1 Prerequisites
2 LPSLAM Controller app
- 2.1 Locating and running the app
- 2.2 Usage
  - 2.2.1 1) Setting the verbosity
  - 2.2.2 2) Loading a configuration
  - 2.2.3 3) Start or Stop tracking
3 Using a Varjo XR-3 HMD

Prerequisites

Camera Calibration: Ensure you have proper camera calibration data. Information on camera calibration can be found here.
Configuration File: A JSON file containing camera calibration parameters and other Visual-SLAM settings. Refer to this page for a complete list of available parameters.

LPSLAM Controller app

Locating and running the app

Navigate to the lpslam_binaries folder:

Within this directory, you should find the executable file lpslam-gui.exe.

You can run the controller app by executing lpslam-gui.exe from your Command Line Interface or simply double-clicking on it. The following GUI will be displayed:

Usage

The controller app is a streamlined version intended to simply control the execution of LPSLAM in real-time.

1) Setting the verbosity

Using the verbosity buttons, you can set the desired verbosity level for the log messages LPSLAM will show in the terminal during its execution. The levels are:

→ Only ERROR log messages will show.
→ ERROR + INFORMATION log messages will show.
→ ERROR + INFORMATION + DEBUG messages will show.

2) Loading a configuration

In the configuration section, load the LPSLAM configuration file. Simply click the LOAD button, and a file explorer window will pop up for you to select your file. The configs folder has the pre-defined configuration lpslam_Varjo_XR3.json for Varjo XR-3 HMD.

3) Start or Stop tracking

Starting and stopping the tracking process in this app is straightforward; simply click the corresponding button:

→ START the tracking process.
→ STOP the tracking process.

Using a Varjo XR-3 HMD

To run LPSLAM with a Varjo XR-3 HMD, modify the configuration file (adjusting cameras and datasources) as shown in the example below.

The correct path to the file orb_vocab.dbow2 must be provided. This file contains a database used to assign identifiers to image features and is referenced by the vocab_file parameter in the VSLAM tracker configuration. The file is in the vocabulary folder, and can be referenced in the configuration file with the path "../vocabulary/orb_vocab.dbow2":

When using a Varjo XR-3 HMD, the camera calibration process can be skipped by using a configuration file without the cameras field. LPSLAM will automatically retrieve the camera parameters at startup.

{
    "_comment" :  "Configuration for Varjo XR-3",
    "manager": {
        "drop_frames": true,
        "thread_num": 4,
        "show_live": false
    },
    "cameras": [
        {
            "number": 0,
            "model": "varjo",
            "fx": 1.18706476688385,
            "fy": 1.18706476688385,
            "cx": 0.532978355884552,
            "cy": 0.5058077573776245,
            "f_correction": 1.7,
            "c_correction": 2.0,
            "resolution_x": 1152,
            "resolution_y": 1152,
            "distortion": [
                0.6412177681922913,
                -0.8660373687744141,
                0.47459715604782104,
                -0.002288734307512641,
                -0.0012009869096800685
            ],
            "focal_x_baseline": 43.20569431080538,
            "rotation": [
                0.9999300244141561,
                0.009785937266698777,
                0.006646932159989518,
                -0.009785385681041777,
                0.9999521152969042,
                -0.0001155009611359007,
                -0.006647744158775169,
                5.045008421054563e-05,
                0.9999779022320736
            ]
        },
        {
            "number": 1,
            "model": "varjo",
            "fx": 1.2481434345245361,
            "fy": 1.2481434345245361,
            "cx": 0.4319934844970703,
            "cy": 0.4994443356990814,
            "resolution_x": 1152,
            "resolution_y": 1152,
            "distortion": [
                0.7144321799278259,
                -0.9300915002822876,
                0.5433128476142883,
                0.0014141352148726583,
                -0.0017072069458663464
            ],
            "rotation": [
                0.9999397368314507,
                -1.0797726242757499e-14,
                0.010978283367585984,
                -5.53855340397135e-07,
                0.9999999987273943,
                5.044704683978703e-05,
                -0.010978283353614959,
                -5.045008712176573e-05,
                0.9999397355589217
            ]
        }
    ],
    "datasources": [
        {
            "type": "Varjo",
            "configuration": {
                "prescale": 3
            }
        }
    ],
    "processors": [
        {
            "type": "Undistort",
            "configuration": {}
        }
    ],
    "trackers": [
        {
            "type": "VSLAMStereo",
            "configuration": {
              "camera_setup": "stereo",
              "use_CUDA": false,
              "use_OpenCL": false,
              "live_view": true,
              "viewer_FPS": 22,
              "vocab_file": "../vocabulary/orb_vocab.dbow2",
              
              "emit_map": true,
              "enable_mapping": true,
              "loop_closure": true,
              "map_file_name": "../map.db",
              "use_map_database": false,
              
              "undistort_image": false,
              
              "min_triangulated_pts": 30,
              "depth_threshold": 20.0,
              "max_keypoints": 1200,
              "scale_factor": 1.2,
              "num_levels": 8,
              "ini_keypoints_threshold": 20,
              "min_keypoints_threshold": 7,

              "forward_high_res_nav": false,
              "forward_IMU": false,
              "forward_nav_state": false,
              "reloc_with_navigation": false,
              "wait_for_navigation": false
            }
        }
    ]
}

With Varjo Base running in the background, launch GUI controller with your configuration file to start LPSLAM.

LP-RESEARCH Knowledge Base

[KnowledgeBase] Running LPSLAM