Signal processing apparatus, signal processing method, and non-transitory computer readable medium

A signal processing method comprising:

• a step of acquiring a phase difference signal of backscattered light of laser light, by an optical fiber sensor configured to convert dynamic distortion of an optical fiber, at a first gauge length that is a predetermined section, into a phase difference of the backscattered light of the laser light passing through the first gauge length;
• and
• a step of obtaining phase difference data of the backscattered light of the laser light at a second gauge length shorter than the first gauge length, from the acquired phase difference signal of the backscattered light of the laser light.

A non-transitory computer readable medium having recorded thereon a program to cause a signal processing apparatus to execute:

• a step of acquiring a phase difference signal of backscattered light of laser light, by an optical fiber sensor configured to convert dynamic distortion of an optical fiber, at a first gauge length that is a predetermined section, into a phase difference of the backscattered light of the laser light passing through the first gauge length;
• and
• a step of obtaining phase difference data of the backscattered light of the laser light at a second gauge length shorter than the first gauge length, from the acquired phase difference signal of the backscattered light of the laser light.