1、BRITISH STANDARD BS ISO/IEC 19794-10:2007 Information technology Biometric data interchange formats Part 10: Hand geometry silhouette data ICS 35.040 BS ISO/IEC 19794-10:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2007 BSI 20
2、07 ISBN 978 0 580 55166 6 National foreword This British Standard was published by BSI. It is the UK implementation of ISO/IEC 19794-10:2007. The UK participation in its preparation was entrusted to Technical Committee IST/44, Biometrics. A list of organizations represented on this committee can be
3、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. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd.
4、 No. Date Comments Reference number ISO/IEC 19794-10:2007(E)INTERNATIONAL STANDARD ISO/IEC 19794-10 First edition 2007-06-01 Information technology Biometric data interchange formats Part 10: Hand geometry silhouette data Technologies de linformation Formats dchange de donnes biomtriques Partie 10:
5、Donnes de la silhouette de la gomtrie de la main BS ISO/IEC 19794-10:2007ii iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Conformance. 1 3 Normative references . 1 4 Terms and definitions. 1 5 General. 3 5.1 Byte order 3 5.2 Use of FCCs for data compression. 3 5.3 CBEFF Format owner and
6、 format type. 4 6 Silhouette acquisition requirements. 4 6.1 Overview 4 6.2 Hand orientation . 4 6.3 Aspect ratio . 5 6.4 Presentation 6 6.5 Coordinate system 6 7 Hand geometry interchange format (BDB format) 7 7.1 General record header 8 7.2 Hand geometry view record (HGVR). 9 Annex A (informative)
7、 Sample hand geometry data packet. 17 Annex B (informative) Best practices. 19 BS ISO/IEC 19794-10:2007iv Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodi
8、es 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 fields of mutual interest. Other i
9、nternational 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 drafted in accordance with the rules gi
10、ven 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 International Standard requires approval
11、 by at least 75 % of the national bodies casting a vote. 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 for identifying any or all such patent rights. ISO/IEC 19794-10 was prepared by Joi
12、nt Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 37, Biometrics. ISO/IEC 19794 consists of the following parts, under the general title Information technology Biometric data interchange formats: Part 1: Framework Part 2: Finger minutiae data Part 3: Finger pattern spectr
13、al data Part 4: Finger image data Part 5: Face image data Part 6: Iris image data Part 7: Signature/sign time series data Part 8: Finger pattern skeletal data Part 9: Vascular image data Part 10: Hand geometry silhouette data The following part is under preparation: Part 11: Signature/sign processed
14、 dynamic data BS ISO/IEC 19794-10:2007v Introduction In the Access Control and Time Management communities, hand geometry has been an option to add biometrics to traditional security systems. While several hand geometry systems have been developed into products, each vendor has traditionally relied
15、on a proprietary algorithm and has stored a proprietary template. This has made it impossible to transfer data from one vendors system to anothers, forcing end users to sole- source their hand geometry solution. To allow integration of hand geometry systems from multiple vendors, a nonproprietary in
16、terchange format must be adopted. This part of ISO/IEC 19794 is intended to provide a data interchange format (a CBEFF biometric data block BDB) for applications requiring an interoperable hand geometry record. The information consists of a variety of mandatory and optional items including data capt
17、ure parameters, standardized hand position and vendor- specific information. This information is intended for interchange among organizations that rely on automated devices and systems for identification or verification purposes based on the information from hand geometry. While this part of ISO/IEC
18、 19794 mandates a particular data format, it does not mandate a particular algorithm. For example, a user may be enrolled on a system from one vendor and verified on a system from another. Because hand geometry products have historically relied on measurements taken from a hand silhouette, this form
19、at stores hand silhouette data rather than color or grayscale image data. To increase the flexibility of the data format, provisions have been made to store views of the left and right hands, in addition to multiple views of each hand. Specific implementations of this part of ISO/IEC 19794 that are
20、constrained by storage space (such as smart card applications) may wish to limit the number of views stored for each hand. Such limitations are outside the scope of this part of ISO/IEC 19794, but reduced choices can prejudice interoperability. It is well known that the presentation of a biometric s
21、ample affects algorithm performance. While image acquisition and hand placement requirements are outside the scope of this part of ISO/IEC 19794, Annex B is provided as guidance for those wishing to adhere to industry “best practices”. BS ISO/IEC 19794-10:2007blank1 Information technology Biometric
22、data interchange formats Part 10: Hand geometry silhouette data 1 Scope This part of ISO/IEC 19794 specifies a data interchange format (a CBEFF biometric data block BDB) that can be used for storing, recording and transmitting the information obtained from a hand silhouette. This part of ISO/IEC 197
23、94 defines the content, format and units of measurement for the exchange of hand silhouette data in a BDB. Information formatted in accordance with this part of ISO/IEC 19794 can be recorded on machine-readable media or transmitted by data communication between systems. 2 Conformance A biometric dat
24、a block conforms to this part of ISO/IEC 19794 if it satisfies the format requirements specified within the normative clauses of this part of ISO/IEC 19794 and has internal consistency based on capture from an actual hand. 3 Normative references The following referenced documents are indispensable f
25、or the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO/IEC 19785-1, Information technology Common Biometric Exchange Formats Framework Part 1: Data elemen
26、t specification ISO/IEC 19784-1, Information technology Biometric application programming interface BioAPI specification 4 Terms and definitions For the purposes of this document, the following terms and definitions apply. 4.1 biometric data block BDB block of data with a defined format that contain
27、s one or more biometric samples or biometric templates NOTE In the case of this part of ISO/IEC 19794, the BDB contains the hand silhouette of one or both hands, perhaps with multiple views. BS ISO/IEC 19794-10:20072 4.2 biometric sample information obtained from a biometric device, either directly
28、or after further processing NOTE The silhouette of a hand is an example of a biometric sample. 4.3 camera point of view effective location and orientation of a camera that would result in the observed hand silhouette NOTE The effective location is specified rather than the actual location due to the
29、 possibility of algorithmic transformations and various hand-scanning technologies such as movable linear arrays, etc. 4.4 capture process of taking a biometric sample from an end user 4.5 Freeman Chain Code FCC compact method for representing the contours of an object NOTE First made popular by Her
30、bert Freeman. 4.6 image resolution number of pixels per unit distance in the interchanged image NOTE This may be the result of processing a captured image. The original captured image may have been subsampled, scaled, interpolated or otherwise processed to produce a silhouette suitable for automated
31、 hand recognition. 4.7 live capture process of capturing a biometric sample through an interaction between an end user and a biometric system 4.8 hand geometry view record HGVR block of data that contains a hand silhouette captured from one camera point of view during one hand placement NOTE The blo
32、ck contains metadata, silhouette data and optional extended data. 4.9 pixel picture element located on an n by m matrix of picture elements, where n is the horizontal component and m is the vertical component 4.10 platen reference surface on which a hand is placed during imaging NOTE The platen will
33、 often contain alignment pins to promote repeatable finger placement. 4.11 side-view data taken from the thumb side or the little-finger side of the hand cf. top-view BS ISO/IEC 19794-10:20073 4.12 side-view reference plane physical or imaginary plane on which the side-view silhouette is projected 4
34、.13 tip finger end of the fingernail or the end of the flesh at the end of the finger, whichever produces the longer silhouette NOTE See Figure 3 a). 4.14 top-view data taken from the palm side of the hand or the back side of the hand cf. side-view 4.15 web area connecting two adjacent fingers at th
35、eir connection point to the palm NOTE See Figure 3 a). 5 General 5.1 Byte order For the purposes of transfer and storage of the BDB, the more significant bytes of any multi-byte quantity are present before less significant bytes. NOTE This is commonly referred to as a “big-endian” encoding, or “netw
36、ork byte” order. Within a byte, the bits are numbered from 0 to 7, where 7 is the “most significant bit” (MSB) and bit 0 the “least significant bit” (LSB). 5.2 Use of FCCs for data compression To conserve space, the hand silhouette shall be recorded using a Freeman Chain Code (FCC). NOTE This repres
37、entation requires only 2-3 bits per pixel along the perimeter of the silhouette. The FCC has long been used to represent black-and-white contours. Each element of the FCC shall be stored immediately following its predecessor, without regard to byte boundaries. If necessary, the silhouette shall be p
38、added with trailing zeros to ensure that the BDB is an integral number of octets. Two forms of FCC are supported by this part of ISO/IEC 19794. The 8-way FCC uses three bits per pixel to represent the direction from one pixel to an adjacent pixel. The 4-way FCC uses two bits per pixel by eliminating
39、 the diagonal directions allowed in the 8-way FCC. Silhouette data contained in BDBs conforming to this part of ISO/IEC 19794 (see clause 2) shall be body- centric and not grid centric FCCs as shown in Figure 1 (starting/ending points are shown as squares, intermediate points as circles). BS ISO/IEC
40、 19794-10:20074 a) Body-centric 8-way FCC = 4,4,4,7,7,0,2,2 b) Grid-centric 8-way FCC = 4,4,4,5,7,7,7,0,1,2,2,3 Figure 1 Body-centric and grid-centric Freeman Chain Code 5.3 CBEFF Format owner and format type The BDB format specified in this part of ISO/IEC 19794 shall be embedded in a CBEFF-complia
41、nt Biometric Information Record (BIR) according to ISO/IEC 19785-1. The structure of a hand geometry silhouette BIR is depicted in Figure 2, where the CBEFF Standard Biometric Header (SBH) is mandatory, and the CBEFF Security Block (SB) is optional. Figure 2 Overview of a hand geometry silhouette bi
42、ometric information record NOTE The CBEFF signature holds data that enables the integrity and/or the originator of the hand geometry silhouette BIR to be verified electronic signature or message authentication code (MAC). The CBEFF Format Owner identifier assigned by the CBEFF Registration Authority
43、 to ISO/IEC JTC 1/SC 37 shall be used in the CBEFF SBH associated with the BDB. This is the sixteen-bit value 0x0101 (hexadecimal 101 or decimal 257). There is one CBEFF Format Type code assigned to the data record specified in this part of 19794. This code shall be included in the CBEFF SBH. The si
44、xteen-bit value 0x0018 (hexadecimal 18 or decimal 24) shall be used for data records specified in this part of 19794. 6 Silhouette acquisition requirements 6.1 Overview It is not the purpose of this part of ISO/IEC 19794 to specify the method of data capture or the order of process steps used to cap
45、ture the silhouette. However, after data acquisition and processing, each silhouette shall have the orientation shown in Figure 3 a) for top-view images, or Figure 3 b) for side-view images. 6.2 Hand orientation The silhouette shall represent either the left or right hand and shall be presented in o
46、ne of the orientations depicted in Figures 3 a) and 3 b). NOTE Silhouettes taken from a left hand pinned platen shall be flipped (mirror image) to match the form of Figure 3a). CBEFF SBH Hand Geometry Silhouette BDB CBEFF SB BS ISO/IEC 19794-10:20075a) Top-view images b) Side-view images Figure 3 St
47、andard hand orientation for images 6.3 Aspect ratio The aspect ratio shall be 1:1, within a tolerance of 2%. NOTE 1 The following example may be useful in calculating the aspect ratio: Assume a grid with 25 mm spacing is placed at the camera centerline, with the grid normal to the centerline axis. T
48、he aspect ratio of a captured image may be calculated by counting the number of pixels between the grid lines 25 mm from the origin. A system that counts 100 pixels in the x direction and 108 pixels in the y direction has an 8% error compared to the ideal 1:1 aspect ratio. 3 2 1 4 0 5 6 7 8-way FCC
49、Directions 1 2 0 3 4-way FCC Directions Web Web Web Tip Tip Tip Tip Web 3 2 1 4 0 5 6 7 8-way FCC Directions 1 2 0 3 4-way FCC Directions BS ISO/IEC 19794-10:20076 NOTE 2 “Aspect ratio” relates to the digital characteristics of the stored data, not to physical characteristics of the scanning device. 6.4 Presentation In order to obtain the best hand recognition performance and interoperability, certain mandatory requirements reg
