Virtual Reality (VR) techniques enable their users to dive into a usually computer-generated world with various degrees of so-called immersion into the virtual scenes. This refers to the perceived integration of oneself into the virtual world, which also has been termed the “presence” felt by the user. The main sensory input for this purpose is usually visual, but other modalities might be addressed as well, especially auditory and haptic modalities.
For visual VR presentation, at least two components are needed:
- firstly, a tracking system which monitors the user’s head movements in real-time,
- secondly, a projection system that presents digitally rendered images to the user, synchronized with the head movement of the person.
In the CIMH VR Facility, we have several different devices for this purpose: The Cavelab consists of an Automatic Virtual Environment (CAVE) system, consisting of four canvasses, including the floor, onto which high-resolution images are projected in real-time.
The user of a CAVE wears a pair of shutter glasses, which you might know from 3D cinemas, which carry passive tracking markers on top. In our other setups, requiring a more compact setup, we use head-mounted displays (HMDs) such as the Oculus Rift and the HTC Vive, both being well-known products in the consumer-segment, and also affordable for the interested layman.
For movement analysis and recording, there is an OptiTrack Motion Capture system installed in the Motionlab. The user wears a motion capture suit while performing various body movements. These moves are then “captured” as movement records, which can be projected on a skeleton- or stick-model of the human body. Most naturalistic is the movement transfer into digital characters (“avatars”). The movements can also be used in real-time applications.
Other devices in the VR Lab include an omnidirectional treadmill for virtually navigating through a landscape, and data gloves for gesture recognition. In addition, we have a hand-held 3d scanner for scanning real-world objects and persons, which can provide the basis for embedding virtual replica in virtual environments.
Advantages / disadvantages compared to other methods
It is important to note that VR techniques are not a method per se to measure physiological or behavioral data, but rather serve as a means to set up highly controllable experimental situations with a better resembling to “real life”, due to their sensory and interactive complexity and richness. In this sense, the actual strength of VR technologies lies in their use as an intervention in therapeutic contexts and as a tool for complex multisensory stimulation in research contexts. For collecting data beyond head movements in real-time, researchers also rely on physiological, neurophysiological and psychological questionnaires. Mostly, these measures can be combined easily with VR. Especially peripheral autonomous measures as heart frequency and skin conductance might be applied, but also more sophisticated methods, such as fNIRS or EEG.
Setting up a VR experiment is a complex task, which requires the researcher to carefully design the experiment in a way that makes use of the specific advantages of VR. The main practical challenges usually lie in creating or purchasing the digital content and in programming the interactive virtual environment. The VR facility user group is a forum for users to help each other in addressing these challenges.
Risks / Limitation
There are no general risks involved in using VR equipment. The most prominent risks arise from some users being vulnerable to experience nausea and motion sickness after some time of HMD use.
Zentralinstitut für Seelische Gesundheit (ZI) - https://www.zi-mannheim.de