Hybrid_HMD_Tracking_RS

This library contains implementations of sensor fusion methods which merge two 6DoF tracking sources for a virtual reality headset. One source (the so-called inside-out tracking) is always available, but it is relative to an arbitrary reference frame. The other source (the so-called outside-in tracking) is fixed with respect to a global reference frame, but it may become temporarily unavailable.

The code was used for the article:

R. Monica, D. Lodi Rizzini and J. Aleotti,
"Adaptive Complementary Filter for Hybrid Inside-Out Outside-In HMD Tracking With Smooth Transitions,"
IEEE Transactions on Visualization and Computer Graphics,
doi: 10.1109/TVCG.2024.3464738

Several methods have been implemented, following a common interface (src/tracking_interface.h). In particular, the approach proposed in the article is mostly contained in the file src/directed_complementary_tracking.cpp. A pure C-based interface is also available in the header tracking_library.h, which is suitable for integration in a Unity plugin.

This repository also contains scripts to generate Fig. 11, Fig. 12, Fig. 13, Fig. 16 and Fig. 17 of the article, as required by the Graphics Replicability Stamp Initiative.

The software is released under the 3-clause BSD license. For portability, the repository also contains a copy of the Eigen3 library, which is released under the Mozilla Public License v. 2.0, and Manif, which is released under the MIT license.

The dataset collected in the article is also available at https://rimlab.ce.unipr.it/~rmonica/hybrid_hmd_tracking_dataset.zip, and it is released under a Creative Commons Attribution 4.0 International License.

Installation

The tracking library is written in C++ (C++17 required) and it is cross-platform. It should compile on both Windows and Linux using CMake.

Scripts to generate the figures of the paper require Linux (tested on Ubuntu 22.04 and 24.04) and the following dependencies:

Dependencies

• g++
• cmake
• bash
• gnuplot
• R (Rscript executable)
• curl
• unzip

Installation using Ubuntu APT:

sudo apt install g++ cmake gnuplot-x11 r-base curl unzip

The Rscript executable should be found using env. If not, edit the hashbang of files traj_test_new/elab/fit_sigmoid.sh and traj_test_new/elab/compute_sign_th.sh to point to the executable.

Build

Standard CMake build:

mkdir build
cd build
cmake ..
make

These commands are also listed in the script build.sh.

Replicability stamp

This code can be used to replicate the results presented in Figures 11, 12, 13, 16 and 17 of the article

R. Monica, D. Lodi Rizzini and J. Aleotti,
"Adaptive Complementary Filter for Hybrid Inside-Out Outside-In HMD Tracking With Smooth Transitions," 
IEEE Transactions on Visualization and Computer Graphics,
doi: 10.1109/TVCG.2024.3464738

To generate the figures, run the script replicability_stamp.sh. The script does the following:

1. Downloads the dataset of the user study from https://rimlab.ce.unipr.it/~rmonica/hybrid_hmd_tracking_dataset.zip.
2. Parses the dataset and collects the discontinuities reported by the users as a function of the tracking approach.
3. Generates Fig. 11, Fig. 12 and Fig. 13.
4. Simulates the tracking methods presented in the paper on each trajectory recorded in the dataset.
5. Uses the mean position and rotation error to produce Fig. 16 and Fig. 17.

The figures are saved in the repository root in .eps format.