1、Designation: E2765 11Standard Practice forUse of Image Capture and Storage Technology in ForensicDocument Examination1This standard is issued under the fixed designation E2765; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice provides procedures to be used by forensicdocument examiners (Guide E444) using image capture ands
3、torage technology.1.2 These procedures are applicable whether the use of theimage capture technology involves an item(s) associated witha matter under investigation (questioned or known items), or isfor reference.1.3 These procedures include evaluation of the sufficiencyof the available imaging capt
4、ure and storage technologies.1.4 Procedures are also outlined for image archiving.1.5 The particular methods employed in a given casedepend upon the nature of the item, or the question at hand, orboth.1.6 This practice might not cover all aspects of the use ofimage capture and storage technology inv
5、olving unusual oruncommon items.1.7 This practice cannot replace the requisite knowledge,skills, or abilities acquired through appropriate education,training (Guide E2388), and experience and should be used inconjunction with sound professional judgment.1.8 This standard does not purport to address
6、all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E312 Practice for
7、Description and Selection of Conditionsfor Photographing Specimens Using Analog (Film) Cam-eras and Digital Still Cameras (DSC)E444 Guide for Scope of Work of Forensic DocumentExaminersE1422 Guide for Test Methods for Forensic Writing InkComparisonE1732 Terminology Relating to Forensic ScienceE2195
8、Terminology Relating to the Examination of Ques-tioned DocumentsE2388 Guide for Minimum Training Requirements for Fo-rensic Document Examiners2.2 SWGIT Documents:3Section 1 Overview of SWGIT and the Use of ImagingTechnology in the Criminal Justice SystemSection 2 Considerations for Managers Migratin
9、g to DigitalImaging TechnologySection 3 Guidelines for Field Applications of ImagingTechnologies in the Criminal Justice SystemSection 5 Recommendations and Guidelines for the Use ofDigital Image Processing in the Criminal Justice SystemSection 8 General Guidelines for Capturing Latent Impres-sions
10、Using a Digital CameraSection 11 Best Practices for Documenting Image Enhance-mentSection 13 Best Practices for Maintaining the Integrity ofDigital Images and Digital VideoSection 15 Best Practices for Archiving Digital and Multi-media Evidence (DME) in the Criminal Justice System2.3 SWGIT/SWGDE Doc
11、uments:4SWGIT/SWGDE Digital and Multimedia Evidence Glos-sary3. Terminology3.1 For definitions of terms in this Practice, refer to Termi-nology E1732 and Terminology E2195.1This practice is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommit
12、tee E30.02 on QuestionedDocuments.Current edition approved March 1, 2011. Published March 2011. DOI: 10.1520/E2765-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer t
13、o the standards Document Summary page onthe ASTM website.3Information regarding Scientific Working Group on Imaging Technology(SWGIT) is available from International Association for Identification (IAI), 2535Pilot Knob Road, Suite 117, Mendota Heights, MN 55120-1120, http:/www.theiai.org.4Informatio
14、n regarding Scientific Working Group on Imaging Technology/Scientific Working Group on Digital Evidence (SWGIT/SWGDE) is available fromInternational Association for Identification (IAI), 2535 Pilot Knob Road, Suite 117,Mendota Heights, MN 55120-1120, http:/www.theiai.org.1Copyright ASTM Internationa
15、l, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2.1 archive copy, na copy of data placed on mediasuitable for long-term storage, from which subsequent workingcopies can be produced. SWGIT/SWGDE3.2.2 archive i
16、mage, nany image placed on media that issuitable for long-term storage. SWGIT/SWGDE3.2.3 archiving, nthe process of storing data in a mannersuitable for long-term availability and retrieval.SWGIT/SWGDE3.2.4 capture, nthe process of recording data, such as animage, video sequence, or audio stream. SW
17、GIT/SWGDE3.2.5 capture device, na device used in the recording ofdata. SWGIT/SWGDE3.2.6 CD/DVD (compact disc/digital versatile disc),noptical disk technology formats designed to function asdigital storage media. SWGIT/SWGDE3.2.7 compression, nthe process of reducing the size of adata file. (See also
18、 lossless compression and lossy compres-sion.) SWGIT/SWGDE3.2.8 copy, nan accurate reproduction of information.SWGIT/SWGDE3.2.9 data, ninformation in analog or digital form that canbe transmitted, stored, or acted upon. SWGIT/SWGDE3.2.10 digital image, nan image that is represented bydiscrete numeri
19、cal values organized in a two-dimensionalarray; when viewed on a monitor, projected image or printedon paper, it appears similar to a photograph.SWGIT/SWGDE3.2.11 image, na visually observable counterpart of anobject produced by means of imaging technology.3.2.12 image, vto produce a digital, or ana
20、log, observablecounterpart of an object by means of imaging technology.3.2.13 image averaging, nthe process of averaging simi-lar images, such as sequential video frames, to reduce noise instationary scenes. SWGIT/SWGDE3.2.14 image enhancement, nany process intended toimprove the visual appearance o
21、f an image or specific featureswithin an image. SWGIT/SWGDE3.2.15 image output, nthe means by which an image ispresented for examination or observation. SWGIT/SWGDE3.2.16 image processing, nany activity that transforms aninput image into an output image. SWGIT/SWGDE3.2.17 image processing log, na re
22、cord of the steps usedin the processing of an image. SWGIT/SWGDE3.2.18 imaging technology, nany system (or method)used to capture, store, process, analyze, transmit, or produce animage. Such systems include film, electronic sensors, cameras,video devices, scanners, printers, computers, etc.SWGIT/SWG
23、DE3.2.19 intermediate storage, nany media, or device, onwhich data is temporarily stored for transfer to permanent orarchival storage. SWGIT/SWGDE3.2.20 interpolation, na method of image processingwhereby one pixel, block, or frame is created, used or stored,based on the differences between the prev
24、ious and subsequentpixel, block, or frame of information. This is often done toincrease the apparent clarity of an image. SWGIT/SWGDE3.2.21 line pairs per millimetre (LP/mm), na measure ofthe spatial resolution of an image conversion device.SWGIT/SWGDE3.2.22 lossless compression, ncompression in whi
25、ch nodata is lost and all data can be retrieved in its original form.SWGIT/SWGDE3.2.23 lossy compression, ncompression in which data islost and cannot be retrieved in its original form.SWGIT/SWGDE3.2.24 media, nobjects on which data can be stored.SWGIT/SWGDE3.2.25 metadata, ndata, frequently embedde
26、d within afile, that describes a file or directory, and which can include thelocations where the content is stored, dates and times, appli-cation specific information, and permissions.SWGIT/SWGDE3.2.26 native file format, nthe original form of a file.SWGIT/SWGDE3.2.26.1 DiscussionA file created with
27、 one applicationcan often be read by others, but a files native format remainsthe format it was given by the application that created it.3.2.27 noise, nvariations or disturbances in brightness orcolor information in an image that do not arise from the scene.SWGIT/SWGDE3.2.27.1 DiscussionSources of n
28、oise include film grain,electronic variations in the input device sensor and circuitry,and stray electromagnetic fields in the signal pathway. Itfrequently refers to visible artifacts in an image.3.2.28 original image, nan accurate and complete replicaof the primary image, irrespective of media; for
29、 film andanalog video, the primary image is the original image.SWGIT/SWGDE3.2.29 primary image, nrefers to the first instance inwhich an image is recorded onto any media that is a separate,identifiable object (for example, a digital image recorded onflash media). SWGIT/SWGDE3.2.30 processed image, n
30、any image that has undergoneenhancement, restoration or other operation.SWGIT/SWGDE3.2.31 proprietary file format, nany file format that isunique to a specific manufacturer or product.SWGIT/SWGDE3.2.32 resolution, nthe act, process, or capability ofdistinguishing between two separate but adjacent pa
31、rts orstimuli, such as elements of detail in an image, or similarcolors. SWGIT/SWGDE3.2.33 storage media, nany object on which data ispreserved. SWGIT/SWGDE3.2.34 traditional enhancement techniques, ndigital im-age processing techniques that have direct counterparts intraditional photographic darkro
32、oms; they include brightnessand contrast adjustment, color balancing, cropping, and dodg-ing and burning. SWGIT/SWGDE3.2.35 validation, nthe process of performing a set ofexperiments, which establishes the efficacy and reliability of atool, technique or procedure or modification thereof.SWGIT/SWGDEE
33、2765 1123.2.36 verification, nthe process of confirming the accu-racy of an item to its original. SWGIT/SWGDE3.2.37 video, nthe electronic representation of a sequenceof images, depicting either stationary or moving scenes. It mayinclude audio. SWGIT/SWGDE3.2.38 work copy, na copy (or duplicate) of
34、a recording,or data, that can be used for subsequent processing or analysis,or both. SWGIT/SWGDE4. Significance and Use4.1 The procedures outlined here are grounded in thegenerally accepted body of knowledge and experience in thefield of forensic document examination, forensic photography,and forens
35、ic digital imaging. By following these procedures aforensic document examiner can use image capture technologyreliably in support of examinations. This support can include:4.1.1 Documentation of the item(s) submitted for examina-tion, its condition upon receipt, and its condition at variouspoints du
36、ring the examination process;4.1.2 Demonstration of findings and the bases for determi-nations;4.1.3 Visualization of features and characteristics not read-ily perceptible to the human eye.4.2 The effects of prior storage, handling, testing, or chemi-cal processing (for example, for latent prints) c
37、an interfere withcertain characteristics to an extent that can limit (or evenpreclude) subsequent imaging. Whenever possible, captureimages of the item to be examined prior to any chemicalprocessing. Handle items appropriately to avoid compromisingsubsequent examinations of any kind.4.3 The technolo
38、gical evolution of hardware, or software, orboth can impact subsequent ability to access archived images.NOTE 1For further discussion see SWGIT, Section 1.5. Interferences5.1 Items can have inherent limitations that interfere withthe procedures in this practice, such as those due to thecondition of
39、the items submitted for examination. Limitationsshould be noted and documented.6. Equipment and Requirements6.1 Image capture device capable of sufficient resolution toreliably record the desired detail.6.2 Appropriate energy source(s) of sufficient intensity andappropriate spectral energy distribut
40、ion to allow the desireddetail to be distinguished.6.3 Calibration devices for dimensional, white balance, andexposure determinations.6.3.1 Appropriate ruler(s) in SI (metric), or IP (inch-pound)units, or both.6.3.2 Color and neutral gray objects for calibration stan-dards, both reflective and trans
41、mitted.6.4 Image output device(s) (for display or hardcopy produc-tion) capable of sufficient resolution and color balance forintended purpose(s).6.5 Media and appropriate systems for intermediate storageand archiving of images.6.6 Other apparatus and software as appropriate.6.7 Sufficient time and
42、facilities to complete all applicableprocedures.7. Procedure7.1 Perform all applicable procedures. These procedures donot have to be performed in the order given.7.2 Contemporaneously document the procedures per-formed in sufficient detail to allow for an independent reviewand assessment of the imag
43、es by a forensic document examiner(Guide E444). Include any relevant setting(s) and variable(s).7.3 At various points in these procedures, an examinersdetermination that a particular feature is not present or that anitem is lacking in a desired quality can indicate that theprocedure(s) involving ima
44、ging technology should be discon-tinued or limited. It is at the discretion of the examiner todiscontinue the procedure(s) at that point and report accord-ingly, or to continue with the applicable procedures to theextent possible. Document the reason(s) for such a decision.7.4 Calibrate or conduct a
45、ppropriate performance checks,maintain, and operate equipment in accordance with themanufacturers(s) recommendations or with a procedure(s)that has undergone validation.7.4.1 To ensure proper functioning, it can be useful toperform an initial test run, capturing an image of a standardizeditem that g
46、ives known results. Ascertain that the resultingimage is acceptable before proceeding; if the test capture is notacceptable when compared to the known capture from thestandardized item, make required correction(s) to the equip-ment or method.7.5 Conduct an initial assessment of each item to determin
47、ethe imaging equipment and procedure(s) to be used.7.5.1 Determine the appropriate image capture device basedupon the size and shape of the item, the required resolution andfield of view, and any specialized lighting requirement(s).7.5.1.1 Flatbed scanners can be used for image capture withflat item
48、s, such as sheets of paper or photographic prints, andalso for three-dimensional objects where a shallow depth offield will suffice.7.5.1.2 Three-dimensional objects and items needing spe-cial lighting set-ups typically require the use of a camera.7.5.1.3 Infrared imaging requires the use of special
49、izedequipment (Guide E1422).7.5.1.4 Reflected ultraviolet imaging requires the use ofspecialized equipment (Guide E1422).7.5.2 Whenever possible, remove item(s) from protectivepackaging, as images captured without intervening packagingare preferable.7.6 Capture images that are accurate representations of theitem and that record the desired, or needed, detail.7.6.1 Capture images at an optical (not interpolated) reso-lution and a pixel depth necessary to reproduce the desireddetail of interest on the output device(s) used for evaluation or
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