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Table of Contents

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`manager` section

The manager acts as the primary interface between the user and theVisual-SLAMbackend. It allows users to set, enable, and disable general functionalities of LPSLAM.

Argument	Type	Description
`create_occupancy`	`bool`	Activate/deactivate filling the occupancy grid.
`drop_frames`	`bool`	Allow to drop frames if the processing time is too slow.
`occupancy_file`	`string`	File to save the generated occupancy map.
`record`	`bool`	Enable/disable recording data.
`record_raw`	`bool`	If `"record": true`, record raw data.
`replay_chunks`	`int`	Number of items in the processing batch when replaying data.
`show_live`	`bool`	Activate/deactivate a live view of the camera input.
`thread_num`	`int`	Number of threads to use for processing.

`cameras` section

Here, one sets the crucial calibration parameters for the utilized camera. These parameters define the relationship between 3D points in the world and their corresponding image projections. Accurate calibration ensures the camera model accurately reflects the real world, allowing for precise reconstruction of the environment in Visual-SLAM.

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When using a stereo camera, each camera requires its own configuration within the same file. They are differentiated by numerical identifiers, with the left camera typically assigned 0 and the right camera assigned to 1. Notably, the parameters focal_x_baseline, translation, and rotation (or rotation_vec) are only specified for the first camera.

`datasources` section

This section configures the image data source to use and defines its general settings.

File Source

This data source is utilized when it is desired to utilize LPSLAM with a pre-recorded dataset file (.pb) in replay mode.

Argument		Type	Description
`type`		`string`	`FileSource`
`configuration`		`list`
	`camera_position`	`vector<double>`	Camera’s relative position.
	`camera_orientation`	`vector<double>`	Camera’s relative quaternion orientation.
	`file_names`	`string`	File path.

LeapMotion and Rigel

Argument		Type	Description
`type`		`string`	`LeapMotion` `Rigel`
`configuration`		`list`
	`camera_position`	`vector<double>`	Camera’s relative position.
	`camera_orientation`	`vector<double>`	Camera’s relative quaternion orientation.

OpenCV

Generally, this data source type can be used for any camera that the system detects and can be accessed via OpenCV (e.g. StereoLabs ZED2)

Argument		Type	Description
`type`		`string`	`OpenCV`
`configuration`		`list`
	`camera_position`	`vector<double>`	Camera’s relative position.
	`camera_orienation`	`vector<double>`	Camera’s relative quaternion orientation.
	`camera_number`	`int`	ID of the input camera in the system.
	`grayscale`	`bool`	Enable/disable grayscale as the color order.
	`width`	`int`	The horizontal resolution of the camera image sensor, in pixels.
	`height`	`int`	The vertical resolution of the camera image sensor, in pixels.
	`stereo_mode`	`string`	The orientation of the stereo camera. Available options: `horizontal` `vertical`
	`fps`	`float`	Framerate of input images.
	`exposure`	`float`	Exposure value for the camera.
	`gain`	`float`	Gain value for the camera.
	`opencv_logging_verbose`	`bool`	Activate/deactivate OpenCV’s verbosity.
	`target_fps`	`int`	The desired `fps` if these were not set at the camera driver level.

Varjo

This type is for using Varjo XR-3 HMD cameras as data source.

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Argument		Type	Description
`type`		`string`	`Varjo`
`configuration`		`list`
	`camera_position`	`vector<double>`	Camera’s relative position.
	`camera_orientation`	`vector<double>`	Camera’s relative quaternion orientation.
	`prescale`	`int`

Others

Argument

Type

Description

type

string

Available options:

RaspiCam

Requires LPSLAM_BUILD_PICAM

OpenVR

Requires LPSLAM_BUILD_OPENVR

LeapSDK

Requires LPSLAM_BUILD_LEAPSDK

OpenZen

Requires LPSLAM_BUILD_OPENZEN

Webots

Requires LPSLAM_BUILD_WEBOTS

Zed

RequiresLPSLAM_BUILD_ZEDCAM

ZedSdk

Requires LPSLAM_BUILD_ZEDSDK

configuration

list

{}

`trackers` section

The mechanism or object responsible for the tracking functionality is referred to as a tracker. Here, one sets the specific configuration for it.

VSLAM

Argument

Type

Description

type

string

VSLAMMono
VSLAMStereo

configuration

list

General

camera_setup

string

Available options:

monocular
stereo
RGBD

config_from_file

string

Path of a direct configuration YAML file for the Visual-SLAM backend.

live_view

bool

Activate/deactivate theviewer.

only_orientation

bool

Activate/deactivate sending poses with only orientation information.

proxy_port

int

Port number to which the poses will be sent.

tracking_id

int

An ID for the tracker.

Info
This should match with the `trackingId` parameter corresponding to LPSLAM in LPVR’s configuration.

viewer_FPS

int

Images per second to show in the viewer.

use_CUDA

bool

Enable/disable using CUDA.

use_OpenCL

bool

Enable/disable using OpenCL.

undistort_image

bool

Enable/disable undistorting the images for better feature estimation and tracking.

Same effect as the processor "Undistort".

vocab_file

string

Path of the file containing the Bag of Words database to assign identifiers to the visual features.

Mapping

emit_map

bool

Enable/disable publishing the generated map in real-time.

enable_mapping

bool

Enable/disable creating a map and only perform localization.

loop_closure

bool

Enable/disable looking for loop closure poses to add to the pose graph.

map_file_name

string

If "use_map_database": true, the path of the .db file containing the map database.

use_map_database

bool

Enable/disable using a map database.

Visual

Features

depth_threshold

float

Depth threshold used to compute ORB keypoints.

min_triangulated_points

int

Minimum number of triangulated points required for a successful pose update in the Visual-SLAM backend.

max_keypoints

int

Maximum number of keypoints to estimate.

ini_keypoints_threshold

int

Initial threshold for intensity difference when examining pixels around the potential corner detected by FAST. ORB starts with comparing intensities around the corner based on this parameter.

min_keypoints_threshold

int

Minimum acceptable intensity difference for a pixel to be considered part of the corner feature. It acts as a filter. Only corners where a certain number of pixels (defined by ORB) exhibit an intensity difference greater than this parameter are retained as features.

num_levels

int

Total number of levels in the image pyramid created by ORB.

scale_factor

float

Multiplicative factor by which the image is progressively scaled down to create a pyramid of images. Each level in the pyramid represents a different scale of the original image.

Others

forward_high_res_nav

bool

Activate/deactivate forwarding data with a higher rate than the image fps for smoother visualization.

forward_IMU

bool

Enable/disable processing and forwarding IMU data to the Visual-SLAM backend.

forward_nav_state

bool

Enable/disable processing and forwarding navigation odometry data to the Visual-SLAM backend.

max_laser_age

float

The maximum age of laser data before it’s considered outdated when using a laser scanner and a camera in the system.

reloc_with_navigation

bool

Enable/disable relocalize with navigation odometry data.

wait_for_navigation

bool

Enable/disable waiting for navigation odometry data to be processed.

Marker

Requires LPSLAM_BUILD_CHILITAGS

Argument

Type

Description

type

string

Marker

configuration

list

marker_size

float

The size of the marker, in meters.

process_noise

float

Scaling factor for the Process Noise Covariance Q of Chilitags' Kalman Filter.

Info
Larger values in `Q` tend to decrease the resistance against motion.

observation_noise

float

Scaling factor for the Observation Noise Covariance R of Chilitags' Kalman Filter.

Info
Larger values in `R` tend to increase the resistance against motion.

proxy_port

int

Port number to which the poses will be sent.

show_tags

bool

Enable/disable showing a window with the tracked tag.

detect_only

int

If its desired to detect only one marker, the number ID of the desired marker.

`processors` section

This section allows to apply some pre-defined image processing methods to the incoming images.

Camera Calibration

To be deprecated.

Argument	Type	Description
`type`	`string`	`CameraCalibration`
`configuration`	`list`	`{}`

Coordinates Alignment

To be deprecated.

Requires LPSLAM_BUILD_OPTIMIZER

Argument	Type	Description
`type`	`string`	`CoordAlign`
`configuration`	`list`	`{}`

Image Blackout

To be deprecated.

Argument

Type

Description

type

string

BlackoutImage

Blacks out the image frames between 150 and 190.

configuration

list

{}

Image Thresholding

This image processor thresholds the images using truncate fixed-level thresholding.

Argument		Type	Description
`type`		`string`	`ThresholdImage`
`configuration`		`list`
	`auto_threshold`	`bool`	Whether automatically determine the threshold via Otsu’s algorithm.
	`threshold`	`int`	Threshold value `[0, 255]` to use if `auto_threshold` is `false`.

Intensity Adjustment

This image processor adjusts the contrast of the images by mapping the input intensity range to a specified output range.

Argument		Type	Description
`type`		`string`	`AdjustIntensity`
`configuration`		`list`
	`lower_bound`	`double`	Lower bound of the output intensity range.
	`upper_bound`	`double`	Upper bound of the output intensity range.

Online Photometric Calibration

This performs Online Photometric Calibration with the upcoming images to generate the camera’s inverse response function. For further details about it refer to: Online Photometric Calibration of Auto Exposure Video for Realtime Visual Odometry and SLAM (P. Bergmann, R. Wang, D. Cremers), In IEEE Robotics and Automation Letters (RA-L), volume 3, 2018 (pdf).

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Argument		Type	Description
`type`		`string`	`PhotoCalib`
`configuration`		`list`
	`patch_size`	`int`	Image patch size used in the frontend tracker.
	`pyramid_levels`	`int`	Number of image pyramid levels used in the frontend tracker.
	`num_active_features`	`int`	Number of features kept for each frame.
	`num_rapid_exposure_images`	`int`	Number of images used for rapid exposure time estimation.
	`num_active_frames`	`int`	Number of frames kept in the database.
	`keyframes_spacing`	`int`	Spacing for sampling keyframes in the backend optimization.
	`min_valid_keyframes`	`int`	Minimum number of keyframes a feature should appear.

Undistortion

This image processor undistorts the images based on the camera parameters and lens model.

Argument	Type	Description
`type`	`string`	`Undistort`
`configuration`	`list`	`{}`

`markers` section

Requires LPSLAM_BUILD_CHILITAGS.

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Versions Compared

Old Version 1

New Version Current

Key

`manager` section

`cameras` section

`datasources` section

File Source

LeapMotion and Rigel

OpenCV

Varjo

Others

`trackers` section

VSLAM

Marker

`processors` section

Camera Calibration

Coordinates Alignment

Image Blackout

Image Thresholding

Intensity Adjustment

Online Photometric Calibration

Undistortion

`markers` section

Page Comparison

Versions Compared

Old Version 1

New Version Current

Key

manager section

cameras section

datasources section

File Source

LeapMotion and Rigel

OpenCV

Varjo

Others

trackers section

VSLAM

Marker

processors section

Camera Calibration

Coordinates Alignment

Image Blackout

Image Thresholding

Intensity Adjustment

Online Photometric Calibration

Undistortion

markers section

`manager` section

`cameras` section

`datasources` section

`trackers` section

`processors` section

`markers` section