ASTM_E_3023_-_15.pdf

Designation:E302315Standard Practice forProbability of Detection Analysis for Versus a Data1This standard is issued under the fixed designation E3023;the number immediately following the designation indicates the year oforiginal adoption or,in the 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.Scope1.1 This practice defines the procedure for performing astatistical analysis on Nondestructive Testing(NDT)versus adata to determine the demonstrated probability of detection(POD)for a specific set of examination parameters.Topicscoveredincludethestandardversusaregressionmethodology,POD curve formulation,validation techniques,and correct interpretation of results.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address 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:2E178 Practice for Dealing With Outlying ObservationsE456 Terminology Relating to Quality and StatisticsE1316 Terminology for Nondestructive ExaminationsE1325 Terminology Relating to Design of ExperimentsE2586 Practice for Calculating and Using Basic StatisticsE2782 Guide for Measurement Systems Analysis(MSA)E2862 Practice for Probability of Detection Analysis forHit/Miss Data2.2 Department of Defense Document:3MIL-HDBK-1823A Nondestructive Evaluation System Re-liability Assessment3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 analyst,nthe person responsible for performing aPOD analysis on versus a data resulting from a PODexamination.3.1.2 decision threshold,dec,nthe value of abovewhich the signal is interpreted as a find and below which thesignal is interpreted as a miss.3.1.2.1 DiscussionA decision threshold is required tocreate a POD curve.The decision threshold is always greaterthan or equal to the noise threshold and is the value of thatcorresponds with the flaw size that can be detected with 50%POD.3.1.3 demonstrated probability of detection,nthe calcu-lated POD value resulting from the statistical analysis of the versus a data.3.1.4 false call,n the perceived detection of a disconti-nuity that is identified as a find during a POD examinationwhen no discontinuity actually exists at the inspection site.3.1.5 noise,nsignal response containing no useful targetcharacterization information.3.1.6 noise threshold,noise,nthe value of below whichthe signal is indistinguishable from noise.3.1.6.1 DiscussionThe noise threshold is always less thanor equal to the decision threshold.The noise threshold is usedto determine left censored data.3.1.7 probability of detection,nthe fraction of nominaldiscontinuity sizes expected to be found given their existence.3.1.8 saturation threshold,sat,nthe value of associatedwith the maximum output of the system or the largest value of that the system can record.3.1.8.1 DiscussionThe saturation threshold is used todetermine right censored data.3.2 Symbols:3.2.1 adiscontinuity size.3.2.2 the measured signal response for a given disconti-nuity size,a.3.2.2.1 DiscussionThe measured signal response is as-sumed to be continuous in nature.Units depend on the NDT1This test method is under the jurisdiction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.10 onSpecialized NDT Methods.Current edition approved June 15,2015.Published August 2015.DOI:10.1520/E302315.2For 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 to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk,DODSSP,Bldg.4,SectionD,700RobbinsAve.,Philadelphia,PA19111-5098,http:/dodssp.daps.dla.mil.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 inspection system and can be,for example,scale divisions,number of contiguous illuminated pixels,or millivolts.3.2.3 apthe discontinuity size that can be detected withprobability p.3.2.3.1 DiscussionEach discontinuity size has an indepen-dent probability of being detected and corresponding probabil-ity of being missed.For example,being able to detect a specificdiscontinuity size with probability p does not guarantee that alarger size discontinuity will be found.3.2.4 ap/cthe discontinuity size that can be detected withprobability p with a statistical confidence level of c.3.2.4.1 DiscussionAccording to the formula in MIL-HDBK-1823A,ap/cis a one-sided up