Method and apparatus for film weave correction
US4104680A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 24, 1977 |
| Grant date | Aug 1, 1978 |
| Priority date | — |
| Expiry date | Jan 24, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/843
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for film weave correction is disclosed in connection with a moving beam-type recorder or flying spot scanner device having a continuous-motion film drive in which the film is edge-guided rather than sprocket hole-guided as during playback. The film weave correction apparatus causes the beam to sweep, at least once for each frame being scanned, horizontally across a sprocket hole defined in the film adjacent to the frame. A detector behind the film detects the beams's crossing of the sprocket hole edge. The apparatus compares the time of occurrence of this edge crossing with a reference time and generates therefrom a film weave correction signal. This signal is applied to the horizontal deflection circuitry of the device and causes the beam to be shifted in such a way that the horizontal position of each scanned frame remains constant with respect to the position of the adjacent sprocket hole rather than with respect to the film edge or film guide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.