Abstract: A film instability compensating system compensates for the effects of film instability in a film gate. The film instability compensation system includes a positional transducer for measuring the position of the film edge relative to a sprocket hole which is maintained in contact with a sprocket tooth by a pressure roller. The positional transducer measures the distance between the film edge and a sprocket hole and then measures deviations from the distance for subsequent sprocket holes to determine a compensation signal. The output of the positional transducer is coupled to a delay unit which delays the signal corresponding to the error at a particular sprocket hole until that sprocket hole reaches the film gate. Signals representative of the cyclic errors caused by the relative lateral displacement of the sprocket holes, are stored in a memory and are applied to a subtractor circuit.

Abstract: To avoid the effect of blemishes in a CRT phosphor of a CRT film scanner a map is produced identifying areas of the phosphor that are blemished. When a line scan traverses a blemish the signal produced by that scan is inhibited and the area of film is rescanned with the film in a different position relative to the scanner.

Abstract: Compensation for phosphor burn in a CRT scanner is achieved by offsetting the scan by half a line spacing on alternate scans when the film is stationary in the scanner. To avoid unpleasant effects the offset scan output is supressed and the previous frame output frozen in the frame store 24. The previous frame is output again from the frame store in place of the offset scan output.Offset scanning is not performed when a control adjustment is made to avoid a juddering effect on the displayed output.

Abstract: A telecine can be adapted to write video signals onto film. The film gate and flying spot scanner are enclosed in a light-tight shield and a four-segment (R, G, B, and clear) color filter wheel is interposed in the optical path between the scanner and the imaging optics. The CRT grid is modulated sequentially by R, G, and B components of the video signals which are preprocessed for shading and color errors. The film may be scanned a number of times under the modulation of each component, and displaced in both X and Y directions to increase resolution. In a preferred embodiment, the scan is displaced by 1/4-pixel for each of four scans to increase horizontal resolution and, for each horizontal displacement, four scans are performed, spaced 1/4-line apart, to increase vertical resolution. Thus, each frame is scanned 16 times per color component, and 48 times in all.

Abstract: In a flying spot telecine including cathode ray tube scanning circuit for generating flying spot and a photodetector for receiving light transmitted by a film strip being scanned by the telecine, a control circuit is provided for causing the CRT scanning circuit to scan an area (18) corresponding to the position of one or more perforations (16) in the film strip (10) being scanned. The output from the photodetector during a scan of the area (18) provides a correction signal for adjusting the video signal level. Preferably, the scan of the area (18) is performed during line blanking or frame blanking periods.

Abstract: An intermittent motion flying spot telecine capable of operating in real time provides an adequate film pull down time to allow the use of pin-registration by including a digital scan corrector (18) and a picture store and sequential-to-interlace converter (19) and by adjusting the CRT scanning circuitry (24). Three measures are employed: (I) the film is scanned with a sequential scanning raster and subsequent sequential-to-interlace conversion is performed, so as to combine two field blanking intervals into one longer one, (II) data is written into the picture store at a faster rate than required for the output and read out at a conventional rate, and (III) a triangular line scanning waveform is employed to allow line flyback time to be removed and the instantaneous line rate increased.

Abstract: A dual range A/D converter includes a gain matching circuit for balancing the upper end of the transfer curves of the level-dependent dual A/D signal paths of the converter so as to control crossover between the paths. One path (high gain path) is provided with signal gain that is a nominal multiple of gain applied to the other path (low gain path). A digital comparator compares the digital code word output of flash A/D converters included in the respective paths, with the output from the high gain path being scaled down to correspond to the output from the low gain path. If a difference is detected, the upper ladder reference of the flash converter in the low gain path is adjusted until the respective gain difference becomes substantially an exact multiple. When this matching is combined with black level correction, which equalizes the lower end of the transfer curves, a fully self-calibrating dual range A/D converter is obtained.

Abstract: A flying spot telecine includes a control processor for generating and storing a MINIMUM GAIN REFERENCE value representing a minimum gain of each of a plurality of PMT sections which detect light transmitted by a film strip that is being scanned by a light spot. The control processor also generates and stores a MAXIMUM GAIN REFERENCE value representing a maximum gain of each of the plurality of PMT sections. A system gain control provides control signals to the plurality of PMT sections to control the voltage applied thereto. During subsequent operation of the telecine to modify control signals provided to each of the plurality of PMT sections dependent upon the stored MINIMUM GAIN REFERENCE and MAXIMUM GAIN REFERENCE value for the respective one of the plurality of PMT sections independently of the control signals provided to the others of the plurality of PMT sections.

Abstract: In a flying spot telecine used to generate video signals by scanning a film, the scanning raster is adjustable angularly relative to the film being scanned. The output video signal hence represents the image on the film but angularly displaced relative to the orientation of the film itself. Using this method angular and rotational picture effects can be generated without the need for expensive computer memory or complex processing of picture information. The method can be applied to produce similar angular and rotational effects in a film writer. In such a system, unexposed film is repeatedly scanned by the flying spot scanner, the beam of which is modulated in turn by R, G and B video signals.

Abstract: In a flying spot telecine used to generate video signals by scanning a film, the scanning raster is adjustable angularly relative to the film being scanned. The output video signal hence represents the image on the film but angularly displaced relative to the orientation of the film itself. Using this method angular and rotational picture effects can be generated without the need for expensive computer memory or complex processing of picture information.