Introduction

There are many formats used for coding graphics data. For 2D areas the most frequently used are the following: JPEG, MPEG, GIF, TIF, TGA, PCX, PNG, POC, BMP, WMP, CDR, IFF, IMG, WPG, EPS, and others. For 3D areas there are the following: DXF, TSX, NFF, OFF and others. Individual types of files differ in the type of compression, depth of color, structure (bitmap or vector), and intended. We learn more about some of them in the following section.

Coding information

    The basic ISO standard for coding alphanumeric information, setting a basic 7-bit code table, is the IS 646, known also as ASCII code (containing all together 128 characters).

    The IS 2022 expands coding from 7-bit coding to 8-bit coding, enabling a mechanism for coding of more varied sets of characters (e.g., the Japanese alphabet). Later, there comes also a 16-bit code, the UNICODE, where every glyf (a letter, a digit, a symbol, a sign or mark) has its own code.

Here are also some other ISO standards for coding :

  • JBIG for monochromatic images
  • JPEG for static images
  • MPEG for moving pictures
  • HyTime and MHEG for multimedia information
  • HyperODA, a hyperdocument
  • MIDI for music information
  •     It is now necessary to note that besides international standards there are many graphics formats used by a large community of big companies and by the community of users. Some strong companies, in this way, try to protect their markets (e.g., companies like Tektronix, AutoCad have their own standards which are not international); in this way they bind the customers of their products to them, because these products are mostly not fully compatible with products of other companies.

    ISO standards for image coding

    JBIG

        JBIG (Progressive Bi/level image compression standard) is an ISO standard used for coding monochromatic image.

    JPEG

        The JPEG (Joint Photographic Expert Group, ISO/IEC 10918 Digital compression and coding of continuous-tone still image) is known for storing individual static raster image. The JPEG enables setting of the quality of compression with regard to the resulting file (this means, setting a quality from the range from 0 to 100 percent, where a 75 percent setting is reasonable for WWW). At present, there is at the design stage a new algorithm, which can compress images up to 200x, without a significant loss of quality. The LPEG2000, that is the ISO15444, at the time of its release in 2001, will use the wavelet transformation instead of the Fourier transformations, used in the classic JPEG.

    MPEG

        The MPEG (Moving Picture Experts Group) is an ISO and IEC standard for storing and processing video sequences. The MPEG has three sections: the MPEG – Video, the MPEG – Audio, and the MPEG – System. The MPEG – Video compresses a sequence of video frames, the MPEG – Audio compresses a sequence of tones, and the MPEG – System integrates these sections into a resulting video sequence. You can find more information about MPEG in the Chapter 17.4.

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