GB1351660A - Flying spot film scanner - Google Patents

Abstract

1351660 Television RANK ORGANISATION Ltd 25 Oct 1972 [27 Oct 1971] 49890/71 Heading H4F In an intermittent motion flying spot film scanner in which film pull-down is effected during a period of time between successive field scans which is longer than the field blanking interval and in which each film frame is scanned over at least two television fields, the first field scan of each film frame is delayed by an amount not exceeding the field blanking interval to allow the pull-down to be completed. As particularly described, the sawtooth waveforms from a field scan generator controlling the scanner are selectively delayed by a switching arrangement S 1 , S 2 , and a one millisecond delay T, Fig. 1, but the field sync. pulses may be delayed instead. A complementary switched delay arrangement acts on the video signals produced by the scanner to produce evenly spaced field scans again, Fig. 2 (not shown). In a colour film scanner, three of the latter arrangements may act on the colour video signals but preferably the colour signals are encoded (PAL, NTSC) and passed through a single arrangement. Since the delay in the arrangement of Fig. 1, is used when the complementary video signal arrangement does not introduce a delay and vice versa, a single delay may be incorporated in a switching system arranged to provide both functions, Fig. 3 (not shown). Details of operation are given both for 50 and 60 fields per second systems, i.e. two television fields per film frame, or alternately two and three fields per frame.