Method for the automatic correction of errors in image registration during film scanning

Apparatus for television image scanning of perforated motion picture film having a succession of image frames and at least one reference mark associated with each frame, said apparatus comprising:

• (a) servo drive means, including a capstan, for continuously moving said film past an image scanning location;
• (b) scanning means, at said image scanning location, for scanning the image frames of said film and producing video signals in response thereto;
• (c) memory means, having a start input, for temporarily storing video signals;
• (d) means, disposed immediately adjacent said image scanning location, for scanning said reference marks on said film and producing scan output signals in response thereto;
• (e) signal processing means, coupled to receive said scan output signals, for producing frame-start pulses and horizontal position value signals;
• (f) tachometer means, arranged to engage the film perforations, for producing film position signals;
• (g) control and switchover means, coupled to receive said frame-start pulses and said film position signals, for producing vertical control signals, said vertical control signals being supplied to said servo drive means for controlling the film motion speed;
• (h) first delay circuit means, coupled to receive said vertical control signals, for adjusting the film scan line with respect to the start input of said memory means;
• (i) horizontal position control means, coupled to receive said horizontal position value signals, for producing horizontal control signals;
• (j) phase lock circuit means, responsively timed by said frame-start pulses, for producing a frequency signal;
• (k) second delay circuit means having two inputs and being coupled at one input to said horizontal position control means and at the other input to said phase lock circuit means, for producing horizontal frequency signals;
• (l) preamplifier means, coupled to said scanning means and to said second delay circuit means, for amplifying said video signals in synchronism with said horizontal frequency signals;
• (m) video processor means, coupled to said preamplifier means and to said second delay circuit means, for processing the amplified video signals in response to said horizontal frequency signals, said video processor means producing output video signals which are supplied to said memory means,
• whereby video signals may be read from said memory means with horizontal and vertical synchronization in synchronism with studio timing pulses.