1、 INCITS/ISO/IEC TR 29794-4:2010 2015 (ISO/IEC TR 29794-4:2010, IDT) Information technology - Biometric Sample Quality - Part 4: Finger image data (Technical Report) INCITS/ISO/IEC TR 29794-4:2010 2015 PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing po
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5、al Standard. Date of Registration: 2/1/2015 Published by American National Standards Institute, 25 West 43rd Street, New York, New York 10036 Copyright 2015 by Information Technology Industry Council (ITI). All rights reserved. These materials are subject to copyright claims of International Standar
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7、the prior written permission of ITI. All requests pertaining to this standard should be submitted to ITI, 1101 K Street NW, Suite 610, Washington DC 20005. Printed in the United States of America ii ITIC 2015 All rights reserved Reference numberISO/IEC TR 29794-4:2010(E)ISO/IEC 2010TECHNICAL REPORT
8、ISO/IECTR29794-4First edition2010-04-01Information technology Biometric sample quality Part 4: Finger image data Technologies de linformation Qualit dchantillon biomtrique Partie 4: Donnes dimage de doigt ISO/IEC TR 29794-4:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In acco
9、rdance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes l
10、icensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for prin
11、ting. Every 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. COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2010 All rights reserved. Unless othe
12、rwise 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 of the requester. ISO copyrigh
13、t 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 ii ISO/IEC 2010 All rights reservedISO/IEC TR 29794-4:2010(E) ISO/IEC 2010 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1
14、 2 Normative references1 3 Terms and definitions .1 4 Symbols and abbreviated terms 2 5 Finger Image Quality.2 5.1 Defect factors of finger image2 5.2 Standardization approaches for exchange of finger image quality .3 6 Finger Image Quality Analysis .3 6.1 Introduction3 6.2 Local Analysis .3 6.2.1 C
15、onstituent of Local Analysis3 6.2.2 Approaches to Local Analysis of Finger Image .3 6.3 Global Analysis9 6.3.1 Constituent of Global Analysis 9 6.3.2 Approaches to Global Analysis of Finger Image .10 6.4 Unified Quality Score 12 6.4.1 Methodology for Combining Quality Metrics12 6.4.2 Weighted Averag
16、e .13 6.4.3 Pattern Classifier .13 6.4.4 Area Consideration .14 Bibliography15 ISO/IEC TR 29794-4:2010(E) iv ISO/IEC 2010 All rights reservedForeword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for world
17、wide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in
18、 fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are draf
19、ted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an Inter
20、national Standard requires approval by at least 75 % of the national bodies casting a vote. In exceptional circumstances, the joint technical committee may propose the publication of a Technical Report of one of the following types: type 1, when the required support cannot be obtained for the public
21、ation of an International Standard, despite repeated efforts; type 2, when the subject is still under technical development or where for any other reason there is the future but not immediate possibility of an agreement on an International Standard; type 3, when the joint technical committee has col
22、lected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example). Technical Reports of types 1 and 2 are subject to review within three years of publication, to decide whether they can be transformed into International Standards. Te
23、chnical Reports of type 3 do not necessarily have to be reviewed until the data they provide are considered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible
24、 for identifying any or all such patent rights. ISO/IEC TR 29794-4, which is a Technical Report of type 2, was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 37, Biometrics. ISO/IEC 29794 consists of the following parts, under the general title Informati
25、on technology Biometric sample quality: Part 1: Framework Part 4: Finger image data Technical Report Part 5: Face image data Technical Report ISO/IEC TR 29794-4:2010(E) ISO/IEC 2010 All rights reserved vIntroduction The quality of finger image data is defined to be the predicted behavior of the imag
26、e in a matching environment. Thus, the quality information is useful in many applications. ISO/IEC 19784-1 and ISO/IEC 19785-1 do allocate a quality field and specify the allowable range for the scores, with the recommendation that the score be divided into four categories with a qualitative interpr
27、etation for each category. Image quality fields are also provided in the fingerprint data interchange formats standardized in ISO/IEC 19794-2, ISO/IEC 19794-3, ISO/IEC 19794-4, and ISO/IEC 19794-8. However, there is no standard way to interpret the quality score that facilitates the interpretation a
28、nd interchange of the finger image quality scores. The purpose of this part of ISO/IEC 29794 is to provide an informative technical report on methodologies for objective, quantitative quality score expression and interpretation for finger images. It will complement ISO/IEC 29794-1 in developing a re
29、ference finger image corpus. Such a reference corpus can be built upon the availability of public finger images, which should then be used for quality score normalization. TECHNICAL REPORT ISO/IEC TR 29794-4:2010(E) ISO/IEC 2010 All rights reserved 1Information technology Biometric sample quality Pa
30、rt 4: Finger image data 1 Scope For aspects of quality specific to the finger image modality, this part of ISO/IEC 29794: specifies terms and definitions that are useful in the specification, use, and test of finger image quality metrics; defines the interpretation of finger image quality scores; id
31、entifies or defines finger image corpora for the purpose of serving as information for algorithm developers and users; develops statistical methodologies specific to finger image corpora for characterizing quality metrics to facilitate interpretation of scores and their relation to matching performa
32、nce. Performance assessment of quality algorithms and standardization of quality algorithms are outside the scope of this part of ISO/IEC 29794. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition ci
33、ted applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO/IEC 29794-1, Information technology Biometric sample quality Part 1: Framework 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO/
34、IEC 29794-1 and the following apply. 3.1 foreground region region of a finger image that contains valid finger image patterns NOTE The most evident structural characteristic of a valid finger image is a pattern of interleaved ridges and valleys. 3.2 local region block of m x n pixels of the foregrou
35、nd of a finger image, where m and n are smaller than the width and the height of the finger image 3.3 finger image quality assessment algorithm algorithm that reports a quality score for a given finger image sample ISO/IEC TR 29794-4:2010(E) 2 ISO/IEC 2010 All rights reserved3.4 finger image corpus
36、collection of finger image samples 3.5 finger image quality category common attribute or property of a group of finger images that causes them to perform or behave similarly for a class of fingerprint matchers 4 Symbols and abbreviated terms FQAA finger image quality assessment algorithm DFT discret
37、e Fourier Transform QSN quality score normalization QAID quality algorithm identification ppi pixel per inch, which is analogous to dot per inch (dpi). 5 Finger Image Quality 5.1 Defect factors of finger image A finger image obtained from a scanner is not always perfect. It may contain defects cause
38、d by the user character (e.g users skin condition), user behavior (e.g. improper finger placement), imaging (e.g scanner limitation or imperfection), or environment (e.g. impurities on the scanner surface). Some of the defects and their factors can be listed as follows: 1. Defect caused by user char
39、acter A. Extreme skin conditions such as very wet, very dry, etc. B. Scars C. Wrinkles D. Blisters E. Eczema F. Impurities such as dirt, latent print, etc. 2. Defect caused by imaging A. Sampling error B. Low contrast or signal-to-noise ratio C. Distortion D. Erroneous or streak lines E. Uneven back
40、ground F. Insufficient dynamic range G. Non-linear or non-uniform grayscale output H. Pixels not available due to hardware failure I. Aliasing problems 3. Defect caused by user behavior A. Elastic deformation B. Improper finger placement such as too low, rotated, etc. C. Insufficient area of finger
41、image 4. Defect caused by environment A. Humidity B. Light C. Impurities on the scanner surface ISO/IEC TR 29794-4:2010(E) ISO/IEC 2010 All rights reserved 3The performance of an automated fingerprint recognition system will be affected by the amount of defects or the degree of imperfection present
42、in the finger image. Therefore, it is necessary to compute the quality score of the finger image produced. Section 6 suggests several possible approaches to compute the finger image quality. The quality score shall be predictive of the performance of an automatic fingerprint recognition system. Furt
43、hermore, the quality score should preferably be scanner-independent and source-independent. 5.2 Standardization approaches for exchange of finger image quality As the finger image quality affects the performance of the fingerprint recognition system, the knowledge of quality can and is currently bei
44、ng used to process finger images differently, by for example, invoking some image enhancement methods prior to feature extraction, invoking different matchers based on quality or simply changing the threshold of the system. In fact, the use of finger image quality to enhance the overall performance
45、of the system is increasingly growing. Therefore, there is a need to standardize the quantitative quality score expression and interpretation so that a common interpretation of the quality scores is achieved. This can be done, as suggested in ISO/IEC 29794-1, by either Quality Algorithm Identificati
46、on (QAID), or Quality Percentile Rank upon standardization of a Quality Score Normalization (QSN) corpus. 6 Finger Image Quality Analysis 6.1 Introduction A complete finger image quality analysis should examine both the local and global structures of the finger image. Fingerprint local structure con
47、stitutes the main texture-like pattern of ridges and valleys within a local region while valid global structure puts the ridges and valleys into a smooth flow for the entire fingerprint. The quality of a finger image is determined by both its local and global structures. This section describes the c
48、urrent most significant features and characteristics of finger images at both local and global structures that are related to performance of fingerprint recognition systems. Some of these algorithms are described in 6.2 and 6.3 and can also be found in 5-8,10,11. The finger image is assumed to have
49、resolution of 500 ppi. For other resolutions, the resolution dependent parameters should be scaled accordingly. Possible initial finger image corpuses are the publicly available Fingerprint Verification Competition (FVC) 2000, 2002, 2004, and 2006 4 corpuses. 6.2 Local Analysis 6.2.1 Constituent of Local Analysis A finger image is partitioned into blocks such that each block contains sufficient ridge-valley infor
