Image
In common usage, an
image (from
Latin imago) or
picture is an artefact that reproduces the likeness of some
subject -- usually a physical object or a person.
Images may be two-dimensional (e.g. a
photograph) or three dimensional (e.g. a
statue). They are typically produced by
optical devices -- such as a cameras, mirrors,
lenses,
telescopes, microscopes, etc. and natural objects and phenomena, such as the human
eye or water surfaces.
The word
image is also used in the broader sense of any two-dimensional figure or illustration, e.g. a
map, a
graph, a
pie chart, an
abstract painting, etc. In this wider sense, images can also be produced manually (by
drawing,
painting,
carving, etc.), by
computer graphics technology, or a combination of the two (see
pseudo-photograph).
A
volatile image is one that exists only for a short period of time, e.g. the
reflection of an object by a mirror, a
projection of the
sun on a wall by a
pinhole camera, or a scene displayed on a
cathode ray tube. A
fixed image, also called
hardcopy, is one that has been recorded on a material object, such as
paper or
textile.
A
mental image exists in someone's mind: something one remembers or imagines. The subject of an image need not be real; it may be an
abstract concept, such as a
graph or function -- or an
imaginary entity or being.
Specialized meanings
The word also has many specialized meanings in various disciplines and contexts:
- In geometric optics, a lens can produce a real image or a virtual image. \n* In many other scientific and technical contexts, image usually means a two-dimensional signal -- a physical phenomenon that can be modeled as a function from a two-dimensional domain (such as the plane or a rectangle) to some set of values, usually real numbers or vectors. This sense covers not only digital images but also analog ones, such as photographs. See image processing.\n* In computer graphics and digital image processing, the word image almost always means digital image or, by extension, any computer description of an image, e.g. a raster map, an image file, or a 2D computer graphics model. For embedding an image in a webpage, see HTML element#Images.\n* In computer science the word image can also mean an exact (bit-by-bit) copy of the contents of some device, such as a hard disk, floppy disk, CD-ROM, etc.. In particular,\n** A core image (or core dump) is a faithful copy of the data stored in the main memory of a computer or process. \n** An executable image is a structured file containing machine instructions and data, which can be loaded into a process's virtual memory and executed. See kernel (computers).\n* In mathematics, an image is a value or set of values of a function. Specifically, let f be a function from the set X to the set Y. If a is an element of X, then its image under f is the value f(a). If A is a subset of X, then its image under f is f(A) = {f(a) : a∈A}. Finally, the image of f itself is f(X), i.e. the same as the range of f.\n* In finance, the image is a coefficient (stock image) that bridges a stock's fundamental value and its market price.\n* In philosophy, an image is a conception or idea.\n* In religion, an image is an idol or icon.\n* In social psychology an image is a representation.
Also Image Comics is an Americann publisher of
comic books.
See also
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