| 摘要 |
Processing apparatus for automatically cutting (or otherwise operating on) a filmstrip during advancement thereof into positions precisely related to the cutter by referencing to the transversely oriented center lines, rather than leading or trailing edges, of marks or cuts longitudinally spaced along an edge of the filmstrip. Sensor means having a mark detector and responsive to duration of a first time interval initiated by the mark's leading edge passing the sensing detector and terminated by the mark's trailing edge passing the detector, computes the correct filmstrip feed distance from the true center line of each mark to the associated next stopping point wherein the filmstrip is presented to the cutter. It does so by counting the pulses controlling filmstrip feed rate established by a stepping motor drive, after first dividing the pulse frequency in half during only said first time interval, such count continuing to a preset number selected to be reached after said first time interval.
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