1、 ISO 2012 Photography and graphic technology Extended colour encodings for digital image storage, manipulation and interchange Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB) Photographie et technologie graphique Codages par couleurs tendues pour stockage, manipulation et
2、change dimage numrique Partie 3: Codage dimage en couleurs RVB par rfrence dentre par voie mtrique TECHNICAL SPECIFICATION ISO/TS 22028-3 Second edition 2012-08-01 Reference number ISO/TS 22028-3:2012(E) ISO/TS 22028-3:2012(E) ii ISO 2012 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2012 All
3、 rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country o
4、f the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ISO/TS 22028-3:2012(E) ISO 2012 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normati
5、ve references 1 3 T erms and definitions . 2 4 Requirements 5 4.1 General . 5 4.2 Adopted white . 7 4.3 Reference medium primaries and white point . 7 4.4 RIMM RGB, ERIMM RGB, FP-RIMM RGB colour image encoding 7 4.5 Inverse RIMM RGB transformation 11 Annex A (informative) Example colour rendering tr
6、ansform from RIMM RGB to ROMM RGB .14 Bibliography .19 ISO/TS 22028-3:2012(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through IS
7、O technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates c
8、losely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. D
9、raft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requir
10、ement for such documents, a technical committee may decide to publish other types of document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it is approved by more than 50 % of the member
11、s of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An ISO/PAS or ISO/TS is reviewed after three
12、 years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either be transformed into an International Stan
13、dard or be withdrawn. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TS 22028-3 was prepared by Technical Committee ISO/TC 42, Photography. This
14、 second edition cancels and replaces the first edition (ISO/TS 22028-3:2006), which has been technically revised. ISO/TS 22028 consists of the following parts, under the general title Photography and graphic technology Extended colour encodings for digital image storage, manipulation and interchange
15、: Part 1: Architecture and requirements Part 2: Reference output medium metric RGB colour image encoding (ROMM RGB) Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB) Technical Specification The following parts are under preparation: Part 4: European Colour Initiative RGB col
16、our image encoding eciRGB (2008) Technical Specification iv ISO 2012 All rights reserved ISO/TS 22028-3:2012(E) Introduction This part of ISO 22028 has been developed in order to meet the industry need for a complete, fully- documented, publicly-available definition of a wide-primary scene-referred
17、extended colour gamut red-green-blue (RGB) colour image encoding. This encoding provides a way to represent scene-referred images that does not limit the colour gamut to those colours capable of being displayed on a CRT monitor, or require the use of negative RGB colourimetry coordinates. A scene-re
18、ferred extended colour gamut colour encoding is particularly desirable for professional photography applications. For example, colours captured by digital cameras, as well as conventional capture devices such as photographic film, can be outside those that can be represented within the colour gamut
19、of a typical monitor or other types of output devices. Similarly, scene-referred images can have a larger luminance dynamic range than output-referred images since they have not been modified by a colour rendering process to fit the images to a specific output medium applying appropriate tone and co
20、lour reproduction aims. Retaining the unrendered scene-referred image data has the advantage that it preserves the option to make decisions about how a particular image is to be rendered. For example, a scene-referred image of a backlit scene can retain information about both the dark foreground reg
21、ion and the bright background region of the scene. This information can be used to make a properly exposed print of either the foreground region or the background region, or alternatively can be used to create an improved image by rendering the two regions differently. By using a standard scene-refe
22、rred extended colour gamut colour image encoding, images can be stored, interchanged and manipulated without restricting the image to a particular rendering intent or output device. The reference input medium metric RGB (RIMM RGB) colour encoding specified in this part of ISO 22028 meets the needs o
23、f these types of applications. An extended dynamic range version of this colour image encoding known as extended reference input medium metric RGB (ERIMM RGB), and a floating point version known as FP-RIMM RGB are also specified for use with high-dynamic range input sources. The scene-referred RIMM
24、RGB colour image encoding is intended to be complementary to the output-referred ROMM RGB colour image encoding specified in ISO/TS 22028-2. Both colour encodings are based on the same “wide RGB” additive colour space to facilitate the development of image processing algorithms and simple colour ren
25、dering transformations to convert scene-referred RIMM RGB images to rendered output-referred ROMM RGB images. The International Organization for Standardization (ISO) draws attention to the fact that it is claimed that compliance with this document may involve the use of patents concerning extended
26、range colour encodings given in 4.4 and 4.5. ISO takes no position concerning the evidence, validity and scope of this patent right. The holder of this patent right has assured ISO that he/she is willing to negotiate licences under reasonable and non-discriminatory terms and conditions with applican
27、ts throughout the world. In this respect, the statement of the holder of this patent right is registered with ISO. Information may be obtained from Director, Intellectual Property Agreements and Standards Eastman Kodak Company 343 State StreetRochester New York 14650-0211, USA Attention is drawn to
28、the possibility that some of the elements of this document may be the subject of patent rights other than those identified above. ISO shall not be held responsible for identifying any or all such patent rights. ISO 2012 All rights reserved v Photography and graphic technology Extended colour encodin
29、gs for digital image storage, manipulation and interchange Part 3: Reference input medium metric RGB colour image encoding (RIMM RGB) 1 Scope This part of ISO 22028 specifies a family of scene-referred extended colour gamut RGB colour image encodings designated as reference input medium metric RGB (
30、RIMM RGB). Digital images encoded using RIMM RGB can be manipulated, stored, transmitted, displayed or printed by digital still picture imaging systems. Three precision levels are defined using 8-, 12- and 16-bits/channel. An extended luminance dynamic range version of RIMM RGB is also defined, desi
31、gnated as extended reference input medium metric RGB (ERIMM RGB). Two precision levels of ERIMM RGB are defined using 12- and 16-bits/channel. FP-RIMM RGB, a floating point version of RIMM RGB, defines the expression method of RIMM RGB in a floating point figure. Three precision levels of FP-RIMM RG
32、B are defined using 16-, 32- and 64-bits/channel. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including a
33、ny amendments) applies. ISO 12234-2, Electronic still-picture imaging Removable memory Part 2: TIFF/EP image data format ISO 22028-1:2004, Photography and graphic technology Extended colour encodings for digital image storage, manipulation and interchange Part 1:Architecture and requirements ISO 116
34、64-1, Colorimetry Part 1: CIE standard colorimetric observers 1) CIE Publication 15, Colorimetery IEEE 754, IEEE Standard for Floating-Point Arithmetic 1) Replaces ISO/CIE 10527. TECHNICAL SPECIFICATION ISO/TS 22028-3:2012(E) ISO 2012 All rights reserved 1 ISO/TS 22028-3:2012(E) 3 T erms an d defini
35、ti ons For the purposes of this document, the following terms and definitions apply. 3.1 adapted white colour stimulus that an observer who is adapted to the viewing environment would judge to be perfectly achromatic and to have a luminance factor of unity; i.e. absolute colourimetric coordinates th
36、at an observer would consider to be a perfect white diffuser NOTE The adapted white can vary within a scene. 3.2 additive RGB colour space colourimetric colour space having three colour primaries (generally red, green and blue) such that CIE XYZ tristimulus values can be determined from the RGB colo
37、ur space values by forming a weighted combination of the CIE XYZ tristimulus values for the individual colour primaries, where the weights are proportional to the radiometrically linear colour space values for the corresponding colour primaries NOTE 1 A simple linear 3 3 matrix transformation can be
38、 used to transform between CIE XYZ tristimulus values and the radiometrically linear colour space values for an additive RGB colour space. NOTE 2 Additive RGB colour spaces are defined by specifying the CIE chromaticity values for a set of additive RGB primaries and a colour space white point, toget
39、her with a colour component transfer function. 3.3 adopted white spectral radiance distribution as seen by an image capture or measurement device and converted to colour signals that are considered to be perfectly achromatic and to have an observer adaptive luminance factor of unity; i.e. colour sig
40、nals that are considered to correspond to a perfect white diffuser NOTE 1 The adopted white can vary within a scene, if such variation is supported by the imaging system. NOTE 2 The adopted white is not required to be an estimate or approximation of the adapted white. For example, if a scene lit by
41、tungsten illumination is captured using a DSC with the white balance set to D55 (daylight), the adopted white will be D55 but the adapted white will be closer to a tungsten illuminant (e.g. ISO 7589 Studio Tungsten or CIE Illuminant A). NOTE 3 See 3.1. 3.4 colourimetric colour space colour space hav
42、ing an exact and simple relationship to CIE colourimetric values NOTE Colourimetric colour spaces include those defined by CIE (e.g. CIE XYZ, CIELAB, CIELUV), as well as colour spaces that are simple transformations of those colour spaces (e.g. additive RGB colour spaces). 3.5 colour component trans
43、fer function single variable, monotonic mathematical function applied individually to one or more colour channels of a colour space NOTE 1 Colour component transfer functions are frequently used to account for the nonlinear response of a reference device and/or to improve the visual uniformity of a
44、colour space. NOTE 2 Generally, colour component transfer functions will be nonlinear functions such as a power-law (i.e. “gamma”) function or a logarithmic function. However , in some cases a linear colour component transfer function can be used. 3.6 colour encoding generic term for a quantized dig
45、ital encoding of a colour space, encompassing both colour space encodings and colour image encodings 2 ISO 2012 All rights reserved ISO/TS 22028-3:2012(E) 3.7 colour gamut solid in a colour space, consisting of all those colours that are either present in a specific scene, artwork, photograph, photo
46、mechanical, or other reproduction, or capable of being created using a particular output device and/or medium 3.8 colour image encoding digital encoding of the colour values for a digital image, including the specification of a colour space encoding, together with any information necessary to proper
47、ly interpret the colour values such as the image state, the intended image viewing environment and the reference medium NOTE 1 In some cases, the intended image viewing environment will be explicitly defined for the colour image encoding. In other cases, the intended image viewing environment can be
48、 specified on an image-by-image basis using metadata associated with the digital image. NOTE 2 Some colour image encodings will indicate particular reference medium characteristics, such as a reflection print with a specified density range. In other cases, the reference medium will not be applicable
49、, such as with a scene-referred colour image encoding, or will be specified using image metadata. NOTE 3 Colour image encodings are not limited to pictorial digital images that originate from an original scene, but are also applicable to digital images with content such as text, line art, vector graphics and other forms of original artwork. 3.9 colour rendering mapping of image data representing the colour-space coordinates of the elements of a scene to output- referred image data representing the colour space
