NAME

Agc - Automatic gain control with first arrival detection


SYNOPSIS

Agc window=200 detect=0 dwind=10 thresh=25. < in.H > out.H


INPUT PARAMETERS

window - integer
      [200]: length of the window in number of samples
dwind - integer
       [10]: length of the detection window in number of samples
detect - integer
        [0]:  detection off (Default value)    1:  detection on
thresh - real
      [25.]: threshold (see comments below)
n1,n2,n3 - integer
      standard seplib parameters


DESCRIPTION

Gain program with first arrival detection


COMMENTS

        Agc gains seismic traces by normalizing each sample by the
        power of a window of samples surrounding that point.
        When the detect= is set to 1, agc is not applied on a trace
        until a first arrival is detected. The first arrival is  
        detected when a moving dwind exceeds an initial dwind by a 
        threshold factor.


EXAMPLE

        Agc < in.H window=200 detect=1 dwind=10 thresh=25. > out.H
        Applies agc on a trace based on a trace window of 200 samples. 
        Agc is only applied after the first arrival has been detected 
        using a detection window of 10 samples. The detection of the 
        first arrival is based on an amplitude change between consecutive 
        detection windows of 25%.


CATEGORY

seis/filter