An A Priori Knowledge Based Wiener Filtering Approach to Ultrasonic Scattering Amplitude Estimation

Neal, Steven P.; Thompson, Donald O.

doi:10.1007/978-1-4613-1893-4_92

Cited by 6 publications

(17 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(Neal and Thompson 1987). The derivation presented here differs significantly from the derivation outlined by Elsley et al (1980) in that they assumed A(w) and n(w) had zero mean.…”

Section: Ill-posednessmentioning

confidence: 86%

“…Equation (3.21) can be written in the form of a weighting term, times the first bracketed term, plus a second weighting term, Wg, times the second bracketed term (Neal and Thompson 1987). Using this format and based on Eq.…”

Section: I" I'mentioning

confidence: 99%

“…In the system used here, the ringing noise is a low frequency noise with its greatest strength near the lower limit of the bandwidth (i.e., in the 2MHz range). Given the importance of low frequency information in some flaw characterization approaches (Richardson and Elsley 1979, Richardson 1980, Richardson 1984 and in scattering amplitude estimation outside of the bandwidth at low frequencies (Addison et al 1982, Gray 1982, Thompson and Gray 1982, Cohen-TenoudJi et al 1984, Clark et al 1986, Neal and Thompson 1987, Koo 1988, successful elimination of the ringing noise can be critical. However, the significance of this component depends on a number of factors including the pulser/receiver (and the settings used), transducer, host material, flaw depth, and flaw signal strength.…”

Section: Reference Signal Measurementmentioning

confidence: 99%

“…In other words, the filter uses two pieces of information: 1) that which is contained within F(w)/H(w) and was learned from the ultrasonic interrogation of the flaw, and 2) prior knowledge of the flaw distribution as represented by E[A(a))]. In order to emphasize this concept, henceforth, the unconstrained deconvolution, F(w)/H(w), will be referred to as the experimental result (Neal and Thompson 1987). The weighting term form also shows that the second term, V2(w)E[A(M)], essentially provides for a scattering amplitude estimate in regions were V^((id) has forced the experimental result to zero.…”

Section: Time (Sec)mentioning

confidence: 99%

“….90 Time (sec) The performance of the optimal Wiener filter will now be considered in terms of quantified error calculations between estimated and calculated scattering amplitudes Thompson 1987, Neal andThompson 1988). was shown that the weighting terms for the o^=50wm and o^=75wm cases were nearly the same.…”

mentioning

confidence: 99%

See 4 more Smart Citations

A prior knowledge based optimal Wiener filtering approach to ultrasonic scattering amplitude estimation

Neal

Thompson

1989

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

, "A prior knowledge based optimal Wiener filtering approach to ultrasonic scattering amplitude estimation " (1988). Retrospective Theses and Dissertations. 8877. http://lib.dr.iastate.edu/rtd/8877 INFORMATION TO USERSThe most advanced technology has been used to photo graph and reproduce this manuscript from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.Oversize materials (e.g., maps, drawings, charts) are re produced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. These are also available as one exposure on a standard 35mm slide or as a 17" x 23" black and white photographic print for an additional charge.Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Signature was redacted for privacy.Signature was redacted for privacy.Signature was redacted for privacy. The work reported here is associated with flaw characterization.This work is motivated from an engineering perspective by considering two fundamentally different approaches to life prediction that can be found in fatigue of materials and structures. In a simplistic sense, a "safe life"or "zero defects" fatigue life prediction approach (Coffin and Tiffany 1976) assumes that once a flaw is macroscopic, i.e., once a flaw has grown to a size which can be detected by NDE techniques, failure is imminent and the component must be taken out of service. With this approach, qualitative NDE indicating the presence or absence of a flaw provides sufficient information to determine if a component should be retired. An alternative approach, which is sometimes referred to as a "damage tolerance" approach, is based on a fracture mechanics methodology (Coffin and Tiffany 1976, Rolfe and Barsom 1977). With this approach, instead of assuming that all flawed components must be taken out of service, the 2 severity of the flaw is assessed and a more rational determination of the remaining life of the component is made. To implement this approach, quantitative flaw characterization is required. As a minimum...

show abstract

“…(Neal and Thompson 1987). The derivation presented here differs significantly from the derivation outlined by Elsley et al (1980) in that they assumed A(w) and n(w) had zero mean.…”

Section: Ill-posednessmentioning

confidence: 86%

Section: I" I'mentioning

confidence: 99%