An Introduction to S-Transform for Time-Frequency Analysis S.K. Steve Chang SKC-2009
Question: Do we live in… Time-Domain or Frequency-Domain? SKC-2009
Time Domain vs Frequency Domain Time information is lost Frequency (Hz) Spectrum Time (Seconds) Waveform SKC-2009
Spectrogram (time-Frequency) Time (Seconds) Frequency (HZ) SKC-2009
Fourier Transform & Short Time Fourier Transform Window SKC-2009
STFT Fourier Transform SKC-2009
STFT: Fixed Window, Fixed Resolution Window Length Frequency Resolution Time Resolution SKC-2009
Example (400 msec sample) SKC-2009
(T=25 ms) Poor Frequency Resolution SKC-2009
(T=125 ms) Fixed Resolution SKC-2009
(T=375 ms) Fixed Resolution SKC-2009
(T=1000 ms) Poor High Frequency Time Resolution SKC-2009
S-Transform & Short Time Fourier Transform SKC-2009
Gaussian Window for S-Transform Function of Frequency SKC-2009
Gaussian Window for S-Transform High Frequency Low Frequency Time Shifted SKC-2009
and from SKC-2009
Two Chirps and Two Bursts S-T STFT Wigner SKC-2009
S-Transform and Wavelet Transform Mother Wavelet: SKC-2009
S-Transform is not Wavelet Transform Mother Wavelet does not have zero mean: Morlet’s Wavelet Phase Correction SKC-2009
Generalized S-Transform Resolution p TimeFrequency Standard Deviation SKC-2009
Generalized S-Transform: Bi-Gaussian SKC-2009
Generalized S-Transform: Bi-Gaussian Sharper Front Edge For Arrival Time Sacrifice Frequency Resolution SKC-2009
Generalized S-Transform: Bi-Gaussian Sharper Arrival Time SKC-2009
Generalized S-Transform: Your Own SKC-2009
Generalized S-Transform: Your Own Constraint: SKC-2009
Examples - Applications Engine Knock Pressure STFT S-Transform with New Window S-Transform SKC-2009
Power Disturbance Detection Power Disturbance Contour Stationary Phase Power Disturbance SKC-2009
Earthquake Detection Noisy Signal Time-Frequency Filter Inverse S-Transform Earthquake Signal SKC-2009
Earthquake Seismology Original Data Filter 1 Filter 2 S-Filters SKC-2009
Seismic Data STFTS- Transform Seismic Trace SKC-2009
Medical: Forearm Blood Flow Rest Activities Occlusion SKC-2009
Geomagnetic Storm Induced Current SKC-2009
Gear Vibration Signal Decoposition Helicopter Rotor under Fatigue Test Transient Components SKC-2009
Image Analysis Original ImageDominant Frequency SKC-2009
S-Transform We live in Time-Frequency World. Similar to Short-Time Fourier Transform Similar to Continuous Wavelet Transform Generalized S-Transform: Many Different Window Choices Time-Frequency Analysis: Many Applications SKC-2009