Topic:
How does the event picking algorithm work in Autopix?

Description:
 

Solution:
The Event picking method compares the amplitude and the wavelength of the event
on the target trace with the picked event on the current (source) trace in
discrete tests using the supplied Amplitude Factor and Wavelength Factor. This
method separates the effect of amplitude variations from changes in wavelength
(frequency). This is the preferred method if the event being picked separates
from a broad peak into a doublet.

The Event picking method uses the following equations where the amplitude factor
is X and the two amplitudes are A1 and A2. If the amplitudes between the two
traces satisfy one of these equations, the amplitudes are said to match.
If A1 > 0 then
 A1 < (1 + X)A2 for A1 > A2
 A2 < (1 + X)A1 for A1 < A2.
When A1 < 0 then A1 = -A1 and A2 = -A2 are substituted into the above equations.
If the amplitude values do not pass the above test, they are run through the
epsilon test as follows:
 epsilon = X(RMSsurvey /10)
 epsilon > |A1 - A2|
If the amplitudes fail the first test, but pass the epsilon test they are said
to match.

Similar tests (except the epsilon test) are made for the wavelengths. When both
the amplitude and wavelength match, the pick is successful. Increasing either
factor will relax the picking criteria. Decreasing either factor will make the
picking stricter. Normal ranges would be between 0.4 and 1.0. 



Last Modified on: 11-FEB-99