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1、Reference number ISO/IEC 16485:2000(E) ISO/IEC 2000 INTERNATIONAL STANDARD ISO/IEC 16485 First edition 2000-09-15 Information technology Mixed Raster Content (MRC) Technologies de linformation Contenu des rasters-multiples (MRC) Copyright International Organization for Standardization Provided by IH
2、S under license with ISO Licensee=Rock Island Arsenal/9983967100, User=Schabilion, Shelley Not for Resale, 04/10/2007 07:20:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/IEC 16485:2000(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance wi
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5、ry care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO/IEC 2000 All rights reserved. Unless otherwise specified, no part of this publi
6、cation 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 of the requester. ISO copyright office Case postale 56 ? CH-1211 Gen
7、eva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.ch Web www.iso.ch Printed in Switzerland ii ISO/IEC 2000 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Rock Island Arsenal/9983967100, User=Schabilio
8、n, Shelley Not for Resale, 04/10/2007 07:20:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/IEC 16485:2000(E) ISO/IEC 2000 All rights reservediii CONTENTS Page Forewordiv Introduction and background.v 1Scope1 2References1 3Definitions2 4Conventions3 5Image representa
9、tion3 6Stripe structure .4 6.1Three-layer stripe (3LS).4 6.2Two-layer stripe (2LS).4 6.3One-layer stripe (1LS)5 7Image coding5 7.1Spatial resolution5 7.2Stripe width and layer width 5 7.3Stripe height and layer height.6 7.4Layer combination6 8Layer transmission order6 9Data format.6 9.1Overview6 9.2
10、Page data structure .7 9.2.1Start of page marker segment.7 9.2.2Optional marker segments9 9.2.2.1 Layer base colour gamut range marker segment (OMSg), MRC10 entry.9 9.2.2.2 Layer base colour illuminant marker segment (OMSi), MRC11 entry10 9.2.2.3 MRC3 to MRC9 and MRC12 to MRC254 entry for future ext
11、ensions.11 9.2.3TN (Termination Number).11 9.3Stripe data structure11 9.4EOP (End of Page).13 9.5Layer data structure13 9.6Data format summary.13 9.6.1High-level data format summary13 9.6.2Detail data format summary.13 Annex A - Mixed Raster Content (MRC) Modes 2 and 3.22 Copyright International Org
12、anization for Standardization Provided by IHS under license with ISO Licensee=Rock Island Arsenal/9983967100, User=Schabilion, Shelley Not for Resale, 04/10/2007 07:20:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/IEC 16485:2000(E) iv ISO/IEC 2000 All rights reserv
13、ed 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 tec
14、hnical 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 p
15、art in the work. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical com
16、mittee 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 International Standard may be the subject of patent rights.
17、ISO and IEC shall not be held responsible for identifying any or all such patent rights. International Standard ISO/IEC 16485 was prepared by the International Telecommunication Union (ITU) (as ITU-T Recommendation T.44) and was adopted, under a special “fast-track procedure”, by Joint Technical Com
18、mittee ISO/IEC JTC 1, Information technology, in parallel with its approval by national bodies of ISO and IEC. Annex A forms a normative part of this International Standard. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Rock Island Arsenal/9
19、983967100, User=Schabilion, Shelley Not for Resale, 04/10/2007 07:20:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/IEC 16485:2000(E) ISO/IEC 2000 All rights reservedv Introduction and background The Mixed Raster Content (MRC) Recommendation is a way of describing r
20、aster-oriented (scanned and/or rasterized synthetic images) documents with both bi-level (text and/or line-art) and multi-level (colour/continuous-tone) data within a page. The goal of this MRC Recommendation is to make exchange of raster-oriented mixed content colour documents among users with vari
21、ed communication systems possible with higher speed, higher image quality and modest computing resources (memory, storage and processing power). The dramatic increase in exchange of electronic documents has raised customer expectations and requirements for raster-oriented documents. Colour must be e
22、xchanged just as graceful and efficiently as black image quality in a scan anywhere - print anywhere environment is directly related to the exchange of device independent data forms and the rendering compromises made by the output engine; fast printing with modest resources is related to low complex
23、ity of the format. The best approach to achieve high compression ratios and retain quality is to compress the different segments of the raster data according to their individual attributes. Text and line-art data (bi-level data) would be compressed with an approach that puts high emphasis on maintai
24、ning the detail and structure of the input. Pictures and colour gradients (multi-level data) would be compressed using an approach that puts a high emphasis on maintaining the smoothness and accuracy of the colours. These different data types (bi-level and multi-level) are often conceptualized as be
25、ing on separate layers/planes within the page. This separation of the data by importance of content (spatial detail vs. colour) also directly implies that it is advantageous to use different resolutions for the different data, with a high spatial resolution used for text/line-art and high colour res
26、olution for images/gradients. This concept of data separation by importance of content has led to development of the base mode 3-layer model on which the MRC Recommendation is built. Provisions to extend the model beyond the base mode are defined in Annexes to this Recommendation. The base mode 3-la
27、yer model identifies three basic data types that may be contained within a page. These are multi-level data associated with contone colour (continuous-tone and/or palletized colour) image for which mid-to-low spatial and high colour resolution is typically appropriate for good reproduction; bi-level
28、 data associated with high detail of text/line-art for which high spatial and low colour resolution is typically appropriate for good reproduction; multi-level data associated with multi-level colours of the text/line-art data for which mid- to-high spatial and mid-colour resolution is typically app
29、ropriate for good reproduction. Each page within the MRC model is processed independently. The data types within each page are represented in distinct layers (also referred to as planes) to be image processed, compressed and transmitted independently. Multi-level contone data may be represented in t
30、he lower layer, bi-level in the middle layer and multi- level data of text/line-art colours in the upper layer. The lower and upper layers will from here on be referenced as the background and foreground layers respectively, see Figure 1. The process of image regeneration is controlled by the middle
31、 bi-level layer that acts as a mask or selector to select whether pixels from the background contone layer or foreground text/line-art colour layer will be reproduced. Due to its selection function this layer is referenced as the mask or selector layer, throughout this Recommendation the middle laye
32、r will be referenced as the mask layer. When the value of a mask layer pixel is one (1), the corresponding pixel from the foreground is selected and reproduced. When the value Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Rock Island Arsenal
33、/9983967100, User=Schabilion, Shelley Not for Resale, 04/10/2007 07:20:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/IEC 16485:2000(E) vi ISO/IEC 2000 All rights reserved of the mask layer pixel is zero (0) the corresponding pixel from the background is selected an
34、d reproduced, see Figure 2. Given limited device memory in many facsimile implementations and that mixed content pages often have a mixture of: text/line-art (monochrome or coloured) regions; contone image regions; text/line-art (monochrome or coloured) and contone image regions. There are provision
35、s to subdivide the page into horizontal stripes that span the entire width of the page and isolate individual regions, see Figure 3. Stripes are composed of one or more layers as determined by the image type within the stripe. The mask layer must span the entire width and height of the stripe. The b
36、ackground and foreground layers need not span the width and height of the stripe. Reduction in the amount of white space coded in the background or foreground layers can be realized by taking advantage of the image width and height data included in the layer data stream and a horizontal and vertical
37、 offset provision. The default of the foreground base colour is black (layer base colour can be changed to any colour). The base colour is defined such that at mask pixel locations (value = 1) where a corresponding foreground pixel is not present, the foreground layer base colour is applied. The def
38、ault of the background base colour is white (layer base colour can be changed to any colour). The base colour is defined such that at mask pixel locations (value = 0) where a corresponding contone image is not present, the background layer base colour is applied, see Figure 4. The 3-layer model has
39、3 types of horizontal stripes that are implemented according to the type of data being addressed: 3-layer stripe (3LS), so referenced since it contains all three of the foreground, mask and background layers as in Figure 1. The 3LS is appropriate when addressing an image that contains both multi-col
40、oured text/line-art and contone image or monochrome text/line-art on coloured background and contone image, as in stripes 3 and 5 of Figures 3 and 8; 2-layer stripe (2LS), so referenced since it contains coded data for two of the three layers (the third is set to a fixed value). The two layers may b
41、e mask and background, as in Figure 6a or mask and foreground layers, as in Figure 6b. All combination of multiple layers shall include the mask layer. The 2LS is appropriate when addressing an image that contains monochrome text/line-art and contone image or coloured text/line-art and no contone im
42、age, as in stripes 2 and 7 of Figures 3 and 8; 1-layer stripe (1LS), so referenced since it contains coded data for only one of the three layers (the other two are set to fixed values). The one layer may be mask, as in Figure 7a, background, as in Figure 7b or foreground, as in Figure 7c. The 1LS is
43、 appropriate when addressing an image that contains one of monochrome text/line-art, contone image or possibly richly coloured graphics, as in stripes 1, 4 and 6 of Figures 3 and 8. Figure 8 provides an illustration of the various stripe types that may apply to the various image regions within a pag
44、e. The 3-layer model requires application of a multi-level coding scheme to the background and foreground layers. Any ITU multi-level coding (such as JPEG or JBIG, as defined in Recommendation T.81 and T.43, respectively) may be used for the background or foreground. A bi-level coding scheme is requ
45、ired for the mask layer, any ITU bi-level coding (such as JBIG or MMR, as defined in Recommendations T.85 and T.6, respectively) may be used, see Figure 5. The specific coders used throughout the page and over the various layers are identified at the start of each page. This information is provided
46、by parameters in a Start of Page (SOP) Marker Segment. The spatial resolution of the mask layer, to be used throughout the page, is also identified by a SOP parameter. Layers with varied spatial resolutions may be combined within a stripe, the resolution of the foreground and background layers must
47、be integral factors of the mask resolution layer, see Figure 5. The specific resolutions being used in the foreground and background layers are identified within a marker segment at the start of each layer within a stripe. A Start of Stripe marker segment contains parameters indicating type of strip
48、e (1LS, 2LS or 3LS), the foreground and Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Rock Island Arsenal/9983967100, User=Schabilion, Shelley Not for Resale, 04/10/2007 07:20:24 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/IEC 16485:2000(E) ISO/IEC 2000 All rights reservedvii background layer base colour, offset of the foreground and/or background, the stripe height (number of lines) and the mask layer coded data length (number of octets). An SOP marker segment denotes the beginning of an MRC page. Th