Optical device, information processing method, and computer program product
According to an embodiment, an optical device includes a light selection unit, an imaging element, and a deriving unit. The light selection unit splits an irradiated light beam into a plurality of spectral beams of different wavelength regions. The imaging element captures a subject irradiated with the spectral beams including beams of at least two different wavelengths to acquire a spectral image. The deriving unit derives a surface property or shape information of the subject from a specified result obtained by specifying, by the deriving unit, an irradiation region irradiated with each of the spectral beams on the subject based on a mixing ratio of the spectral beams and received light intensity of each of the spectral beams included in the spectral image.
1. An optical device comprising:
one or more hardware processors configured to function as:
an imaging sensor configured to capture a subject irradiated with a plurality of spectral beams that is split by a light selection unit configured to split an irradiated light beam into the plurality of spectral beams of different wavelength regions to acquire a spectral image, the plurality of spectral beams including beams of at least two different wavelengths;
a deriving unit configured to derive a surface property or shape information of the subject from a specified result obtained by specifying, by the deriving unit, an irradiation region irradiated with each of the spectral beams on the subject based on a mixing ratio of the spectral beams and received light intensity of each of the spectral beams included in the spectral image; and
an irradiation unit that includes:
a light source; and
an optical element configured to reduce an angle of divergence of the light beam emitted from the light source,
the optical element is a lens,
the light source is disposed in a focal point region of the lens, and
the lens causes the light beam emitted from the light source to be quasi-parallel light.
2. The optical device according to claim 1 , wherein
the light selection unit splits the irradiated light beam into the spectral beams as a first spectral beam of a first wavelength region and a second spectral beam of a second wavelength region,
the imaging element captures the spectral image of at least the split first wavelength region and the split second wavelength region, and
the deriving unit derives the surface property or the shape information from the specified result obtained by specifying an irradiation region irradiated with each of the first spectral beam and the second spectral beam on the subject based on first received light intensity of the first wavelength region and second received light intensity of the second wavelength region included in the spectral image.
3. The optical device according to claim 2 , wherein the deriving unit derives the surface property or the shape information from the specified result obtained by specifying a first irradiation region irradiated only with the first spectral beam of the first wavelength region, a second irradiation region irradiated with the first spectral beam and the second spectral beam, and a third irradiation region irradiated only with the second spectral beam, on the subject.
4. The optical device according to claim 2 , wherein the deriving unit derives the surface property or the shape information based on the first received light intensity and the second received light intensity after removing a dark current component.
5. The optical device according to claim 2 , wherein
the light selection unit includes a first wavelength selection region through which the first spectral beam passes, and a second wavelength selection region through which the second spectral beam passes, and
the first wavelength selection region and the second wavelength selection region are disposed at different positions.
6. The optical device according to claim 5 , wherein a size of a light emitting surface of a light source that emits the light beam is substantially the same as a size of the first wavelength selection region through which the first spectral beam passes.
7. The optical device according to claim 5 , wherein a size of a light emitting surface of a light source that emits the light beam is substantially larger than a size of the first wavelength selection region through which the first spectral beam passes.
8. The optical device according to claim 1 , wherein the light source includes a light emitting surface having a finite size.
9. The optical device according to claim 1 , wherein
the optical element is a concave mirror,
the light source is disposed in a focal point region of the concave mirror, and
the concave mirror causes the light beam emitted from the light source to be quasi-parallel light.
10. The optical device according to claim 1 , wherein the light selection unit is a diffraction grating.
11. The optical device according to claim 1 , wherein
the optical element
contains a transparent medium, and
includes a reflective surface having a paraboloid shape or a quasi-paraboloid shape on an outer surface of the transparent medium, and the light source is disposed in a focal point region of the reflective surface.
12. The optical device according to claim 11 , wherein
the optical element includes an incident surface having a planar shape and being opposed to the reflective surface, and
the incident surface is disposed to be opposed to a light emitting surface of the light source.
13. The optical device according to claim 1 , wherein
the light selection unit is disposed between the light source and the lens, and
the lens forms an image of a light beam that passes through the light selection unit, on the subject.
14. An information processing method implemented in an optical device comprising one or more hardware processors configured to function as an imaging sensor and a deriving unit, the method comprising:
capturing, by the imaging sensor, a subject irradiated with a plurality of spectral beams that is split by a light selection unit configured to split an irradiated light beam into the plurality of spectral beams of different wavelength regions to acquire a spectral image, the plurality of spectral beams including beams of at least two different wavelengths; and
deriving, by the deriving unit, a surface property or shape information of the subject from a specified result obtained by specifying an irradiation region irradiated with each of the spectral beams on the subject based on a mixing ratio of the spectral beams and received light intensity of each of the spectral beams included in the spectral image,
wherein
the one or more hardware processors are configured to further function as an irradiation unit that includes:
a light source; and
an optical element configured to reduce an angle of divergence of the light beam emitted from the light source,
the optical element is a lens,
the light source is disposed in a focal point region of the lens, and
the lens causes the light beam emitted from the light source to be quasi-parallel light.
15. A computer program product having a non-transitory computer readable medium including programmed instructions, wherein the instructions, when executed by an optical device comprising one or more hardware processors configured to function as an imaging sensor and a deriving unit, cause the one or more hardware processors to perform:
capturing, by the imaging sensor, a subject irradiated with a plurality of spectral beams that is split by a light selection unit configured to split an irradiated light beam into the plurality of spectral beams of different wavelength regions to acquire a spectral image, the plurality of spectral beams including beams of at least two different wavelengths;
deriving, by the deriving unit, a surface property or shape information of the subject from a specified result obtained by specifying an irradiation region irradiated with each of the spectral beams on the subject based on a mixing ratio of the spectral beams and received light intensity of each of the spectral beams included in the spectral image,
wherein
the one or more hardware processors are configured to further function as an irradiation unit that includes:
a light source; and
an optical element configured to reduce an angle of divergence of
the light beam emitted from the light source, wherein
the optical element is a lens,
the light source is disposed in a focal point region of the lens, and
the lens causes the light beam emitted from the light source to be quasi-parallel light.