Abstract: An electronic graphic system (1) comprises a memory (2) for storing data representing an image and a user operable stylus and touch tablet combination (4) by which the user can select a notional painting implement a color with which to paint and can create data defining positions in the image at which painting is to occur. An address generator (5) is arranged to generate address data identifying addresses in the memory (2) corresponding to the user created position data. The stylus and touch tablet (4) is pressure sensitive and generates a parameter depending on the pressure applied via the stylus by the user. The address generator (5) generates address data at intervals dependent on the instantaneous value of the pressure related parameter. In one embodiment the interval is a distance between identified addresses in the memory (2) and in another embodiment the interval is a period of time. In this way the system simulates an implement having a paint flow rate which is pressure related.

Abstract: A video graphics system in which an effect can be produced in selected portions of a image held in a first store. Image data in the first store relating to a user defined area of interest in the image is copied to a second store and processed in accordance with a user selected function. The area of interest is selected by the user by magnifying and shifting a displayed representation of the image so that the area of interest is displayed and then selecting a locking function which retains parameters associated with the shifting and magnifying of the displayed image. Once the image data relating to the area of interest has been processed it can be painted onto the image held in the first store to produce the desired effect. By processing only the selected area of interest the speed of processing is increased.

Abstract: An electronic graphic system for modifying image pixels includes a framestore 21 and a pipeline brush processor 22. Image pixels are read out of the framestore 21 in batches and applied to an input of the brush processor 22. Other data representing colour shape and pressure of a line drawn by a user on a touch tablet 17 by way of a stylus 18 is also input to the processor 22. As the pixels pass through the processor 22 they are modified by the other data. Batches of modified pixels are written back to the framestore 21. The reading and writing of pixels from the framestore 21 is interleaved with the reading of pixels for display as an image on a monitor 16. The system also includes an arrangement for interpolating stylus pressure to remove visible discontinuities or other changes in the drawn image resulting from significant changes in stylus pressure.

Abstract: A system for creating high resolution video images for later use in printing or the like. The operator draws with a stylus on a touch tablet (28) and video signals are processed to produce a high resolution image corresponding to what is drawn, the signals being stored in a high resolution store (25). While the processing of the signals progresses certain signals are copied to a lower resolution viewing store (26) and these signals read to a display (27) where the image can be viewed by the operator. In one example the store (25) is notionally divided into areas and when the signals representing a stroke drawn by the operator are present in an area the whole area is copied to the viewing store. Typically about four areas need to be copied in a frame period so the stroke drawn by the operator can be seen as he is drawing it. The image on display (27) may be a low resolution version of the whole image or a high resolution version of part of the image.

Abstract: An amplification circuit comprises a detector (15) for detecting transmitted radio signals in the range 0.5 GHz to 20 GHz and a wideband logarithmic video amplifier (WLVA 16). The WLVA is fabricated on an application specific integrated circuit (17) for example with a temperature sensor (20). The output from the temperature sensor is supplied to a second ASIC (24) which samples the temperature signal and supplies compensation signals read from a non-volatile memory device.

Abstract: An electronic graphic system is arranged such that data relating to the black separation of an image is made available for modification independently from other data representing the image. In a preferred embodiment black separation data is written into a monochrome framestore 8 and modifications to the separation can be effected by way of a stylus and touch tablet combination 6 and associated drawing circuitry 16.

Abstract: Video image creation in which a raster-scan monitor displays an image comprising realistic, inherently non-aliased strokes created by combining proportions of the values of: (i) pixels defining a simulated brush moving along the image as an artist moves a pen on a tablet in continuous strokes; and (ii) the values of the pixels in the image that are under the brush at the time. The pixel values resulting from such combining replace the corresponding pixel values in the image so that, after an initial portion of a stroke, the pixel values in the image which are under the brush and therefore will be combined with the brush values comprise pixel values which are the cumulative result of a number of previous such combining operations. Manual pressure on the pen controls the proportions used in such combining operations. As the artist presses harder on the pen, the effect seen on the monitor is that more "paint" is applied.

Abstract: A system for manipulating video image signals, in which digitized composite video signals (i.e. D2 digitally encoded PAL or NTSC) are converted to component video signals (i.e. luminance and color difference signals) allowing selected pixels to be modified. In addition, the unconverted composite video signals are also stored and a key signal is generated which indicates which of the converted (i.e. component) pixels have been modified. An output signal is then produced by combining the manipulated signals and the unmanipulated signals in proportions determined by said key signal.

Abstract: A system in which a characteristic of individual picture points is provided to an accuracy of m binary bits but conveyed by n bits, where n is less than m. The value of a lower order bit of the n bit signal is switched to cause said binary value to represent, for any one picture point, either a value above or a value below the original value. The new values are distributed without order among the picture points with a probability dependent upon the value of the (m-n) lowest order bits of the desired value.

Abstract: 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.

Abstract: A character generator provides video signals representing desired characters which may be held in a store capable of rapid access. The character information is processed in a manipulator to provide a change in shape, size or orientation for example. Field stores receive this manipulated information via switches as well as reference information from a generator. Read out from the respective field stores is arranged to occur when information is not being received by that store. After read out, the information is replaced by reference information, prior to the receipt of further manipulated character information. The reference information may be configured so as to include a portion of previously derived image data.

Abstract: 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.

Abstract: A video processing system which can produce a different shape of output picture than the input. Addresses into which incoming picture points must be written to produce the desired shape changes are stored in a shape store. These addresses can also be manipulated in real time so that the position of the shape they define is changed. For example a Mercator projection of a map can be projected onto a globe and this globe could then be tilted, rotated etc.

Abstract: An electronic graphic system is suitable for use in modifying data defining an initial high resolution image. In the system data relating to a user defined low resolution control image controls the combining of other image data with data defining a low resolution representation of the initial image. In this way the system produces data representing a low resolution combined image which is continously displayed on a display monitor. Once desired modifications have been achieved by the user to the image displayed on the display monitor, the low resolution control image data is converted into a high resolution representation. The high resolution control image is used to control the combining of the other image data with the initial high resolution image data to produce data defining a modified high resolution image. The other image data may be a user defined color or another image, for example.

Abstract: A video processing system for use in combining a first video image sequence comprising a number of image frames and a second sequence of video image frames to create a composite video image sequence is disclosed. The system comprises a stylus and touch tablet combination and is arranged to define on a frame-by-frame basis at least four reference points representing corners of a keyframe in three dimensional space notionally projected onto a monitor screen. A transforming circuit transforms the addresses of pixels in a frame of the first video image sequence so as to cause the pixels to represent the frame as projected onto the display screen from the same location in three dimensional space as the keyframe. A combiner combines the transformed frame with a corresponding frame of the second video sequence to produce the composite video image sequence.

Abstract: A system for processing video signals to produce slow motion television pictures is disclosed. A sequence is produced of output frames at broadcast rate by combining a decreasing proportion of pixel values of a first frame (i) stored in a first frame store with an increasing proportion of fixed valves of a second frame (i+1) stored in a second frame store. On completing a cycle the second frame (i+1) is treated as the first frame and a new second frame (i+2) is provided from a third frame store.

Abstract: Electronic image processing for manipulating data representing a three dimensional object. The three dimensional object. The three dimensional position and color of surface elements of an object are stored wherein the data for each surface element represents characteristics of a finite elemental area of the surface or skin of an object. The data may be displayed in two dimensions to provide real time manipulation of the three dimensional data.

Abstract: Sources of video signals representing an object (e.g. an aircraft), optionally movable, and a scene provide data stored in frame stores (b 1,5). Distance (optionally variable) from the observer of the object and near and far distances at transitions between features in the scene are stored respectively in frame store (4) and (7a, 7b). Within the boundaries of the object and in the neighborhood of the lines of transition, between features of the scene, quantities stored in object and scene stencil frame stores (3, 6) vary from 0 to 1. All frame stores are read simultaneously, driven by a microprocessor (2), the picture point scanning element sequentially. A comparator (11) compares distances, and the results of the comparison, together with the values stored in the stencil frame stores, determine the tone displayed at each element. Near features obscure distant ones, and sharp transitions are softened.

Abstract: An electronic image composition system in which in a preview mode of operation an image or image portion is manipulated and displayed substantially in real-time. In a compositing mode the image is finally composed (or stuck) into a background image. During the previewing stage, only a selected number of pixels representing the image are transformed and the remainder are derived from said transformed pixels by filtering or, preferably, replication.

Abstract: A video editing and processing system is so arranged that frames of video signals (1) from a store (3) can be displayed (7) in reverse order while associated audio signals (9) are delivered in normal order, so that the sound is heard in the usual manner.