Abstract: A real-time video data gradation control which modifies each component of the video data as a function of at least one other component and outputs the modified components to drive a monitor.

Abstract: A chroma keying system 1 processes foreground image data representing a foreground subject in front of a matte, together with background data representing a background image, to produce composite image data representing the foreground subject and the background in place of the matte. A programmable look up table 8 is provided for receiving on a pixel-by-pixel basis the most significant bits (MSBs) of the foreground image data and outputting in response thereto range data representing limits of a keying range. An interpolator 9 is also provided for interpolating the range data depending on the least significant bits (LSBs) of the foreground image data and outputting keying data. A combiner 4 combines the foreground image data and the background image data on a pixel-by-pixel basis in response to the keying data to produce the composite image data. The system is operable in a calibration mode in which a generator 15 is connected to input the colour point data to an external keyer.

Abstract: An electronic graphic system 1 processes image data defining color values of a multiplicity of pixels that together form an image. The system 1 comprises a processing unit 14 in which image data from an image store 2 is processed with other image data from a store 9. The processing is effected on a pixel-by-pixel basis depending on control data in a control store 15 and on a predetermined gamma factor defining a relationship between color values and corresponding light values. The processing unit 14 thereby produces processed color value data representing a manipulated version of the image in which the light content of pixels has been varied by the other image data depending on the control data and the gamma factor.

Abstract: An image processing system 20 comprises a format converter 21 for receiving a first signal having a larger bandwidth and a second signal having a smaller bandwidth, the first and second signals together representing an image. A processor 23 is arranged to process the first and second signals to produce signals representing a manipulated version of the image. The system further comprises a deriving circuit 25 which is arranged to derive from information in the larger bandwidth signal additional information for the smaller bandwidth signal. The deriving circuit derives an unknown value of a pixel as represented by the smaller bandwidth signal from known values of the pixel and the pixels adjacent thereto as represented by the larger bandwidth signal and from known values of the adjacent pixels as represented by the smaller bandwidth signal. The deriving circuit facilitates conversion of the first and second signals into another signal format representing the image.