1、American National Standardfor Photography Digital Still Cameras Guidelines for ReportingPixel-Related SpecificationsANSI/I3A IT10.7000-2004ANSI/I3AIT10.7000-2004ANSI/I3A IT10.7000-2004American National Standardfor PhotographyDigital Still Cameras Guidelines for ReportingPixel-Related SpecificationsS
2、ecretariatInternational Imaging Industry AssociationApproved June 24, 2004 American National Standards Institute, Inc.Approval of an American National Standard requires review by ANSI that therequirements for due process, consensus, and other criteria for approval havebeen met by the standards devel
3、oper.Consensus is established when, in the judgement of the ANSI Board ofStandards Review, substantial agreement has been reached by directly andmaterially affected interests. Substantial agreement means much more thana simple majority, but not necessarily unanimity. Consensus requires that allviews
4、 and objections be considered, and that a concerted effort be madetowards their resolution.The use of American National Standards is completely voluntary; theirexistence does not in any respect preclude anyone, whether he has approvedthe standards or not, from manufacturing, marketing, purchasing, o
5、r usingproducts, processes, or procedures not conforming to the standards.The American National Standards Institute does not develop standards andwill in no circumstances give an interpretation of any American NationalStandard. Moreover, no person shall have the right or authority to issue aninterpr
6、etation of an American National Standard in the name of the AmericanNational Standards Institute. Requests for interpretations should beaddressed to the secretariat or sponsor whose name appears on the titlepage of this standard.CAUTION NOTICE: This American National Standard may be revised orwithdr
7、awn at any time. The procedures of the American National StandardsInstitute require that action be taken periodically to reaffirm, revise, orwithdraw this standard. Purchasers of American National Standards mayreceive current information on all standards by calling or writing the AmericanNational St
8、andards Institute.American National StandardPublished byAmerican National Standards Institute, Inc.25 West 43rd Street, New York, NY 10036Copyright 2004 by International Imaging Industry Association (I3A)All rights reserved.No part of this publication may be reproduced in anyform, in an electronic r
9、etrieval system or otherwise,without prior written permission of the publisher.Printed in the United States of AmericaiContentsPageForeword ii1 Scope . 12 Normative references . 13 Terms and definitions . 14 Relationship between pixel-related terms for image sensors and DSCs 35 Rules for reporting 5
10、5.1 Number of effective pixels 65.2 Total number of image sensor cells 65.3 Number of Recorded Pixels 75.4 Number of Output Pixels 75.5 Image File Size. 85.6 Image Data Compression Ratio . 85.7 Sensor Cell Pitch 95.8 Focal Plane Size. 95.9 35mm-equivalent Focal Length 105.10 Sensor optical format 10
11、Table1 Sensor optical formats 11Figures1 Relationships of pixel-related terms for image sensors 42 Relationship of pixel-related terms for image sensors and DSCs 5Annexes A Examples of suitable specifications 12B Bibliography 13iiForeword (This foreword is not part of American National Standard ANSI
12、/I3A IT10.7000-2004.)This standard has been developed in order to meet the industry need for a standard-ized method of reporting the pixel-related specifications (e.g., the “number of pixels“)for digital still cameras (DSCs). Without an ANSI standard, several different methodswill continue to be use
13、d by various camera vendors, causing significant user confu-sion. In July 2001, the Japan Camera Industries Association (JCIA) in Japan adopt-ed a “Guideline for Noting Digital Camera specifications in Catalogs“, which providesstandardized pixel-related definitions for DSCs. In July 2002, JCIA was d
14、issolvedand the Camera and Imaging Products Association (CIPA) was formed. CIPA nowhas responsibility for the JCIA guideline. I3A/IT10 and CIPA have cooperated in thedevelopment of this complementary standard for the USA.The pixel-related specifications defined in this standard are not a ranking of
15、the im-age quality of the DSC. For example, it is possible that a first DSC with a smaller re-ported value will provide better image quality than a second DSC having a largerreported value. ISO TC42 - Photography has developed a number of standards formeasuring image quality related attributes of a
16、DSC. These include ISO12232:1998, Photography - Electronic still picture cameras - Determination of ISOspeed; ISO 12233:2000, Photography - Electronic still picture cameras - Resolutionmeasurements; ISO 14524:1999, Photography - Electronic still picture camera -Methods for measuring opto-electronic
17、conversion functions (OECFs); and ISO15739:2003, Photography - Electronic still picture imaging - Noise measurements.It is possible that an ISO standard specifying guidelines for reporting pixel-relatedspecifications for DSCs will be developed in the future. Once such an ISO standardis published, it
18、 is anticipated that this standard will be withdrawn.Annexes A and B of this standard are for information only.Suggestions for the improvement of this standard will be welcome. They should beforwarded to the International Imaging Industry Association, Inc. (I3A), 550 Mama-roneck Avenue, Suite 310, H
19、arrison, NY 10528, e-mail: i3astdsi3a.org.This standard was processed and approved for submittal to ANSI by I3A TechnicalCommittee IT10, Electronic Still Picture Imaging. Committee approval of the stan-dard does not necessarily imply that all committee members voted for its approval.At the time it a
20、pproved this edition of the standard, the IT10 Committee had the fol-lowing members:Kenneth Parulski, I3A/IT10 Chair Jack Holm, I3A/IT10 Vice-ChairJames A. Peyton, I3A/IT10 SecretariatOrganization Represented Name of RepresentativeAdobe Systems, Inc. Scott FosheeCanon Development Americas, Inc Sharo
21、n HenleyTodd Newman (Alt.)Eastman Kodak Company Kenneth ParulskiDaryl Hunt (Alt.)Kevin Spaulding (Alt.)Brian Keelan (Alt.)Sean Kelly (Alt.)Tim Looney (Alt.)Timothy Whitcher (Alt.)Don Williams (Alt.)Scott Houchin (Alt.)iiiOrganization Represented Name of RepresentativeFotonation .Eran SteinbergFoveon
22、, Inc. Paul HubelHewlett-Packard Company .Jack HolmRamon Garrido (Alt.)Ingeborg Tastl (Alt.)Mark Gorzynski (Alt.)Pieter van Zee (Alt.)Intel Corporation.Werner MetzJostens Research & DevelopmentJohn SouterLifetouch, Inc.Ron AntosRIT Franziska FreySamsung Electronics Jangwook ShimSony Electronics .Eri
23、c EdwardsAndrew Chiu (Alt.)ViewQuest Technologies, IncJeff LeeIndividual ExpertEric WalowitAMERICAN NATIONAL STANDARD ANSI/I3A IT10.7000-2004American National Standard for Photography Digital Still Cameras Guidelines for Reporting Pixel-Related Specifications 1 1 Scope This standard specifies guidel
24、ines for reporting pixel-related specifications (e.g., the number of camera pixels) of a digital still camera, for the purposes of camera labeling, camera packaging, advertising, and the like. It is applicable to monochrome and color digital still cameras using one or more image sensors 2 Normative
25、references The following standard contains provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this American
26、National Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. ISO 12231:1998 Photography Electronic still picture imaging Terminology 3 Terms and definitions For the purposes of this document, the following terms and definitions
27、apply: 3.1 digital still camera (DSC) A device that incorporates an image sensor and produces a digital signal representing a still picture. NOTE: A digital camera is typically a portable, hand-held device. The digital signal is usually recorded on a digital storage media, such as a solid-state memo
28、ry card or magnetic disk. 3.2 effective pixels The number of photoelements included in an area equal to the picture area plus the ring pixel area, as defined in this standard. NOTE: The definition of effective pixels is based on the definition of the “Number of Effective Pixels” in the JCIA Guidelin
29、e for Noting Digital Camera Specifications in Catalogs. ANSI/I3A IT10.7000-2004 2 3.3 35mm-equivalent focal length The measured focal length of a DSC camera lens multiplied by a normalization factor, as defined in this standard. NOTE: The normalization factor is equal to the ratio of the focal plane
30、 diagonal distance used for 35mm film photography and the focal plane diagonal distance of the image sensor used in the DSC. 3.4 focal plane size The horizontal and vertical distances of the focal plane of an image sensor that receives illumination from a portion of the scene that is represented in
31、the image file provided by a DSC, as defined in this standard. 3.5 image compression A process that alters the way digital image data are encoded in order to reduce the size of an image file. 3.6 image data compression ratio The ratio of the size of the compressed image data to the size of the image
32、 data that was input to the image compression process, as defined in this standard. 3.7 image file size The amount of data that comprises one image frame stored in the digital storage media of a DSC, as defined in this standard. 3.8 imager size The classification of the focal plane size of an image
33、sensor, as defined in this standard. 3.9 number of output pixels The number of horizontal and vertical luminance pixels comprising one picture frame, which is output by the DSC via a cable or wireless connection, as defined in this standard. 3.10 number of recorded pixels The number of horizontal an
34、d vertical luminance pixels comprising one picture frame stored on the digital recording media of a DSC, as defined in this standard. 3.11 picture area The number of photoelements on the image sensor which receive illumination from the scene through the cameras optical lens, and which represent a po
35、rtion of the scene which is represented in the image file provided by the DSC. 3.12 pixel The contraction of picture element, smallest geometric unit of information in a digital representation of an image, corresponding to a single spatial sample. ANSI/I3A IT10.7000-2004 3 NOTE 1: For a single-chann
36、el (e.g. monochrome) image, a pixel value can be represented as a single digital code value. NOTE 2: The number of pixels in a digital image can be arbitrarily increased or decreased as a result of resampling. NOTE 3: It is common to also use the term pixel to mean a photoelement on an image sensor,
37、 a display element on an image display, or a printed element on a hardcopy print. 3.13 resolution The measure of the ability of a digital image capture system, or a component of a digital image capture system, to depict spatial picture detail. 3.14 sensor cell pitch The horizontal and vertical spaci
38、ng of photoelements on an image sensor. NOTE: For an image sensor that provides “square pixels”, the sensor cell pitch is equal in the horizontal and vertical dimensions. 3.15 total number of image sensor cells The number of cells in the image sensor array, including all effective image sensor cells
39、 and all optical black cells, as defined in this standard. 4 Relationship between pixel-related terms for image sensors and DSCs Figure 1 shows an example of the relationships between pixel-related terms for image sensors. In many DSCs, the image circle provided by the camera lens completely encircl
40、es area C, and illuminates all of the usable image sensor cells. However, in this particular example, the camera lens provides an image circle that does not illuminate all of the image sensor cells in area C. As a result, the number of effective pixels in area B is significantly smaller than the num
41、ber of image sensor cells in area C. ANSI/I3A IT10.7000-2004 4 A: Picture area - Photoelements which capture a portion of the scene included in the image file. B: Number of effective pixels (including ring photoelements) used to produce the image file C: Maximum usable sensor cells (Maximum number o
42、f photoelements guaranteed by image sensor vendor) D: Effective image sensor cells (Number of photoelements on the image sensor) E: Total number of image sensor cells (Number of photoelements plus optical black cells on image sensor) Figure 1 Relationships of pixel-related terms for image sensors Fi
43、gure 2 shows an example of the relationship between pixel-related terms for DSC cameras. The DSC stores an image file that represents an image corresponding to the picture area of the image sensor. The number of effective pixels is equal to the picture area plus the number of ring pixels. The total
44、number of image sensor cells is larger than the number of effective pixels, since some of the cells are opaque, or are outside the ring pixel area. The number of recorded pixels may be significantly larger or smaller than the picture area value, if the DSC performs interpolation or decimation prior
45、to recording. The number of output pixels provided by the DSC may be significantly larger or smaller than the number of recorded pixels, if the Image sensor optical blackcells Image circle provided by the camera lens Ring photoelements used for image processing, but not directly represented in the i
46、mage file ANSI/I3A IT10.7000-2004 5 DSC system performs interpolation or decimation when playing back the stored image file. This playback processing may be provided by the DSC itself or by a separate device, such as a host computer. Figure 2 Relationship of pixel-related terms for image sensors and
47、 DSCs 5 Rules for reporting When reporting any pixel-related specifications for DSCs, the number of effective pixels shall be reported using the highest priority notation. All other pixel-related specifications defined in this standard are optional, and do not need to be reported. Using the highest
48、priority notation means that the value is reported using the largest font and most prominent placement in labeling or advertising. When multiple pixel-related specifications are reported, careful consideration should be used to ensure that the other reported values, such as the number of total image
49、 sensor cells, or the number of recorded pixels, cannot be confused with the number of effective pixels. Stored ImageFileResamplingOutputImageNumber of Output PixelsNumber of Recorded PixelsResamplingImageCompressionImage Data Compression RatioImage File SizeImage SensorTotal Number of Image Sensor CellsPictureAreaNumber of Effective PixelsANSI/I3A IT10.7000-2004 6 5.1 Number of effective pixels The number of effective pixels is the number of physical photoelements in the picture area, plus the number of ring pixels. The number of ring pixels is the reasonable, minimu
