| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and apparatus for extracting a pupillary margin, which is capable of accurately and easily measuring the outer rim of a pupil, and a pupillary margin extraction program. SOLUTION: A pupil diameter computing section 14 discriminates the pupillary portion from its surrounding by comparing a signal level of every picture element on a scanning signal line of a black and white shaded image of an eyeball taken by a CCD camera 13 and a threshold value and computes the diameter of the pupil. A control section 2 outputs a threshold setting signal to set a threshold on the basis of the diameter of the pupil inputted from the pupil diameter computing section 14, and a threshold setting section 3 outputs a threshold set in accordance with the threshold setting signal to the pupil diameter computing section 14. The control section 2 outputs a threshold setting signal continuously varying the threshold to the threshold setting section 3 and captures the result of computation of a pupil diameter from the pupil diameter computation section 14 every time when the threshold setting section 3 varies the threshold. An area of a threshold in which the pupil diameter becomes nearly constant is obtained and the threshold is set at a value within the area. |
