Responses
A BCI Essentials back end provides a single type of meaningful response: predictions. The index of the most likely class or stimulus item inferred by the classifier is provided along with a confidence ratio for every possibility.
| Format | Example |
|---|---|
{label}:[{probabilities}...],... | 1:[0.52 0.47 0.01] |
ping | ping |
Pings may be sent to test the connection and keep it alive.
Predictions
Classification results are sent following the end of a trial or epoch when no training target is indicated by the relevant event markers; a training target of -1.
Predictions are sent at different intervals for different paradigms:
| Paradigm | When to Expect a Prediction |
|---|---|
| P300 | End of Trial |
| SSVEP | *End of Epoch or Trial |
| Motor Imagery | *End of Epoch or Trial |
For paradigms with arbitrary trial periods such as SSVEP and Motor Imagery, a back end may send predictions at the end of every Epoch or at the end of a Trial. In the later case, comma-delimited predictions for each constituent epoch will be listed in one message.
2:[0.2853 0.7147],1:[0.8230 0.1770],2:[0.4573 0.5427],1:[0.9358 0.0642]
It is recommended to use the most recent result
Label Indexing
The value provided in a prediction response is 1-indexed [1-n] referencing an arbitrary collection of targets/classes.