| 摘要 |
PURPOSE:To improve yield by obtaining the distribution of the diameter ratio of the core to clad in the longitudinal direction of a starting preform by picture processing and using the part within the control values as the effective part. CONSTITUTION:White parallel beams 30 are injected from behind the starting preform 10 of an optical fiber to be measured. The beams are two-dimensionally inputted to an electronic computer 34 by using a TV camera 32 (e.g. CCD camera). The inputted pictures are analyzed by the computer to recognize the preform and as the distribution of brightness in the radial direction of the preform 10. The (a) in the brightness pattern is the boundary point between the clad and air, and the (b) is the boundary point between the core and clad. A certain threshold is imparted to the brightness data by the four points A, B, C and D shown in the figure, and the data are binarized to detect the boundary points (a) and (b) as the edge. The (a-a) and (b-b) distances are then digitized to obtain the diameter ratio of the core to clad at an optional point in the preform. The part within the specified values is found to be the effective part. |
