Topic:
Algorithm used for Instantaneous Frequency and how the min/max values are treated.

Description:
1) What algorithm does GeoQuest use in the instantaneous frequency calculation?
2) How are the values outside the max and min frequency window treated? 

Solution:
1) fft -> zero out negative frequencies -> multiply by the quadrature trace
   which is derived from the Hilbert transform -> inverse fft -> THEN TAKE:
 
  (U*derivitive of V) - (V*derivitive of U)/(U^2 + V^2)
 
  then if you use weighting:
  SQRT (U^2 + V^2)
 
  If you use smoothing and weighting:
  Reflection strength * (U*derivitive of V) - (V*derivitive of U)/(SQRT U^2)
 
 
2) How this value compares to the min & max frequency value:
   if it is less than the min then it is set to the min
   if it is more than the max then it is set to the max




Last Modified on: 24-MAR-99