Leakage inspection device, leakage inspection method, and storage medium

1. A leakage inspection device comprising:

at least one memory storing a set of instructions; and

at least one processor configured to execute the set of instructions to:

determine a measurement time;

measure vibration waveforms for the measurement time by using at least two sensors set to a pipe;

calculate a cross-correlation function of the measured vibration waveforms;

detect peaks of the cross-correlation function at least twice in the measurement time; and

determine that leakage occurs in a case where the peaks are repeatedly detected in the measurement time,

wherein

the at least one processor is further configured to execute the set of instructions to:

calculate a histogram function indicating a relationship between a water use time at one time and a frequency from information indicating the water use time; and

determine, as the measurement time, a time period in which a probability representing a probability that a sound source is a disturbance caused by use of water is equal to or less than a predetermined value determined in advance based on the histogram function.

2. The leakage inspection device according to claim 1 , wherein

the at least one processor is further configured to execute the set of instructions to:

determine whether the peaks are repeated in the measurement time based on a detection result of the peaks;

in a case where the peaks are determined to be repeated in the measurement time, determine that a sound source of the vibration waveform is leakage; and

in a case where the peaks are not determined to be repeated in the measurement time, determine that the sound source of the vibration waveform is not leakage.

3. The leakage inspection device according to claim 1 , wherein

the at least one processor is further configured to execute the set of instructions to:

determine an integration time in which values of the cross-correlation function of the vibration waveform are accumulated based on a S/N ratio of the vibration waveform; and

detect a peak of the cross-correlation functions integrated for the integration time.

4. The leakage inspection device according to claim 1 , wherein

the at least one processor is further configured to execute the set of instructions to:

calculate a determination accuracy rate function indicating a relationship between a probability of correct determination of a type of the sound source of the vibration waveform and a time by using statistical data of a water use time;

calculate an inspection efficiency function indicating a relationship between an efficiency of a leakage inspection and a time by using information regarding an inspection plan;

calculate an economic efficiency function indicating an economic efficiency of a leakage inspection with respect to a time from the determination accuracy rate function and the leakage inspection efficiency function; and

determine, based on the economic efficiency function, the measurement time in such a way that the economic efficiency of the leakage inspection is maximized.

5. A leakage inspection method comprising:

determining a measurement time;

measuring vibration waveforms for the measurement time by using at least two sensors set to a pipe;

calculating a cross-correlation function of the measured vibration waveforms;

detecting peaks of the cross-correlation function equal to or more than twice in the measurement time; and

determining that leakage occurs in a case where the peaks are repeatedly detected in the measurement time,

wherein the method further comprises:

calculating a histogram function indicating a relationship between a water use time at one time and a frequency from information indicating the water use time; and

determining, as the measurement time, a time period in which a probability representing a probability that a sound source is a disturbance caused by use of water is equal to or less than a predetermined value determined in advance based on the histogram function.

6. A non-transitory computer-readable storage medium that stores a program for causing a computer to execute processing comprising:

determining a measurement time;

measuring vibration waveforms for the measurement time by using at least two sensors set to a pipe;

calculating a cross-correlation function of the measured vibration waveforms;

detecting peaks of the cross-correlation function equal to or more than twice in the measurement time; and

determining that leakage occurs in a case where the peaks are repeatedly detected in the measurement time,

wherein the processing further comprises:

calculating a histogram function indicating a relationship between a water use time at one time and a frequency from information indicating the water use time; and

determining, as the measurement time, a time period in which a probability representing a probability that a sound source is a disturbance caused by use of water is equal to or less than a predetermined value determined in advance based on the histogram function.