Developments in minimum entropy deconvolution
department or school: Science, Faculty of
department or school: Earth, Ocean and Atmospheric Sciences, Department of
data provider: DSpace
degree campus: UBCV
creator: Nickerson, William Alexander
issued: 2010-06-27T16:58:36Z
issued: 1986
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Minimum entropy deconvolution (MED) is investigated in light of recent work, and reports of poor performance in the deconvolution of real reflection seismograms. The problems with MED fall into two catagories. The first contains problems related to operator design such as avoiding local extrema in the simplicity criterion, problems with bandwidth, and the selection of filter length and preprocessing parameters. The second is the determination of model validity for the data at hand. MED is based on the iterative maximization of a data simplicity criterion which exhibits multiple extrema. A geometrical interpretation of this algorithm leads to an intuitive alternative algorithm, the projection method, and to the conclusion that iteration starting filter governs which extremum is reached and hence output wavelet delay. Choice of starting filter is therefore tantamount to a wavelet phase assumption and there is no basis for choosing the standard, centred impulse, starting filter if the global extremum is desired. An optimum lag MED algorithm is proposed to achieve the global maximum. Bandlimiting, data tapering and other aspects of MED operator design are discussed. No criterion exists for assessing MED model validity. Studies with various synthetic reflectivity statistics reveal that "sparseness" and "simplicity" are poor descriptors of the minimum entropy assumption. Preliminary attempts to quantify MED applicability are made but fail and indicate that any successful measure must include both underlying reflectivity and wavelet characteristics. Examples using synthetic data show the advantages of the bandlimited optimum lag MED algorithm over a conventional starting filter method.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/26015
note: DEVELOPMENTS IN MINIMUM ENTROPY DECONVOLUTION by WILLIAM ALEXANDER NICKERSON A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF GEOPHYSICS AND ASTRONOMY We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o the r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA JANUARY,1986 © WILLIAM ALEXANDER NICKERSON, JANUARY,1986 In p resen t ing this thesis in partial fu l f i lment of the requ i rements for an a d v a n c e d d e g r e e at the Univers i ty of Brit ish C o l u m b i a , I agree that the Library shall m a k e it freely avai lable for re fe rence a n d s tudy . I further agree that p e r m i s s i o n for ex tens ive c o p y i n g o f this thesis fo r scho lar ly p u r p o s e s may be g ran ted by the h e a d of m y d e p a r t m e n t o r by his o r her representat ives . It is u n d e r s t o o d that c o p y i n g o r p u b l i c a t i o n of this thesis for f inancia l gain shall no t b e a l l o w e d w i t h o u t m y wr i t ten p e r m i s s i o n . D e p a r t m e n t T h e Un ivers i ty o f Brit ish C o l u m b i a 1956 M a i n M a l l V a n c o u v e r , C a n a d a V 6 T 1Y3 \ DE-6(3 /81) A b s t r a c t Minimum en t r o p y d e c o n v o l u t i o n (MED) i s i n v e s t i g a t e d i n l i g h t of r e c e n t work, and r e p o r t s of poor performance i n the d e c o n v o l u t i o n of r e a l r e f l e c t i o n seismograms. The problems w i t h MED f a l l i n t o two c a t a g o r i e s . . The f i r s t c o n t a i n s problems r e l a t e d t o o p e r a t o r d e s i g n such as a v o i d i n g l o c a l extrema i n the s i m p l i c i t y c r i t e r i o n , problems w i t h bandwidth, and the s e l e c t i o n of f i l t e r l e n g t h and p r e p r o c e s s i n g p arameters. The second i s the d e t e r m i n a t i o n of model v a l i d i t y f o r the d a t a a t hand. MED i s based on the i t e r a t i v e m a x…
has type: Thesis/Dissertation
is shown at: 10.14288/1.0052981
language: eng
degree discipline: Geophysics
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/26015