One of the trademark/brand names that Apple Inc use for their Mac family of personal computers.

Last updated: 2009-05-05


<data, graphics>

1. Data representing a two-dimensional scene. A digital image is composed of pixels arranged in a rectangular array with a certain height and width. Each pixel may consist of one or more bits of information, representing the brightness of the image at that point and possibly including colour information encoded as RGB triples.

Images are usually taken from the real world via a digital camera, frame grabber, or scanner; or they may be generated by computer, e.g. by ray tracing software.

See also image formats, image processing.

Last updated: 1994-10-21


2. The image (or range) of a function is the set of values obtained by applying the function to all elements of its domain. So, if f : D -> C then the set f(D) = { f(d) | d in D } is the image of D under f. The image is a subset of C, the codomain.

Last updated: 2000-01-19

image formats

<graphics, file format>

There are many formats used to store images in files. GIF, TIFF and JPEG are very common. Others are BIFF, bmp, Clear, FITS, IFF, NFF, OFF, PCX, PNG, TGA, XBM.

Some of these are documented on-line at the following sites:

The Graphics File Format Page. The NCSA file formats archive. The Avalon repository.


Last updated: 1997-08-07

image map


An image in an HTML document with "hot spots" which when clicked on in a suitable browser, act as anchors or links to other information. For example, an image of a map of the world might provide links to resources related to different countries. Clicking on a country would take the user to the relevant information.

[Documentation URL?]

Last updated: 1995-12-05

image processing


Computer manipulation of images. Some of the many algorithms used in image processing include convolution (on which many others are based), FFT, DCT, thinning (or skeletonisation), edge detection and contrast enhancement. These are usually implemented in software but may also use special purpose hardware for speed.

Image processing contrasts with computer graphics, which is usually more concerned with the generation of artificial images, and visualisation, which attempts to understand (real-world) data by displaying it as an artificial image (e.g. a graph). Image processing is used in image recognition and computer vision.

Silicon Graphics manufacture workstations which are often used for image processing. There are a few programming languages designed for image processing, e.g. CELIP, VPL.

See also Pilot European Image Processing Archive.

Usenet newsgroup: sci.image.processing.

[Other algorithms, languages? FAQ?]

Last updated: 1995-04-12

image recognition

<graphics, artificial intelligence>

The identification of objects in an image. This process would probably start with image processing techniques such as noise removal, followed by (low-level) feature extraction to locate lines, regions and possibly areas with certain textures.

The clever bit is to interpret collections of these shapes as single objects, e.g. cars on a road, boxes on a conveyor belt or cancerous cells on a microscope slide. One reason this is an AI problem is that an object can appear very different when viewed from different angles or under different lighting. Another problem is deciding what features belong to what object and which are background or shadows etc. The human visual system performs these tasks mostly unconsciously but a computer requires skillful programming and lots of processing power to approach human performance.

Last updated: 1997-07-20



The production of graphic images, either from a video camera or from digitally generated data (see visualisation), or the recording of such images on microfilm, videotape or laser disk.

See also scanner.

Last updated: 1997-07-20

Imago Europe plc

A UK Internet provider. There sevice is called Imago On-line. E-mail: <[email protected]>.

Imago On-line

An Internet electronic mail and news service in the United Kingdom provided by Imago Europe plc.

A one year subscription to the service costs just seventy five pounds plus VAT and offers dial-up access with a graphical user interface for users of Macintosh and Microsoft Windows PCs and the Apple Newton MessagePad PDA family.


A tool which generates Makefiles from a template, a set of cpp macros, and a per-directory input file called an Imakefile. This allows machine dependencies (such has compiler options, alternate command names, and special make rules) to be kept separate from the descriptions of the various items to be built.

imake is distributed with, and used extensively by, the X Window System.

Last updated: 1995-02-21




Internet Message Access Protocol



A REXX interpreter for SunOS.

Current version 1.3 [?].

Last updated: 2000-11-07


intermodulation distortion



(From SF fandom via Usenet) In My Humble Opinion. Also seen in variant forms such as IMO, IMNSHO (In My Not-So-Humble Opinion) and IMAO (In My Arrogant Opinion).

[Jargon File]

Last updated: 1998-09-24


Initial Microprogram Load

immediate version

child version

Imminent Death Of The Net Predicted!


Since Usenet first got off the ground in 1980-81, it has grown exponentially, approximately doubling in size every year. On the other hand, most people feel the signal-to-noise ratio of Usenet has dropped steadily. These trends led, as far back as mid-1983, to predictions of the imminent collapse (or death) of the net. Ten years and numerous doublings later, enough of these gloomy prognostications have been confounded that the phrase "Imminent Death Of The Net Predicted!" has become a running joke, hauled out any time someone grumbles about the S/N ratio or the huge and steadily increasing volume, or the possible loss of a key node or link, or the potential for lawsuits when ignoramuses post copyrighted material etc.

[Jargon File]

Last updated: 1998-09-24







1. IMProved Mercury autocode.


2. An extensible dialect of ALGOL 60, for CDC 1604.

["Experience with an Extensible Language", Edgar T. Irons, CACM 13(1):31-39, Jan 1970].


3. Interpretive Menu Processor.


4. IMPlementation language.


5. Interface Message Processor.

Last updated: 1996-04-07

impact printer


The earlier, noisier kind of printer where part of the mechanism comes into contact with the paper. The term would only be only used in contrast to "non-impact printer". Examples include line printer, daisy wheel printer, golf ball printer, dot matrix printer, Braille printer.

Last updated: 1998-10-13


<electronics, physics>

Opposition to flow of alternating current. Impedance consists of resistance plus reactance (capacitive or inductive). Measured in Ohms.

Last updated: 2003-12-02


imperative language

imperative language


Any programming language that specifies explicit manipulation of the state of the computer system, not to be confused with a procedural language, which specifies an explicit sequence of steps to perform.

An example of an imperative (but non-procedural) language is a data manipulation language for a relational database management system. This specifies changes to the database but does not necessarily require anyone to specify a sequence of steps.

Both contrast with declarative languages, which specify neither explicit state manipulation nor a sequence of steps.

Last updated: 2007-10-02

imperative programming

imperative language

Imperial College of Science, Technology and Medicine


(IC, ICST&M) One of the colleges of London University. The Department of Computing is the home of FOLDOC.

IC Home.

Last updated: 2005-05-09

Imperial Software Technology


A software engineering company which emerged from Imperial College in about 1982. It enjoys a world-wide reputation for technical excellence as a software product and technology provider in the Open Systems market. Its flagship product is X-Designer, the award-winning graphical user interface builder. It also has considerable expertise in the Z language and Formal Methods.

Last updated: 1995-11-23

IMPlementation language


(IMP) An extension of B with floating-point operations, developed by W. Davidsen at General Electric in 1970 for the GE 600. It was also cross-compiled to VAX and Intel 8080.

Last updated: 1996-04-07



implicit parallelism


A feature of a programming language for a parallel processing system which decides automatically which parts to run in parallel.

The best way of providing implicit parallelism is still (1995) an active research topic. The problem is to generate the right number of parallel tasks of the right size (or "granularity"). Too many tasks and the system gets bogged down in house-keeping, or memory for waiting tasks runs out, too few tasks and processors are left idle.

The best performance is usually achieved with explicit parallelism where the programmer can annotate his program to indicate which parts should be executed as independent parallel tasks.

Last updated: 1995-02-16

implicit type conversion


(Or "coercion") The abilty of some compilers to automatically insert type conversion functions where an expression of one type is used in a context where another type is expected.

A common example is coercion of integers to reals so that an expression like sin(1) is compiled as sin(integerToReal(1)) where sin is of type Real -> Real.

A coercion is usually performed automatically by the compiler whereas a cast is an explicit type conversion inserted by the programmer.

See also subtype.

Last updated: 1997-07-28



(=> or a thin right arrow) A binary Boolean function and logical connective. A => B is a true implication unless A is true and B is false. The truth table is

 A B | A => B
 F F |   T
 F T |   T
 T F |   F
 T T |   T

It is surprising at first that A => B is always true if A is false, but if X => Y then we would expect that (X & Z) => Y for any Z.

If A is actually an expression X & Y then the implication is called a syllogism.

Last updated: 2009-10-28





To read data that is not in the native format of the application. For example, a web browser will have its own way of storing bookmarks but it will usually provide a function to import bookmarks from Internet Explorer. The alternative is to provide an independent external conversion utility but this is usually less convenient for the user.

Last updated: 2004-11-15

imprecise probability


A probability that is represented as an interval (as opposed to a single number) included in [0,1].

Last updated: 2001-02-21

IMProved Mercury autocode


(IMP) A version of Autocode used to program the Edinburgh Multi Access System (EMAS), one of the first operating systems written in a high-level language, apparently predating Unix.

Luis Damas' Prolog interpreter in IMP for EMAS led to C-Prolog.

[Papers in J. British Computer Society].

Last updated: 1996-04-07


Internet Monthly Report


Information Management System

IMS 6100

Intersil 6100



One of the companies that made very early microprocessor systems.

[Where? When? Who? What?]

Last updated: 1995-05-12

IMS/Data Base


(IMS/DB) A hierarchical high performance database for IBM mainframes, part of IMS. IMS/DB is implemented on top of VSAM and uses its underlying data structures.

Last updated: 1999-01-11

IMS/Data Communications


(IMS/DC) The teleprocessing monitor/transaction processing sytem in IMS from IBM.

Last updated: 1999-01-11


Integrated Modelling Support Environment


International Multimedia Teleconferencing Consortium

Nearby terms:

Illinois Functional ProgrammingILOCIlog SolveriMacimageimage formatsimage map

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