ISO/IEC 14492:2001/Amd 3:2012
(Amendment)Information technology — Lossy/lossless coding of bi-level images — Amendment 3: Extension to colour coding
Information technology — Lossy/lossless coding of bi-level images — Amendment 3: Extension to colour coding
Technologies de l'information — Codage avec ou sans perte des images au trait — Amendement 3: Extension au codage de la couleur
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Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 14492
First edition
2001-12-15
AMENDMENT 3
2012-12-01
Information technology — Lossy/lossless
coding of bi-level images
AMENDMENT 3: Extension to colour coding
Technologies de l'information — Codage avec ou sans perte des
images au trait
AMENDEMENT 3: Extension au codage de la couleur
Reference number
ISO/IEC 14492:2001/Amd.3:2012(E)
©
ISO/IEC 2012
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ISO/IEC 14492:2001/Amd.3:2012(E)
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ii © ISO/IEC 2012 – All rights reserved
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ISO/IEC 14492:2001/Amd.3:2012(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
Amendment 3 to ISO/IEC 14492:2001 was prepared jointly by Joint Technical Committee ISO/IEC JTC 1,
Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia
information, in collaboration with ITU-T. The identical text is published as ITU-T Rec. T.88 (2000 E)/Amd.3.
© ISO/IEC 2012 – All rights reserved iii
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ISO/IEC 14492:2001/Amd.3:2012 (E)
INTERNATIONAL STANDARD
ITU-T RECOMMENDATION
Information technology – Lossy/lossless coding of bi-level images
Amendment 3
Extension to colour coding
1) Clause 2, Normative References
Append a new reference as follows (with the additions underlined):
– Recommendation ITU-T T.45 (2000), Run-length colour encoding.
2) Clause 4.2, Symbol definitions
Insert new symbols COLEXTFLAG, CPCOMPLEN, CPDEFCOLS, CPEXCOLS, CPNCOMP, CPNVALS, GBCOLS,
GBCOMBOP, GBFGCOLID, SBCOLS, SBCOLSECTSIZE and SBFGCOLID as follows (with the additions
underlined):
(Symbols left untouched)
Clow Low-order 16 bits of C
COLEXTFLAG A parameter indicating whether the generic region segment is extended to represent a coloured
bitmap
CONTEXT The values of the pixels in a template used in the generic or generic refinement decoding
procedure
CPCOMPLEN The length (in bytes) of each component's value
CPDEFCOLS The default colour set
CPEXCOLS The colours defined in the colour palette segment
CPNCOMP The number of colour components
CPNVALS The number of colour values coded in this segment
(Symbols left untouched)
GB The prefix used for many of the variables associated with a generic (bitmap) region decoding
procedure
GBCOLS An array containing the colours used in a generic region segment
GBCOMBOP The combination operator used in a generic region decoding procedure
GBFGCOLID The 4-byte integer indicating the foreground colour of the generic region segment
(Symbols left untouched)
SB The prefix used for many of the variables associated with a symbol (bitmap) region decoding
procedure
SBCOLS An array of colours used in a text region segment
SBCOLSECTSIZE The colour section length
Rec. ITU-T T.88 (2000)/Amd.3 (05/2011) 1
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ISO/IEC 14492:2001/Amd.3:2012 (E)
(Symbols left untouched)
SBDEFPIXEL The default for pixels in a text region
SBFGCOLID The three 1-byte integers indicating the foreground colour of the text region segment
(Symbols left untouched)
3) Clause 6.2.2, Input parameters
Add new rows of GBCOLS, GBCOMBOP and COLEXTFLAG after GBATY , and add a new Note f), in Table 2 as
4
follows (with the additions underlined):
Table 2 – Parameters for the generic region decoding procedure
Size
Name Type Signed? Description and restrictions
(bits)
(Rows left untouched)
b)
GBATY Integer 8 Y The Y location of the adaptive template pixel A .
4 4
f)
GBCOLS Array of colours (colour palette) An array containing the colours used in this generic region.
GBCOMBOP Operator The combination operator for this generic region. Shall take on
f)
the value REPLACE.
COLEXTFLAG Integer 1 N A parameter indicating whether the generic region segment is
extended to represent coloured bitmap.
(Notes left untouched)
f)
Unused if COLEXTFLAG = 0.
4) Clause 6.2.4, Variables used in decoding
Add a new row of GBFGCOLID after CONTEXT, and add a new Note b) in Table 4 as follows (with the additions
underlined):
Table 4 – Variables used in the generic region decoding procedure
Size
Name Type Signed? Description and restrictions
(bits)
(Rows left untouched)
a)
CONTEXT Integer 16 N The values of the pixels in the template.
GBFGCOLID Integer 32 N The 4-byte integer indicating the colour palette ID of the
b)
foreground colour for the generic region segment.
(Notes left untouched)
b)
Unused if COLEXTFLAG = 0.
5) New clause 6.2.7, Colour extension of generic region segment
Add a new clause 6.2.7 after clause 6.2.6, as follows:
6.2.7 Colour extension of generic region segment
If COLEXTFLAG is 1, after the decoding procedure described in 6.2.5 or 6.2.6, read GBFGCOLID which is a 4-byte
integer indicating the colour palette ID, and set the colour specified by GBCOLS[GBFGCOLID] to the segment's
foreground colour.
The background colour of the segment of which COLEXTFLAG is 1 is regarded as transparent.
NOTE – GBFGCOLID (the foreground colour information) has a fixed 4-byte field and is put at the end of the region segment
only when COLEXTFLAG is 1. The decoder can find the address of GBFGCOLID by subtracting 4 from the segment data
length recorded in the segment header.
2 Rec. ITU-T T.88 (2000)/Amd.3 (05/2011)
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ISO/IEC 14492:2001/Amd.3:2012 (E)
6) Clause 6.4.2, Input parameters
Revise the description and restrictions of SBCOMBOP, add new rows of COLEXTFLAG and SBCOLS after
SBRATY , and new Notes e) and f) in Table 9 as follows (with the additions underlined):
2
Table 9 – Parameters for the text region decoding procedure
Size
Name Type Signed? Description and restrictions
(bits)
(Rows left untouched)
SBCOMBOP Operator The combination operator for this text region. May take on the values
e)
OR, AND, XOR, XNOR and REPLACE.
(Rows left untouched)
c)
SBRATY Integer 8 Y The Y location of the adaptive template pixel RA .
2 2
COLEXTFLAG Integer 1 N A parameter indicating whether the generic region segment is
extended to represent coloured bitmap.
f)
SBCOLS Array of colours An array containing the colours used in this text region.
(Notes left untouched)
e)
REPLACE operator is used if and only if COLEXTFLAG = 1.
f)
Unused if COLEXTFLAG = 0.
7) Clause 6.4.4, Variables used in decoding
Add new rows of SBCOLSECTSIZE and SBFGCOLID after HO , and Note b) after Note a) in Table 11 as follows (with
I
the additions underlined):
Table 11 – Variables used in the text region decoding procedure
Name Type Size Signed? Description and restrictions
(bits)
(Rows left untouched)
a)
HO Integer 32 N The height of IBO .
I I
b)
SBCOLSECTSIZE Integer 32 N The colour section length.
SBFGCOLID Array of integers An array of colour palette ID, indicating the colour of each symbol
b)
instance.
a)
Unused if SDREFINE = 0.
b)
Unused if COLEXTFLAG = 0.
8) Clause 6.4.5, Decoding the text region
Insert Figure AMD3-1 after Figure 17 as follows:
Initial STRIPT values
First strip
Second strip
…
Last strip
Colour section
Figure AMD3-1 – Coded structure of a text region extended for colour text
Rec. ITU-T T.88 (2000)/Amd.3 (05/2011) 3
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ISO/IEC 14492:2001/Amd.3:2012 (E)
9) Clause 6.4.5, Decoding the text region
Insert Figure AMD3-2 after Figure 20:
Colour palette IDs
Colour section length
Figure AMD3-2 – Coded structure of colour section
10) Clause 6.4.5, Decoding the text region
Insert new Notes after Figure AMD3-2:
NOTE 3bis – If COLEXTFLAG is 1 then a colour section, which specifies the colours of all symbol instances, is put at the end
of the region as shown in Figure AMD3-1. The colour section consists of two parts as shown in Figure AMD3-2: colour palette
IDs and colour section length. The colour palette IDs, which is encoded in the data structure based on Rec. ITU-T T.45, contains
the information that specifies the colour of every symbol instances in the segment. The colour section length is a 4-byte field that
contains the length of the colour section, in bytes.
NOTE 3ter – The background colour of the segment of which COLEXTFLAG is 1 is regarded as transparent.
11) Clause 6.4.5, Decoding the text region
Change the procedures itemized by 3) and 4) to 4) and 5) respectively, and insert a new procedure 3) as follows (with
the modifications and additions underlined):
3) If COLEXTFLAG is 1, decode the colour section as described in 6.4.12.
(Procedures left untouched)
4) Decode each strip as follows:
(Procedures left untouched)
5) After all the strips have been decoded, the current contents of SBREG are the results that shall be
obtained by every decoder, whether it performs this exact sequence of steps or not.
12) Clause 6.4.5, Decoding the text region
In the sub-procedure 4)-c), which is previously itemized by 3)-c), change the sub-sub-procedures itemized by ix), x) and
xi) to x), xi) and xii) respectively, and insert a new sub-sub-procedure ix) after procedure viii), as follows (with the
modifications and additions underlined):
ix) If COLEXTFLAG is 1, set the colour specified by SBCOLS[SBFGCOLID[NINSTANCES]] to the
foreground colour of the symbol instance bitmap IB .
I
x) Draw IB into SBREG. Combine each pixel of IB with the current value of the corresponding pixel in
I I
SBREG, using the combination operator specified by SBCOMBOP. Write the results of each
combination into that pixel in SBREG.
xi) Update CURS as follows:
(Procedures left untouched)
xii) Set:
NINSTANCES = NINSTANCES + 1
13) Clause 6.4.5, Decoding the text region
Insert a new Note at the end of 6.4.5, as follows:
NOTE 6 – The colour palette (SBCOLS) is created by concatenating the default colour set (CPDEFCOLS) and the additional
colours (CPEXCOLS) defined i
...
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