
\lefthead{Claerbout}
\righthead{Practical inversion tutorial}
\footer{SEP--61}
\title{Preface to practical inversion tutorial}
\author{Jon F. Claerbout}
\ABS{
My book revisions have lead to three chapters that form
a practical inversion tutorial.
Included in the tutorial are some new research results, namely
(1) antialias velocity estimation,
(2) weighting function for separation of pressure and shear waves,
(3) properties of interpolation-error filters, and
(4) blind deconvolution of an all-pass filter.
}
\par
Continuing revisions of my first book
``Fundamentals of Geophysical Data Processing''
are leading me so far from the from the original book
that I am contemplating a new title
``Dissecting Earth Soundings''
and completion in 1991.
I am including the three chapters that have undergone
the most recent alteration.
They happen to be contiguous and could be entitled
``Practical inversion tutorial.''
Much of this material has appeared before in SEP reports,
but I felt obliged to include the old with the new,
in order to avoid a lack of continuity.

\par
Although the material is billed as being tutorial,
it includes some new research results
as well as many interesting examples.
The new results are:
\begin{itemize}
\item
Chapter 6. Section 5 describes a new anti-alias method of velocity analysis.
\item
Chapter 7. This chapter begins by examining the separation
of pressure and shear waves.
The solution illustrates the importance of choosing an appropriate
weighting function in any inversion scheme.
\item
Chapter 8. The whole chapter is new.  The hoary conclusion that blind
deconvolution cannot find an all-pass filter is shown to be invalid,
and an estimation method based on interpolation-error (IE) filters is given
and demonstrated.
It seems to be a new result that IE filters
invert the spectrum of their input
and a new recognition that IE filters can play a significant role
in determining an appropriate weighting in inversion problems.
\end{itemize}

\shead{ACKNOWLEDGEMENT}
I especially like to thank Bill Harlan who spent the summer
with us and made some major contributions to these lectures.
He strongly influenced chapter 7 section 2 and provided the example there.
He suggested a splitting up of my conjugate-gradients-for-beginners program
that makes it much easier to build upon.
He wrote section 5 of chapter 7 on statics corrections,
and he wrote section 6 of chapter 8 on wavelet corrections in the near surface.

\REF
\reference{Claerbout, J.F., Book3 or revised parts of FGDP,
	SEP-60, p. 303-347}
\reference{Claerbout, J.F., Fundamentals of geophysical data processing,
	1976, reprinted in 1985 by Blackwell Scientific Publications}
