Discriminant signal recognition manner null of optical

摘要

PURPOSE: To precisely recognize the discrimination symbols of an optical disk. ;CONSTITUTION: An image of a ring-shaped mirror surface part given the discrimination symbols is picked up, the ring-shape image is transformed into an XY orthogonal coordinate system, and a discrimination symbol image 101 is cut. Main axes of inertia passing the centers of gravity of respective images are found and the center value of the tilt values of the respective main axes is calculated. A straight line crossing an array axis at angle ϕ obtained by subtracting angle θ, that the center value indicates, from 90° is regarded as an initial projection axis, which is rotated at a specific angle pitch to calculate the image lengths of the discrimination symbol array projected on the projection axis for every angle. The minimum image length among the calculated image lengths of the discrimination symbol array is detected, and the angle ϕa at this time is subtracted from 90° to obtain the tilt angle θa of the discrimination symbol image. The symbols are normalized into corresponding model symbols according to the tilt angle θa and the size of the discrimination symbol image, and the normalized image is compared with the model symbols to recognize whether or not the degree of matching is within a predetermined permissible range.;COPYRIGHT: (C)1996,JPO