| US 7,489,333 B2 | ||
| Ophthalmologic image pickup apparatus | ||
| Yasuhiro Dobashi, Tochigi (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Jun. 01, 2004, as Appl. No. 10/858,250. | ||
| Claims priority of application No. 2003-176346 (JP), filed on Jun. 20, 2003. | ||
| Prior Publication US 2004/0263677 A1, Dec. 30, 2004 | ||
| Int. Cl. H04N 3/36 (2006.01) | ||
| U.S. Cl. 348—78 [351/206] | 3 Claims |
| 1. An ophthalmologic image pickup apparatus which picks up an image of a fluorescence of a fluorescent agent in a fundus of
an eye of a person to be examined after injecting the fluorescent agent into a vein of the person, comprising:
an observation illumination light source for illuminating the eye of the person when the eye is observed;
an image pickup illumination light source for illuminating the eye of the person when an image of the eye is picked up;
timer means for measuring an elapsed time from injection of the fluorescent agent into the vein of the person;
image pickup means for picking up the image of the eye;
illuminance detecting means for detecting an illiminance value of the eye from at least one of an image signal from the image
pickup means and an amplifying ratio of the image pickup means; and
calculation means for calculating a predicting formula:
α×β−γ(t−τ) used for predicting a variation of the illuminance value of the eye in accordance with the elapsed time after stopping illumination
of the eye by the observation illumination light source, on a basis of a relation between the elapsed time and the illuminance
value of the eye during observation of the eye, wherein t is the elapsed time, and wherein α, β, γ, and τ are arbitrary constants
obtained from experimental values; and
exposure control means for determining at least one of a light intensity of the image pickup illumination light source and
the amplifying ratio of the image pickup means at a time when the image pickup illumination light source emits after stopping
the illumination of the eye by the observation illumination light source, on a basis of the calculated predicting formula.
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