1、INTERNATIONAL TELECOMMUNICATION UNIONITU-TT.82TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITUCorrigendum 2(03/2001)SERIES T: TERMINALS FOR TELEMATIC SERVICESCorrigendum 2: Information technology Codedrepresentation of picture and audio information Progressive bi-level image compressionCAUTION !PREPUBL
2、ISHED RECOMMENDATIONThis prepublication is an unedited version of a recently approved Recommendation.It will be replaced by the published version after editing. Therefore, there will bedifferences between this prepublication and the published version.FOREWORDThe International Telecommunication Union
3、 (ITU) is the United Nations specialized agency in the field oftelecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ ofITU. ITU-T is responsible for studying technical, operating and tariff questions and issuingRecommendations on them with a view to standa
4、rdizing telecommunications on a worldwide basis.The World Telecommunication Standardization Assembly (WTSA), which meets every four years,establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations onthese topics.The approval of ITU-T Recommendations is covered
5、 by the procedure laid down in WTSA Resolution 1.In some areas of information technology which fall within ITU-Ts purview, the necessary standards areprepared on a collaborative basis with ISO and IEC.NOTEIn this Recommendation, the expression “Administration“ is used for conciseness to indicate bot
6、h atelecommunication administration and a recognized operating agency.INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation mayinvolve the use of a claimed Intellectual Property Right. ITU takes no position concerning the eviden
7、ce,validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or othersoutside of the Recommendation development process.As of the date of approval of this Recommendation, ITU had/had not received notice of intellectualproperty, protected by patents, which may
8、 be required to implement this Recommendation. However,implementors are cautioned that this may not represent the latest information and are therefore stronglyurged to consult the TSB patent database. ITU 2001All rights reserved. No part of this publication may be reproduced or utilized in any form
9、or by any means,electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU.ITU-T T.82/Cor.2 (03/2001) Prepublished version 1Corrigendum 2 to Recommendation T.82: Information technology -Coded representation of picture and audio information -Progressive bi-
10、level image compressionSummaryCorrigendum 2 makes changes to Sections 6.1.2, 6.2.6.1 and 6.8.2.9 and to Figure 27.1) In 6.1.2, change the third bullet as follows: A pixel reference in a stripe above the current one shall return the actual value of the pixel, unlessthe pixel is above the image or in
11、the previous stripe of this layer which is terminated with SDRST, inwhich case the background-border-rule for the image top shall be applied.2) In 6.2.6.1, change the last paragraph as follows:For the first stripe of a layer, or after SDRST at the end of the previous stripe in a layer, set AT pixelt
12、o its default location. After SDNORM at the end of the previous stripe in a layer, set AT pixel locationto its value at the end of the previous stripe of the layer.Further discussion of adaptive template pixels and the variables yAT, X, and Yappears in 6.7.3.3) In 6.8.2.9, change the first sentence
13、as follows:If this stripe is at the top of the image or the previous stripe of this layer is terminated with SDRST,the probability-estimation states for all possible values of CX are set to 0 (that is, the equiprobablestate).ITU-T T.82/Cor.2 (03/2001) Prepublished version 24) In 6.8.2.9, change the
14、Figure 27 as follows:Yes NoFor all CX, set ST(CX) and MPS(CX) totheir values at the end of the previousstripe of this layer.Set AT pixel location to its value at theend of the previous stripe of this layer.When in lowest resolution layer, setLNTPy1 to its value at the endof the previous stripe of th
15、is layer.For referencing pixels across top stripeboundary, use pixel values from theprevious stripe of this layer.SC=0A=0x10000C=0CT=11First stripe of thislayer or after SDRST?For all CX,ST(CX)=0MPS(CX)=0Set AT pixel to its default location.When in lowest resolution layer, setLNTPy1 value to 1.For r
16、eferencing pixels across top stripeboundary, use pixel values from thebackground-border-rule in 6.1.2.5) Change the “The new-length marker” to “The NEWLEN marker” in the Note 1 of 6.2.6.26) Change the Technical Corrigendum1, III 8) to the following:“Change the three instances of “comment “ or “Comment” to “COMMENT” in 6.2.6.3”_
