21-05-2012, 12:59 PM
TERMINAL EQUIPMENT AND PROTOCOLS FOR TELEMATIC SERVICES
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Introduction
This CCITT Recommendation | ISO/IEC International Standard was prepared by CCITT Study Group VIII and the Joint
Photographic Experts Group (JPEG) of ISO/IEC JTC 1/SC 29/WG 10. This Experts Group was formed in 1986 to
establish a standard for the sequential progressive encoding of continuous tone grayscale and colour images.
Digital Compression and Coding of Continuous-tone Still images, is published in two parts:
– Requirements and guidelines;
– Compliance testing.
This part, Part 1, sets out requirements and implementation guidelines for continuous-tone still image encoding and
decoding processes, and for the coded representation of compressed image data for interchange between applications.
These processes and representations are intended to be generic, that is, to be applicable to a broad range of applications for
colour and grayscale still images within communications and computer systems. Part 2, sets out tests for determining
whether implementations comply with the requirments for the various encoding and decoding processes specified in Part
The user’s attention is called to the possibility that – for some of the coding processes specified herein – compliance with
this Recommendation | International Standard may require use of an invention covered by patent rights. See Annex L for
further information.
The requirements which these processes must satisfy to be useful for specific image communications applications such as
facsimile, Videotex and audiographic conferencing are defined in CCITT Recommendation T.80. The intent is that the
generic processes of Recommendation T.80 will be incorporated into the various CCITT Recommendations for terminal
equipment for these applications.
In addition to the applications addressed by the CCITT and ISO/IEC, the JPEG committee has developped a compression
standard to meet the needs of other applications as well, including desktop publishing, graphic arts, medical imaging and
scientific imaging.
Annexes A, B, C, D, E, F, G, H and J are normative, and thus form an integral part of this Specification. Annexes K, L
and M are informative and thus do not form an integral part of this Specification.
This Specification aims to follow the guidelines of CCITT and ISO/IEC JTC 1 on Rules for presentation of CCITT |
ISO/IEC common text.
Scope
This CCITT Recommendation | International Standard is applicable to continuous-tone – grayscale or colour – digital still
image data. It is applicable to a wide range of applications which require use of compressed images. It is not applicable to
bi-level image data.
This Specification
– specifies processes for converting source image data to compressed image data;
– specifies processes for converting compressed image data to reconstructed image data;
– gives guidance on how to implement these processes in practice;
– specifies coded representations for compressed image data.
NOTE – This Specification does not specify a complete coded image representation. Such representations may include
certain parameters, such as aspect ratio, component sample registration, and colour space designation, which are applicationdependent.
Normative references
The following CCITT Recommendations and International Standards contain provisions which, through reference in this
text, constitute provisions of this CCITT Recommendation | International Standard. At the time of publication, the
editions indicated were valid. All Recommendations and Standards are subject to revision, and parties to agreements
based on this CCITT Recommendation | International Standard are encouraged to investigate the possibility of applying
the most recent edition of the Recommendations and Standards listed below. Members of IEC and ISO maintain registers
of currently valid International Standards. The CCITT Secretariat maintains a list of currently valid CCITT
Recommendations.
– CCITT Recommendation T.80 (1992), Common components for image compression and communication –
Basic principles.
3 Definitions, abbreviations and symbols
3.1 Definitions and abbreviations
For the purposes of this Specification, the following definitions apply.
3.1.1 abbreviated format: A representation of compressed image data which is missing some or all of the table
specifications required for decoding, or a representation of table-specification data without frame headers, scan headers,
and entropy-coded segments.
3.1.2 AC coefficient: Any DCT coefficient for which the frequency is not zero in at least one dimension.
3.1.3 (adaptive) (binary) arithmetic decoding: An entropy decoding procedure which recovers the sequence of
symbols from the sequence of bits produced by the arithmetic encoder.
[attachment=22554]
Introduction
This CCITT Recommendation | ISO/IEC International Standard was prepared by CCITT Study Group VIII and the Joint
Photographic Experts Group (JPEG) of ISO/IEC JTC 1/SC 29/WG 10. This Experts Group was formed in 1986 to
establish a standard for the sequential progressive encoding of continuous tone grayscale and colour images.
Digital Compression and Coding of Continuous-tone Still images, is published in two parts:
– Requirements and guidelines;
– Compliance testing.
This part, Part 1, sets out requirements and implementation guidelines for continuous-tone still image encoding and
decoding processes, and for the coded representation of compressed image data for interchange between applications.
These processes and representations are intended to be generic, that is, to be applicable to a broad range of applications for
colour and grayscale still images within communications and computer systems. Part 2, sets out tests for determining
whether implementations comply with the requirments for the various encoding and decoding processes specified in Part
The user’s attention is called to the possibility that – for some of the coding processes specified herein – compliance with
this Recommendation | International Standard may require use of an invention covered by patent rights. See Annex L for
further information.
The requirements which these processes must satisfy to be useful for specific image communications applications such as
facsimile, Videotex and audiographic conferencing are defined in CCITT Recommendation T.80. The intent is that the
generic processes of Recommendation T.80 will be incorporated into the various CCITT Recommendations for terminal
equipment for these applications.
In addition to the applications addressed by the CCITT and ISO/IEC, the JPEG committee has developped a compression
standard to meet the needs of other applications as well, including desktop publishing, graphic arts, medical imaging and
scientific imaging.
Annexes A, B, C, D, E, F, G, H and J are normative, and thus form an integral part of this Specification. Annexes K, L
and M are informative and thus do not form an integral part of this Specification.
This Specification aims to follow the guidelines of CCITT and ISO/IEC JTC 1 on Rules for presentation of CCITT |
ISO/IEC common text.
Scope
This CCITT Recommendation | International Standard is applicable to continuous-tone – grayscale or colour – digital still
image data. It is applicable to a wide range of applications which require use of compressed images. It is not applicable to
bi-level image data.
This Specification
– specifies processes for converting source image data to compressed image data;
– specifies processes for converting compressed image data to reconstructed image data;
– gives guidance on how to implement these processes in practice;
– specifies coded representations for compressed image data.
NOTE – This Specification does not specify a complete coded image representation. Such representations may include
certain parameters, such as aspect ratio, component sample registration, and colour space designation, which are applicationdependent.
Normative references
The following CCITT Recommendations and International Standards contain provisions which, through reference in this
text, constitute provisions of this CCITT Recommendation | International Standard. At the time of publication, the
editions indicated were valid. All Recommendations and Standards are subject to revision, and parties to agreements
based on this CCITT Recommendation | International Standard are encouraged to investigate the possibility of applying
the most recent edition of the Recommendations and Standards listed below. Members of IEC and ISO maintain registers
of currently valid International Standards. The CCITT Secretariat maintains a list of currently valid CCITT
Recommendations.
– CCITT Recommendation T.80 (1992), Common components for image compression and communication –
Basic principles.
3 Definitions, abbreviations and symbols
3.1 Definitions and abbreviations
For the purposes of this Specification, the following definitions apply.
3.1.1 abbreviated format: A representation of compressed image data which is missing some or all of the table
specifications required for decoding, or a representation of table-specification data without frame headers, scan headers,
and entropy-coded segments.
3.1.2 AC coefficient: Any DCT coefficient for which the frequency is not zero in at least one dimension.
3.1.3 (adaptive) (binary) arithmetic decoding: An entropy decoding procedure which recovers the sequence of
symbols from the sequence of bits produced by the arithmetic encoder.