Abstract: An image signal processing system is described in which image data in an interlaced format is converted to full frame format prior to application of any vertical processing, A swing buffer 40 is employed with Field 0 being written into the even addresses of a DRAM 44 forming one side of the swing buffer under control of an write controller 48. Field 1 is written into the odd addresses, The data in full frame format is read from consecutive addresses in the DRAM 44 into a signal processing engine 62 whilst the next frame is being written into the DRAM 46 forming the other arm of the swing buffer 40. This arrangement allows data that was captured in full frame format to be vertically processed in full frame format thereby preserving its vertical resolution. The full frame image data was converted out of full frame format prior to receipt by the image processing system for compatibility with hardware developed for interlaced format data.

Abstract: A video signal generating apparatus comprises a first microprocessor (10) including a memory (16) for receiving and storing in non-real time instructions for the generation of a range of video signals, such as test patterns, digital multi-effect keys or wipe patterns for a digital switcher, and a second microprocessor (14) for reading the instructions and generating a selected required video signal in real time.

Abstract: A method of generating an output video signal includes processing two or more input digital video signals so as to manipulate images that they represent and combining the processed signals to form the output video signal, which represents a composite image in which the manipulated images appear to fly through one another. In a first pass, a digital video effect generator (1) is supplied (4) with one of input video signals and is responsive to data (5) representing at least the manipulation to which the image represented by that one input signal is to be subjected to process that one input signal to subject the image represented thereby to the manipulation intended for that image. The processed signal resulting from the first pass is recorded (VTR1).

Abstract: Apparatus for manipulating a picture (P1) represented by a video signal (V1) includes a picture manipulator (16R, 16G, 16B, 18R, 18G, 18B) responsive to data representing a desired manipulation to manipulate the picture by changing at least one geometrical parameter thereof. The picture manipulator is controlled by a computer (40) that comprises a keyboard 48 and track ball assembly (50) for entering command information indicative of how the picture is to be manipulated. The computer (40) incorporates processing software that enables the computer to act as processor means responsive to the command information to generate the data representing a desired manipulation. The computer (40) has a VDU (42) and incorporates display software responsive to the command information to cause the VDU to display a frame which is subjected to the same manipulation as that desired for the picture.

Abstract: A digital picture signal processing apparatus has memories each capable of storing digital words representing respective pixels which, when arranged in a two-dimensional array, make up a picture. A read address generator produces a digital read address identifying the position of a set of the stored words to be read from respective different ones of the memories, the words of the set representing a set of pixels so positioned relative to one another as to constitute at least some of the pixels of a portion of the picture. The read address comprises at least one least significant bit (LSB) for each of the coordinate directions. A digital filter has a number of multipliers equal to the number of words in the set and each being connected to a data bus of a respective memory so as to receive a respective one of the set of words read therefrom, and a plurality of coefficient memories.

Abstract: Video signal processing apparatus, for example a television standards converter (12), for motion adaptive or motion compensated processing a video signal in dependence on inter-field or inter-frame information, comprises a reader (21) for reading scene discontinuity information relating to the video signal, which may be expressed in time codes, from a recording medium such as a magnetic disc, the apparatus being controlled in dependence on the read information to cause the processing of the video signal to change to being dependent on intra-field or intra-frame information at a scene discontinuity.

Abstract: Access to a two-dimensional (2-D) portion of a digital picture signal, the signal being made of a plurality of digital words representing respective pixels (P) when, when arranged in a 2-D array, make up the picture, is achieved as follows. The words are allocated into groups such that the pixels (P) represented by the words of each group make up a 2-D area (T0, T1, etc.) of the picture having a shape and size which is the same for all of the groups, the shape being such that the areas tessellate with one another to constitute at least part of the picture. Each word is stored in one of a plurality of memories (M0 to M15), the number of which is equal to the number of pixels (P) in the 2-D area (T0, T1, etc.), such that, for each pixel position in the area, the words from all of the groups representing the pixels having that pixel position in the area are stored in a respective one of the memories. Then, a set of the stored words which represent a set of pixels are read in parallel.

Abstract: Apparatus for controlling the combining of video signals includes a field rate microprocessor (10) that generaes edge data defining the edges of a polygonal first picture (KP) which is to be keyed into a second picture (B) to produce a composite picture. Two line rate microprocessors (16, 18) generate from the edge data, for each horizontal scanning line of the composite picture in which a row of pixels corresponding to that scanning line is intersected by edges of the first picture, signals representing: the horizontal locations of first and second start pixels, namely those of the row of pixels in which first and second edges (e.g. Eb, E2), respectively, of the first picture (KP) start to intersect the row; the gradients of the first and second edges; and a key value (the proportion of the first picture to be contained in a pixel of the composite picture) for each of the first and second start pixels.

Abstract: Apparatus for generating an image for digital scene simulation, the apparatus comprising a first store for storing address data defining the three-dimensional shape of an object, a second store for storing video data defining the two-dimensional surface detail of the object, a matrix circuit for manipulating the address data to move the object (by translating it, changing its orientation, or both translating it and changing its orientation), a perspective transformation device for perspective tansforming the manipulated address data to form transformed address data defining a two-dimensional image of the object after the manipulation, and a third store in which the video data is written, under control of the transformed address data, in the form of output video data defining a two-dimensional image of the object after the manipulation and with the surface detail.

Abstract: A video signal memory which may form a field memory in a special effects equipment of a high definition video system, provides storage of n.sup.2 m video data words and includes an array of n by n memory modules each capable of storing m video data words corresponding respectively to sample values at respective sample positions of a raster display, a first group of n buses for supplying data and address signals to the n columns respectively of the array, a second group of n buses for supplying data and address signals to the n rows respectively of the array, and means selectively to enable the first or second group of buses in each write cycle of the video signal memory and in the write cycle to supply over the enabled group of buses up to n data and address signals wherein the address designates the address in a memory module in the corresponding column or row of the array and the data is the data to be stored in the memory module.

Abstract: An infinite impulse response (IIR) filter is operative to filter an input signal that comprises a sequence of digital words spaced in time by an interval T. The filter includes delay circuitry that delays the input signal by successive increments of time equal to T so as to cause the production of a series of relatively delayed signals in which each signal is delayed by T with respect to the previous signal in the series. IIR processing units receive respective groups of the series of signals, the groups being offset with respect to one another by one word. The units are operative during each of plural successive clock periods equal to 2T to process respective sets of words obtained from the respective groups of the series of signals so as to produce two output words. A multiplexer combines each two output words produced during each clock period equal to 2T to constitute a filtered output signal comprising a sequence of output words spaced in time by the interval T.

Abstract: Digital video sample values from a first sample domain are mapped to a second sample domain using a mapping function which involves a change in image size, for example, for a digital video effects unit. The apparatus comprises an address generator and a processor for computing, for each sample position in the second sample domain, the position of a point in the first sample domain which, using the mapping function, would map onto that sample position in the second sample domain, and an interpolator for obtaining from available input sample values an interpolated sample value for that point in the first sample domain, the interpolated sample value being used as the sample value for the sample position in that second sample domain.

Abstract: A video signal memory which may, for example, form a field memory in a special effects equipment of a high definition video system, provides storage for n.sup.2 m video data words and has n.sup.2 memory modules each capable of storing m video data words corresponding respectively to sample values at respective sample positions of a raster display, each memory module being arranged to store one only of the video data words in any square of n by n sample positions of the raster in any one write cycle, and means to write up to n video data words corresponding to n adjacent collinear sample positions of the raster in the video memory in any one write cycle.

Abstract: An image signal processing apparatus comprises a memory (12) and an address generator (14) that generates addresses for allocation to successive words of a digital input signal (10) representing an input image for mapping those words (or words obtained by interpolation therefrom) into the memory (12) in such a manner that individual portions of the mapped image stored in the memory may be compressed and/or rotated with respect to corresponding portions of the input image. A digital filter (40) of variable bandwidth effects two-dimensional filtering of the image before it is stored in the memory (12). Local scaling factor computation means (42) monitors the addresses allocated by the address generator (14) to successive sets of words of the input signal corresponding to successive local image areas and computes from each set of addresses, for the corresponding set of words, a local scaling factor representing the extent of compression and/or rotation of the local area.

Abstract: A method of processing video signals to achieve a visual effect involving three-dimensional manipulation of an input image includes the use of a circuit for determining pixel address by pixel address whether in the resulting transformed image the front or the back of the input image should be displayed. The circuit comprises a device defining an incremental surface in the transformed image by at least three adjacent non-collinear pixel addresses from the transformed image, a circuit for determining from the transformed pixel addresses whether or not a vector normal to the incremental surface points towards or away from a viewing point, and a device for selecting for display at one of the transformed pixel addresses the corresponding portion of the front or the back of the input image in dependence on whether the vector points towards or away from the viewing point.

Abstract: A video signal processing circuit receiving an input sample data relating to sample positions in a video field and in association with the sample data for each sample position associated z data indicating the apparent position of the sample data in a direction perpendicular to a video display of the video field, a first memory for storing the sample data relating to each sample position in the video field, a second memory for storing the z data relating to each sample position in the video field, and a comparator circuit for comparing for each sample position in the video field the value of the input said data with the z data for that sample position stored in the second memory and for supplying a write enable signal only if the value of the input z data represents a sample position in front of that represented by the stored data, the input sample data being written into the first memory and the new z data being written into the second memory under control of a write enable signal.

Abstract: A method of and apparatus for processing video signals to achieve a visual effect corresponding to that which would be achieved if an input two-dimensional image were projected on to a three-dimensional surface is disclosed. A video signal is formed into digitized sample values each having an input pixel address comprising X and Y coordinate values. X and Y scaling multipliers and Z coordinate values corresponding to the respective pixel addresses on the three-dimensional surface to which each of the input pixel addresses will be moved in achieving the effect are stored in a mapping store. Multipliers multiply the X and Y coordinate values of each input pixel address by the corresponding X and Y scaling multipliers, and the resulting scaled X and Y coordinate values and the associated Z coordinate values are supplied to a perspective transformation device to derive the output X and Y coordinate values corresponding to the effect.