DRAWING REFERENCE ANGLE RECOGNITION DEVICE AND METHOD, COMPUTER PROGRAM AND DISK DEVICE

摘要

A drawing reference angle recognition device (38) is provided with a pulse signal producing means (38), an angle position identification means (38), and a drawing reference angle recognition means (38). An optical disk (50) has a data recording surface (51) and a label surface (52) that are disposed opposite each other and a center hole that passes through the center of each of the data recording surface and the label surface. Unique information is recorded at least in a part of the concentric circular region (58a) around the center hole on the label surface of the optical disk (50). When a visible image is drawn on the label surface, the pulse signal producing means (38) produces a pulse signal in accordance with a part of the specific information, the angle position identification means (38) identifies the present angle position on the label surface on the basis of the pattern of the produced pulse signal, and the drawing reference angle recognition means (38) recognizes a predetermined drawing reference angle on the basis of the identified present angle position.