bitmap

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bitmap

Computing
a picture created on a visual display unit where each pixel corresponds to one or more bits in memory, the number of bits per pixel determining the number of available colours
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

bitmap

(graphics, file format)
A data file or structure which corresponds bit for bit with an image displayed on a screen, probably in the same format as it would be stored in the display's video memory or maybe as a device independent bitmap. A bitmap is characterised by the width and height of the image in pixels and the number of bits per pixel which determines the number of shades of grey or colours it can represent. A bitmap representing a coloured image (a "pixmap") will usually have pixels with between one and eight bits for each of the red, green, and blue components, though other colour encodings are also used. The green component sometimes has more bits that the other two to cater for the human eye's greater discrimination in this component.

See also vector graphics, image formats.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

bitmap

A binary representation in which a bit or set of bits corresponds to some part of an object such as an image or font. For example, in monochrome systems, one bit represents one pixel on screen. For gray scale or color, several bits in the bitmap represent one pixel. The term may refer to the image itself or to the memory area that holds the bits that represent the image. See pixel and rasterize.

Graphics and Tables
A bitmap is usually associated with graphics, in which the bits are a direct representation of the pixels in the image. However, bitmaps can be used as tables to represent and keep track of anything, where each set of bits is assigned a value or condition. See bitmapped graphics. For graphics fundamentals, see graphics.


A Monochrome Bitmap
The left half of this diagram shows the bits in the bitmap, and the right half depicts what would show on screen. In monochrome systems, one bit is used to represent one pixel. Images that are scanned into the computer are turned into bitmaps, and bitmaps can be created in a paint program.
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References in periodicals archive ?
Then, many copies of the authentication codes are embedded into the bit maps based on the permutation operation.
If the character generator is not used, as with the high resolution monochrome graphics mode of the IBM color graphics adapter used by the NK-DOS 02 system, then 16 Kbytes of display memory are available to store the necessary character bit maps for the 640 x 200 screen.
The 16 Kbytes of display memory in the NK-DOS 02 system is used for direct storage of the Chinese and ASCII character bit maps. In a Chinese-English system, an ASCII character normally takes up half the number of columns and therefore half the display space of a Chinese character.
The new Transactional Bit Map Indexing available in CACHE 5 will be especially useful for complex queries, such as DNA testing for infectious diseases, molecular oncology, mutational analysis, and human identity testing.
These indexes provide a powerful alternative to conventional B-tree indexes, hash clusters and bit maps. They are a vital aspect to achieving good performance with incremental updates.
The table illustrates that B-Trees do not tolerate large keys; while hash indexes can suffer performance problems with low cardinality or clustered key distributions; and bit map indexes do not handle high cardinality keys well.
Vanguard's sound, remastered using Super Bit Map technology, belies its 1964 origins.
Data can be displayed as isometric plots, cross-sectional graphs, radar plots, bit maps and color graphs.
However, active archiving is designed for relational data, while HSM is best suited for other types of data such as document files, bit maps, and video clips.
Such a strategy must be based upon an architecture that integrates all the text, image bit maps, profiles, and other compound document elements of corporate virtual files, into a document life cycle.