Brain-Computer Interfaces (BCIs) are a novel means of human-computer interaction relying on the direct measurement of brain signals. Possible applications consist of replacing, restoring, improving, enhancing and supplementing the natural outputs of the central nervous system, as well as for brain functions investigation. In considering daily-life constraints, researchers are exploring the possibility to provide visual stimuli by means of smart glasses or visors, which are increasingly exploited in extended reality (XR). Moreover, to detect the elicited potentials, commercial devices for electroencephalography (EEG) are taken into account. Nevertheless, those studies were more application-oriented and they did not deal with a metrological characterization of the stimulation and detection equipment.
In bridging this gap, metrology was considered for a significant enhancement of the BCI systems both in terms of designing and in operational understanding. It was demonstrated that, although often overlooked, applied metrology plays an important role in this field. Indeed, if the stimulation and detection equipment is not fully characterized, the measures of interest for the brain-computer interface system may result in misleading interpretation of the brain functioning. Instead, by means of the mentioned results, one can compare the measured brain signals with the behaviour of the equipment in the time and frequency domains, so to correctly identify the contribution of the “human transducer” in the BCI measurement chain.
