Abstract: A photographic system 1 comprising a digital still camera 3 for producing an output signal, means 11 for processing the output signal with a pre-recorded picture signal to produce a revised image signal and means 13 for printing the revised image, wherein the means 11 for processing uses chroma-key processing 37,39 to insert a background picture signal into a key color-characterized region of a foreground picture signal The invention results in a novel application of chroma-key processing to produce good quality still photographs using a simple and robust system.

Abstract: In digital image processing, it is often necessary to alter the image by performing a zoom operation thereon. Such an operation is carried out with the use of a spatial interpolation unit. Described herein is a spatial interpolation unit which comprises a discrete set of filters for which at least some of the cut-off frequencies are logarithmically spaced.

Abstract: A video image alteration apparatus is described that separates the vertical and horizontal aspects of image alteration. Pixels relating to an input image derived from a frame of film are sampled at a predetermined rate related to a film scanning speed and a television line standard, and the flow of pixel information is coordinated through a memory section by write control and read control signals. A frame store, which stores image pixel data corresponding to at least one film frame, includes a line output and address inputs for selecting a line start position and a line advance increment. To obtain the aforementioned spatial separation, a line store, which is responsive to the line output of the frame store for storing at least one line of image pixel data, includes a pixel output and address inputs for selecting a pixel start position and a pixel advance increment.

Abstract: An interpolation filter is used in television standards conversion to decimate an input sequence of higher definition signals into an output sequence of lower definition signals. The filter is partitioned into a plurality of computational stages. Within each stage, the decimation coefficients are stored in a random access coefficient memory and applied to a multiplier to generate the product of a digital input signal and a stored coefficient. The RAM is operable in two modes: a first mode in which new sets of coefficients are serially input to the RAM during the field blanking period and a second mode in which different stored coefficients are output to the multiplier for consecutive digital signals to effect a non-integer decimation ratio.

Abstract: A video color signal compensator monitors, on a generally continuous basis the signal levels for three primary colors, and for certain operating zones introduces matrixing to drive the overall video signal toward neutral. Such matrixing, for example, is employed to diminish undesired hue effects in low light level areas of an image and to introduce detail in saturated image areas.