Have a look at this section of the gflags documentation.
Basic maplab flags
Here is a short list of the basic maplab flags that are needed to load and store a map, specify which mission a command should operate on and manage the map resources.
-map_folder (The folder on which a console command operates.) type: string
default: ""
-map_key (The map key for a console command.) type: string default: ""
-map_mission (The mission ID a command should operate on.) type: string
default: ""
-map_mission_list (List of comma separated mission IDs a command should
operated on.) type: string default: ""
-overwrite (If set to true, existing files on the disks will get
overwritten.) type: bool default: false
-target_map_key (Target map key for copy and move commands.) type: string
default: ""
-copy_resources_to_external_folder (Set this to true to migrate the
resources to an extneral folder (by creating a copy of the resources)
before saving the map. This flag will be reset after every use.)
type: string default: ""
-copy_resources_to_map_folder (Set this to true to migrate the resources to
the map folder (by creating a copy of the resources) before saving the
map. This flag will be reset after every use.) type: bool default: false
-maps_folder (Folder which contains one or more maps on the filesystem.)
type: string default: "."
-move_resources_to_external_folder (Set this to true to migrate the
resources to an extneral folder (by moving the resources) before saving
the map. This flag will be reset after every use.) type: string
default: ""
-move_resources_to_map_folder (Set this to true to migrate the resources to
the map folder (by moving the resources) before saving the map. This flag
will be reset after every use.) type: bool default: false
-resource_folder (Specifies the resource folder for certain commands.)
type: string default: ""
List all parameters
In order to get a full list of all parameters that are available for a specific maplab executable, call the executable with the --help flag. Example:
rosrun rovioli rovioli --help
A complete list can also be obtained from inside the maplab console by typing:
<any_valid_command> --help
This list will be quite extensive, and it helps to narrow down your search with grep:
rosrun rovioli rovioli --help | grep loop
Unfortunately grep will not work inside the console.
Find parameters for a specific algorithm
Maplab uses prefixes for most of the gflags to associate them with a specific algorithm or map component. Examples:
-ba_* # bundle adjustment
-lc_* # loop closure
-vis_* # visualization
-vi_map_landmark_* # landmarks and landmark quality metric
-dense_* # dense reconstruction
-lba_* # legacy bundle adjustment
In order to get a list of all parameters that are related to the bundle adjustment, use the auto completion function in the console or grep the complete parameter list:
# Type and TAB:
optvi --ba
# Result:
--ba_altitude_meters --ba_min_landmarks_per_frame
--ba_fix_accel_bias --ba_num_iterations
--ba_fix_gyro_bias --ba_outlier_rejection_reject_every_n_iters
--ba_fix_landmark_positions --ba_outlier_rejection_reject_using_reprojection_error
--ba_fix_ncamera_extrinsics_rotation --ba_outlier_rejection_reprojection_error_other_mission_px
--ba_fix_ncamera_extrinsics_translation --ba_outlier_rejection_reprojection_error_px
--ba_fix_ncamera_intrinsics --ba_use_cgnr_linear_solver
--ba_fix_velocity --ba_use_jacobi_scaling
--ba_include_inertial --ba_use_outlier_rejection_solver
--ba_include_visual --ba_visualize_every_n_iterations
--ba_latitude --bag_file
For more details about a specific parameter, search for the description in the full parameter list:
# Type:
rosrun maplab_console maplab_console --help | grep -e "-lc_" -A 1
# Result:
-lc_projected_quantizer_filename (File where to read the projected
quantizer from.) type: string default: ""
-lc_projection_matrix_filename (The name of the file for the projection
matrix.) type: string default: ""
-lc_target_dimensionality (The target dimensionality of the projection.)
type: int32 default: 10
--
-lc_edge_covariance_scaler (Scaling the covariance of loopclosure edges. It
is identity by default.) type: double default: 9.9999999999999995e-08
-lc_edge_min_distance_meters (The minimum loop-closure gap distance such
that a loop-closure edge is created.) type: double default: 1
-lc_edge_min_inlier_count (The minimum loop-closure inlier count to add a
loop-closure edge.) type: int32 default: 20
-lc_edge_min_inlier_ratio (The minimum loop-closure inlier ratio to add a
loop-closure edge.) type: double default: 0.5
-lc_min_inlier_count (Minimum inlier count for loop closure.) type: int32
default: 10
-lc_min_inlier_ratio (Minimum inlier ratio for loop closure.) type: double
default: 0.20000000000000001
-lc_nonlinear_refinement_p3p (If nonlinear refinement on all ransac inliers
should be run.) type: bool default: false
-lc_num_ransac_iters (Maximum number of ransac iterations for absolute pose
recovery.) type: int32 default: 100
-lc_ransac_pixel_sigma (Pixel sigma for ransac.) type: double default: 2
--
-lc_filter_underconstrained_landmarks (If underconstrained landmarks should
be filtered for the loop-closure.) type: bool default: true
-lc_use_random_pnp_seed (Use random seed for pnp RANSAC.) type: bool
default: true
--
-lc_visualize_outliers (If outlier matches should be published on the loop
closure topic.) type: bool default: false
--
-lc_knn_epsilon (Epsilon approximation value for the nearest neighbor
search.) type: double default: 3
-lc_knn_max_radius (Max radius for the nearest neighbor search.)
type: double default: 20
--
-lc_detector_engine (Which loop-closure engine to use) type: string
default: "inverted_multi_index"
-lc_fraction_best_scores (Fraction of best scoring keyframes/vertices that
are considered for covisibility filtering.) type: double default: 0.25
-lc_min_image_time_seconds (Minimum time between matching images to allow a
loop closure.) type: double default: 10
-lc_min_verify_matches_num (The minimum number of matches needed to verify
geometry.) type: uint64 default: 10
-lc_num_neighbors (Number of neighbors to retrieve for loop-closure. -1
auto.) type: int32 default: -1
-lc_num_words_for_nn_search (Number of nearest words to retrieve in the
inverted index.) type: int32 default: 10
-lc_scoring_function (Type of scoring function to be used for scoring
keyframes.) type: string default: "accumulation"
--
-lc_num_descriptors_to_train (Number of descriptors used for training.)
type: int32 default: 100000
-lc_number_of_vocabulary_words (Number of words in the vocabulary.)
type: int32 default: 1000
-lc_product_quantization_num_components (Number of components for product
quantization.) type: int32 default: 1
-lc_product_quantization_num_dim_per_component (Number of components for
product quantization.) type: int32 default: 5
-lc_product_quantization_num_words (Number of words in the product
vocabulary.) type: int32 default: 256
--
-lc_kdtree_accelerator_eps (Epsilon for the NN search inside the kd-tree
based search accelerators.) type: double default: 0.10000000000000001
--
-lc_kmeans_levels (Number of levels in the vocabulary tree.) type: int32
default: 4
-lc_kmeans_splits (Number of splits in the kmeans step per level.)
type: int32 default: 10
-lc_num_kmeans_restarts (Number of restarts for the kmeans.) type: int32
default: 5
--
-lc_only_against_other_missions (If true, no inter-mission loop-closures
are sought.) type: bool default: false
--
-lc_switch_variable_value (The value for the switch variable of the
loop-closure edges, between 0.0 (edge is ignored) and 1.0 (edge is being
--
-lc_switch_variable_variance (The variance for the switch variable of the
loop-closure edges.) type: double default: 1e-08