A template-free approach for waveform extraction of gravitational wave
  events
  We develop a general data-driven and template-free method for the extraction
of event waveforms in the presence of background noise. Recent
gravitational-wave observations provide one of the significant scientific areas
requiring data analysis and waveform extraction capability. We use our method
to find the waveforms for the reported events from the first, second, and third
LIGO observation runs (O1, O2, and O3). Using the instantaneous frequencies
derived by the Hilbert transform of the extracted waveforms, we provide the
physical time delays between the arrivals of gravitational waves to the
detectors.
