Optical digitizer

A cursor device (100) is movable manually over a transparent plate (10) beneath which can be disposed a document (20) bearing markings (22) to be traced by an index mark (114) in a projecting arm (112). A cursor device (100) is thereby positioned relative to fluoroscent markings (12) on the transparent plate (10). The fluorescent markings are illuminated by light of one wavelength from a source (122) and a filter (124) in a housing (110) of the cursor device. Fluorescent light thereby stimulated is collected by a lens (126) passed by a filter (128) and received by a charge coupled device sensor (130). When a switch (140) is operated to complete a circuit, the signals from the charge coupled device (130) are passed to a processor (200) which can determine the position and orientation of the cursor device (100) because of the distinctive pattern information in the fluorescent markings (12).