Title:
SIGNAL PROCESSING METHOD IN SPECIFICATION METHOD FOR LEAK POSITION IN PIPE
Document Type and Number:
Japanese Patent JP3295682
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a signal processing method in which a leak position can be specified precisely by a method wherein a cross spectrum after a signal processing operation is inverse-Fourier-transformed and the cross-correlation function of a plurality of sound-wave signals is found.
SOLUTION: First, a sound-wave signal is A/D-converted and Fourier- transformed (F-1). A cross spectrum is found (F-2). The cross spectrum is divided into a phase characteristic and an amplitude characteristic (F-3). The amplitude characteristic of the cross spectrum is smoothed (F-4). Then, an inessential band in the amplitude characteristic of the cross spectrum is changed into a zero value (F-5). By using a corrected amplitude characteristic and the phase characteristic, a cross spectrum is created (F-6). The created cross spectrum is inverse-Fourier-transformed (F-7). By its inverse Fourier transform, a cross- correlation function in which a peak due to a noise is removed is obtained. On the basis of the cross-correlation function, a leak position is specified (F-8).
Inventors:
Kyousuke Wakasa
Application Number:
JP34193096A
Publication Date:
June 24, 2002
Filing Date:
December 20, 1996
Export Citation:
Assignee:
Tokyo Gas Co., Ltd.
International Classes:
G06F17/15; G06T7/60; G01M3/24; (IPC1-7): G01M3/24; G06T7/60
Domestic Patent References:
| JP587669A | ||||
| JP5470883A | ||||
| JP6323945A | ||||
| JP1311232A |
Attorney, Agent or Firm:
Hiroo Suzuki