Apparatus and method for identification with reference image and reference distance

An identification method for identifying whether an optical device matches an identification target using an identification system, comprising the steps of:

• with respect to a normal to a first surface of the identification target, an incident side of light is in a negative angular range, and a specular reflection side of the light is in a positive angular range, the first surface of the identification target including a diffraction grating that emits diffracted light in the negative angular range, the identification system including an irradiation unit and an imaging unit on a second surface of the identification system, the second surface being oriented toward the optical device, the second surface is a flat surface,
• the identification method comprising steps comprising:
• applying visible light to a surface of the optical device, wherein a surface of the irradiation unit that applies the visible light is parallel to the second surface of the identification device;
• capturing an image of the surface of the optical device with an angle between the normal of the surface of the optical device and a direction of the diffracted light that is emitted from the surface of the optical device and is entering the imaging unit being a reference angle, the reference angle being formed by the normal to the first surface of the identification target and a direction of the diffracted light that is emitted from the first surface fof the identification target and is entering the imaging unit and being an angle at which the light diffracted by the diffraction grating is capable of being recorded by the imaging unit, the diffracted light enters the imaging unit through a surface that is parallel to the second surface;
• estimating a distance between the surface of the optical device and the imaging unit as an estimated value;
• determining whether the estimated value matches a reference distance, the reference distance being between the first surface of the identification target and the imaging unit and being a distance at which the light diffracted by the diffraction grating is capable of being recorded by the imaging unit;
• determining whether the image captured by the imaging unit matches a reference image, the reference image being formed from the light diffracted by the diffraction grating;
• and
• identifying the optical device as the identification target when conditions are satisfied including a condition that it is determined that the estimated value matches the reference distance and a condition that it is determined that the image captured by the imaging unit matches the reference image, wherein the distance between the irradiation unit and the imaging unit is 5 mm or more and 20 mm or less along the second surface of the identification system and wherein an operating distance between the first surface of the identification target and the imaging unit is 50 mm or more and 200 mm or less.

A non-transitory computer-readable medium comprising an identification program for causing a system including an irradiation unit and an imaging unit to act as an identification system that identifies whether an optical device matches an identification target, comprising:

• with respect to a normal to a first surface of the identification target, an incident side of light is in a negative angular range, and a specular reflection side of the light is in a positive angular range,
• the first surface of the identification target includes a diffraction grating that emits diffracted light in the negative angular range,
• the irradiation unit and the imaging unit are included on a second surface of the apparatus, the second facing being oriented toward the optical device, the second surface being a flat surface,
• the identification program causing the apparatus to execute steps comprising:
• applying visible light to a surface of the optical device, wherein a surface of the irradiation unit that applies the visible light is parallel to the second surface;
• capturing an image of the surface of the optical device with an angle between the normal of the surface of the optical device and a direction of the diffracted light that is emitted from the surface of the optical device and is entering the imaging unit being a reference angle, the reference angle being formed by the normal to the first surface of the identification target and a direction of the diffracted light that is emitted from the first surface of the identification target and is entering the imaging unit and being an angle at which the light diffracted by the diffraction grating is capable of being recorded by the imaging unit, the diffracted light enters the imaging unit through a surface that is parallel to the second surface;
• estimating a distance between the surface of the optical device and the imaging unit as an estimated value;
• determining whether the estimated value matches a reference distance, the reference distance being between the first surface of the identification target and the imaging unit and being a distance at which the light diffracted by the diffraction grating is capable of being recorded by the imaging unit;
• determining whether the image captured by the imaging unit matches a reference image, the reference image being formed from the light diffracted by the diffraction grating;
• and
• identifying the optical device as the identification target when conditions are satisfied including a condition that it is determined that the estimated value matches the reference distance and a condition that it is determined that the image captured by the imaging unit matches the reference image, wherein the distance between the irradiation unit and the imaging unit is 5 mm or more and 20 mm or less along the second surface of the identification system and wherein an operating distance between the first surface of the identification target and the imaging unit is 50 mm or more and 200 mm or less.