EP0042601A1
Expired / Lapsed
EP
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Non-destructive inspection by frequency spectrum resolution
Assignee: Hitachi Ltd
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Filing: 1981-06-19
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Granted: —
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Expires: 2001-06-19
Abstract
Abstract A method of inspecting non-destructively a specimen for examining presence or absence of a defect in the specimen, in which an ultrasonic wave is emitted from a probe (2) and a reflected wave from the specimen (1) is received by the probe (2) whose output signal is processed to determine the presence or absence of the defect. The signal processing includes steps of extracting characteristic parameters from a frequency spectrum of the ultrasonic echo and comparing the extracted parameter with corresponding experimentally or theoretically determined value. The invention makes it possible to automatically determine discriminatively whether the reflector of the ultrasonic echo is a configured portion, a weld boundary or a defect of a specimen to be inspected.
Inventors
- 👤 Sakae Sugiyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 19:01
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/44; G01N29/4409; G01N29/4427; G01N29/04; G01N29/12; G01N29/34; G01N29/348; G01N29/4445; G01N29/46; G01N2291/00; G01N2291/04; G01N2291/044; G01N2291/26; G01N2291/267
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
A method of inspecting non-destructively a specimen for examining presence or absence of a defect (F) in said specimen (1), in which an ultrasonic wave is emitted from a probe (2) and a reflected wave from said specimen (1) is received by said probe (2) whose output signal is processed to determine the presence or absence of said defect (F1), comprising: a) a first step for deriving a signal representative of a frequency spectrum of said received signal; b) a second step of deriving at least two characteristic parameters (f, q) of the frequency spectrum from said frequency spectrum signal; and c) a third step for comparing signals representative of the characteristic parameters (f, q) as derived with signals representative of predetermined corresponding characteristic parameters.
Claim 2
Independent Claim
125 words
A method of inspecting non-destructively a specimen for examining presence or absence of a defect (F) in said specimen (1), in which an ultrasonic wave is emitted from a probe (2) and a reflected wave from said specimen (1) is received by said probe (2) whose output signal is processed to determine the presence or absence of said defect (F1), comprising: a) a first step for deriving a signal representative of a frequency spectrum of said received signal; b) a second step of deriving at least two characteristic parameters (f, q) of the frequency spectrum from said frequency spectrum signal; and c) a third step for comparing signals representative of the characteristic parameters (f, q) as derived with signals representative of predetermined corresponding characteristic parameters.
Claim 3
Dependent Claim
36 words
A non-destructive inspecting method according to claim 1, wherein said characteristic parameters (f, q) includes a maximum spectrum density and a standard deviation of frequency spacing between maxima in the frequency spectrum of said echo signal.
Claim 4
Dependent Claim
148 words
A non-destructive inspection apparatus, comprising: means (2, 3) for emitting an ultrasonic wave from a probe and receiving an echo reflected from a specimen (1) to be inspected to thereby convert said echo into a corresponding electric signal; a frequency analyzer (4) for determining a frequency spectrum of said echo from said electric signal; storage means (8) for storing therein at least a set of characteristic parameter values of frequency spectra of echoes which are determined previously for plural states of the specimen to be inspected, and arithmetic operation unit (5, 6, 7) for arithmetically determining at least a set of characteristic parameter values (f, q) on the basis of the output signal from said frequency analyzer (4), comparing said arithmetically determined parameter values with at least one set of the predetermined corresponding parameter values stored in said storage means (8) and outputting the results of said comparison.
Claim 5
Dependent Claim
148 words
A non-destructive inspection apparatus, comprising: means (2, 3) for emitting an ultrasonic wave from a probe and receiving an echo reflected from a specimen (1) to be inspected to thereby convert said echo into a corresponding electric signal; a frequency analyzer (4) for determining a frequency spectrum of said echo from said electric signal; storage means (8) for storing therein at least a set of characteristic parameter values of frequency spectra of echoes which are determined previously for plural states of the specimen to be inspected, and arithmetic operation unit (5, 6, 7) for arithmetically determining at least a set of characteristic parameter values (f, q) on the basis of the output signal from said frequency analyzer (4), comparing said arithmetically determined parameter values with at least one set of the predetermined corresponding parameter values stored in said storage means (8) and outputting the results of said comparison.
Claim 6
Independent Claim
172 words
A method of inspecting non-destructively a specimen (1) for examining presence or absence of a defect in said specimen, in which an ultrasonic wave is emitted from a probe (2) and a reflected wave from said specimen is received by said probe whose output signal is processed to determine the presence or absence of said defect, wherein said signal processing includes steps of arithmetically determining a frequency spectrum of the ultrasonic echo received by said probe (2) to thereby extract two parameters of a bary-center frequency (f G ) and a frequency specing (Δf) of said frequency spectrum; plotting said two parameters (f a ; Af) on a two-dimensional map having one axis along which one of said parameters is taken and the other axis along which the other of said parameters is taken; and determining discriminatively whether reflector is an inner worked portion or a crack present in said specimen by referring to a boundary line between the inner worked portion and the crack, said boundary line having been predetermined experimentally.
Claim 7
Independent Claim
172 words
A method of inspecting non-destructively a specimen (1) for examining presence or absence of a defect in said specimen, in which an ultrasonic wave is emitted from a probe (2) and a reflected wave from said specimen is received by said probe whose output signal is processed to determine the presence or absence of said defect, wherein said signal processing includes steps of arithmetically determining a frequency spectrum of the ultrasonic echo received by said probe (2) to thereby extract two parameters of a bary-center frequency (f G ) and a frequency specing (Δf) of said frequency spectrum; plotting said two parameters (f a ; Af) on a two-dimensional map having one axis along which one of said parameters is taken and the other axis along which the other of said parameters is taken; and determining discriminatively whether reflector is an inner worked portion or a crack present in said specimen by referring to a boundary line between the inner worked portion and the crack, said boundary line having been predetermined experimentally.
References Cited (Backward Citations)
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