BrainAccess Connect C/C++ API Reference
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SSVEP classifier
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This section describes functions available for accessing the SSVEP classifier algorithm.

The steady-state  visual evoked potential (SSVEP) is a repetitive evoked potential that is produces when viewing flashing stimuli.
Activity at the same frequency as the visual stimulation can be detected in the occipital areas of the brain.

SSVEP classifier can recognize steady-state visual evoked potentials (SSVEP). Meaning that given a visual stimulus flickering at a constant frequency, SSVEP classifier can determine if the user is currently looking at it.
This can be used as motionless control, where the user chooses an option by looking at the corresponding visual stimulus.

The workflow of using SSVEP classifier is as follows:  

1. Acquisition Setup. We recommend using 2-6 electrodes in the ocipital region (O1, O2, P3, P4, Oz, Pz) with reference at Fp1 and bias at Fp2.
2. Initialize classifier with desired frequency combinations, prediction time interval and EEG sampling rate.
3. Get predictions on input data

See all function descriptions for more information.

.. toctree::
   :maxdepth: 4

.. doxygenfile:: ssvep_classifier.h
   :path: ../../../brainaccess-bci-connect/docs/doxygen/xml/ 

Visual P300 classifier
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This section describes functions available for accessing the Visual P300 classifier algorithm.

The P300 (P3) wave is an event-related potential (ERP) component elicited in the process of decision making. The P300 is thought to reflect processes involved in stimulus evaluation or categorization.
It is usually elicited using the oddball paradigm, in which low-probability target items are mixed with high-probability non-target (or "standard") items. When recorded by electroencephalography (EEG), it surfaces as a positive deflection in voltage with a latency (delay between stimulus and response) of roughly 250 to 500 ms. The signal is typically measured most strongly by the electrodes covering the parietal lobe 
:ref:`[1] <cit1>`
.
This can be used as lie detector :ref:`[2] <cit2>`, speller :ref:`[3] <cit3>` etc.

The workflow of using Visual P300 classifier is as follows:

1. Acquisition Setup. 8 electrode setup (F3, F4, C3, C4, P3, P4, O1, O2) with reference at Fp1 and bias at Fp2 is required.
2. Initialize classifier with future use number of repetitions (responses to the same stimulus, 1 or 3 trials)
3. Get predictions on input data sampled at 250 Hz

See all function descriptions for more information.

.. toctree::
   :maxdepth: 4

.. doxygenfile:: p300_classifier.h
   :path: ../../../brainaccess-bci-connect/docs/doxygen/xml/