Receiver, early anomaly detection system and method, and computer-readable medium
A detection unit receives an optical signal that has passed through a space to be measured. A spectrum extraction unit extracts a range to be measured from the optical signal received by the detection unit. The spectrum extraction unit extracts an optical signal formed as a gas molecule of a gas to be measured absorbs energy of the optical signal. A determination unit determines the presence of an anomaly in the space to be measured based on a waveform of the optical signal extracted by the spectrum extraction unit.
1. A receiver, comprising:
a memory storing instructions;
a processor configured to execute the instructions; and
at least one detector configured to receive an optical signal that has passed through a measurement space;
wherein the processor is configured to execute the instructions to:
extract an optical signal falling within a measurement range from the optical signal received by the at least one detector;
determine a presence of an anomaly in the measurement space using a waveform of the extracted optical signal formed as a gas molecule of a measurement gas absorbs energy of the optical signal; and
perform signal processing on the extracted optical signals obtained by performing a plurality of instances of wavelength sweeping to shape spectral intensity of the extracted optical signals into two-dimensional data in which a first direction corresponds to one wavelength sweeping and a second direction corresponds to a number of the wavelength sweeping,
wherein the presence of an anomaly is determined using the two-dimensional data.
2. The receiver according to claim 1 , wherein the processor is configured to execute the instructions to:
extract a feature of the waveform of the optical signal in the measurement range; and
determine the presence of the anomaly using the extracted feature of the waveform.
3. The receiver according to claim 2 , wherein the processor is configured to execute the instructions to extract, as the feature, at least one of a distance between a local maximum and a local minimum in the waveform of the optical signal or a distance between two local minima located across a local maximum in the waveform of the optical signal.
4. The receiver according to claim 1 , wherein the processor is configured to execute the instructions to:
calculate a likelihood of at least one of a state being anomalous or a state being normal using a learning result from learning a waveform of the optical signal observed in a normal state and a waveform of the optical signal observed in an anomalous state and the waveform of the extracted optical signal; and
determine the presence of the anomaly using the calculated likelihood.
5. The receiver according to claim 1 , wherein the optical signal is transmitted in a predetermined wavelength-sweeping range and is wavelength-modulated.
6. The receiver according to claim 1 , wherein:
the optical signal includes two or more optical signals having different wavelengths,
the at least one detector is configured to receive each of the two or more optical signals, and
the processor is configured to execute the instructions to:
extract a measurement range from each of the received two or more optical signals; and
determine the presence of the anomaly using each waveform of the two or more optical signals.
7. The receiver according to claim 6 comprising two or more detectors configured to receive the respective two or more optical signals.
8. The receiver according to claim 6 , wherein:
the two or more optical signals are output alternately into the measurement space, and
each of the two or more optical signals is received in synchronization with a timing at which the optical signals are alternated.
9. The receiver according to claim 8 , further comprising a controller configured to synchronize the timing at which the optical signals are alternated and a timing at which each optical signal is received.
10. An anomaly detection system, comprising:
a transmitter configured to transmit an optical signal into a measurement space; and
the receiver according to claim 1 .
11. The anomaly detection system according to claim 10 , wherein the transmitter includes:
a light source configured to output the optical signal; and
a driver configured to drive the light source to sweep a wavelength by modulating the wavelength of the optical signal output from the light source.
12. The anomaly detection system according to claim 10 , wherein the transmitter includes a light source configured to output an optical signal of a band broader than an absorption band of the measurement gas.
13. The anomaly detection system according to claim 10 , wherein
the processor is configured to execute the instructions to:
extract a feature of the waveform of the optical signal in the measurement range; and
determine the presence of the anomaly using the extracted feature of the waveform.
14. The anomaly detection system according to claim 13 , wherein the processor is configured to execute the instructions to extract, as the feature, at least one of a distance between a local maximum and a local minimum in the waveform of the optical signal or a distance between two local minima located across a local maximum in the waveform of the optical signal.
15. The anomaly detection system according to claim 10 , wherein
the processor is configured to execute the instructions to:
calculate a likelihood of at least one of a state being anomalous or a state being normal using a learning result from learning a waveform of the optical signal observed in a normal state and a waveform of the optical signal observed in an anomalous state and the waveform of the extracted optical signal; and
determine the presence of the anomaly using the calculated likelihood.
16. An anomaly detection method, comprising:
receiving an optical signal that has passed through a measurement space;
extracting an optical signal falling within a measurement range from the received optical signal;
determining a presence of an anomaly in the measurement space using a waveform of the extracted optical signal formed as a gas molecule of a measurement gas absorbs energy of the optical signal; and
performing signal processing on the extracted optical signals obtained by performing a plurality of instances of wavelength sweeping to shape spectral intensity of the extracted optical signals into two-dimensional data in which a first direction corresponds to one wavelength sweeping and a second direction corresponds to a number of the wavelength sweeping,
wherein the presence of an anomaly is determined using the two-dimensional data.
17. A non-transitory computer-readable medium storing a program that, if executed, causes a processor to execute a process comprising:
extracting an optical signal falling within a measurement range from a received optical signal that has passed through a measurement space;
determining a presence of an anomaly in the measurement space using a waveform of the extracted optical signal formed as a gas molecule of a measurement gas absorbs energy of the optical signal; and
performing signal processing on the extracted optical signals obtained by performing a plurality of instances of wavelength sweeping to shape spectral intensity of the extracted optical signals into two-dimensional data in which a first direction corresponds to one wavelength sweeping and a second direction corresponds to a number of the wavelength sweeping,
wherein
the presence of an anomaly is determined using the two-dimensional data.