STABILIZING SYSTEM FOR FILM SCANNER

摘要

This disclosure applies to an apparatus for scanning a film having a succession of frames along its length, the apparatus including a film transport for moving the film at a substantially uniform rate past a scanning position, means for electronically scanning the frames at the scanning position, and means for initially registering each frame to be scanned with the scanning beam. There is disclosed an improved system for continuously retaining registration between a particular frame being scanned and the scanning beam. Means are provided for continuously sensing changes in the velocity of the film during scanning of the particular frame and for generating a velocity error signal indicative of said changes. Further means are provided for accumulating values of the velocity error signal to produce a displacement error signal representative of the distance by by which velocity changes have displaced the particular film frame with respect to its initial registration with the scanning beam. Finally, means are provided for continuously correcting the scanning beam position in accordance with the displacement error signal. In a preferred embodiment of the invention, the correcting means includes an auxiliary deflection yoke for the scanning tube, the yoke receiving correction signals from both a dynamic framing circuit and the displacement error circuit.