LPVR-DUO in an Airborne Helicopter

In-Flight VR

Imagine soaring through the skies as a pilot, testing the limits of a helicopter’s capabilities while feeling the rush of wind and turbulence. Now imagine that you don’t see the real world outside and the safe landing pad that your helicopter is approaching but a virtual reality (VR) scene where you are homing in on a ship in high seas. The National Research Council Canada (NRC) and Defence Research and Development Canada (DRDC) have brought this experience to life with their groundbreaking Integrated Reality In-Flight Simulation (IRIS).

IRIS is not your ordinary simulator; for one, it’s not sitting on a hexapod, it’s airborne. It’s a variable-stability helicopter based on the Bell 412 that can behave like other aircraft and can simulate varying weather conditions; combine that with a VR environment and you have a tool that allows safely training operations in the most adverse conditions. In particular it is used for Ship Helicopter Operating Limitations (SHOL) testing.

Mission-Critical Application with LPVR-DUO

The LPVR-DUO system is what makes VR possible on this constantly moving platform. This cutting-edge AR/VR tracking system seamlessly merges the inertial measurements taken by the headset with the helicopter’s motion data and a camera system mounted inside the cabin to provide the correct visuals to the pilot. The challenges of using cameras to track the VR headset inside the tight environment of the helicopter while lighting conditions are ever-changing are overcome by using an ART SmartTrack 3 system. This system follows an arrangement of reflective markers attached to the pilot’s helmet. The VR headset is attached to the helmet in such a way that the pilot can wear it as if it were a pair of night vision goggles. Put together, this allows displaying a virtual world to the pilot, even in the most extreme maneuvers.

To ensure an authentic experience, the IRIS system incorporates real-time turbulence models, meticulously crafted from wind tunnel trials. These turbulence effects are seamlessly integrated into the aircraft’s motion and into the VR scene, providing pilots with precise proprioceptive and vestibular cues. It’s a symphony of technology and innovation in the world of aviation testing.

In-Cockpit Implementation

The optical tracking system relies on highly reflective marker targets on the helmet to track movement in three dimensions. Initially, only five markers were installed, strategically placed for optimal tracking. But the pursuit of perfection led NRC to create custom 3D-printed low-reflectivity helmet molds, allowing them to mount a dozen small passive markers. This significantly improved tracking reliability in various lighting conditions and allowed for a wider range of head movement.

Recently, NRC put this remarkable concept to the test with actual flight trials. The response from pilots was nothing short of exhilarating. They found the system required minimal adaptation, exhibited no noticeable lag, and, perhaps most impressively, didn’t induce any motion sickness. Even the turbulence effects felt incredibly realistic. Surprisingly, the typical VR drawbacks, such as resolution and field of view limitations, had minimal impact, especially during close-in shipboard operations. It’s safe to say that IRIS has set a new standard for effective and immersive aviation testing.

Publication of Results

The NRC team presented their results at the Vertical Flight Society’s 79th Annual Form in two papers [1]  and [2] and they also have a blog post on their site.

NOTE: Image contents courtesy of Aerospace Research Centre, National Research Council of Canada (NRC) – Ottawa, ON, Canada

High-performance Use Cases of LPVR & Varjo Headsets

Components of a VR/AR Operating System

Augmented and virtual reality technology helps boost worker productivity in various fields such as automotive, aerospace, industrial production, and more. Whereas the context of these applications is usually fairly specific, some aspects are common to many of these use cases. In this article, we will specifically explore the topic of pose tracking of Varjo head mounted displays (HMDs) based on LP-RESEARCH’s LPVR operating system. We will further on show two customer use cases that utilize LPVR in different ways.

In a typical VR/AR setup, you find three main subsystems as shown in the illustration below:

With our LPVR operating system, we connect these three building blocks of an VR/AR system and make them communicate seamlessly with each other while providing a simple, unified interface to the user. Depending on the specific use case, users might select different types of hardware to build their VR/AR setup. Therefore LPVR offers a wide range of interface options to adapt to systems from various manufacturers.

LPVR Flavors

LPVR operates in different flavors, we can group end applications into two categories:

  • LPVR-CAD – Static AR/VR setups, where multiple users operate and collaborate in one or more joint tracking volumes. These tracking volumes can be situated in different locations.
  • LPVR-DUO – AR/VR systems that are located in a vehicle or on a motion platform: such systems have special requirements, especially on the tracking side. If, for example, you would want to track a headset inside a car, displaying a virtual cockpit anchored to the car frame, and a virtual outside world fixed to a global coordinate system, means of locating the car in the world and referencing the HMD locally in the car frame are required.

 

In the following paragraphs, we will introduce two customer use cases that cover these two basic scenarios.

Large-scale Industrial Design at Hyundai

– Varjo XR-3 at Hyundai Design Center with optical markers attached. Image credit: Hyundai

For the Korean automotive company Hyundai Motor Corporation, we created a large, location-based virtual reality installation at their research and development center in Namyang, Korea. The system is used to showcase, amend and modify prototype and production-ready automobile designs.

This application uses optical outside-in tracking and LP-RESEARCH’s LPVR-CAD solution to track up to 20 users wearing head-mounted displays. While LPVR allows a mix of different headset types to operate in the same tracking volume, the Varjo XR-3 gives the most outstanding performance to inspect objects in high resolution and great detail. Additionally to an HMD, users carry hand controllers for a total of more than 40 tracked objects in a space close to 400 sqm.

– Hyundai’s collaborative virtual reality design experience. Image credit: Hyundai

Responsiveness is achieved by using LPVR-CAD to combine data from the inertial measurement unit built into the headsets and information from the optical tracking system. The optical system uses 36 infrared cameras to track the 160 markers attached to the HMDs and hand controllers. Perfectly smooth and uninterrupted position and orientation data of each user’s HMD is achieved by using LP-RESEARCH’s sensor fusion algorithms.

Depending on the type of headset, users either wear a backpack PC, connect to a host wirelessly or use an extra-long cable to connect directly to a rendering PC outside the tracking volume.

“Currently, we are actively utilizing VR from the initial development stage to the point of development. In the future, we plan to increase accessibility and usability by simplifying equipment using wireless HMDs. For this, improving the speed and stability of wireless internet is essential, which we plan to address by introducing 5G. In addition, LP RESEARCH’s technology is essential for multi-user location sharing within a virtual space.” – SungMook Kang, Visualization Specialist, Hyundai Motor Company

Next-level Automotive Entertainment with CUPRA

Imagine.. playing Mario cart, your hands are gripping the wheel, and you are in Neo Tokyo, on a race track. Futuristic buildings keep flying by while you race ahead, drifting into long turns and leaving your competitors behind you.

Now imagine you are no longer in your living room, you are sitting in an actual race car, buzzing around in an empty parking lot. Instead of looking through the windshield with your own eyes, you are wearing a Varjo XR-3 HMD. What you see outside the car is a virtual world, it’s Neo Tokyo.

– The view through the Varjo XR-3 headset. Image credit: CUPRA

As the car moves on the parking lot, you move inside the virtual world. When you move your head inside the car’s cockpit, the motions of your head are accurately tracked.

– Varjo XR-3 inside the cabin of the Urban Rebel. Image credit: Fonk Magazine

– Cupra’s Urban Rebel drifting on the test course

Together with the Norwegian company Breach VR, we have implemented this experience for the automotive company CUPRA. CUPRA is relentlessly pushing the technology of their vehicles into the future, striving to provide a novel driving experience to their customers.

Tracking of the vehicle and the Varjo XR-3 inside the vehicle is achieved with LP-RESEARCH’s automotive tracking systems LPVR-DUO. As the headset’s gyroscope sensors record the superimposed motion data of the car and the user inside the car, a specialized sensing system, and the algorithm are required to separate the two.

The result of this cascade of exceptional technology is a compellingly immersive driving experience of the future. The combination of an outstanding visualization device like the Varjo XR-3, LPVR state-of-the-art tracking, BreachVR’s 3D software and design and, last but not least, the incredible CUPRA race cars make for an exciting ride that you’ll greatly enjoy and never forget. Come and join the ride!

Check this blog blog post in the Varjo Insider Blog.

Check out our Instagram for further use cases with Varjo’s HMDs: @lpresearchinc

LPVR-AIR Demo at SIGGRAPH 2023

Ready – Steady – Go!

We had an exciting week at the Siggraph 2023 computer graphics conference in Los Angeles showcasing LPVR-AIR! Together with optical tracking systems maker Optitrack and content creator Meptik we developed a real-time racing experience using trikes. On these trikes exhibition attendees were able to race in a small concourse we set up at the exhibition site. Each trike rider we equipped with a Meta Quest virtual reality headset showing a Mario Kart-like track using our LPVR-AIR tracking and real-time streaming solution.

The twist: We attached an Optitrack active marker target to each HMD so we were able to have multiple players move in a globally referenced tracking volume. With LPVR-AIR we don’t render the 3D content on the HMDs themselves, but wirelessly transmit it from specialized rendering PCs. This allows us to display high polygon-count content on the HMDs without exceeding the limited computing power of the standalone headsets.

We are still working on a dedicated product page for LPVR-AIR, but already created a solid amount of documentation how to use the solution. Have a look at it here. The document also gives an insight into the specialities and limitations of the system.

Use-Cases Outside Gaming

LPVR series solutions are the industry standard for large-area VR and AR tracking. They enable consumer and professional headsets to work in conjunction with professional-grade tracking and motion capture systems, leveraging their power both in terms of precision and coverage of large areas. While in this demonstration, the trikes were tracked from the outside, we also enable headset tracking completely contained inside moving platforms such as simulators or cars. We are constantly developing and updating it according to our customers’ needs.

Thanks to everybody who stopped by and pedaled their way around the course. Great riding, well done!

New Features in LPVR Version 4.8

Introduction

Our LPVR series is the primary solution on the market for users who want to expand the scope of their virtual reality or mixed reality headsets by using external tracking systems such as ART, OptiTrack or Vicon. Use cases are varied and range from entertainment (location based VR) and engineering use cases (ergonomic studies in AR) to helicopters and virtual cars which are actually driving on Japan’s public roads. At LP-Research, we have continuously developed the LPVR series of solutions over the past years. We have expanded its scope, added support for new headsets, and included new functions.

The image below shows an LPVR installation based on design content created by automotive prototyping company Phiaro Inc. in Tokyo, Japan.

The latest release is version 4.8.0, which we released in June of 2023.  As usual, it comes in two flavors:

  • LPVR-CAD which supports stationary use-cases, and
  • LPVR-DUO which is our variant for moving platforms, be they cars or simulators.

We support all the major tethered headsets (SteamVR headsets, Pimax, Varjo).  We also support Meta Quest series headsets and the Vive Focus 3 with our LPVR-Air series of products. If you have a current support contract, you are eligible for an update.

A Brief Overview of LPVR-CAD and LPVR-DUO

It’s maybe best to summarize some of the capabilites that our products add to the various commercial headsets.  For more details, feel free to visit the product pages for LPVR-CAD and LPVR-DUO, respectively:

  • Cover arbitrary large areas and have VR scenes taking place in them
  • Have an arbitrary number of users interact in such a space
  • Do VR/AR inside a car or any other moving platform
  • Track your user to sub-millimeter precision together with any number of props with no perceivable latency
  • Use SteamVR controllers without the Lighthouses

We can do this because our proprietary sensor fusion algorithms allow us to combine the measurements of high-precision motion tracking camera systems with the measurements of the headset’s Inertial Measurement Unit (IMU). For the case of a moving platform, we can additionally incorporate data from an IMU installed on the platform to provide for a responsive, accurate performance also in those circumstances.

New Features

For a short overview of the changes in each version, please refer to our Release Notes. Here we will give some highlights and dig into some details. LPVR 4.8.0 is the result of continuous development in the half year or so since our previous releases.

New GUI Organization and Visual LPVR-DUO Configuration Interface

The most obvious change to users will be the reorganized GUI which streamlines the setup, completely doing away with the need to enter any JSON codes, while coming on a more cleanly organized surface. Especially for our LPVR-DUO users this means a vast simplification of the system.  We have maintained the old configuration interface as an option to guarantee compatibility with existing workflows, but we don’t think that users will have to resort to it. Please let us know if your experience is different. If your headset tracking body is already calibrated, you should now be able to setup LPVR-DUO with some five mouse clicks.

When you load up the configuration, it will look something like this. Note that you no longer are led to a JSON editor where you manually have to enter the configuration. Instead you are greeted by a friendly, informative GUI.

At the bottom of the page, you will see links to the Documentation, a Calibration screen, and an Expert Mode, basically the old JSON editor. The Calibration screen is used for the setup of the Platform IMU and simplifies it down to a few mouse clicks in the usual case. No more looking for some quaternion values in log files! Please check out the corresponding documentation.

Varjo Headset Eye Point Adjustments

Together with Varjo and with cooperation of several of our customers we were able to identify and correct some imprecisions in the handling of the headset’s position. These would show up as small coordinate mismatches between the optical tracking coordinates and the coordinates reported to VRED or Unity etc. Additionally, this would lead to some unnatural motion of AR overlays, especially when turning the head.

Optimal performance requires updating both Varjo Base to at least version 3.10 and LPVR to at least version 4.8.0.  Updating Varjo Base fixes the underlying issue, updating LPVR corrects the interfacing.  If you cannot update Varjo Base, you can still update LPVR-CAD-Varjo to version 4.8.0 and enable a workaround.  To do so, please open the Varjo Base configuration GUI on the System tab and then add patchPositionBug=true in the field labeled Additional Settings followed by clicking the “Submit” button. Note while this works around the issue in Varjo Base before version 3.10, it is not recommended to use this option with the updated versions of Varjo Base.

Varjo Configuration Refinements

Different environments call for different setups.  Some of our users use administrator accounts, others have multiple users but want them to use the same configuration.  We have updated the way we organize on-disc storage of the configuration to address these possibilities.  In particular you can now establish a system-wide configuration default, and you can override it per-user.  In the case of LPVR-CAD, additionally, the configuration is entered inside Varjo Base by default, but to allow users greater flexibility, it has always been possible to use our web interface or files on disk to perform the configuration.  While these are not the preferred choice, it was previously not possible to see from Varjo Base whether the on-disk configuration is in use.  We have added a prominent status information that points to the configuration, as in the screen shot below.  In the case of LPVR-DUO the configuration is always loaded from disk as the added flexibility of our configuration page is required,, but in LPVR-CAD the user will have to opt in. We describe the process briefly below.

The user can setup a global, systemwide default configuration in %ProgramData%/Varjo/VarjoTracking/Plugins/LP-Research/LPVR-CAD-Varjo/configuration/settings.json. Changes on the configuration page will not change this configuration, but will instead be written to the per-user configuration %LocalAppData%/LP-Research/LPVR-CAD-Varjo/settings.json. If either file is present, the configuration inside Varjo Base will be ignored. For LPVR-DUO, there is no configuration interface inside Varjo Base, instead the user will always point their web browser to http://localhost:7119. This configuration relies on the same files, but with the subdirectory LPVR-CAD replaced by LPVR-DUO. So a system-wide default configuration can be placed in %ProgramData%/Varjo/VarjoTracking/Plugins/LP-Research/LPVR-DUO-Varjo/configuration/settings.json, and a per-user override can sit in %LocalAppData%/LP-Research/LPVR-DUO-Varjo/settings.json.

LPVR-DUO Demonstration

In order to familiarize you with the neighborhood of our office and, more importantly, to show what can be done with LPVR-DUO, here is an in-car mixed reality demonstration. The video screens on the glove box may look almost real but they are an overlay imposed on the see-through camera image of a Varjo XR-3 using an out-of-the-box LPVR-DUO set. Notice how the screens firmly remain in place during turns of the user’s head as well as turns of the car itself, even when diving into some of the steeper roads of the Motoazabu area in central Tokyo.

Large-scale VR Application Case: the Holodeck Control Center

The AUDI Holodeck

LPVR interaction

Our large-scale VR solution allows any SteamVR-based (e.g. Unity, Unreal, VRED) Virtual Reality software to seamlessly use the HTC VIVE headset together with most large-room tracking systems available on the market (OptiTrack, Vicon, ART). It enables easy configuration and fits into the SteamVR framework, minimizing the effort needed to port applications to large rooms.

One of our first users, Lightshape, have recently released a video showing what they built with our technology.  They call it the Holodeck Control Center, an application which creates multi-user collaborative VR spaces. In it users can communicate and see the same scene whether they are the same real room or in different locations. The installation showcased in the video is used by German car maker Audi to study cars that haven’t been built yet.

Our technology is essential in order to get the best VR experience possible on the 15m × 15m of the main VR surface, combining optical tracking data and IMU measurements to provide precise and responsive positioning of the headsets.  Please have a look at Lightshape’s video below.

Ready for the HTC Vive Pro

In the near future, this installation will be updated to the HTC Vive Pro which our software already supports. The increased pixel density of this successor of the HTC Vive will make the scenes look even more realistic. The resolution is high enough to actually read the various panels once you are in the drivers seat! Besides that, we are also busy studying applications of the front-facing cameras of the Vive Pro in order to improve multi-user interaction.

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