A survey of signal processing Flashcards
Key questions addressed in this paper
Key Signal processing components of BCI, Signal Processing Algorithms used in BCI, promising Signal Processing Techniques
General Structure of BCI System was explored in this paper. What are the three components of BCI Transducer?
Artifact Processor, Feature Generator, Feature Translator
Artifact Processor
Removes the artifacts from the electrical signal after it has been amplified.
Feature Generator
Transforms resultant signals into feature values that correspond to the underlying neurological mechanism employed by the user for control
Feature Generator can be concatnetation of these three components
signal enhancement, feature extraction, feature selection / dimensionality reduction
In some BCI designs, why is pre-processing performed prior to the extraction of features?
To increase the signal-to-noise ratio of the signal.
What is the goal of feature selection / dimensionality reduction component?
Reduce the number of features and channels used so that very high dimensional and noisy data are excluded.
What does Feature Translator do?
Translates the features into logical(device-independent) control signals, such as a two-state discrete output.
What kinds of algorithm does translation algorithm use?
Linear Classification Methods[Classical Statistical Analyses] / Nonlinear Classification Methods [Neural Networks]
Feature Translator may consist of these two components
Feature Classification, Post-Processing
Main goal of feature classification component
classifying the features into logical control signals
The role of the BCI Transducer
Translating the user’s brain activity into logical (or device-independent) control signals.
What does Electrophysiological sources refer to in BCI systems
Neurological Mechanisms or processes employed by a BCI user to generate control signals.
What is mu rhythm?
- is an index of action execution, observation and imagery.
- is a brain wave pattern that can be measured by electroencephalography (EEG) and is associated with a number of brain functions
bilateral
involving both sides of the body
The mu rhythm covers a frequency range of —– and is typically localized over —-.
covers a frequency range of (8–13 Hz) and is typically localized over bilateral sensorimotor cortex.
Modulation of the mu rhythm likely reflects the synchronization of —— of the motor cortex.
Modulation of the mu rhythm likely reflects the synchronization of pyramidal neurons of the motor cortex.
Mu Rhythm is strongly and symmetrically — during the performance of contralateral motor acts.
Mu Rhythm is strongly and symmetrically suppressed during the performance of contralateral motor acts.
What is ERD in Mu-ERD
event-related desynchronization (ERD)
a decrease in the relative power of a specific frequency band in an electroencephalogram (EEG) in response to stimulation
What is ERD?
a decrease in the relative power of a specific frequency band in an electroencephalogram (EEG) in response to stimulation
ERD vs ERS
ERD is a decrease in power, while event-related synchronization (ERS) is an increase in power. Both ERD and ERS are time-locked to the event, but not phase-locked.
In BCI preprocssing methods, what is CAR?
a technique that removes noise from recordings by averaging the electrical activity across all scalp channels and subtracting that average from each channel
CAR
minimizes uncorrelated sources of signal and noise through averaging, while eliminating sources of noise common to all sites.
