Standard Practice for Probability of Detection Analysis for <emph type="bdit"><?Pub _font FamName="Times New Roman"?>&#xe2;<?Pub /_font?></emph> Versus <emph type="bdit">a</emph> Data

SIGNIFICANCE AND USE
5.1 The POD analysis method described herein is based on well-known and well-established statistical methods. It shall be used to quantify the demonstrated POD for a specific set of examination parameters and known range of discontinuity sizes under the following conditions.  
5.1.1 The initial response from a nondestructive evaluation inspection system is measurable and can be classified as a continuous variable.  
5.1.2 The relationship between discontinuity size (a) and measured signal response (â) exists and is best described by a linear regression model with an error structure that is normally distributed with mean zero and constant variance, σ2. (Note that “linear” refers to linear with respect to the model coefficients. For example, a quadratic model  is a linear model.)  
5.2 This practice does not limit the use of other statistical models if justified as more appropriate for the â versus a data.  
5.3 This practice is not appropriate for data resulting from a POD examination on nondestructive evaluation systems that generate an initial response that is binary in nature (for example, hit/miss). Practice E2862 is appropriate for systems that generate a hit/miss-type response (for example, fluorescent penetrant).  
5.4 Prior to performing the analysis it is assumed that the discontinuity of interest is clearly defined; the number and distribution of induced discontinuity sizes in the POD specimen set is known and well documented; the POD examination administration procedure (including data collection method) is well designed, well defined, under control, and unbiased; the initial inspection system response is measurable and continuous in nature; the inspection system is calibrated; and the measurement error has been evaluated and deemed acceptable. The analysis results are only valid if the â versus a data are accurate and precise and the linear model adequately represents the â versus a data.  
5.5 The POD analysis method described herein is consistent ...
SCOPE
1.1 This practice defines the procedure for performing a statistical analysis on Nondestructive Testing (NDT) â versus a data to determine the demonstrated probability of detection (POD) for a specific set of examination parameters. Topics covered include the standard â versus a regression methodology, POD curve formulation, validation techniques, and correct interpretation of results.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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14-Jun-2015
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ASTM E3023-15 - Standard Practice for Probability of Detection Analysis for <emph type="bdit"><?Pub _font FamName="Times New Roman"?>&#xe2;<?Pub /_font?></emph> Versus <emph type="bdit">a</emph> Data
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E3023 − 15
Standard Practice for
1
Probability of Detection Analysis for â Versus a Data
This standard is issued under the fixed designation E3023; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This practice defines the procedure for performing a 3.1 Definitions of Terms Specific to This Standard:
statistical analysis on NondestructiveTesting (NDT) â versus a
3.1.1 analyst, n—the person responsible for performing a
data to determine the demonstrated probability of detection
POD analysis on â versus a data resulting from a POD
(POD) for a specific set of examination parameters. Topics
examination.
covered include the standard â versus a regression
3.1.2 decision threshold, â ,n—the value of â above
dec
methodology, POD curve formulation, validation techniques,
which the signal is interpreted as a find and below which the
and correct interpretation of results.
signal is interpreted as a miss.
1.2 The values stated in inch-pound units are to be regarded
3.1.2.1 Discussion—A decision threshold is required to
as standard. The values given in parentheses are mathematical
create a POD curve. The decision threshold is always greater
conversions to SI units that are provided for information only
than or equal to the noise threshold and is the value of â that
and are not considered standard.
corresponds with the flaw size that can be detected with 50%
1.3 This standard does not purport to address all of the
POD.
safety concerns, if any, associated with its use. It is the
3.1.3 demonstrated probability of detection, n—the calcu-
responsibility of the user of this standard to establish appro-
lated POD value resulting from the statistical analysis of the â
priate safety and health practices and determine the applica-
versus a data.
bility of regulatory limitations prior to use.
3.1.4 false call, n—– the perceived detection of a disconti-
2. Referenced Documents nuity that is identified as a find during a POD examination
2
when no discontinuity actually exists at the inspection site.
2.1 ASTM Standards:
E178 Practice for Dealing With Outlying Observations 3.1.5 noise, n—signal response containing no useful target
E456 Terminology Relating to Quality and Statistics characterization information.
E1316 Terminology for Nondestructive Examinations
3.1.6 noise threshold, â ,n—the value of â below which
noise
E1325 Terminology Relating to Design of Experiments
the signal is indistinguishable from noise.
E2586 Practice for Calculating and Using Basic Statistics
E2782 Guide for Measurement Systems Analysis (MSA) 3.1.6.1 Discussion—The noise threshold is always less than
E2862 Practice for Probability of Detection Analysis for or equal to the decision threshold. The noise threshold is used
Hit/Miss Data to determine left censored data.
3
3.1.7 probability of detection, n—the fraction of nominal
2.2 Department of Defense Document:
discontinuity sizes expected to be found given their existence.
MIL-HDBK-1823A Nondestructive Evaluation System Re-
liability Assessment
3.1.8 saturation threshold, â ,n—the value of â associated
sat
with the maximum output of the system or the largest value of
â that the system can record.
1
This test method is under the jurisdiction of ASTM Committee E07 on
3.1.8.1 Discussion—The saturation threshold is used to
Nondestructive Testing and is the direct responsibility of Subcommittee E07.10 on
determine right censored data.
Specialized NDT Methods.
Current edition approved June 15, 2015. Published August 2015. DOI: 10.1520/
3.2 Symbols:
E3023–15.
3.2.1 a—discontinuity size.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.2.2 â—the measured signal response for a given disconti-
Standards volume information, refer to the standard’s Document Summary page on
nuity size, a.
the ASTM website.
3
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
3.2.2.1 Discussion—The measured signal response is as-
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
dodssp.daps.dla.mil. sumed to be continuous in nature. Units depend on the NDT
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E3023 − 15
inspection system and can be, for example, scale divisions, 5.4 Prior to performing the analysis it is assumed that the
number of contiguous illuminated pixels, or millivolts. discontinuity of interest is clearly defined; the nu
...

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