Fluid measurement apparatus, fluid measurement method, and program

1. A fluid measurement apparatus comprising:

an optical emitter capable of radiating light to an irradiation target including a fluid;

an optical detector capable of receiving scattered light scattered by the fluid; and

a controller that includes

a generator configured to generate a first frequency spectrum based on the scattered light,

an acquisition unit configured to acquire a second frequency spectrum based on the fluid in a known flow state, and

an estimation unit configured to estimate a flow state of the fluid based on a characteristic component of the first frequency spectrum,

the controller being configured to estimate a flow state of a measurement target fluid by

causing the generator to generate the first frequency spectrum based on the measurement target fluid and the acquisition unit to acquire the second frequency spectrum, and

then causing the estimation unit to compare a characteristic component of the first frequency spectrum and a characteristic component of the second frequency spectrum.

2. The fluid measurement apparatus according to claim 1 , wherein the irradiation target further includes a flow path in which the fluid flows, and the generator is further configured to generate the first frequency spectrum based on interference light caused by interference between the scattered light scattered by the fluid and scattered light scattered by the flow path.

3. The fluid measurement apparatus according to claim 1 , wherein the first frequency spectrum is generated from a signal based on the Doppler shift of the scattered light.

4. The fluid measurement apparatus according to claim 1 , wherein the characteristic component includes at least one of a value based on an intensity of a specific frequency in the frequency spectrum and a value based on an intensity of a frequency in a specific segment.

5. The fluid measurement apparatus according to claim 4 , wherein the characteristic component is a ratio of an intensity corresponding to at least one specific frequency to an intensity corresponding to at least one frequency other than the specific frequency.

6. The fluid measurement apparatus according to claim 4 , wherein the characteristic component includes at least one of an average intensity and an intensity variance of the specific segment in the frequency spectrum.

7. The fluid measurement apparatus according to claim 4 , wherein the characteristic component is a shape of a specific segment in the frequency spectrum.

8. The fluid measurement apparatus according to claim 7 , wherein the estimation unit is configured to use bilinear approximation or exponential approximation in order to determine whether a shape of the first frequency spectrum and a shape of the second frequency spectrum are similar to each other.

9. The fluid measurement apparatus according to claim 1 , wherein the estimation unit is further configured to cause a learning technique to determine a relationship between the known flow state and a characteristic component of the second frequency spectrum, and then estimate the flow state of the measurement target fluid based on the characteristic component of the first frequency spectrum and the relationship.

10. The fluid measurement apparatus according to claim 1 , wherein the estimation unit is configured to estimate at least one of a flow velocity and a flow rate of the measurement target fluid as the flow state of the measurement target fluid.

11. The fluid measurement apparatus according to claim 1 , wherein the optical emitter radiates laser light.

12. A fluid measurement method comprising:

radiating light to an irradiation target including a measurement target fluid;

receiving scattered light scattered by the measurement target fluid;

and

estimating a flow state of the measurement target fluid by generating a first frequency spectrum based on the scattered light from the measurement target fluid and acquiring a second frequency spectrum based on the measurement target fluid in a known flow state, and then comparing a characteristic component of the first frequency spectrum and a characteristic component of the second frequency spectrum.

13. A non-transitory computer-readable recording medium storing instructions, which when executed by a computer, cause the computer to:

radiate light to an irradiation target including a measurement target fluid;

receive scattered light scattered by the measurement target fluid;

and

estimating a flow state of the measurement target fluid by generating a first frequency spectrum based on the scattered light from the measurement target fluid and acquiring a second frequency spectrum based on the measurement target fluid in a known flow state and then comparing a characteristic component of the first frequency spectrum and a characteristic component of the second frequency spectrum.