Detection of Type-B Artifacts in VEPs using Median Deviation Algorithm
V. Adinarayana Reddy, P. Chandra Sekhar Reddy · IOSR Journal of Electronics and Communication Engineering · 2017
The primary goal of this research work is to introduce temporal artifact detection strategy to detect non responsive channels and trials in visual evoked potentials(VEPs) by tracing out the signals with very low energy and to remove artifacts in multichannel visual evoked potentials.The non responsive channels and trials are identified by calculating the energy of the average evoked potential of each channel, and the energy of the average evoked potential of each trial.Then channel wise and trial wise median test is conducted to detect and remove non-responsive channels and trials.An artifact is defined as any signal that may lead to inaccurate classifier parameter estimation.Temporal domain artifact detection tests include: a clipping (CL) test detect amplitude clipped EPs in each channel, a standard deviation (STD) test that can detect signals with little or abnormal variations in each channel, a kurtosis (KU) test to detect unusual signals that are not identified by STD and CL tests and median deviation test to detect signals containing large number of samples with very small deviation from their normal values.An attempt has been made to apply these techniques to 14-channel visual evoked potentials (VEPs) obtained from different subjects.