Stabilizing system for film scanner

Claim 2

In an apparatus for scanning a film having a succession of frames along its length, said apparatus including a film transport for moving said film at a substantially uniform rate past a scanning position, means for scanning said frames with a beam at the scanning position, and means for initially registering each frame to be scanned with the scanning beam, an improved system for continuously maintaining registration between a particular frame being scanned and the scanning beam comprising: means for continuously sensing changes in the velocity of said film during scanning of the particular frame and for generating a velocity error signal indicative of such changes; means for accumulating values of said velocity error signal to produce a displacement error signal representative of the distance by which velocity changes have displaced the particular film frame with respect to its initial registration with the scanning beam; and means for continuously correcting the scanning beam position in accordance with the displacement error signal.

Claim 3

The system in accordance with claim 1 wherein said means for sensing velocity includes: a tachometer which generates an output pulse train having a pulse rate proportional to the velocity of said film; and means for determining changes in the pulse rate output of said tachometer.

Claim 4

The system in accordance with claim 1 wherein said means for accumulating values of said velocity error signal to produce a displacement error signal comprises an integrator.

Claim 5

The system in accordance with claim 3 wherein means are provided for resetting said integrator at the beginning of each new film frame.

Claim 6

The system in accordance with claim 1 wherein said correcting means comprises an auxiliary deflection means for said scanning means, and means for applying said displacement error signal to said auxiliary deflection means.

Claim 7

The system in accordance with claim 5 wherein said means for initially registering each frame to be scanned with the scanning beam compriseS a dynamic framing circuit, the output of said dynamic framing circuit being applied to said auxiliary deflection means.

Claim 8

The system in accordance with claim 2 wherein said film is driven by a capstan to which said tachometer is mechanically coupled.

Claim 9

An electronic film scanning system comprising: a film transport for moving said film at a substantially uniform rate past a scanning position, said film having a succession of data bearing frames and a plurality of synchronization marks along its length; electronic scanning means operative to scan said frames with a scanning beam as said film is conveyed past said scanning position; photodector means for sensing light from said electronic scanning means transmitted by said scanned film frames and for providing an electrical signal in response thereto; video processing means operative in response to said electrical signal to provide an output signal representative of data contained in said scanned film frames; means for sensing said synchronization marks on said film and for providing output synchronization signals indicative thereof; means for providing reference signals at the power line frequency of the system; a dynamic framing circuit operative in response to said film synchronization signals and said reference signals to produce a dynamic framing signal for initially registering each frame to be scanned with the scanning beam; servo control means coupled to said film transport apparatus and operative in response to said film synchronization signals and said reference signals to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency; means for continuously sensing changes in the velocity of said film during scanning of a particular frame and for generating a velocity error signal indicative of such changes; means for accumulating values of said velocity error signal to produce a displacement error signal representative of the distance by which velocity changes have displaced the particular film frame with respect to its initial registration with the scanning beam; and means for continuously correcting the scanning beam position in accordance with the displacement error signal.

Claim 10

An electronic film scanning system comprising: a film transport for moving said film at a substantially uniform rate past a scanning position, said film having a succession of data bearing frames and a plurality of synchronization marks along its length; electronic scanning means operative to scan said frames with a scanning beam as said film is conveyed past said scanning position; photodector means for sensing light from said electronic scanning means transmitted by said scanned film frames and for providing an electrical signal in response thereto; video processing means operative in response to said electrical signal to provide an output signal representative of data contained in said scanned film frames; means for sensing said synchronization marks on said film and for providing output synchronization signals indicative thereof; means for providing reference signals at the power line frequency of the system; a dynamic framing circuit operative in response to said film synchronization signals and said reference signals to produce a dynamic framing signal for initially registering each frame to be scanned with the scanning beam; servo control means coupled to said film transport apparatus and operative in response to said film synchronization signals and said reference signals to cause said film to be moved at a velocity at which said film synchronization pulses are phase-locked to the power line frequency; means for continuously sensing changes in the velocity of said film during scanning of a particular frame and for generating a velocity error signal indicative of such changes; means for accumulating values of said velocity error signal to produce a displacement error signal representative of the distance by which velocity changes have displaced the particular film frame with respect to its initial registration with the scanning beam; and means for continuously correcting the scanning beam position in accordance with the displacement error signal.

Claim 11

The system in accordance with claim 8 wherein said means for sensing velocity includes: a tachometer which generates an output pulse train having a pulse rate proportional to the velocity of said film; and means for determining changes in the pulse rate output of said tachometer.

Claim 12

The system in accordance with claim 8 wherein said means for accumulating values of said velocity error signal to produce a displacement error signal comprises an integrator.

Claim 13

The system in accordance with claim 10 wherein means are provided for resetting said integrator at the beginning of each new film frame.

Claim 14

The system in accordance with claim 8 wherein said correcting means comprises an auxiliary deflection means for said scanning means, and means for applying said dynamic framing signal and said displacement error signal to said auxiliary deflection means.