Detection system, signal processing device, detection method, and computer program product

1. A detection system comprising:

a detection device configured to detect a change that occurs in a structure or a change in an environment related to the structure;

an acoustic emission sensor configured to detect an acoustic emission wave produced from the structure; and

a processing unit configured to perform first signal processing to process an acoustic emission signal indicating the acoustic emission wave, which is input from the acoustic emission sensor until a first period of time elapses after a detection signal is input from the detection device, the detection signal indicating that a change has occurred in the structure or the environment related to the structure.

2. The system according to claim 1 , wherein the detection device is disposed at a position at which the detection device detects the change that occurs in the structure before the acoustic emission sensor does.

3. The system according to claim 1 , wherein the processing unit processes the acoustic emission signal input from the acoustic emission sensor until the first period of time elapses from elapse of a second period of time after the detection signal is input from the detection device.

4. The system according to claim 3 , wherein

the change that occurs in the structure includes strain of the structure arising from weight of a moving object that enters the structure, and

the second period of time is determined based on a distance between the detection device and the acoustic emission sensor and an average speed of the moving object.

5. The system according to claim 4 , wherein

the detection device includes a camera that captures the moving object that enters the structure, and

when the moving object is included in an image captured by the camera, the detection device inputs the detection signal to the processing unit.

6. The system according to claim 1 , wherein

the detection device is a strain sensor configured to detect magnitude of strain occurring in the structure,

the detection signal indicates the magnitude of the strain occurring in the structure, and

when the magnitude of the strain indicated by the detection signal exceeds a threshold, the processing unit performs the first signal processing on the acoustic emission signal, which is input from the acoustic emission sensor until the first period of time elapses after the detection signal is input from the detection device.

7. The system according to claim 6 , wherein the strain sensor is an acoustic emission sensor configured to detect an acoustic wave in a frequency band indicating strain in the structure.

8. The system according to claim 1 , wherein

the detection device is a vibration sensor configured to detect magnitude of vibration occurring in the structure,

the detection signal indicates the magnitude of the vibration occurring in the structure, and

when the magnitude of the vibration indicated by the detection signal exceeds a threshold, the processing unit performs the first signal processing on the acoustic emission signal, which is input from the acoustic emission sensor until the first period of time elapses after the detection signal is input from the detection device.

9. The system according to claim 1 , wherein

the detection device is a wind velocity sensor configured to detect magnitude of wind velocity with respect to the structure,

the detection signal indicates the magnitude of the wind velocity with respect to the structure, and

when the magnitude of the wind velocity indicated by the detection signal exceeds a threshold, the processing unit performs the first signal processing on the acoustic emission signal, which is input from the acoustic emission sensor until the first period of time elapses after the detection signal is input from the detection device.

10. The system according to claim 1 , wherein

the detection device is a flowmeter configured to detect a flow rate of a fluid flowing through the structure,

the detection signal indicates the flow rate of the fluid, and

when the flow rate indicated by the detection signal exceeds a threshold, the processing unit performs the first signal processing on the acoustic emission signal, which is input from the acoustic emission sensor until the first period of time elapses after the detection signal is input from the detection device.

11. The system according to claim 1 , further comprising:

a processing control unit configured to cause the processing unit to perform at least one of second signal processing to process the acoustic emission signal at all times and the first signal processing; and

a display control unit configured to display, on a display unit, at least one of first signal processing result information that indicates a processing result of the first signal processing and second signal processing result information that indicates a processing result of the second signal processing.

12. The system according to claim 11 , wherein the first

signal processing and the second signal processing include processing to count waveforms that satisfy a predetermined condition, from among waveforms indicated by the acoustic emission signal.

13. A signal processing device connected to a detection device and to an acoustic emission sensor, the detection device being configured to detect a change that occurs in a structure or a change in an environment related to the structure, the acoustic emission sensor being configured to detect an acoustic emission wave produced from the structure, the signal processing device comprising:

a processing unit configured to perform first signal processing to process an acoustic emission signal indicating the acoustic emission waves, which is input from the acoustic emission sensor until a first period of time elapses after a detection signal is input from the detection device, the detection signal indicating that a change has occurred in the structure or the environment related to the structure.

14. A detection method performed by a signal processing device connected to a detection device and to an acoustic emission sensor, the detection device being configured to detect a change that occurs in a structure or a change in an environment related to the structure, the acoustic emission sensor being configured to detect an acoustic emission wave produced from the structure, the method comprising:

performing first signal processing to process an acoustic emission signal indicating the acoustic emission waves, which is input from the acoustic emission sensor until a first period of time elapses after a detection signal is input from the detection device, the detection signal indicating that a change has occurred in the structure or the environment related to the structure.

15. A computer program product comprising a non-transitory

computer-readable medium including programmed instructions, wherein the instructions causes a computer, which is connected to a detection device and to an acoustic emission sensor, the detection device being configured to detect a change that occurs in a structure or a change in an environment related to the structure, the acoustic emission sensor being configured to detect an acoustic emission wave produced from the structure, to function as:

a processing unit configured to perform first signal processing to process an acoustic emission signal indicating the acoustic emission wave, which is input from the acoustic emission sensor until a first period of time elapses after a detection signal is input from the detection device, the detection signal indicating that a change has occurred in the structure or the environment related to the structure.