Film scanner

Claim 2

A control device for obtaining a still picture from an apparatus in which a video film is scanned by a flying spot scanner having a vertical deflection device and the video film has a plurality of luminance signal recorded frames and frames on which color signals are recorded together which pilot signals, each frame being separated from the others by a frame margin at a prescribed pitch, and a pair of the luminance signal recorded frame and color signal recorded frame being scanned simultaneously, said control device comprising: a frame margin signal detector for obtaining a frame margin signal corresponding to a frame margin from a picture signal produced by said scanning by detecting the lack of said pilot signal recorded on the frame margin; and a control circuit which comprises means for detecting a phase difference between the phase of a vertical synchronizing pulse of said vertical deflection device and that of the frame margin signal to produce a control signal the amplitude of which is proportional to said phase difference, and means for supplying the control signal as a DC bias voltage to said vertical deflection device so as to displace vertically the position of the raster formed by said scanning and to bring the position into coincidence with that of the pair of frames.

Claim 3

A control device for obtaining a still picture from an apparatus in which a video film is scanned by a flying spot scanner having a vertical deflection device and the video film has a plurality of frames on which picture signals are recorded, each frame being separated from the others by a frame margin at a prescribed pitch, said control device comprising: a frame margin signal detector for obtaining a frame margin signal corresponding to a frame margin from a picture signal produced by said scanning; and a control circuit supplied with said frame margin signal for producing a control signal to control said vertical deflection device so as to displace vertically the position of the raster formed by said scanning and to bring the position into coincidence with that of a frame, said control circuit comprising: a positive slope bootstrap generating a positive slope saw tooth-form wave in synchronism with the time period when a vertical synchronizing pulse of the vertical deflection device of the flying spot scanner is supplied; frame margin signal gating means supplied with the vertical synchronizing pulse and frame margin signal to extract one frame margin signal when the phase difference occurs between the vertical synchronizing pulse and the frame margin signal; a comparator supplied with the positive slope saw tooth-form wave and the control signal to produce a first output pulse having a width corresponding to a level difference between the positive slope saw tooth-form wave and the control signal; a negative slope bootstrap supplied with the first output pulse to generate a negative slope tooth wave falling in synchronism with the time period when the first output pulse falls; sampling and holding means supplied with the saw tooth-form wave from the negative slope bootstrap and the margin signal extracted by the frame margin signal extraction means to sample and hold the voltage of the negative slope saw tooth-form wave in the time period when the extracted frame margin signal is supplied from the frame margin signal extraction means; and means for supplying the sampled and held voltage to the comparator as one of the comparing input and to the vertical deflection device as the control signal or a DC bias voltage for bringing the position of the raster into coincidence with that of a frame.

Claim 4

A control device for obtaining a still picture from an apparatus in which a video film is scanned by a flying spot scanner having a vertical deflection device and the video film has a plurality of frames on which picture signals are recorded, each frame being separated from the others by a frame margin at a prescribed pitch, said control device comprising: a frame margin signal detector for obtaining a frame margin signal corresponding to a frame margin from a picture signal produced by said scanning; and a control circuit supplied with said frame margin signal for producing a control signal to control said vertical deflection device so as to displace vertically the position of the raster formed by said scanning and to bring the position into coincidence with that of a frame, said control circuit comprising: a positive slope bootstrap generating a positive slope saw tooth-form wave in synchronism with the time period when a vertical synchronizing pulse of the vertical deflection device of the flying spot scanner is supplied; frame margin signal gating means supplied with the vertical synchronizing pulse and frame margin signal to extract one frame margin signal when the phase difference occurs between the vertical synchronizing pulse and the frame margin signal; a comparator supplied with the positive slope saw tooth-form wave and the control signal to produce a first output pulse having a width corresponding to a level difference between the positive slope saw tooth-form wave and the control signal; a negative slope bootstrap supplied with the first output pulse to generate a negative slope tooth wave falling in synchronism with the time period when the first output pulse falls; sampling and holding means supplied with the saw tooth-form wave from the negative slope bootstrap and the margin signal extracted by the frame margin signal extraction means to sample and hold the voltage of the negative slope saw tooth-form wave in the time period when the extracted frame margin signal is supplied from the frame margin signal extraction means; and means for supplying the sampled and held voltage to the comparator as one of the comparing input and to the vertical deflection device as the control signal or a DC bias voltage for bringing the position of the raster into coincidence with that of a frame.

Claim 5

A control device according to claim 2 wherein the frame margin signal extraction means comprises: a first monostable multi-vibrator supplied with the vertical synchronizing pulse to produce a second pulse which has a pulse width wider than n times but narrower than n + 1 times of the period of said vertical synchronizing pulse and rises in synchronism with the vertical synchronizing pulse; a second monostable multi-vibrator supplied with the second pulse to produce a third pulse which has a pulse width narrower than one period of the vertical synchronizing pulse and rises in synchronism with the falling time period of the second pulse; and an AND gate supplied with the frame margin signal and the third pulse to emit the one frame margin signal.

Claim 6

A control device according to claim 2 wherein the sampling and holding means comprises a first sampling and holding unit coupled to the negative slope bootstrap and to the frame margin signal extraction means for sampling and holding the voltage of the negative slope saw tooth-form wave in the time period when the extracted frame margin signal is supplied from the frame margin signal extraction means to produce a control voltage; and a second sampling and holding unit supplied with the control voltage and the vertical synchronizing pulse for sampling and holding the control voltage and giving the control voltage as the control signal from the time when the vertical synchronizing pulse is generated immediately after the extracted frame margin signal is generated.

Claim 7

A control device according to claim 2 wherein the video film has a plurality of luminance signal recorded frames and frames on which color signals are recorded together with pilot signals, and the frame margin signal detector detects the frame margin signal corresponding to a frame margin from the picture signal by detecting the lack of the pilot signal recorded on the frame margin.