The Rank Organisation Plc

Rank Cintel Limited

Digital Projection Limited

Rank Brimar Limited

Eastman-kodak Company

John D Millward

John Gillespie

Roger T Lees

John Wright

Peter W Blaxtan

Brian Wilsher

Ronald Mumford

Ronald W Mumford, Deceased

Kevin D Brown

Peter William Blaxtan

Walter R Godden

A deformable mirror device having a two-dimensional array of mirror elements is driven in such a way to reduce the data rate and remove the need for buffer stores. The mirror elements are loaded row-by-row in response to an n bit video signal in 2,loading operations. Only n rows are loaded in each loading operation, the other rows remaining in their previous conditions, and the loading continues sequentially down the array. The timing of the loading is such that the duration from loading a given row with a first data bit to loading the same row with the next data bit is proportional to the significance of the first data bit.

Deformable mirror device driving circuit and method

A processing system for a spatial light modulator in the form of an array of defomable mirror devices receives a gamma-corrected, video input signal. A de-gamma processor removes all or part of the gamma-correction of the video input signal to match the data to the form of the spatial light modulator.

Spatial light modulators

A spatial light modulator in the form of a deformable mirror device (110) receives from a frame store (116) data which has been formatted by a data formatter (114) subsequent to gamma correction in a ROM look-up table (112). The DMD (110) displays different light levels by being ON for selected periods of a series of durations 4, 8, 16 . . . 1024 varying in proportion to a basic period multiplied by powers of two. The shortest duration 4 for which the DMD can be turned on is a multiple of the basic period, and the series includes additional durations 5, 6 and 7 in the series between the shortest displayable duration 4 and the next power of two 8. Durations 1, 2 and 3 of less than the shortest displayable duration can be displayed by adjusting the turn-on time of a proportion of the adjacent mirrors. The longest duration for which the mirror can be turned on can be employed twice.

A processing system for a spatial light modulator in the form of an array of deformable mirror devices receives a gamma-corrected, color component, video input signal. The input signal is converted to pixel data which is then converted to RGB data. A de-gamma processor removes all or part of the gamma-correction of the pixel data to match the data to the form of the spatial light modulator.

In a high definition flying spot telecine, noise from photomultiplier tubes and afterglow correctors reaches unacceptable levels at high frequencies. The circuit illustrated applied a conventional gamma correction to low frequency components (at 32) but applies a non-linear characteristic to the high frequency components (at 36). The characteristic is chosen to provide the optimum noise performance for positive or negative film. The two parts of the signal are then recombined by adders 40. High frequency processing is carried out on a multiplex of the R, G and B components to reduce complexity (at 16).

Noise reduction in video signals

A continuous-motion flying-spot telecine has twin objective lenses (13,14) which provide beams to scan two adjacent film frames simultaneously. Two sets of light detectors (16,17) are provided, one for each frame being scanned. The detector outputs are applied to a multiple frame store (23; FIG. 2). The scans can take place at half the normal speed, while a conventional rate signal is read out of the store. Problems caused at high frequencies as a result of afterglow on the CRT (10) can thereby be substantially reduced.

Telecines with simultaneous scanning of a plurality of frames

Two photomultipliers (14,16) are arranged one on either side of a CRT (10) primary optical axis adjacent the imaging lens. High frequency components of the detected CRT brightness signal from the two photomultipliers are applied to the 'gate' 32. When the signals are equal, one or other of the signals will be selected by the 'gate'. When the signals are unequal, the lower one will be rejected. Thus signals caused by faceplate (22) dirt are eliminated, since they appear displaced in time from the photomultipliers, due to the spacing of the dirt from the scanning beam and the spacing of the photomultipliers. Phosphor grain and blemish signals occur at the outputs of the photomultipliers simultaneously and are allowed through the 'gate' to provide correction and attenuation of these unwanted signals.

Flying spot scanner burn corrector with dual photomultiplier sampling

A film scanner operable according to dual line standards includes red, green, and blue linear array sensors separated by a line spacing that constitutes substantially integral first and second multiples of the line spacings of the respective line standards. More particularly, in 1125 and 1250 line television standards, the linear arrays are spaced such that the distance is substantially equivalent to 9 lines of the 1125 line standard and 10 lines of the 1250 line standard. The output signal from each linear array is registered to the same line for each standard by inserting separable sets of line delays into the signal paths from two of the linear arrays. The separable delays correspond to the first and second multiples of the respective standards. By switching between the respective sets of delays, an output signal is developed for a selected line standard.

Linear film scanner operable at different line rates

A clamping circuit clamps a threshold of an analog to digital converter (ADC) to a signal level just below the black level of a television signal.

Clamping circuit for an analog to digital converter

This invention concerns a continuous motion flying spot telecine apparatus of the kind comprising a cathode ray tube for effecting flying spot line-by-line scanning of each frame of a film during its motion through a scanning station, opto-electronic converter means for producing from the scanning of each film frame an analogue signal comprising a plurality of lines of which at least a part of each (the active part) contains picture information, an analogue-to-digital converter for sampling the analogue signal at a predetermined clock frequency, a filter for limiting the bandwidth of the analogue signal prior to sampling to avoid interference between the clock frequency and high frequencies in the analogue signal, a store for storing digital signals produced by the sampling, and means for reading out the stored digital signals in a predetermined sequence and at a predetermined rate. In order to permit scanning of different format films or only part of the film frame height without burning the c.r.t., the apparatus further comprises means for selectively changing the line frequency of scanning between at least two values. In order to avoid changing the clock frequency when changing the line frequency, which would necessitate the use of switchable filters, means are provided for controlling the horizontal deflection speed of the flying spot in such manner that for either line scanning frequency the time taken to derive the active part of each line of the analogue signal corresponds to the same number of clock signals in each case. Preferably the last mentioned means comprises means for changing the horizontal scan amplitude of the flying spot in inverse proportion to the change in line scanning frequency.

Continuous motion flying spot telecine

Apparatus for generating color television signals from photographic film by means of a flying spot scanner incorporating a cathode ray tube is provided with a circuit for compensating for differential variations across the color spectrum introduced by variations in the intensity of the scanning beam due to variations in the phosphor, solarization and burning effects on the tube screen, this circuit comprising a photodetector sensitive to the varying intensity scanning beam and feeding a circuit for generating an overall signal representing the variations, selected proportions of this overall compensation signal being used to control respective color channels so that each channel receives a different amount of compensation to compensate for differences in the effects causing such variation across the spectrum of light in the scanning light beam.

CRT film scanner with compensation for local brightness variations of

Apparatus for producing television picture signals from motion picture film by scanning the film horizontally at a scanning station while transporting the film continuously past the scanning station is provided with means for accommodating different film sizes, transport speeds and film format by changing the frequency of the horizontal scan while performing a predetermined number of horizontal line scans in respect of each frame of the film; the line scan signals are stored in a memory, and the memory read to produce a plurality of television picture fields at a different frequency from that at which scanning takes place. The frequency at which the television picture fields are generated is higher than that at which the line scan is effected so that the two are made temporally compatible by repeating certain television fields in order to 'fill-in' for spare time.

Television film scanner

The invention concerns a flying spot telecine apparatus wherein the film is driven at constant speed with a film frame rate which is not exactly half the television field frequency, for example at 24 frames per second where the field frequency is 60 fields per second. To avoid registration problems only one scan of each film frame is made, preferably a sequential scan, and the video processing circuits comprise a storage arrangement into and from which picture information derived from the said one scan is stored and extracted in a desired sequence for producing the necessary number of fields for a complete television signal. To simplify the organisation of the storage arrangement, particularly where the vertical amplitude is adjustable to allow for different film formats, the apparatus comprises means for generating synchronising signals at the desired film frame rate, these signals then being used to synchronise not only the motion of the film but also the vertical deflection of the flying spot and the operation of the storage arrangement.

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Hitchin, United Kingdom

John D Millward