| 摘要 |
PURPOSE:To eliminate the occurrence of various measurement errors and nonuniformity even when an apparatus is used by an unskilled person, by a construction wherein boundary coordinate values of a projected image are taken-in photoelectrically. CONSTITUTION:Conductors 50X and 50Y are provided in the shape of a lattice in the directions X and Y respectively on a screen 5, and each conductor is scanned by a scanning means 40. The means 40 repeats scanning in the directions X and Y alternately, and an X coordinate value counter 41 and a Y coordinate value counter 43 count an X coordinate value and a Y coordinate value respectively and output them to a cursor position coordinate detector 44. A cursor 8 being provided with a photoelectric conversion element, the detector 44 stores the contents of the counter 41 and the counter 43 on the occasion when a photoelectrically converted output signal of the cursor 8 is inverted in phase. An edge position coordinates detector 45 receives the stored coordinate values of the detector 44 as inputs and stores the stored coordinate values in the case when a read signal is outputted from an edge sensor 46. According to this apparatus, a glass scale and a magnifier are dispensed with, and even an unskilled person can execute efficient measurement.
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