1、Designation: E1936 03 (Reapproved 2011)2E1936 15Standard Reference Radiograph forEvaluating the Performance of Radiographic DigitizationSystems1This standard is issued under the fixed designation E1936; the number immediately following the designation indicates the year oforiginal adoption or, in th
2、e case of revision, the year 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 NOTEReference source information was updated editorially in November 2014.2 NOTEReference radiog
3、raph source information was updated editorially in October 2015.1. Scope1.1 This reference radiograph covers a series of test targets suitable for evaluating, quantifying, and documenting performanceparameters of the radiographic digitization process or the electronic image reconstruction process, o
4、r both. This referenceradiograph can be used for visual and electronic analysis of digitization systems. This is the first of three related standards.Subsequent standards will provide guidance on the use of the test targets and recommended system performance levels1.2 This reference radiograph provi
5、des a series of test targets to provide a vehicle for the evaluation of spatial resolution, densitycontrast sensitivity, dynamic range, and spatial linearity as well as other aspects of a digitization system. The test targets aresuitable for evaluating a digitization system with a spatial resolution
6、 down to ;1/1000 in. (25 micrometres () (25 micrometres(m), a density contrast sensitivity down to 0.02 optical density (OD), a density range of 0.5 to 4.5 OD, and a film size capacityof 14 in. (355 mm) wide by 17 in. (431 mm) long.1.3 From time to time, there may be minor changes to the process for
7、 manufacturing of the reference adjunct film. Thesechanges could include changes in the films or processing chemistry used, text designation on the film, etc.; however, in all cases,these changes are reviewed by the Illustration Monitoring Subcommittee to ensure that there are no changes to the func
8、tional useof the reference image. Therefore, the adjunct reference films remain valid for use with this standard regardless of the date ofproduction or the revision level of the text standard.1.4 The values stated in inch-pound units are to be regarded as the standard, with the exception of the spat
9、ial resolution targets(6.2 and 6.7) which are stated in SI units.1.5 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and health practices and determine the applicabili
10、ty of regulatory limitationsprior to use.2. Referenced Documents2.1 ASTM Standards:2E1079 Practice for Calibration of Transmission DensitometersE1254 Guide for Storage of Radiographs and Unexposed Industrial Radiographic FilmsE1316 Terminology for Nondestructive ExaminationsE1411 Practice for Qualif
11、ication of Radioscopic Systems2.2 ASME Standard:Section V, Article 2, Mandatory Appendix VI, Digital Image Acquisition, Display, Interpretation and Storage for NuclearApplications31 This reference radiograph is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct
12、responsibility of Subcommittee E07.02 onReference Radiological Images.Current edition approved Dec. 1, 2011Dec. 1, 2015. Published March 2012January 2016. Originally approved in 1997. Last previous edition approved in 2011 asE1936 - 03(2011)12. DOI: 10.1520/E1936-03R11E2.10.1520/E1936-15.2 For refer
13、encedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American Society of Mechanical Engineers (ASME), ASME I
14、nternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible t
15、o adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Con
16、shohocken, PA 19428-2959. United States12.3 ASTM Adjuncts:Standard Reference Radiograph for Evaluating the Performance of Radiographic Digitization Systems43. Terminology3.1 Definitions:3.1.1 Refer to Terminology E1316 for definitions of terms used in this guide.3.2 Definitions of Terms Specific to
17、This Standard:3.2.1 converging line pairsthe targets located on the reference radiograph that are used to determine the spatial resolution ofthe digitization system.3.2.2 parallel line pairsthe targets located on the reference radiograph that are used in conjunction with the converging linepairs to
18、determine the spatial resolution of the digitization system.3.2.3 reference radiographthe single piece of industrial radiographic film containing all of the reference targets described inthis document.3.2.4 scan lineit is a path that is one pixel high (vertical) by the number of pixels wide (horizon
19、tal), that is captured by thedigitization system. The scan lines are added, one on top of the other, to electronically reproduce the physical (analog) data in thehorizontal (film width) and vertical (film length) directions on the display monitor.3.2.5 spatial linearitythe accuracy to which a digiti
20、zation system reproduces the physical dimension. It is assessed within asingle scan line and from one scan line to the next (horizontal and vertical directions).3.2.6 spatial resolutionit is measured as the minimum distance detectable between two physically spaced lines (see 6.2 spatialresolution ta
21、rgets). It is determined by the sampling rate in physical two-dimensional space and the system unsharpness.3.2.7 targetsthe physical patterns on the reference radiograph that are used to evaluate the radiographic film digitizationsystem.4. Significance and Use4.1 This reference radiograph may be use
22、d to quantify the performance characteristics of a radiographic digitization system orto provide periodic evaluations of a digitization system in a production mode to verify that appropriate operating characteristicsare being maintained. This reference radiograph provides a means for verifying the p
23、erformance of a digitization system in muchthe same way that the tests described in Practice E1411, provide for the verification of a radioscopic imaging system. It may beused to evaluate the performance of a digitization system in accordance with the requirements contained in ASME Section V,Article
24、 2, Mandatory Appendix VI, or other documents invoking requirements of this reference radiograph.4.2 This reference radiograph provides a tool that allows the user to determine the performance of their radiographic digitizationsystem. This reference radiograph may be used, where there is no other ap
25、plicable document, for establishing records of qualityand acceptable levels of performance between the cognizant engineering organization and purchaser of inspected components. ofthe film digitization system. This reference radiograph does not provide guidance on use of the test targets or recommend
26、 systemperformance levels.5. Preparation of Reference Radiograph5.1 The optical densities specified in 6.3 and 6.4 of this document are ascertained using densitometry equipment and techniquesin accordance with Practice E1079, and are supplied with the adjunct reference radiograph. Optical densities
27、are recorded in thecenter 0.12 in. (3 mm) of each of the density targets in 6.3 and 6.4.5.2 Film DeteriorationRadiographic film is subject to wear and tear from handling and use. The extent to which the imagedeteriorates over time is a function of storage conditions, care in handling, and amount of
28、use. Reference radiographic film is noexception and may exhibit a loss of image quality over time. The reference radiograph should therefore be examined each timeit is used for signs of wear and tear, including scratches, abrasions, stains, and so forth. A reference radiograph that shows signsof exc
29、essive wear and tear, which could influence the interpretation and use of the reference radiograph, should be replaced. Aguide for the storage of the reference radiograph is described in Guide E1254.6. Description of Targets6.1 The reference radiograph has five types of targets that may be used to e
30、valuate various parameters of the digitization system.The targets are located within a background density of approximately 3.0 OD. The reference radiograph is divided into three areaswith sizes of 8 in. (203 mm) by 10 in. (254 mm), (254 mm), 11 in. (279 mm) by 14 in. (355 mm), and 14 in. (355 mm) by
31、 17in. (430 mm). These have been created for digitization systems unable to accommodate film sizes up to 14 in. by 17 in. The4 Available from ASTM Headquarters. Order RRE1936.E1936 152reference radiograph may be cut to custom fit a particular digitization system and still contain all of the necessar
32、y targets withineach of these areas that are represented on the illustration in Fig. 1.FIG. 1 Representation of the AdjunctE1936 1536.2 Spatial Resolution TargetsThese consist of three identical groups of at least 6 converging line pairs. The targets have amaximum resolution of no less than 20 line
33、pairs per millimetre (lp/mm) and a minimum resolution of no greater than 1 lp/mm.The three line pair groups are oriented in the 0, 45, and 90 positions. The maximum resolution is oriented toward the cornersof the reference radiograph, Reference marks are provided to indicate spatial resolution at le
34、vels of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15,and 20 lp/mm.6.3 Density Contrast Sensitivity TargetsThese consist of 0.4 in. (1 cm) by 0.4 in. fields centered in 1.6 in. 1.6 in. (4 cm) by1.6 in. blocks of a slightly lower density. Two series of blocks will be are used, one block series with an optical de
35、nsity ofapproximately 2.00 OD on a background of approximately 1.95 OD, an optical density change of 0.05. The second block serieswill have approximately 3.50 OD on a background of approximately 3.40 OD, an optical density change of 0.10. The relativedensity change is more important than the absolut
36、e density. These 2 block series are grouped in no less than six areas on thereference radiograph.6.4 Stepped Density TargetsThese targets are to be used to determine dynamic range and density contrast sensitivity. Theyshall consist of a series of 0.4 in. (1 cm) by 0.4 in. blocks with densities of ra
37、nging from 0.5 to 4.5 OD. There shall be no lessthan 13 blocks aligned in a row with the following approximate densities: 4.5, 4.02, 4, 3.5, 3.02, 3, 2.5, 2.02, 2, 1.5, 1.02, 1, and0.5 OD. These blocks are grouped in no less than eight areas on the reference radiograph.6.5 Sharp Edge TargetEach step
38、ped density target (corresponding to 6.4) with the density 0.5 OD shall have sharp edges tothe background of 3.0 OD.The unsharpness of the sharp edges shall be less than 10 micron (0.0004 in.).This sharp edge shallmaybe used to measure horizontal and vertical line spread functions by differentiation
39、 of step profiles. The normalized magnitude ofthe Fourier transform of a line spread function yields the Modulation Transfer Function (MTF).6.6 Linearity TargetsThese targets provide 1.0 in. (25.4 mm) (25.4 mm) units of measure. They shall be are located in thehorizontal as well as the vertical dire
40、ctions. The linearity targets, or measurement scale, divides the reference radiograph into threedistinct film sizes 8 by 10 in. (203 by 254 mm), 11 by 14 in. (279 by 355 mm), and 14 by 17 in. (355 by 430 mm).6.7 Parallel Line Pair TargetThis target consists of a parallel line pair gage with a resolu
41、tion starting at no greater than 0.5lp/mm and increases to a resolution of no less than 20 lp/mm. This target may be used to determine spatial resolution. It ispositioned near the center of the 8 by 10 in. (203 by 254 mm) area on the reference radiograph.6.8 Additional targets may be located on the
42、reference radiograph as long as they do not interfere with the digitization, orinterpretation, of the targets located in 6.2 through 6.7.7. Keywords7.1 density contrast sensitivity; digitization; line pairs; reference radiograph; spatial linearity; spatial resolution; systemevaluation; target; X-ray
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