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 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: 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 graphic system for producing printed images. The signals representing the image are produced as CMY (cyan, magenta, yellow) printing color component signals and transformed to RGB (red, green, blue) signals for display on a monitor. The transformation circuit is a matrix of arithmetic circuits including look-up tables. The system can also be conditioned so that RGB signals are first produced and these transformed to CMY.

Abstract: A system for processing images typically still images from a slow scan source such as associated with an electron microscope. The analogue source is converted into digital form via an ADC and passes via an adder to a framestore. An output of the framestore is also received by the adder. The capacity of the framestore is sufficiently large to accommodate several hundred summed frames. The image is built up by using all the stored information and all the incoming information. A divider under the control of a frame counter automatically corrects for intensity as the summation of frames progresses, the result being available for monitoring via a digital to analogue converter. Additional mechanisms are disclosed for dealing with other aspects associated with differing frame rates.