公开(公告)号：JPH0847481A

公开(公告)日：1996-02-20

申请号：JP10877095

申请日：1995-05-02

Applicant: ESSILOR INT

Inventor： SHIYURISUTEIAN DEYUKARUUJIYU ,  RISHIYAARU GURISERU ,  NIKORA GIROODO ,  EREENU SOTSUTOKAASA ,  AREN SHIYANSABOWAARU ,  AAME ADADEI

IPC: A61B3/11 ,  A61B3/113 ,  G02C13/00

Abstract: PURPOSE: To perform automatically an accurate measurement by a selected frame by detecting a center position through an analysis of a luminance gradient within each pupil of a spectacled person, and the position of the horizontal and vertical directional linear lines located in the frame tangential direction based on the analysis of the luminance gradient and an extracted frame contour. CONSTITUTION: A window 45 is defined in a center position of a pupil 45 and at every point of the inside image, a luminance gradient norm is detected, to which a threshold value is applied to detect the reflection center. Further, a smaller processing window 44 is installed, the data is converted into a two- value format and the obtained pixel core is made to be the center of the pupil 45. Making the pupil 45 as a basis, processing windows (the left side 46, right side 48, upper side 49 and lower side 47) are defined and a mapping of the luminance gradient norms is calculated in the inside of each window. The point having a larger gradient norm than the threshold value is selected, the vertical directional tangent lines of the frames 11, 13 and the horizontal directional tangent lines of the frames 16, 17 are obtained, respectively, these contours are converted into the two-value format and an image with an inside and outside contours of the frame 41 is obtained within each window.