1、BSI Standards Publication Biometrics interoperability profiles Best practices for slap tenprint captures PD ISO/IEC TS 20027:2015National foreword This Published Document is the UK implementation of ISO/IEC TS 20027:2015. The UK participation in its preparation was entrusted to Technical Committee I
2、ST/44, Biometrics. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2015. Pu
3、blished by BSI Standards Limited 2015 ISBN 978 0 580 87494 9 ICS 35.040 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 October 2015. Amendments/corrigenda
4、 issued since publication Date Text affected PUBLISHED DOCUMENT PD ISO/IEC TS 20027:2015Biometrics interoperability profiles Best practices for slap tenprint captures Profils biomtriques interoprables Recommandations pour les captures de 10 doigts plat ISO/IEC TS 20027 First edition 2015-09-15 Refer
5、ence number ISO/IEC TS 20027:2015(E) TECHNICAL SPECIFICATION ISO/IEC 2015 PD ISO/IEC TS 20027:2015 ii ISO/IEC 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2015, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or
6、 utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO co
7、pyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO/IEC TS 20027:2015(E) PD ISO/IEC TS 20027:2015 ISO/IEC TS 20027:2015(E)Foreword iv 1 Scope . 1 2 Sensor hardware requirement 1 3 Acquisition softw
8、are . 2 3.1 Acquisition process . 2 3.2 User feedback . 2 3.3 Acquisition check 2 3.4 Image processing 3 3.4.1 Segmentation 3 3.4.2 Compression 3 4 Logging and evaluation of data 3 4.1 General . 3 4.2 Logging data 4 4.3 Useful statistical evaluations 4 5 Operational process 5 5.1 General user guidan
9、ce 5 5.2 Acquisition process recommendations 7 6 Operational issues 9 6.1 Placement recommendations . 9 6.2 Calibration recommendations . 9 6.3 Cleaning recommendations 10 6.4 Operator recommendations .10 Annex A (informative) Example of acquisition process .11 Annex B (informative) Example of an ac
10、quisition process based on composite records .12 Annex C (informative) Example of a quality metric for the acquisition process .15 Bibliography .16 ISO/IEC 2015 All rights reserved iii Contents Page PD ISO/IEC TS 20027:2015 ISO/IEC TS 20027:2015(E) Foreword ISO (the International Organization for St
11、andardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the rig
12、ht to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedure
13、s used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial ru
14、les of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). 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. Details of any patent rights iden
15、tified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanatio
16、n on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information The committee responsible for this document
17、is ISO/JTC 1, Information technology, Subcommittee SC 37, Biometrics. It has been adopted from the European Technical Specification, CEN/TS 16428:2012, Biometrics Interoperability profiles Best Practices for slap tenprint captures.iv ISO/IEC 2015 All rights reserved PD ISO/IEC TS 20027:2015 TECHNICA
18、L SPECIFICATION ISO/IEC TS 20027:2015(E) Biometrics interoperability profiles Best practices for slap tenprint captures 1 Scope The main goal of this Technical Specification is to give guidelines to follow during the acquisition process of slap tenprints in order to obtain fingerprints with the best
19、 quality possible within acceptable time constraints. Non-cooperative users are out of the scope of this Technical Specification. When using ten-fingerprint sensors, it is fundamental to know how to use them and how to proceed during the acquisition. This Technical Specification describes how to cap
20、ture fingerprints correctly by specifying best practices for slap tenprint captures. It gives guidance on the following topics: 1) recommendations on the hardware of the fingerprint sensor and its deployment; 2) recommendations on user guidance; 3) recommendations on the enrolment process including
21、a sample workflow; 4) recommendations for developers and system integrators on application software; 5) recommendations on processing, compression and coding of the acquired fingerprint images; 6) recommendations on operational issues and data logging; 7) recommendations on the evaluation of a solut
22、ion and its components. Although this Technical Specification primarily focuses on reaching optimal data quality for enrolment purposes, the recommendations given here are applicable for other purposes. All processes which rely on good quality tenprint slaps can take advantage of the best practices
23、reported here. 2 Sensor hardware requirement Image quality should comply with the quality specifications from ISO/IEC 19794-4 1 . EBTS V 8.002:2008 6 , Annex F, corresponds to ISO/IEC 19794-4:2011, B.1, and BSI TR-03121 5corresponds to ISO/IEC 19794-4:2011, B.3. NOTE 1 This Technical Specification c
24、onsiders optical sensors based on the principle of total internal reflection. However, this does not mean that other technologies cannot be used for tenprint enrolment purposes. As soon as sufficient experiences are available and recommendations can be given on emerging technologies, they will be in
25、cluded in a future version of this document. The sensor device should provide methods for re-calibration in the field by qualified service staff if the device technically supports it. It is recommended that the compliance of a sensor device to the applicable quality standard can be verified at any t
26、ime in the operational environment. NOTE 2 The need for calibration or re-calibration depends on the sensor technology and calibration might not be necessary for all devices. ISO/IEC 2015 All rights reserved 1 PD ISO/IEC TS 20027:2015 ISO/IEC TS 20027:2015(E) 3 Acquisition software 3.1 Acquisition p
27、rocess For the acquisition process, the highest quality images should be used. The acquisition of these images should be done automatically. The sequence of images having the highest quality should be used; if a timeout has occurred then these may be below the desired quality levels. An example for
28、an acquisition process design can be found in Annex A and Annex B, an example for a quality metric can be found in Annex C. 3.2 User feedback The presence of a user interface is strongly advised to give feedback to the user. Feedback can be given, for example, by a screen attached in close neighbour
29、hood to the sensor, illuminated pictograms on the sensor, LEDs assigned to pictograms directly on the sensor. The following information should be given to the user: assistance to finger positioning with images and/or video on the screen and/or audio instructions (for instance to instruct the user to
30、 move its fingers to the left/right/top/bottom); visual and/or audio notification when a successful acquisition has been completed; a quality indicator for each acquisition, which indicator should be simple e.g. a two-state logic (not good/good) or similar; if possible, the reason for a bad quality
31、acquisition (e.g. wrong positioning of the hand). Additional information (e.g. a poster or a video) can be used to illustrate to users how to use the system. This information can be displayed close to the sensor and additionally in the waiting zone. Operators should be trained to give guidance to th
32、e users. 3.3 Acquisition check The software linked to the sensor should take account of the following during the acquisition process in order to perform a better acquisition. Any feedback provided by the sensor software (background correction, quality evaluation, end of acquisition, etc.). A timeout
33、 for capturing the best available image in case the specified quality threshold is not reached. The inability of the subject to provide a full set of fingerprints. Acceptable images for certain fingers may not have been captured, which could be due to missing fingers, inability for the subject to in
34、teract with the sensor correctly, temporary or permanent issues with the subjects fingerprints. The image quality of the captured images. This is to enable the system to finish the acquisition process after the preset quality level or a timeout has been reached.2 ISO/IEC 2015 All rights reserved PD
35、ISO/IEC TS 20027:2015 ISO/IEC TS 20027:2015(E) The subjects fingers have been removed from the sensor at the end of the acquisition process. All two consecutively captured slaps and captured thumbs are not identical. A duplicate check should also be performed to ensure that all expected fingers have
36、 been captured once and once only. NOTE Due to computational time constraints this recommendation could also be enforced by the operator instead of the software. Residual traces have not been acquired. The fingerprint images are as originally acquired. Optionally, segmented images can be produced. H
37、and inversion between left and right slap has not occurred. This check can be based on the different physical characteristics of the shapes of both hands. 3.4 Image processing 3.4.1 Segmentation Independently of physical resolution of the sensor and the image acquired, the resolution of the fingerpr
38、int image should be at least 197 ppcm (500 ppi) and, therefore, can differ from the scan resolution. Depending on the call to capture one, two, three or four fingerprints, this number of individual fingerprints should be extracted from the input image and provided as single fingerprints generated by
39、 a segmentation process which takes into account fingers reported to be missed. For this segmentation process, the following criteria should be fulfilled: Ability to accept rotated fingerprints having the same direction in an angle up to 45 Rotated fingerprints having the same direction should be co
40、rrected to be vertical Segment the first part over the finger (first phalanx) Segmentation should be performed on uncompressed data. Recommended size for fingerprint images is given in ISO/IEC 19794-4:2011, D.1. NOTE Size limitation is done in order to prevent performance issues. 3.4.2 Compression F
41、ingerprint images should be compressed according to the recommendations in ISO/IEC 19794-4:2011, section 8.3.17, “Image compression algorithm”. NOTE 1 The compression ratio should not be too high, a maximum compression ratio of 15 is recommended. NOTE 2 The WSQ compression is mainly used for fingerp
42、rint compression; it has been optimized to be compatible with minutiae calculation. The implementation of the used WSQ algorithm should be certified by the FBI and should be referenced by the respective certificate number (coded in the WSQ header). Multiple lossy compressions should be avoided as th
43、ey harm image quality. 4 Logging and evaluation of data 4.1 General Logging and evaluation data might be subject to national legal constraints and should be handled accordingly. ISO/IEC 2015 All rights reserved 3 PD ISO/IEC TS 20027:2015 ISO/IEC TS 20027:2015(E) 4.2 Logging data The purpose of the l
44、ogging data is not to track people but to give guidance to the staff in charge of the enrolment and to maintain a constant quality of the acquisition process. The following data, or parts of it, should be logged. transaction ID; timestamp of acquisition; duration of biometric acquisition process; nu
45、mber of captured images; number of successful captures; quality scores for all captured fingerprints; overall quality score of captured slap or tenprints sets (if present); information about vendor, software, hardware and versions; information about the origin (e.g. Agency Identifier); information a
46、bout errors (e.g. about uniqueness check, segmentation, etc.) size of acquired data; testing flags (if applicable); demographic data on the subject (gender, age). NOTE It might be appropriate to have a regular logging workflow and an evaluation mode logging workflow with more comprehensive logging d
47、ata. The latter one could be used for regular or incident-based checks of the whole process. When used in a verification or identification scenario, it is recommended to also log results of the verification and identification process. 4.3 Useful statistical evaluations Conducting regular (e.g. every
48、 month, every three month, every year) evaluations on the acquired logging data is recommended. As a minimum, the following basic set of evaluations should be conducted: quality scores distribution; error code distribution; average enrolment duration; distribution of enrolment duration; distribution
49、 of gender and age, especially in relation to quality scores. When used in a verification or identification scenario, it is recommended to also evaluate the accumulated results of the verification or identification attempts.4 ISO/IEC 2015 All rights reserved PD ISO/IEC TS 20027:2015 ISO/IEC TS 20027:2015(E) 5 Operational process 5.1 General user guidance The presence of a user interface is strongly advised to support better acquisition. The follo
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