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Recall the prediction-error filter subroutine
`find_pef()` .
Given a data plane, this subroutine finds a filter that tends
to whiten the spectrum of that data plane.
The output is white residual.
Now suppose we have a data plane where the dip spectrum
is changing from place to place.
Here it is natural to apply subroutine `find_pef()` in local patches.
This is done by subroutine `find_lopef()`.
The output of this subroutine is an array of helix-type filters,
which can be used, for example,
in a local convolution operator
`loconvol` .
lopeflocal PEF
We notice that when a patch has fewer regression equations
than the filter has coefficients, then the filter is taken
to be that of the previous patch.
loconvollocal convolution

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Stanford Exploration Project

4/27/2004