1、 International Telecommunication Union ITU-T T.800 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Corrigendum 1 (01/2007) SERIES T: TERMINALS FOR TELEMATIC SERVICES Information technology JPEG 2000 image coding system: Core coding system Technical Corrigendum 1 ITU-T Recommendation T.800 (2002) Tec
2、hnical Corrigendum 1 ITU-T Rec. T.800 (2002)/Cor.1 (01/2007) i INTERNATIONAL STANDARD ISO/IEC 15444-1 ITU-T RECOMMENDATION T.800 Information technology JPEG 2000 image coding system: Core coding system Technical Corrigendum 1 Summary Corrigendum 1 to ITU-T Rec. T.800 (2002) | ISO/IEC 15444-1:2004 cl
3、arifies the default image dimensions expected for a JP2 file, which are potentially different from the JP2 WIDTH/HEIGHT fields. Source Corrigendum 1 to ITU-T Recommendation T.800 (2002) was approved on 13 January 2007 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure.
4、An identical text is also published as Technical Corrigendum 1 to ISO/IEC 15444-1. ii ITU-T Rec. T.800 (2002)/Cor.1 (01/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardizatio
5、n Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets
6、 every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts pu
7、rview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is vo
8、luntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and t
9、he negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involv
10、e the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recomm
11、endation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http
12、:/www.itu.int/ITU-T/ipr/. ITU 2007 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. T.800 (2002)/Cor.1 (01/2007) iii CONTENTS Page 1) Table I.2 . 1 2) Annex I.5.3 . 1 3) Annex I.5.3.1. 1 4) Annex I.5.
13、3.2 through the remainder of Annex I . 2 ISO/IEC 15444-1:2004/Cor.1:2007 (E) ITU-T Rec. T.800 (2002)/Cor.1 (01/2007) 1 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information technology JPEG 2000 image coding system: Core coding system Technical Corrigendum 1 1) Table I.2 Replace the Image Header bo
14、x Comments field with the following text: This box specifies aspects of the reference grid geometry, number of components and bit depth. 2) Annex I.5.3 Replace the second sentence of the ihdr item with the following text: This box specifies information about the reference grid geometry, bit depth, a
15、nd number of components. 3) Annex I.5.3.1 a) Add the following paragraph to the end of the HEIGHT item: The HEIGHT is not always the same as the default image height. See I.5.3.1.1 for formulae specifying the default image dimensions when no other rendering information is present. The HEIGHT value w
16、ill always be an upper bound on the default image height. b) Add the following paragraph to the end of the WIDTH item: The WIDTH is not always the same as the default image width. See I.5.3.1.1 for formulae specifying the default image dimensions when no other rendering information is present. The W
17、IDTH value will always be an upper bound on the default image width. c) Add a new clause I.5.3.1.1 I.5.3.1.1 Default Image Dimensions In instances where only image samples for individual components are needed, refer directly to the component sample dimension equation B-2. However, when some renderin
18、g is required, lacking other rendering or expansion directives, the default image dimensions aim to maintain the image area aspect ratio and are computed from the codestream SIZ marker as a function of, M, the greatest common divisor (gcd) of all the subsampling factors (XRsiz c , YRsiz c ) for all
19、components of the image. Specifically: M = gcdXRsiz c , YRsiz c| for all c, 0 c Csiz (I-1) And the default image dimensions are: (width, height) = M YOsiz M Ysiz M XOsiz M Xsiz , (I-2) ISO/IEC 15444-1:2004/Cor.1:2007 (E) 2 ITU-T Rec. T.800 (2002)/Cor.1 (01/2007) If M is equal to one, then the refere
20、nce grid image area dimensions shown in WIDTH and HEIGHT are equal to the default image width and height. Otherwise, when M 1, the default image has dimensions smaller than WIDTH and HEIGHT. NOTE For example, suppose there is a codestream with Xsiz = Ysiz = 1024 and XOsiz = 3 and YOsiz = 2. This cod
21、estream in a JP2 file would have an Image Header box with WIDTH = 1021 and HEIGHT = 1022. The default image dimensions, however, will depend upon the values of XRsiz and YRsiz. Here are a few different possibilities: a) If any of the subsampling factors XRsiz cor YRsiz cis one, then M = 1, and the d
22、efault image dimensions will equal WIDTH and HEIGHT. b) If XRsiz = 2 and YRsiz = 4, then M = 2 and the default dimensions are image width = 512 2 = 510 and image height = 512 1 = 511. c) If there are 3 components all with XRsiz c= YRsiz c= 4, then M = 4 and the default image width and height are bot
23、h 256 1 = 255. d) If there are 3 components with XRsiz 0= YRsiz 0= 2, XRsiz 1= YRsiz 1= 3, XRsiz 2= YRsiz 2= 2, then M = 1, and the default image dimensions will equal WIDTH and HEIGHT. 4) Annex I.5.3.2 through the remainder of Annex I Confirm equations I-1 through I-3 and any references to them are
24、 renumbered as I-3 through I-5. Manually renumber if necessary. Printed in Switzerland Geneva, 2007 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors
25、 Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimed
26、ia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound programme and television transmi
27、ssion circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic servic
28、es Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
