Pupil measuring apparatus
AssigneeHamamatsu Photonics K.K.
InventorNaotoshi Hakamata
Life of this patent
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Abstract
A pupil measuring apparatus comprises a mark 1d placed in a space where a background is observable from the two eyes E; a mark moving device 1e for moving the mark 1d between the two eyes E and the background; an illumination optical system 1g for illuminating the two eyes E from the background side; two cameras A, B for respectively imaging the two pupils PP; calculating means 2a to 2e for calculating areas or diameters of the respective pupils thus imaged, from video signals of the two cameras A, B; and a display 3 for providing an output of a graph of change in the areas or diameters calculated against a position of the mark 1d or a time associated with the position on a single screen.
Claims18
A pupil measuring apparatus comprising:
- a mark moving device for moving a position of a mark in a predetermined region from a reference position, said reference position being set at a position where eyes are to be placed;
- an illumination optical system for illuminating said reference position;
- a first camera imaging said eye placed at said reference position;
- calculating means, on the basis of a video signal from said first camera, for performing the following steps of:
- setting a plurality of horizontal lines on an image pickup surface of said first camera, a video signal corresponding to each horizontal line including high, middle and low levels respectively indicating reflected lights from a white sclera, an iris and a pupil of the relevant eye,
- performing a binarizing operation of the video signal on the basis of a reference level to obtain a pulse where a width of the pulse indicates a width of a pupil per the horizontal line, the reference level being set between levels respectively corresponding to the reflected lights from the iris and the pupil,
- calculating averages of the widths per a predetermined group of the horizontal lines in a frame,
- determining a maximum among the calculated averages, and
- storing a center position of a width of the pulse yielding said maximum as a horizontal position of the pupil.
A pupil measuring method comprising the steps of:
- moving a position of a mark in a predetermined region from a reference position, said reference position being set at a position where two eyes are to be placed;
- illuminating said reference position;
- imaging said eye placed at said reference position by a first camera;
- performing, on the basis of a video signal from said first camera, the following steps of:
- setting a plurality of horizontal lines on an image pickup surface of said first camera, a video signal corresponding to each horizontal line including high, middle and low levels respectively indicating reflected lights from a white sclera, an iris and a pupil of the relevant eye,
- performing a binarizing operation of the video signal on the basis of a reference level to obtain a pulse where a width of the pulse indicates a width of a pupil per the horizontal line, the reference level being set between levels respectively corresponding to the reflected lights from the iris and the pupil,
- calculating averages of the widths per a predetermined group of the horizontal lines in a frame,
- determining a maximum among the calculated averages, and
- storing a center position of a width of the pulse yielding said maximum as a horizontal position of the pupil.
Dependencies are inferred from the claim text.