Patent attributes
An eyeglass frame measurement apparatus includes a holding unit; a rotational base and a tracing stylus arranged on the rotational base. Three-dimensional shape of a frame is measured by detecting the movement of the tracing stylus in a radius direction and a warpage direction. Slit place is integrally arranged with the stylus and a light-projection-and-receiving unit that includes a light-emitting portion and a two-dimensional sensor capable of selecting a received pixel is arranged on the base. The two-dimensional sensor includes first and second light-receiving lines not parallel to each other, and includes a first slit not parallel to the first light-receiving line and a second slit not parallel to the second light-receiving line. The movement of the stylus is detected based on a projection position of the first and second slits detected by the first and second light-receiving lines.