Disturbance light identifying apparatus, disturbance light separating apparatus, disturbance light identifying method, and disturbance light separating method

A disturbance light separating apparatus comprising:

• a modulated light irradiation unit which is a light source that irradiates an optical system with modulated light, wherein the modulated light is a light of which a light amount changes in relation to time;
• a light receiving unit that receives light exiting the optical system in response to an incidence of the modulated light from the modulated light irradiation unit;
• and
• a controlling unit that controls the modulated light irradiation unit and the light receiving unit, wherein
• while a light beam incident on the light receiving unit after traveling through an optical path exceeding a reference distance determined on a basis of a designed optical path length of the optical system is defined as a disturbance light component, the controlling unit generates disturbance light component separation information used for separating the disturbance light component from the light exiting the optical system, on a basis of a light beam traveling distance obtained from the light exiting the optical system.

A disturbance light separating apparatus comprising:

• a modulated light irradiation unit which is a light source that irradiates an optical system with modulated light, wherein the modulated light is a light of which a light amount changes in relation to time;
• a light receiving unit that receives light exiting the optical system in response to an incidence of the modulated light from the modulated light irradiation unit;
• a shutter provided between the optical system and the light receiving unit;
• and
• a controlling unit that controls the modulated light irradiation unit, the light receiving unit, and the shutter wherein
• while a light beam incident on the light receiving unit after traveling through an optical path exceeding a reference distance determined on a basis of a designed optical path length of the optical system is defined as a disturbance light component, the controlling unit controls opening and closing of the shutter in such a manner that the shutter is open only during such a time period when the disturbance light component out of the light exiting the optical system does not reach the shutter.

A disturbance light identifying method comprising:

• a step of irradiating, with a modulated light irradiation unit, an optical system with modulated light, wherein the modulated light irradiation unit is a light source, and wherein the modulated light is a light of which a light amount changes in relation to time;
• a step of obtaining information about a light beam traveling distance from light exiting the optical system in response to an incidence of the modulated light;
• and
• a step of identifying, while a light beam incident on a light receiving unit after traveling through an optical path exceeding a reference distance determined on a basis of a designed optical path length of the optical system is defined as a disturbance light component, whether or not the light exiting the optical system contains the disturbance light component, on a basis of the light beam traveling distance obtained from the light exiting the optical system.

A disturbance light separating method comprising:

• a step of irradiating, with a modulated light irradiation unit, an optical system with modulated light, wherein the modulated light irradiation unit is a light source, and wherein the modulated light is a light of which a light amount changes in relation to time;
• a step of obtaining information about a light beam traveling distance from light exiting the optical system in response to an incidence of the modulated light;
• and
• a step of generating disturbance light component separation information, while a light beam incident on a light receiving unit after traveling through an optical path exceeding a reference distance determined on a basis of a designed optical path length of the optical system is defined as a disturbance light component, the disturbance light component separation information being used for separating the disturbance light component from the light exiting the optical system, on a basis of the light beam traveling distance obtained from the light exiting the optical system.