Brain-computer interface for user's visual focus detection
AssigneeMassachusetts Institute of Technology
InventorsSanjay E. Sarma, Alex Armengol Urpi
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Abstract
According to various aspects, a new concept of Steady-State Visually Evoked Potential (SSVEP) based Brain-Computer Interface (BCI) is described where brain-computer communication occurs by capturing SSVEP induced by consciously imperceptible visual stimuli integrated into, for example, a virtual scene. These consciously imperceptible visual stimuli are able to convey subliminal information to a computer. In various embodiments, computer based operations can be mapped to visual elements with associated flickering stimuli, and induced SSVEP can be detected when the user focused upon them. In various embodiments, these visual elements can be introduced into existing display without any perceivable change to content being displayed.
Claims20
A system for controlling a brain computer interface, the system comprising:
- at least one processor operatively connected to a memory;
- a stimulus generator, executed by the at least one processor, configured to generate visual elements for rendering in a display showing content without change perceptible to a viewing user, wherein the stimulus generator is further configured to modulate luminance of at least one visual element in the display at a frequency exceeding a critical fusion rate to display the at least one visual element with an associated flicker rate executed at the frequency exceeding the critical fusion rate to the viewing user;
- at least one electroencephalogram (EEG) sensor to capture brain activity of the viewing user observing the display including the at least one visual element;
- and
- wherein the at least one processor is configured to:
- determine the display viewed by the user is subject to an induced visual effect that would result from rendering the at least one visual element, based on a refresh rate associated with the display;
- eliminate the induced visual effect, wherein elimination of the induced visual effect includes an operation to tune an amplitude of a stimulating signal associated with the at least one visual element to the refresh rate associated with the display;
- detect a visually evoked potential in the captured brain activity of the viewing user associated with the at least one visual element that is induced by modulation of the luminance of the at least one visual element;
- and
- trigger at least one computer function mapped to the respective at least one visual element based on the visually evoked potential detected that is associated with the at least one visual element.
A method for controlling a brain computer interface, the method comprising:
- generating, by at least one processor, visual elements for rendering in a display showing content without change perceptible to a viewing user, wherein generating the visual elements includes modulating luminance of at least one visual element in the display at a frequency exceeding a critical fusion rate to display the at least one visual element having an associated flicker rate at a frequency exceeding a critical fusion rate to the viewing user;
- determining, by the at least one processor, that the display viewed by the viewing user is subject to an induced visual effect that would result from flickering the at least one visual elements based on a refresh rate associated with the display;
- eliminating, by the at least one processor, the induced visual effect, wherein eliminating of the induced visual effect includes tuning an amplitude of a stimulating signal associated with the at least one visual element to the refresh rate associated with the display;
- capturing, by the at least one processor, brain activity of the viewing user observing the display including the at least one visual element from at least one electroencephalogram (EEG) sensor;
- detecting, by the at least one processor, a visually evoked potential in the brain activity associated with the at least one visual element that is induced by modulation of the luminance of the at least one visual element;
- and
- triggering, by the at least one processor, at least one computer function mapped to the respective visual element based on the visually evoked potential detected that is associated with the at least one visual element.
A non-transitory computer-readable medium having computer readable instructions when executed cause a computer to execute a method for controlling a brain computer interface, the method comprising:
- generating visual elements for rendering in a display showing content without change perceptible to a viewing user, wherein generating the visual elements includes modulating luminance of at least one visual element in the display at a frequency exceeding a critical fusion rate to display the at least one visual element having an associated flicker rate at a frequency exceeding a critical fusion rate to the viewing user;
- determining that the display viewed by the viewing user is subject to an induced visual effect that would result from flickering the at least one visual element, based on a refresh rate associated with the display;
- eliminating the induced visual effect, wherein eliminating of the induced visual effect includes tuning an amplitude of a stimulating signal associated with the at least one visual element to the refresh rate associated with the display;
- capturing brain activity of the viewing user observing the display including the at least one visual element from at least one electroencephalogram (EEG) sensor;
- detecting a visually evoked potential in the captured brain activity associated with the at least one visual element that is induced by modulation of the luminance of the at least one visual element;
- and
- triggering at least one computer function mapped to the respective visual element based on the visually evoked potential detected that is associated with the at least one visual element.
Dependencies are inferred from the claim text.