ISO 14096-2 pdf download

ISO 14096-2 pdf download Non-destructive testing — Qualification of radiographic film digitisation systems — Part 2: Minimum requirements
1 Scope
This European Standard specifies three film-digitisation quality classes for the requirements of non-destructive testing.The selected class depends on the radiation energy, penetrated material thickness and the quality level of the originalradiographic fim. This European Standard does not address signal processing, display and storage of the digitiseddata.
2 Normative references
This 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.For datedreferences, subsequent amendments to or revisions of any of these publications apply to this European Standard onlywhen incorporated in it by amendment or revision. For undated references the latest edition of the publication referredto applies (including amendments).
EN 444,Non-destructive testing – General principles for radiographic examination of metallic materials by X- anogamma-rays.
EN 1435,Non-destructive examination of welds — Radiographic examination of welded joints.EN 12681,Founding- Radiographic examination.
EN 14096-1，Non-destructive testing —Qualification of radiographic film digitisation systems — Part 1: Definitions,quantitative measurements of image quality parameters, standard reference film and qualitative control.
ISO 5579,Non-destructive testing —Radiographic examination of metallic materials by X- and gamma rays — Basicrules.
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.3.1
radiographic film digitisation systemdigitiser
sequential 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 an opticaldetector, giving an electric output signal (geometrical digitisation);
b) conversion of the above electrical signal into a numerical value (densitometrical digitisation)3.2
pixel size P
geometrical centre-to-centre distance between adjacent pixels in a row (horizontal pitch) or column (vertical pitch) ofthe scanned image
3.3
optical densityo
logarithmic value to the base 10 of the difuse light intensity ratio in front of (o) and behind (p) the radiographic filimaccording to equation (1):
D= ‘gy-
(1)
3.4
spatial frequency/
described by a sinusoidal intensity variation along a geometrical axis
The period of this function is measured in number of line pairs per millimetre (Ip/mm).3.5
modulation transfer function MTF
normalised magnitude of the Fourier-transform(FT) of the differentiated spatial optical density edge spread function(ESF) (see EN 14096-1 :2003, Figure 1)
it describes the unsharpness function of the digitiser (contrast transmission as a function of the object size).NOTE This MTF calculation is based on optical densities, which correspond to the X-ray dose.
3.6
digital resolution in bit
number of bits provided by the analogue-to-digital converter of the digitiser used for densitometrical digitisationNOTE A digital resolution of N bits corresponds to 2Ndigital values.
3.7
density contrast sensitivity
minimum density variation of the film, which is resolved by the digitiser
This is mostly determined by the digitisation noise of the digitise (quantum noise of the light detector).NOTEThe determination of this value is described in EN 14096-1:2003,4.1.5.
3.8
density range
range of maximum and minimum optical densities,which can be measured by the digitiser
Depending on the construction of the digitiser, this density range can be spit into several working ranges (e.g. by adifferent ililumination power andor a different detector integration time).
3.9
working range wR
range of optical densities,where the digitiser guarantees a minimum density contrast sensitivity in one singleacquisition