Abstract: The image composition system includes framestores 30, 31 for receiving information from first and second picture sources. A processor 33 provides the composed image by using information from these sources. The processor is controlled by picture shape information made available from a third framestore 32. This shape information may be provided by a camera 26 receiving an image of a silhouette for example or the shape can be manually generated via a touch tablet 38. The instantaneous value of the shape controls the blending of the pictures such that portions of the picture can be taken from a scene and inserted without noticeable degredation. Manipulation of the position, orientation or size of the inserted picture portion for example can also be effected.

Abstract: A stylus device for use in a videographic apparatus, includes a housing with a projecting stylus. In operation, pressure changes cause movement of the resiliently mounted stylus. This carries a magnet which co-operates with a Hall Effect transducer such that the pressure variation is converted into signal changes by the transducer. A moveable carrier allows the transducer to be moved to adjust the preload pressure in the stylus together with the preload out-put of the transducer.

Abstract: A processing system includes a processor 10 and frame store 11. Both the frame store and processor are under the control of address mechanism 12. The addressing mechanism 12 can generate the desired information from address information which is only provided on some of the store locations and which is only updated over more than one frame period. The mechanism includes spatial and temporal address interpolators to effect this operation.

Abstract: A video signal processor for effecting frame rate conversion. A number of framestores connected in series receive incoming video signals under the control of a first generator and are available from the respective fieldstores under the control of a second generator. The presence of respective one line delays allow two adjacent lines from the same field to be available for use by respective multipliers and thence to an adder. A comparator determines if significant movement is present and modifies co-efficients to the multipliers, made available from a co-efficient control so as to allow a single field to pass to the output if desired.

Abstract: The disclosed system and method allow an artist to blend a desired color from available source (i.e., menu) colors and use the resulting blend color at the desired part of the picture and/or store the blend color for future use as a source color. A palette mixing area and a menu of colors can be displayed on a video screen. A signal defining a selected source color is generated when the artist touches with a stylus an area on a touch tablet which corresponds to the screen display of the selected color. When the stylus then touches the part of the touch tablet corresponding to a selected part of the palette mixing area on the screen, the screen shows at that selected area a blend of any color preexisting there and the selected color. A signal defining the blend color can be stored for future use as a source color. The proportions of the two colors in a blend can be controlled by stylus pressure, number of overstrokes and/or stylus dwell time.

Abstract: A video image creation system provides intensity or color data from one or more stores. The image is created under manual control which effectively defines the coordinates of the artist's implement at any given time.A processor receives the incoming image data and previously derived data from a frame store and modifies this data in dependence on a parameter available from another store. The created image can be viewed on a monitor.The parameter controls the contribution made from any adjacent, previously created, parts of the image and can be such as to simulate different pencil or brush shapes or types of paint for example. Additional facilities such as pressure sensitivity and blurring can be provided.

Abstract: A multiple picture image manipulation system for receiving video information related to a plurality of pictures. A designation control designates the output priority order of the respective pictures. A priority coder detects picture information having the higher priority present for producing a control signal indicating this detected priority, and a selector controlled by this signal outputs information from the plurality of pictures so as to select from only a single picture designated with the higher priority present where picture overlap occurs to provide a multiple picture image in which one of said pictures masks another without overlap degradation when displayed. Additional facilities for cross-fading following a change in the picture priority may also be included which pictures can have an associated border if desired.

Abstract: 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.

Abstract: A chroma key measuring system for determining the area of chroma key within a television picture. The position of each side of the key area is measured line by line to determine a maximum and minimum value, and top and bottom of the area is determined from the upper and lower cross over positions of the sides to provide an output indicative of the size and position of the key area. This output can be used as a control signal for further equipment generating a further picture which is to be inserted in the key area so that the size and position of the inserted picture is adjusted to correspond to the calculated parameters.

Abstract: A system and method for compensating for drop outs present at the tape output of a video tape recorder. Compensation is effected by storing video information for at least one field in a field or frame store and detecting the presence of drop outs. When a drop out is detected the writing in of information to the store is inhibited so that the previously stored data is retained. The compensator may include additional storage for storing data indicative of drop out and frame identification so as to control processing at the store output to maintain correct color sub-carrier phase.

Abstract: A video control arrangement for a synchronizer includes a joystick for moving the T.V. picture in at least one plane to a first selected position. A memory arrangement receives and holds information on the location of the first preselected position which can be recalled later to effect automatic movement of the T.V. picture to this preselected position.

Abstract: A video compressor including an analogue to digital converter for sampling an incoming video signal, a store for holding the sampled signal and a digital to analogue converter for reconverting the stored signal into analogue form.A processor is provided for processing the video signal prior to conversion and storage. The processor includes means for reducing the frequency of a line locked sub-carrier waveform and means for maintaining the correct subcarrier line to line phasing whereby when predetermined ones of the samples are retained by the store, a compressed picture having correct phase and subcarrier relationships is provided.

Abstract: 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.

Abstract: 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.

Abstract: A high speed digital information storage system comprising means for providing n successive samples of serial data on n parallel paths coincident in time. Holding means are provided for holding the samples prior to storage. Storage means store the serial data samples and means are provided which skew and remultiplex the serial data at the output of the storage means when removed from the storage means. Clocking means provide clocking pulses to the holding means and the storage means in unison at one nth of the serial data rate.

Abstract: A method of storing digital information comprising applying the information in the form of coded pulses to an input of at least one register by means of clock pulses and shifting the information within the register by additional clock pulses between writing in and reading out the information. The number of additional pulses applied is equal to the difference between the total register length and the number of clock pulses used to enter the coded pulses, whereby the information within the register is available to be read out on application of read out pulses to the register.

Abstract: A free standing component cabinet capable of being rapidly reconverted to allow rack mounting thereof. The cabinet comprises a frame normally used for rack mounting which frame includes front rear and side walls and front mounting flanges having holes therein for securing the frame when mounted in a rack. Detachable top and bottom panels enclose the frame. Detachable face plates are mounted one on each of the side walls and abut the front mounting flange. These face plates provide an air duct to allow air to pass from the frame interior to the rear of the cabinet via a vent hole provided in at least one of the side plates. A fan assists the passage of air through the cabinet.

Abstract: A sub carrier phase shifting circuit for use in digital television equipment comprising at least two monostable multivibrators connected in cascade. The sub carrier signal is applied to the first multivibrator. Adjusting means are connected to the control inputs of each multivibrator for adjusting the monostable period of the multivibrators. On receipt of an edge of a sub carrier wave the first multivibrator is driven from a first state to a second state whereby the first multivibrator effects a change of state at its output. The first multivibrator resets to its first state after the monostable period determined by the adjusting means to give an output delayed in relation to the edge of the sub carrier wave. The delayed output causes the second multivibrator to be driven from one state to its other whereby the second multivibrator effects a change of state at its output.

Abstract: A time base corrector for retiming the chrominance and luminance components of a non-phased television picture signal from a PAL video tape recorder to local reference syncs. The time base corrector comprises digital storage means and an analogue-to-digital converter connected to an input of the storage means. A digital-to-analogue converter is connected to the output of the storage means. "Read" clock pulse generating means are connected with the digital-to-analogue converter and the storage means to trigger the same. A first phase comparator means is operative to compare local horizontal reference signals with horizontal pulses from a divider connected to the "Read" clock pulse means for controlling the output frequency of the same.

Abstract: 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.