US 2011/0032481 A1Published application

Fundus camera

AssigneeCanon Kabushiki Kaisha

InventorsKoji Uchida, Satoshi Aikawa, Yasuhiro Dobashi

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Abstract

When a bright spot image A received by an imaging unit is extracted, in step S1, a light emitting surface P of an operational distance index is minutely moved back and forth in an optical axis direction of an imaging optical system toward a cornea. In step S2, bright spots are extracted at a center and maximum positions in back and forth directions of the reciprocation movement. In steps S3 to S5, a size of the bright spot image A at each position is determined, and it is determined whether to move an optical unit forward or backward, or to stop the optical unit based on a relationship between a position of the light emitting surface P and the size of the bright spot image A. In step S5, when it is determined that the optical unit is moved to a proper position, a fundus camera enters into a shooting standby state. In step S8, shooting is performed by pressing a shooting switch.

Claims4

Dependent claims

A fundus camera comprising:

an illumination optical system configured to project a ring-shaped illumination light on a pupil of a subject's eye;
an imaging optical system configured to form a fundus image of the illumination light from a fundus on an imaging plane via an objective lens;
an index projection unit configured to project an operation distance index on a cornea of the subject's eye via the objective lens;
an imaging unit configured to capture a reflection image from the fundus and a reflection image of the operation distance index from the cornea;
a driving unit configured to move the operation distance index in an optical axis direction of the imaging optical system;
an index shape recognition unit configured to recognize an index shape projected on the cornea according to a movement of a light emitting surface of the index projection unit by the driving unit;
and
a detection unit configured to detect operation distances of the illumination optical system and the imaging optical system with respect to the subject's eye based on driving information about the driving unit and an output of the index shape recognition unit.

5 more elements

Dependencies are inferred from the claim text.