| 摘要 |
A detection apparatus for detecting perforation holes (3) of a cinematographic film (1) comprises at least one light source (6, 6', 6"), at least one scanning sensor (7, 7', 7"), which is arranged so as to receive light (8) emitted by the light source (6, 6', 6") after interaction with a perforation zone of the film (1), and an evaluation circuit (13, 14; 13, 13', 14, 16; 13", 14") for detecting, by means of an output signal (L) of the scanning sensor (7, 7', 7"), when an edge of a perforation hole (3) passes through between light source (6, 6', 6") and scanning sensor (7, 7', 7"). The light source (6, 6', 6") emits light which is polarized with a first polarization and the scanning sensor (7, 7', 7") is sensitive selectively to light with a second polarization.
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