Quantel Limited

Faraday Technology Corporation

Alpha Image Limited

Barry D Miles

David Peter Owen

Robert J Long

Phillip Adams

David C Baty

Electrical networks for emulating the response or co-axial transmission

A method and an apparatus for sampling a reference signal so as to generate an error signal indicative of a phase error between an actual sampling phase and a desired sampling phase. The desired sampling phase is displaceable from an optimum sampling phase, so as to facilitate the sampling of an NTSC color burst signal or to effect hue control during sampling of the modulated chroma sub-carrier. The reference signal is sampled at the frequency of said signal and a plurality of said samples are accumulated. After said samples have been accumulated, said accumulation is multiplied by the sine or by the cosine of the phase displacement angle between the optimum sampling phase and the derived sampling phase.

Method and apparatus for sampling a reference signal

A system for creating video images by `drawing` on a touch tablet with a stylus. Addresses designated by the stylus are translated by a computer (16) into addresses in a frame delay store (13). The operator may choose an artists implement, the effect of which is simulated in the image by brush stamp signals representing the distribution power of the implement. Brush stamp signals are provided for a patch of signals round a designated address. During a frame period the brush stamp signals are processed to produce signals representing the effect of overlapping brush stamps for a portion of a line drawn in that period. The store is a frame delay store where the stored signals are continuously recycled. During a cycle of the store signals corresponding to the addresses covered by the brush stamps are sequentially up-dated by combining with incoming video signals in proportions determined by the brush signals. This produces the effect on a screen of a line drawn with the chosen implement.

Video image creation systems combining overlapping stamps in a frame

A system for producing output print-dot data suitable for hard copy printing devices (10). A first framestore (11) stores first intensity-related pixel data at a first resolution, which is converted to first higher resolution print-dot data by a print-dot generator (17,18). A control store (19) stores one-bit control data at the said higher resolution and the output print data is selected from the first print-dot data or from a second source of print dot data in response to the control data. Both sources of print-dot data may be derived from intensity related pixel data generated on an electronic graphic system such as a PAINTBOX (Registered Trade Mark). The high resolution data may also be generated by the system and displayed electronically with full color graphics.

Electronic print-dot generation

A processing circuit which is arranged to operate in three modes. The first mode is to act as a brush processor in video graphics creation combining incoming video signals with stored video signals to produce a graphic signal. The second mode allows an image to be composed from two or more input pictures using stencil signals. The third mode is useful in still picture applications where one frame is to be viewed and the next previewed. Stencil signals allow the operator to cut or fade from one frame to the other.

Video image processing systems

A video movement detector suitable for detecting picture movement and/or noise on a video signal. A first detector detects differences frame by frame on a portion of picture having a plurality of picture points from more than one line. A second detector detects differences frame by frame from a portion of picture having a plurality of picture points from the same line, and a third detector detects differences frame by frame from a portion of a picture comprising a single picture point. Movement is determined to have taken place when the differences measured by the respective detectors exceed predetermined thresholds. The selected thresholds are typically of different values to provide the capability of distinguishing between noise and movement in varying conditions. The movement detection arrangement can be used to control picture manipulation during processing such as in a noise reduction system, standards conversion or picture size change arrangements.

Video picture processing including movement detection

A velocity compensator arrangement for a synchronizer which includes an input oscillator, main store and output oscillator in which the controlling voltage of the input oscillator is sampled during one line and compared with the controlling voltage for the next line. Any voltage difference is converted into digital form and this is stored in a digital store until the corresponding line is read out from the main store. The phase of the output oscillator is shifted in dependence on the voltage difference held in the store. This store may comprise part of the main store or be an independent store.

Video synchronizer with velocity compensation

A video time base corrector includes an analogue-to-digital converter for converting an incoming analogue video signal to digital form, and a store for receiving successive lines of video information in digital form from the converter. A digital-to-analogue converter converts the digital output signal from the store into analogue form. Control means are provided for writing-in and reading out the digital information into and from the store. A triggered voltage controlled input oscillator determines the rate of conversion of the analogue signal to digital form and the rate of writing into the store. An output oscillator controls the rate of reading out of the digital information from the store and the rate of conversion into analogue form. Sampling means sample the input oscillator controlling voltage during one line and measuring means detect any voltage difference in the controlling voltage during successive lines. Holding means retain the detected voltage difference between successive lines and this is applied to phase shifter means for shifting the phase of the output oscillator in dependance on the voltage difference held by the holding means.

Time base corrector

A generator system for producing advanced mixed synchronizing pulses and comprising an equalizing pulse detector capable of detecting the presence of a first equalizing pulse of a mixed synchronizing pulse received at its input and a broad pulse generator. Delay means are provided for inhibiting the generation of the broad pulses for a preset period after the detection of the first equalizing pulse. The delay period is less than the period between the first equalizing pulse and the first broad pulse received whereby the broad pulses from the generator are producible in advance of the broad pulses received at the generator input. The generated pulses are added to the original mixed sync. pulse train whereby a mixed sync. pulse train is producible at the generator system output in which the original broad pulses and some of the equalizing pulses are replaced by the generated broad pulses.

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Newbury, United Kingdom

Barry D Miles