SIST EN 14096-1:2004

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Zerstörungsfreie Prüfung - Qualifizierung von Röntgenfilm-Digitalisierungssystemen - Teil 1: Definitionen, quantitative Messung von Bildqualitätsparametern, Standard-Referenzfilm und QualitätssicherungEssais non destructifs - Qualification des systemes de numérisation des films radiographiques - Partie 1: Définitions, mesures quantitatives des parametres de qualité d'image, film de référence normalisé et contrôle qualitatifNon-destructive testing - Qualification of radiographic film digitisation systems - Part 1: Definitions, quantitative measurements of image quality parameters, standard reference film and qualitative control37.040.25Radiografski filmiRadiographic films19.100Neporušitveno preskušanjeNon-destructive testingICS:Ta slovenski standard je istoveten z:EN 14096-1:2003SIST EN 14096-1:2004en01-marec-2004SIST EN 14096-1:2004SLOVENSKI
STANDARD



SIST EN 14096-1:2004



EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14096-1April 2003ICS 01.040.19; 01.040.37; 19.100; 37.040.25English versionNon-destructive testing - Qualification of radiographic filmdigitisation systems - Part 1: Definitions, quantitativemeasurements of image quality parameters, standard referencefilm and qualitative controlEssais non destructifs - Qualification des systèmes denumérisation des films radiographiques - Partie 1:Définitions, mesures quantitatives des paramètres dequalité d'image, film de référence normalisé et contrôlequalitatifZerstörungsfreie Prüfung - Qualifizierung von Röntgenfilm-Digitalisierungssystemen - Teil 1: Definitionen, quantitativeMessung von Bildqualitätsparametern, Standard-Referenzfilm und QualitätssicherungThis European Standard was approved by CEN on 11 March 2003.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and UnitedKingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2003 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14096-1:2003 ESIST EN 14096-1:2004



EN 14096-1:2003 (E)2ContentspageForeword.31Scope.42Normative references.43Terms and definitions.44Evaluation procedures.75Standard reference film.116Qualitative control and long term stability of the digitisation system.13SIST EN 14096-1:2004



EN 14096-1:2003 (E)3ForewordThis document (EN 14096-1:2003) has been prepared by Technical Committee CEN /TC 138, "Non-destructivetesting", the secretariat of which is held by AFNOR.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by October 2003, and conflicting national standards shall be withdrawn at the latestby October 2003.EN 14096 comprises a series of European Standards for radiographic film digitisation systems which is made up ofthe following:EN 14096-1Non-destructive testing – Qualification of radiographic film digitisation systems – Part 1:Definitions, quantitative measurements of image quality parameters, standard reference film andqualitative controlEN 14096-2Non-destructive testing – Qualification of radiographic film digitisation systems – Part 2: MinimumrequirementsAccording to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Slovakia, Spain, Sweden, Switzerland and the United Kingdom.SIST EN 14096-1:2004



EN 14096-1:2003 (E)4IntroductionRadiographic film systems are used for industrial inspection by X- and gamma rays. To apply modern means ofcomputer support for analysis, transmission and storage the information stored in the radiographic film should beconverted into digital data (digitisation). This European Standard defines minimum requirements to ensure that therelevant information for evaluation of the digital data is preserved during the film digitisation process.1 ScopeThis European Standard specifies procedures for the evaluation of basic performance parameters of theradiographic film digitisation process such as spatial resolution and spatial linearity, density range, density contrastsensitivity and characteristic transfer curve. They can be integrated into the system software and together with astandard reference film (as described in clause 5) used for quality control of the digitisation process. This referencefilm provides a series of test targets for performance evaluation. The test targets are suitable for evaluating adigitisation system with a spatial resolution down to 25 µm, a density contrast sensitivity down to 0,02 opticaldensity, a density range of 0,5 to 4,5 and a film size capacity of (350 x 430) mm². This standard does not addresssignal processing and display of the digitised data.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 584-1, Non-destructive testing
Industrial radiographic film — Part 1: Classification of film systems forindustrial radiography.EN 14096-2, Non-destructive testing — Qualification of radiographic film digitisation systems — Part 2: Minimumrequirements.3 Terms and definitionsFor the purposes of this European Standard, the following terms and definitions apply.3.1radiographic film digitisation systemdigitisersequential application of the two functions below:a) detection of the diffuse transmittance of a small unit area of the film (pixel, picture element) by means of anoptical detector, giving an electric output signal (geometrical digitisation);b) conversion of the above electrical signal into a numerical value (densitometrical digitisation)3.2scanning apertureSAspatial extension (area) on the radiographic film through which the digitiser performs the scanning of one pixel forgeometrical digitisationThe size of the scanning aperture corresponds:SIST EN 14096-1:2004



EN 14096-1:2003 (E)5 in the case of rectangular aperture: to the longer side, in the case of circular aperture: to the diameter.The scanning aperture limits the spatial resolution of the digitiser.3.3pixel sizePgeometrical centre-to-centre distance between adjacent pixels in a row (horizontal pitch) or column (vertical pitch)of the scanned image3.4optical densityDlogarithmic value to the base 10 of the diffuse light intensity ratio in front of (I0) and behind (ID) the radiographic filmaccording to equation (1):DIID0lg(1)3.5edge spread functionESFresulting profile across a step function after digitisationNOTEThis function can be either as light intensity or optical density.3.6digitiser unsharpnessUDblurring of sharp edges by the scanning aperture, scattered light, flare or electronic bandwidthIt is determined from the geometrical distance of the 10% and 90% point of the Edge Spread Function (ESF) from alight intensity step function.3.7spatial frequencyfdescribed by a sinusoidal intensity variation along a geometrical axisThe period of this function is measured in number of line pairs per millimetre (lp/mm).3.8spatial frequency maximum valuefcin theory, this value, in number of line pairs per millimetre, is given by the Nyquist sampling theorem, see equation(2):)*2(/1Pfc(2)Practically, the scanning aperture, the mechanics and the electronics of the digitiser reduce this theoretical value.3.9modulation transfer functionMTFnormalised magnitude of the Fourier-transform (FT) of the differentiated spatial optical density edge spreadfunction (ESF) (see Figure 1)It describes the unsharpness function of the digitiser (contrast transmission as a function of the object size).SIST EN 14096-1:2004



EN 14096-1:2003 (E)6NOTEThis MTF calculation is based on optical densities, which correspond to the X-ray dose.3.10density rangeDRrange of maximum and minimum optical densities, which can be measured by the digitiserDepending on the construction of the digitiser, this density range can be split into several working ranges (e.g. by adifferent illumination power and/or a different detector integration time).3.11characteristic transfer curveCTCrelationship between the optical density of the film and the digitised data3.12digital resolution in bitnumber of bits provided by the analogue-to-digital converter of the digitiser used for densitometrical digitisationNOTEA digital resolution of N bits corresponds to 2N digital values.3.13density sampling pitchDSPoptical density variation corresponding to an increase of 1 in the digitised valueNOTEThis density variation depends on the characteristic transfer curve of the digitiser. The density sampling pitch can bea function of the density.3.14density contrast sensitivityDCSminimum density variation of the film, which is resolved by the digitiserThis is mostly determined by the digitisation noise of the digitiser (quantum noise of the light detector).3.15working rangeDWRrange of optical densities, where the digitiser guarantees a minimum density contrast sensitivity in one singleacquisitionOnly in this density range the digitised data can be used for evaluation. Depending on the digitiser constructionthere can be more than one working range, e.g. for brighter or darker films.3.16single acquisitiondigitisation of one radiographic film performed with one single scanThe result of which is a collection of data not subject to any type of further processing. A unique set of parametersof the digitisation system is used for this acquisition.3.17standard reference filmphotographic image on an industrial radiographic film containing all of the reference targets described in thisdocument3.18targetsphysical patterns on the standard reference film which are used to evaluate the digitiserSIST EN 14096-1:2004



EN 14096-1:2003 (E)74 Evaluation procedures4.1 Evaluation of the characteristic transfer curve, density range, pixel size and density contrastsensitivity4.1.1 Stepped density targetFor the measurement of the characteristic transfer curve, the density range and the density contrast sensitivity ofthe digitiser a stepped density target on a reference radiograph (standard reference film) is required with thefollowing requirements: to cover the optical density interval between D = 0,5 and D = 4,5; the optical density spacing between 2 adjacent steps is not greater than D = 0,5; the area of each step is at least 100 mm²; a fine grain type film (system class C1 in EN 584-1) with light exposure shall be used to achieve a finegranularity resulting into a film noise less than D = 0,01 (at 88,6 µm pixel size).4.1.2 Characteristic transfer curve (CTC)For a unique set of digitiser parameters, an acquisition of the stepped density target on the reference film isperformed. For each density step Di the arithmetic mean value igl of the digitised data values glj,i for an area of(15 x 15) pixel shall be determined according to equation (3):2251jij,i2251glgl(3)The characteristic transfer curve of the digitiser is constructed from the table of Di versus igl.Missing density values between the measured density steps can be interpolated in compliance with the followingconditions: for linear systems (digital data proportional to light intensity) the curve shall be logarithmic, for logarithmic systems (digital data proportional to optical film density, provided by electronic log-amplifiers ordigital LUT) the curve shall be linear.The digital data provided by the digitiser and the corresponding optical density values shall be reported in a tableand/or a diagram.The discrete density values expressed by the digital data shall be named D(gl).Depending on the construction of the digitiser, the CTC can be different for the stepped density target in scanningdirection and perpendicular to it.4.1.3 Density range (DR)The density range of the
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