1、Designation:E134598(Reapproved 2014)Standard Practice forReducing the Effect of Variability of Color Measurement byUse of Multiple Measurements1This standard is issued under the fixed designation E1345;the number immediately following the designation indicates the year oforiginal adoption or,in the
2、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.INTRODUCTIONRecent improvements in the precision and bias of color-measuring instruments have beenaccompa
3、nied by more widespread use of numerical color tolerances based on instrumental measure-ments.As tighter tolerances are specified,they begin to approach the limits of visual perception.Inmany cases,the instrument user has found it difficult to prepare and measure specimens with adequaterepeatability
4、.This practice provides procedures for reducing variability in the mean results of colormeasurement by the use of multiple measurements,and it indicates how many measurements arerequired for a specific reduction.1.Scope1.1 Reduction of the variability associated with averagecolor or color-difference
5、 measurements of object-color speci-mens is achieved by statistical analysis of the results ofmultiple measurements on a single specimen,or by measure-ment of multiple specimens,whichever is appropriate.1.2 This practice provides a means for the determination ofthe number of measurements required to
6、 reduce the variabilityto a predetermined fraction of the relevant color or color-difference tolerances.1.3 This practice is general in scope rather than specific asto instrument or material.2.Referenced Documents2.1 ASTM Standards:2D2244 Practice for Calculation of Color Tolerances andColor Differe
7、nces from Instrumentally Measured ColorCoordinatesD3134 Practice for Establishing Color and Gloss TolerancesE178 Practice for Dealing With Outlying ObservationsE284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE456 Terminology Relating to Quality a
8、nd StatisticsE1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation2.2 Other Standard:SAE J 1545 Recommended Practice for Instrumental ColorDifference Measurement for Exterior Finishes,Textilesand Colored Trim33.Terminology3.1 Definitions of appearance terms in Terminology E284
9、orstatistical terms in Terminology E456 are applicable to thispractice.3.2 Definitions of Terms Specific to This Standard:3.2.1 box and whisker plot,na nonparmetric data analysisdiagram that illustrates the 25,50,and 75%cumulativedistribution of values in a data set(the box)and the expectedrange of
10、values,defined by distance outside the box ends;seewhiskers,see Fig.1.3.2.2 extreme value,na single reading,selected from aseries of readings,whose value is farther from the nearer boxend than 3.0 times the hinge length.3.2.2.1 DiscussionA box and whiskers plot is normallyused to find outliers and e
11、xtreme values.Such values should beeliminated from a series before calculating the series mean,standard deviation,and confidence intervals.3.2.3 hinges,nthe 25 and 75%cumulative distributionpoints in a set of readings taken during a measurement.3.2.3.1 DiscussionHinges represent the values in which1
12、This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.04 on Color andAppearance Analysis.Current edition approved Nov.1,2014.Published November 2014.Originallyapproved in 1990.Last previous edition approved in 2008 a
13、s E1345 98(2008)1.DOI:10.1520/E1345-98R14.2For 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 Society
14、of Automotive Engineers(SAE),400 CommonwealthDr.,Warrendale,PA 15096-0001,http:/www.sae.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 25%of the readings are less than the lower hinge and 75%ofthe readings are less than the upper hin
15、ge.See also hingelength.3.2.3.2 DiscussionHinges are sometimes called the lower(Q1)and upper(Q1)quartile values.3.2.4 hinge length,H,nthe range of values between thelower and upper hinges.3.2.4.1 DiscussionThe hinge length is sometimes calledthe box width or the interquartile range Q3to Q1.3.2.5 out
16、lier,na single reading,selected from a series ofreadings,whose value is further from the nearer box end then1.5 times the hinge length;see 3.2.2.1.3.2.6 samplingnumber,N,nnumberofmultiplemeasurements,or number of multiple specimens,required toreduce the variability of color or color-difference measurementto a desired level.3.2.7 standard deviation of color or color-differencemeasurement,sstandard deviation of the color scale orcolor-difference-scale value,xi,being considered:s 5$(xi2 xavg!2%/n 2
