Brain-computer interface for user's visual focus detection
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.
1 . A system for providing 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 flickering visual elements for rendering in a display of content, the flickering visual elements having an associated flicker rate exceeding a critical fusion rate beyond which flickering cannot be consciously perceived;
at least one electroencephalogram (EEG) sensor, coupled to the at least one processor, to capture EEG data corresponding to brain activity of a user observing the display of content including the flickering visual elements; and
wherein the at least one processor is configured to:
dynamically change a current flickering frequency of a first flickering visual element from a first frequency to a second frequency based on a change in a display position of the first flickering visual element;
detect a visually evoked potential in the captured EEG data associated with the first flickering visual element, based on the current flickering frequency of the first flickering visual element; and
trigger at least one computer function mapped to the first flickering visual element corresponding to the detected visually evoked potential.
2 . The system of claim 1 , wherein the stimulus generator is further configured to modify a non-flickering visual element to incorporate at least a portion having an associated flickering frequency.
3 . The system of claim 2 , wherein the stimulus generator is further configured to modify the existing display without the modification being consciously perceptible.
4 . The system of claim 1 , wherein the at least one processor is configured to generate the flickering visual elements with an amplitude reduction of a respective stimulus signal relative to a maximum/minimum stimulation pattern.
5 . The system of claim 1 , wherein respective flickering visual elements concurrently observable in a display are associated with respective unique signaling properties.
6 . The system of claim 5 , wherein the respective flickering visual elements are associated with a respective unique steady state visually evoked potential (“SSVEP”) based on the associated unique signaling properties.
7 . The system of claim 6 , wherein the at least one processor is further configured to identify a presence of the unique SSVEP in the captured EEG data.
8 . The system of claim 5 , wherein the stimulus generator is further configured to generate a plurality of flickering visual elements with the respective unique signaling properties, and wherein the respective unique signaling properties include at least one of: a unique frequency, unique stimulation pattern, unique stimulation timing, or unique stimulation encoding.
9 . The system of claim 1 , wherein the at least one processor is further configured to process time intervals of the EEG data at partially overlapping time periods.
10 . A method for controlling a brain computer interface, the method comprising:
generating, by at least one processor, flickering visual elements for rendering in a display of content, the flickering visual elements having an associated flicker rate exceeding a critical fusion rate beyond which flickering cannot be consciously perceived;
dynamically changing, by the at least one processor, a current flickering frequency of a first flickering visual element from a first frequency to a second frequency based on a change in a display position of the first flickering visual element;
capturing, by the at least one processor, electroencephalogram (EEG) data corresponding to brain activity of a user observing the display of content including the flickering visual elements;
detecting, by the at least one processor, a visually evoked potential in the captured EEG data corresponding to brain activity associated with the first visual element based on the current flickering frequency of the first flickering visual element; and
triggering, by the at least one processor, at least one computer function mapped to the first flickering visual element corresponding to the detected visually evoked potential.
11 . The method of claim 10 , wherein the method further comprises an act of modifying, by the at least one processor, a non-flickering visual element to incorporate at least a portion having an associated flickering frequency.
12 . The method of claim 11 , wherein the act of modifying, by the at least one processor, is executed without the modification being consciously perceptible.
13 . The method of claim 10 , wherein the method further comprises generating, by the at least one processor, the flickering visual elements with an amplitude reduction in an associated flickering stimulus signal relative to a maximum/minimum stimulation pattern.
14 . The method of claim 10 , wherein the method further comprises associating, by the at least one processor, respective flickering visual elements concurrently observable in a display with respective unique signaling properties based at least in part on a respective display position.
15 . The method of claim 14 , wherein the method further comprises associating, by the at least one processor, the respective flickering visual elements with respective unique steady state visually evoked potentials (“SSVEP”) based on the associated unique signaling properties.
16 . The method of claim 15 , wherein the method further comprises identifying, by the at least one processor, a presence of the unique SSVEP in the EEG data corresponding to captured brain activity.
17 . The method of claim 14 , wherein generating, by the at least one processor, the flickering visual elements includes generating respective flickering visual elements with at least one of: a unique frequency, a unique stimulation pattern, a unique stimulation timing, and a unique stimulation encoding.
18 . The method of claim 10 , wherein the method further comprises an act of processing, by the at least one processor, time intervals of the EEG data at partially overlapping time periods.
19 . A non-transitory computer-readable medium having computer readable instructions that when executed cause a computer to execute a method for controlling a brain computer interface, the method comprising:
generating flickering visual elements for rendering in a display of content, the flickering visual elements having an associated flicker rate exceeding a critical fusion rate beyond which flickering cannot be consciously perceived;
dynamically changing a current flickering frequency of a first flickering visual element from a first frequency to a second frequency based on a change in a display position of the first flickering visual element;
capturing electroencephalogram (EEG) data corresponding to brain activity of a user observing the display of content;
detecting a visually evoked potential in the captured EEG data corresponding to brain activity associated with the first visual element based on the current flickering frequency of the first flickering visual element; and
triggering at least one computer function mapped to the first flickering visual element corresponding to the detected visually evoked potential.
20 . The non-transitory computer-readable medium of claim 19 , wherein the method further comprises modifying a non-flickering visual element to incorporate at least a portion having an associated flickering frequency.