In pipe arrangement leakage position specific manner the signal processing manner

摘要

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).