POSITIONING METHOD FOR SPHERICAL MATTER

PURPOSE:To perform the accurate positioning of a spherical matter in a short time by scanning almost an entire part of a spherical matter after controlling the position of the spherical matter via an actuator based on the reading signal for a shadow of the spherical matter containing recess parts set regularly that is produced by illumination. CONSTITUTION:A spherical matter 1 like a golf ball, etc. that contains recess parts set regularly is supported by a vacuum chuck 17 which is revolved by a step motor 16 of an actuator 6 for axes Y and X. Then a shadow of the matter 1 is produced by the illumination of an illuminator 2 set in the direction of the axis X. The shadow of the matter 1 is detected optically by a camera 10 and the digital picture signals undergone the photoelectric conversion are used for the eliminating arithmetic and compression of the background data, the emphasis of a bright/dark pattern, etc. via a picture processor 30. Then a point where the processing result obtained by the rotation of an axis Z is maximum is decided as the position of the matter 1. Then the matter 1 is revolved along the axis Y and the positioning actions are repeated at least to three areas different by 90 deg. on the equator. As a result, the entire part of the matter 1 is substantially scanned for positioning the matter 1 accurately in a short time.