ASTM_E_2545_-_07_2012.pdf

Designation:E254507(Reapproved 2012)Standard Test Method forObjective Measurement of Gingival Color Using Digital StillCameras1This standard is issued under the fixed designation E2545;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.INTRODUCTIONThe color of gingiva is an important parameter used to ascertain certain medical and estheticinformation.RGB color values for gingiva are derived from the native signals generated by a digitalstill camera,DSC,by broadband measurement of the reflectance of gingiva.This Test Method,E2545,specifies the procedure used for the color measurement of gingival color at 45 relative to the sampleplane containing the gingiva under a nearly equal energy illuminating at 45 and viewing at 0.Thismethod is appropriate for evaluating the color of facial gingiva.1.Scope1.1 This test method covers the procedure,instrumentalrequirements,standardization procedures,material standards,measurement procedures,and parameters necessary to makeprecise measurements of gingival color.In particular it ismeant to measure the color of gingiva in human subjects.1.2 Digital images are used to evaluate gingival color on thefacial labial or buccal surfaces of the gingiva.The marginalgingival tissue adjacent to natural teeth may be of particularinterest for analysis.All other non-relevant parts;such as teeth,tongue,spaces,dental restorations or prostheses,etc.,must beseparated from the measurement and the analysis.All localizeddiscoloration;such as stains,inclusions,pigmentations,etc.,may be separated from the measurement and the analysis.1.2.1 The broadband reflectance factors of gingiva and thesurrounding tissue are measured.The colorimetric measure-ment is performed using an illuminator(s)that provides con-trolled illumination on the gingiva using a digital still camerato capture the digital image.1.3 Data acquired using this test method may be used toassess personal gingival color for the purposes of identifyingoverall health status,health status at specific sites in the mouth,or to track changes in personal health status for individualsover time.Pooled data may be used to assess gingival color,health and disease among populations in epidemiologicalsurveys,evaluation of comparative product efficacy,or safetyand treatment response in clinical trials involving gingivalhealth or disease.1.4 The apparatus,measurement procedure,and data analy-sis technique are generic,so that a specific apparatus,measure-ment procedure,or data analysis technique may not be ex-cluded.1.5 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.6 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:2E179 Guide for Selection of Geometric Conditions forMeasurement of Reflection and Transmission Propertiesof MaterialsE284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple MeasurementsE1767 Practice for Specifying the Geometries of Observa-tion and Measurement to Characterize the Appearance ofMaterials1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.06 on ImageBased Color Measurement.Current edition approved Feb.1,2012.Published February 2012.Originallyapproved in 2007.Last previous edition approved in 2007 as E2545 07.DOI:10.1520/E2545-07R12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.2 ISO Publications:3ISO 173211 Colour characterization of digital still cameras(DSCs)Part 1:Stimuli,metrology,and test proceduresISO/IEC 15441:2000 JPEG2000 Information technology JPEG 2000 image coding system Part 1:Core codingsystem,commonly known as JPEG 2000 jp2 file format2.3 ISCC Publications:4Technical Report 20031 Guide to Material Standards andTheir Use in Color Measurement2.4 Other Publications:5TIFF Tagged Image File Format3.Terminology3.1 Terms and definitions in Terminology E284 are appli-cable to this test method.3.2 Definitions:Terms included in this section are peculiarto this standard.3.2.1 angle of incidence,n1and optional 2,the polarangle b