1、Designation: E2916 13Standard Terminology forDigital and Multimedia Evidence Examination1This standard is issued under the fixed designation E2916; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This is a compilation of terms and correspondingdefinitions used in the examination of digital and multimediaevidence to include the areas of
3、 computer forensics, imageanalysis, video analysis, forensic audio, and facial identifica-tion.1.2 Legal or scientific terms that generally are understood ordefined adequately in other readily available sources may notbe included.2. Referenced Documents2.1 ASTM Standards:2C670 Practice for Preparing
4、 Precision and Bias Statementsfor Test Methods for Construction MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1732 T
5、erminology Relating to Forensic ScienceE2808 Guide for Microspectrophotometry and Color Mea-surement in Forensic Paint Analysis2.2 ANSI/NIST Standards:3ANSI/NIST-ITL 1-2011 Data Format for the Interchange ofFingerprint, Facial, and Other Biometric InformationNIST SP 800-86 Guide to Integrating Foren
6、sic Techniquesinto Incident ResponseNIST SP 800-88 Guidelines for Media Sanitization2.3 ISO Standards:4ISO 9000 Quality ManagementISO/IEC Guide 2:2004 Standardization and Related Activi-ties General VocabularyISO/IEC 19794-5 Information Technology BiometricData Interchange Formats Part 5: Face Image
7、 Data2.4 IEEE Standards:5IEEE 100-2000 The Authoritative Dictionary of IEEE Stan-dards Terms, 7th Edition2.5 ASCLD/LAB Publication:6ASCLD/LAB International Supplemental Requirements(Testing), 2011 Edition3. Significance and Use3.1 This terminology includes general as well as discipline-specific defi
8、nitions as they apply across the spectrum of imageanalysis, computer forensics, video analysis, forensic audio,and facial identification.4. Terminology: Terms and Definitions4.1 Definitions:achievable resolution, resolving power, nthe measure ofimaging systems practical limit to distinguish betweens
9、eparate adjacent elements, typically by imaging a knownreference standard.acquisition, nin computer forensics, the process of using anaccess interface to read digital data from a digital source andto create a destination object.ad hoc image, nsee uncontrolled image.administrative review, na procedur
10、e used to check case-work for consistency with agency/laboratory policy andeditorial practice.allocated space, allocated storage, nin computer forensics,the portions of storage that are assigned or reserved foractive instructions or for data.IEEE 100-2000, (C) 610.10-1994w1This terminology is under
11、the jurisdiction of ASTM Committee on ForensicSciences and is the direct responsibility of Subcommittee E30.12 on Digital andMultimedia Evidence.Current edition approved June 1, 2013. Published July 2013. DOI: 10.1520/E2916-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orc
12、ontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/ww
13、w.nist.gov.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),445 Hoes Ln., Piscataway, NJ 08854, http:/www.ieee.org.6Available from American Soc
14、iety of Crime Laboratory Directors LaboratoryAccreditation Board (ASCLD/LAB), 139 J Technology Drive, Garner, NC 27529,http:/www.ascld-lab.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1anthropometric analysis, nin facial identif
15、ication,anex-plicit measurement of landmarks on a face and a comparisonof these measurements between two samples.anti-forensics, nthe application of a process to modify,conceal or destroy information to inhibit or prevent theeffectiveness of forensic science examinations.archive, ndata stored for lo
16、ng-term availability and retrieval.archive, vto store data in a manner suitable for long-termavailability and retrieval.archive image, nin computer forensics,abit stream dupli-cate of data placed on media that is suitable for long-termstorageartifact, na by-product, artificial feature, or change res
17、ultingfrom human activity or a technical process. (Comparenoise).DISCUSSIONExamples include speckles in a scanned picture,“blocking” in compressed images, distortion in over-saturated audio,and the automatic creation of temporary files due to normal usage of acomputer.aspect ratio, nthe ratio of the
18、 width to the height of arectangle, such as an image, a pixel, or an active videoframe.attempt, nin facial identification, a submission of a singleset of biometric samples to a biometric system for identifi-cation or verification. (Compare biometric search).audio enhancement, nthe processing and fil
19、tering of audiorecordings to improve the signal quality and intelligibility ofthe signals of interest, such as speech, by attenuating noise orotherwise increasing the signal-to-noise ratio.authentication, n(1) the process of substantiating that theasserted provenance of data is true; (2) the process
20、 ofsubstantiating that data are accurate representations of whatthey are purported to be.backlight, nin facial identification, a light source placedbehind a subject in a controlled capture that reduces back-ground shadows.backlit, adja characteristic of a subject or an object that isilluminated from
21、 behind.batch mode search, nin facial identification, a mode ofsearching records in an automated system in which a groupof probes are simultaneously or sequentially launched.batch search mode, nsee batch mode search.bias, nthe difference between the expectation of the testresults and an accepted ref
22、erence value.E177, E456, E691, C670binning, nin facial identification,(1) any technique used bya facial recognition (FR) system to organize or optimizesearching based upon some piece(s) of metadata; (2) theprocess of parsing (examining) or classifying data to accel-erate or improve biometric matchin
23、g.biometric match, nin facial identification, determinationthat two samples correspond to the same source based onsome level of computer-evaluated similarity.DISCUSSIONDoes not inherently imply that the probe and candidateis the same person.biometrics, n(1) a set of measureable anatomical,physiologi
24、cal, or behavioral characteristic that can be used todiscriminate members of a population; (2) collectively, a setof automated processes used to discriminate members of apopulation using measureable anatomical, physiological,behavioral characteristics, or combinations thereof.biometric search, nthe
25、submission of a biometric referenceas a probe against a biometric system for identification(one-to-many) or verification (one-to-one). (Compare at-tempt).bit stream, na continuous stream of bits transmitted over achannel with no separators between the character groups.IEEE 100-2000, (C) 610.7-1995,
26、610.10-1994wbit stream duplicate, nin computer forensics, an exact,bit-for-bit reproduction of all data objects independent ofany physical media upon which that data is stored. (Comparecopy).cache, nin computer forensics, a temporary storage area setaside on a processor, in memory, or in a filesyste
27、m to keepfrequently needed data readily available, designed to speedup processing and improve performance.capture, n(1) the process of recording data such as an image,video sequence, or audio stream; (2) in facial identification,the process of collecting a biometric sample from anindividual via a se
28、nsor.capture, vto record data, such as an image, video sequence,audio stream, or biometric sample to digital storage, often bymeans of a sensor.capture card, frame grabber, na piece of computer hard-ware that accepts an analog or digital signal and outputs thesignal as digital data.capture device, n
29、device used in the recording of data.carve, vin computer forensics, to extract a portion of data forthe purpose of analysis.certification authority, n(1) in computer forensics, a trustedthird party entity that issues digital certificates certifying theownership of a public key by the subject named i
30、n thecertificate, and trusted by both entities engaged in a digitaltransaction; (2) in facial identification, a body that issuesbiometric documents and certifies that the data stored on thedocuments are genuine.chain of custody, nthe procedures and documents thataccount for the possession of a sampl
31、e by tracking itshandling and storage from its point of collection to its finaldisposition. E1732clarification, nsee enhancement.E2916 132clarify, nsee enhance.class characteristics, nin facial identification and imageanalysis, characteristics common to many objects or indi-viduals (for example, the
32、 color, make, or model of objects,and for faces, the overall shape of the nose, eyes, or mouth).clear, vin computer forensics, to overwrite storage space ona medium with non-sensitive data, which may includeoverwriting not only the logical storage location of files, butmay include all addressable lo
33、cations. NIST SP 800-88cluster, nin computer forensics, a group of contiguoussectors on storage media, typically the smallest unit ofallocation in a filesystem.codec, nan algorithm to encode and decode digital data,typically to reduce the amount of data for transmission orstorage.DISCUSSIONA codec i
34、s not a storage format, but may be required tointerpret stored data.cognitive bias, n(1) a mental error caused by ones simpli-fied information processing strategies; it does not result fromany emotional or intellectual predisposition toward a certainjudgment but rather from subconscious mental proce
35、duresfor processing information; (2) a mental error that is consis-tent and predictable; (3) a set of influences that may affectthe reliability and validity of ones observations and conclu-sions.cognitive image analysis, nin image and video analysis,aprocess used to extract visual information from a
36、n image byhuman evaluation.colorimetry, nthe conversion of instrumental light measure-ments into psychophysical descriptions or numerical nota-tions that can be correlated with visual evaluations of colorand color differences. E2808color range, nsee petency test, nan evaluation of a persons knowledg
37、eand ability before performing independent work in forensiccasework. ASCLD/LABcomposite video signal, na single analog video signal thatcombines a base-band luminance signal with color informa-tion by modulating a subcarrier with chroma signals, typi-cally using one of the National Television System
38、 Commit-tee (NTSC), Phase Alternating Line (PAL), or SequentialColor with Memory (SECAM_ pression, na process to reduce the size of a data file orstream while attempting to retain the original semanticmeaning of that pression ratio, nthe ratio of the size of the data beforecompression to that of aft
39、er puter forensics, nthe scientific examination, analysis, orevaluation of digital evidence in legal matters.conclusion, na position reached after consideration of a setof facts or examination results.confirmation bias, nthe tendency to search for data orinterpret information in a manner that suppor
40、ts ones pre-conceptions.contextual bias, na deviation in human judgment caused byfactors external to the data that is logically relevant to thedecision at hand.control, nmaterial of established origin that is used toevaluate the performance of a test or comparison. E1732controlled image, nin facial
41、identification, a photographicimage captured in accordance with facial identification (FI)or facial recognition (FR) standards or guidelines (forexample, a drivers license photo).copy, vto reproduce information with some level of accuracy.DISCUSSIONDepending on the process used, copying might result
42、 inthe loss of data. (Compare bit stream duplicate).CSI effect, nperception of the near infallibility of forensicscience in response to popular media.data, ninformation in analog or digital form that can betransmitted or processed.data file, na file consisting of stored data (that is, text,numbers,
43、graphics, etc.) as compared to a program file ofcommands and instructions for a digital device.deblur, vto restore an image by attempting to reversedegradation caused by blur.decryption, na process to return encrypted data to itsoriginal unencrypted condition.deinterlace, vto separate an interlaced
44、video frame into itstwo discrete fields.demonstrative comparison, nin video analysis, a method ofpresenting similarities or differences, or both among imagesor objects, or both without rendering an opinion regardingidentification or exclusion.depth of field, nthe distance that is in focus (sharp) wh
45、encapturing an image based upon the camera and lens, andtheir settings.digital device, nelectronic equipment which can create,process or store digital data.digital evidence, ninformation of probative value that isstored or transmitted in binary form.digital image, nin image analysis, a photographic
46、image thatis represented by discrete numerical values organized in atwo-dimensional array.Focal Encyclopedia of Photography7digital object, na collection of logically related information.digital source, na container of digital data that can beacquired by an acquisition tool.7Focal Encyclopedia of Ph
47、otography, 3rd edition, Richard D. Zakia and LeslieStroebel, Eds., Focal Press, 1996.E2916 133digital video recorder, DVR, na stand-alone embeddedsystem or a computer-based system for recording video and,optionally, audio data.digital zoom, na digital camera function that simulates anoptical zoom by
48、 cropping and enlarging a digital imagewithout increasing the resolution or detail.directory, nin computer forensics, an object or structure usedto group files together within a filesystem.directory listing, nin computer forensics, a list of files and,optionally, file properties contained within a f
49、ilesystem.download, v(1)in audio, image, and video analysis,toretrieve audio, video, image, or transactional data from arecording device (for example, DVR system); (2) in com-puter forensics, to receive data from another digital source.dynamic range, n(1) in image analysis, the differencebetween the brightest highlight and darkest value that asensor can detect and record in a single image; (2) in audioand video analysis, the ratio of the strongest
