SIST EN ISO 14096-1:2026
(Main)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 14096-1:2026)
- Abstract
This document specifies procedures for the evaluation of basic performance parameters of the radiographic film digitisation process, such as spatial resolution and spatial linearity, density range, density contrast sensitivity and characteristic transfer curve, which are applied in ISO 14096-2. These procedures can be integrated into the system software, and together with a standard reference film (see Annex B), used for quality control of the digitisation process. This reference film provides a series of test targets for performance evaluation. The test targets are suitable for evaluating a digitisation system with a basic spatial resolution down to 10 µm, a density contrast sensitivity down to 0,02 optical density, a density range of 0,5 to 4,5 and a film size capacity of (350 × 430) mm2.
This document does not address signal processing and display of the digitised data.
- Status
- Not Published
- Public Enquiry End Date
- 20-Nov-2025
- Technical Committee
- PKG - Testing of metallic materials
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 18-Sep-2026
- Due Date
- 23-Nov-2026
SIST EN ISO 14096-1:2026 is a CEN standard for non-destructive testing. It specifies how to evaluate radiographic film digitisation systems, including spatial resolution, spatial linearity, density range, density contrast sensitivity and the characteristic transfer curve, and how to use a standard reference film for quality control.
SIST EN ISO 14096-1:2026 is aimed at people qualifying and operating digitisers used to turn industrial radiographic film into digital data for X- and gamma-ray inspection. It focuses on the digitisation process itself and leaves signal processing and display of the digitised data outside its scope.
What does SIST EN ISO 14096-1:2026 specify?
SIST EN ISO 14096-1:2026 specifies procedures for evaluating the basic performance parameters of a radiographic film digitisation system. The document is built for qualification and quality control, so readers can check whether a digitiser preserves the information on the film in a way that is fit for later evaluation.
The document is organized into scope, normative references, terms and definitions, symbols and abbreviated terms, evaluation procedures, presentation of results, and qualitative control and long-term stability. It also includes two informative annexes that explain the MTF calculation and describe the standard reference film.
| Annex | What it covers |
|---|---|
| Annex A | MTF calculation and the steps used to derive it from the edge response function |
| Annex B | Standard reference film, its test targets, preparation, storage, handling and documentation |
SIST EN ISO 14096-1:2026 excludes signal processing and display of the digitised data. In practice, that means the standard is about how the scanner or digitiser performs at capture and how that performance is checked, not about how images are later processed on screen.
What are the key requirements of SIST EN ISO 14096-1:2026?
SIST EN ISO 14096-1:2026 sets out a practical test framework for characterising a digitiser with standard targets and repeatable measurements. The most important requirements are in Clause 5 and Clause 7.
Quantitative evaluation of key parameters
Clause 5.1 requires a stepped density target on the standard reference film for the characteristic transfer curve (CTC), density range and density contrast sensitivity. The target has to span the density interval used by the document, with small enough steps to show how the digitiser responds across the range. In practice, this gives a buyer or lab a way to check whether the system can read both low-density and high-density film areas.
Clause 5.1.2 defines how the CTC is built from the digitised gray levels of each density step. The document also states how the curve is interpreted for linear and logarithmic systems, and it calls for the digital values and corresponding optical densities to be reported in a table and/or diagram. This matters because the CTC is the link between what is on the film and what the digitiser outputs.
Clause 5.1.3 defines density range from the CTC. It also covers the case where the digitiser can read densities above the standard stepped target, using an added homogenous film with known density. That is important for systems intended for darker films, because it extends the evaluation beyond the base target.
Clause 5.1.4 determines pixel size from spatial linearity targets in both the row and column directions. The larger value becomes the reported pixel size. This matters because the pixel size limits the basic spatial resolution the system can achieve.
Clause 5.1.5 defines density contrast sensitivity from the standard deviation of calibrated optical densities over a neighbourhood of 225 pixels. The document also describes a practical approach using repeated scans and a difference image when the system allows it. In use, this tells the reader how much density difference the digitiser can resolve at a given density level.
Resolution, unsharpness and artefacts
Clause 5.2 covers spatial frequency maximum value, digitiser unsharpness, the modulation transfer function (MTF) and basic spatial resolution (SR). It allows the use of converging or parallel line pair targets to determine the highest visible spatial frequency, while warning about aliasing and moiré effects. This helps users avoid overestimating resolution from a poorly aligned test.
Clause 5.2.3 uses a step edge to measure digitiser unsharpness through the edge response function (ERF), and Clause 5.2.4 points to Annex A for MTF calculation. Clause 5.2.5 then derives SR from the 10 % MTF value, or allows a direct check with a duplex wire or line pair target. In practice, these methods show how sharply the digitiser reproduces fine detail.
Clause 5.3 requires checks for blooming or flare, digitisation artefacts, and geometric distortions. It also calls for inspection for transport-related scratching after scanning. For users, this is the part that catches real-world problems such as streaks, dirt, overshoot, and film handling damage.
Presentation of results and ongoing control
Clause 6 requires the main results to be presented as a spider web diagram with quality numbers taken from Table 2. This gives a compact summary of scan time, spatial resolution, working range and density contrast sensitivity. It is useful when comparing digitisers or documenting system performance.
Clause 7 sets up qualitative control and long-term stability checks. A normal check confirms the key parameters, while an extended check covers the full procedure set and is used after installation and repair. The document also says the timing of checks and acceptance levels should be defined by the quality assurance system, which makes the standard adaptable to plant practice.
What terms does SIST EN ISO 14096-1:2026 define?
- Radiographic film digitisation system - a digitiser that first measures film transmittance at small pixel areas and then converts the signal into numerical values.
- Scanning aperture (S) - the area on the film used for scanning one pixel; it limits the digitiser’s basic spatial resolution.
- Pixel size (P) - the centre-to-centre spacing between adjacent pixels, measured horizontally or vertically, with the larger value reported.
- Digitiser unsharpness (U) - the blurring introduced by the aperture, scattered light, flare or electronics.
- Modulation transfer function (MTF) - a measure of how well the digitiser transfers contrast at different object sizes.
- Density contrast sensitivity (ΔD) - the smallest density change that the digitiser can resolve.
- Working range (WR) - the density range in which the digitiser guarantees its minimum density contrast sensitivity in a single acquisition.
- Standard reference film - a photographic image on industrial radiographic film that contains most of the test targets used in the document.
Who uses SIST EN ISO 14096-1:2026?
SIST EN ISO 14096-1:2026 is used by non-destructive testing laboratories, radiography service providers, equipment manufacturers, and quality assurance teams that qualify or verify film digitisation systems. It is also relevant to buyers who need to specify performance for a digitiser before purchase or acceptance.
In practice, users apply the standard when they need to:
- compare digitiser performance against a defined reference film,
- check whether a system preserves spatial detail and density information,
- document acceptance after installation or repair,
- monitor long-term stability,
- support industrial inspection workflows that rely on digitised radiographic film.
What changed in SIST EN ISO 14096-1:2026 from the previous edition?
SIST EN ISO 14096-1:2026 replaces the first edition, ISO 14096-1:2005, and the document states that it has been technically revised. The listed changes are:
- definitions of terms 3.2, 3.6, 3.7, 3.13, 3.16 and 3.17 were updated,
- Clause 4 on symbols and abbreviated terms was added,
- Clause 5.1.3 was expanded for digitisers that can capture densities above 4.5,
- Clause 5.1.5 gained extra detail on the calculation of the standard deviation and a new note,
- Clause 5.2.5 on direct determination of SR was added,
- Clause 6 on presentation of results was added, including Figure 2,
- Table 2 with quality numbers was added,
- Figure 1 was added with examples of line pair test patterns for direct SR evaluation,
- the MTF calculation moved to Annex A,
- the standard reference film description moved to Annex B,
- editorial updates were made.
Which standards are used with SIST EN ISO 14096-1:2026?
SIST EN ISO 14096-1:2026 cites three standards as normative references or direct companions:
- ISO 11699-1 - provides the film classification used when the stepped density target calls for a fine-grain C1 film.
- ISO 14096-2 - gives the minimum requirements for qualification and is used in the extended check to determine the digitisation system class.
- ISO 19232-5 - provides the duplex wire image quality indicator method used for basic spatial resolution and related measurements.
What does the SIST EN ISO 14096-1:2026 document contain?
SIST EN ISO 14096-1:2026 contains the formulas, test methods and reporting structure needed to qualify a radiographic film digitisation system. It includes calculations for optical density, CTC, density contrast sensitivity, ERF, MTF and SR, plus a table of symbols and abbreviated terms.
The document also contains a spider web result format, a quality-number scale, and figure-based examples of direct SR evaluation. Annex A shows how the MTF is derived from the ERF through the line spread function, and Annex B describes the standard reference film in detail, including its target layout, preparation, handling, storage and certificate content.
Relations
- Effective Date
- 17-Sep-2026
- Effective Date
- 19-Jul-2023
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Frequently Asked Questions
SIST EN ISO 14096-1:2026 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "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 14096-1:2026)". This standard covers: This document specifies procedures for the evaluation of basic performance parameters of the radiographic film digitisation process, such as spatial resolution and spatial linearity, density range, density contrast sensitivity and characteristic transfer curve, which are applied in ISO 14096-2. These procedures can be integrated into the system software, and together with a standard reference film (see Annex B), used for quality control of the digitisation process. This reference film provides a series of test targets for performance evaluation. The test targets are suitable for evaluating a digitisation system with a basic spatial resolution down to 10 µm, a density contrast sensitivity down to 0,02 optical density, a density range of 0,5 to 4,5 and a film size capacity of (350 × 430) mm2. This document does not address signal processing and display of the digitised data.
This document specifies procedures for the evaluation of basic performance parameters of the radiographic film digitisation process, such as spatial resolution and spatial linearity, density range, density contrast sensitivity and characteristic transfer curve, which are applied in ISO 14096-2. These procedures can be integrated into the system software, and together with a standard reference film (see Annex B), used for quality control of the digitisation process. This reference film provides a series of test targets for performance evaluation. The test targets are suitable for evaluating a digitisation system with a basic spatial resolution down to 10 µm, a density contrast sensitivity down to 0,02 optical density, a density range of 0,5 to 4,5 and a film size capacity of (350 × 430) mm2. This document does not address signal processing and display of the digitised data.
SIST EN ISO 14096-1:2026 is classified under the following ICS (International Classification for Standards) categories: 19.100 - Non-destructive testing; 37.040.25 - Radiographic films. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN ISO 14096-1:2026 has the following relationships with other standards: It is inter standard links to SIST EN ISO 14096-2:2020, SIST EN ISO 14096-1:2020. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
SIST EN ISO 14096-1:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 14096-1:2025
01-november-2025
Neporušitvene preiskave - Kvalificiranje sistemov za digitaliziranje radiogramov -
1. del: Definicije, kvantitativne meritve parametrov kakovosti radiografske slike,
standardni referenčni radiogram in kvalitativna kontrola (ISO/DIS 14096-1:2025)
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/DIS 14096-1:2025)
Zerstörungsfreie Prüfung - Qualifizierung von Röntgenfilm-Digitalisierungssystemen -
Teil 1: Definitionen, quantitative Messung von Bildqualitätsparametern, Standard-
Referenzfilm und Qualitätssicherung (ISO/DIS 14096-1:2025)
Essais non destructifs - Qualification des systèmes de numérisation des films
radiographiques - Partie 1: Définitions, mesures quantitatives des paramètres de qualité
de l’image, film de référence normalisé et contrôle qualitatif (ISO/DIS 14096-1:2025)
Ta slovenski standard je istoveten z: prEN ISO 14096-1
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
37.040.25 Radiografski filmi Radiographic films
oSIST prEN ISO 14096-1:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN ISO 14096-1:2025
oSIST prEN ISO 14096-1:2025
DRAFT
International
Standard
ISO/DIS 14096-1
ISO/TC 135/SC 5
Non-destructive testing —
Secretariat: DIN
Qualification of radiographic film
Voting begins on:
digitisation systems —
2025-09-01
Part 1:
Voting terminates on:
2025-11-24
Definitions, quantitative
measurements of image quality
parameters, standard reference film
and qualitative control
Essais non destructifs — Qualification des systèmes de
numérisation des films radiographiques —
Partie 1: Définitions, mesures quantitatives des paramètres de
qualité d'image, film de référence normalisé et contrôle qualitatif
ICS: 37.040.25
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 14096-1:2025(en)
oSIST prEN ISO 14096-1:2025
DRAFT
ISO/DIS 14096-1:2025(en)
International
Standard
ISO/DIS 14096-1
ISO/TC 135/SC 5
Non-destructive testing —
Secretariat: DIN
Qualification of radiographic film
Voting begins on:
digitisation systems —
Part 1:
Voting terminates on:
Definitions, quantitative
measurements of image quality
parameters, standard reference film
and qualitative control
Essais non destructifs — Qualification des systèmes de
numérisation des films radiographiques —
Partie 1: Définitions, mesures quantitatives des paramètres de
qualité d'image, film de référence normalisé et contrôle qualitatif
ICS: 37.040.25
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
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Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 14096-1:2025(en)
ii
oSIST prEN ISO 14096-1:2025
ISO/DIS 14096-1:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 4
5 Evaluation procedures . 5
5.1 Evaluation of the characteristic transfer curve, density range, pixel size and density
contrast sensitivity .5
5.1.1 Stepped density target .5
5.1.2 Characteristic transfer curve (CTC) .5
5.1.3 Density range (D ) .6
R
5.1.4 Pixel size (P) .6
5.1.5 Density contrast sensitivity (ΔD ) .6
CS
5.2 Evaluation of the spatial frequency maximum value, digitiser unsharpness, basic
spatial resolution of the digitiser and modulation transfer function .7
5.2.1 General .7
5.2.2 Spatial frequency maximum value ( f ) .7
C
5.2.3 Digitiser unsharpness (U ) .7
D
5.2.4 Determination of the modulation transfer function (MTF) .8
D
5.2.5 Determination of the basic spatial resolution (SR ) of the digitiser .
b
5.3 Other evaluations .9
5.3.1 Blooming or flare .9
5.3.2 Digitisation artefacts .9
5.3.3 Geometric distortions . .9
6 Presentation of results . 9
7 Qualitative control and long term stability of the digitisation system .11
7.1 Normal check .11
7.2 Extended check .11
7.3 Test periods and long-term stability .11
Annex A (informative) MTF calculation .12
Annex B (informative) Standard reference film . 14
Bibliography . 17
iii
oSIST prEN ISO 14096-1:2025
ISO/DIS 14096-1:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of
patents which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 135, Non-destructive testing, Subcommittee
SC 5, Radiation methods.
This second edition cancels and replaces the first edition (ISO 14096-1:2005), which has been technically
revised.
The main changes are as follows:
— definitions of terms 3.2, 3.6, 3.7, 3.13, 3.16 and 3.17 updated;
— clause 4 symbols and abbreviations added;
— in clause 5.1.3, details added on digitisers capable to capture densities D>4,5;
— in clause 5.1.5 details on the calculation of the standard deviation σ of the calibrated density D(gl ) and
D
Note 2 added;
D
— determination of the basic spatial resolution of the digitiser (SR ) added in the new clause 5.2.5;
b
— new clause 6 "Presentation of results” with a new figure 2 added;
— new table 2 with quality numbers for representation of results in fig. 2 added;
D
— new figure 1 presents examples of line pair test pattern for direct evaluation of SR ;
b
— “MTF calculation” moved to Annex A and “standard reference film” description moved to Annex B;
— editorial updated.
A list of all parts in the ISO 14096 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
oSIST prEN ISO 14096-1:2025
ISO/DIS 14096-1:2025(en)
Introduction
Radiographic film systems are used for industrial inspection by X- and gamma rays. To apply means of
computer support for analysis, transmission and storage the information stored in the radiographic film
should be converted into digital data (digitisation). This document defines minimum requirements to ensure
that the relevant information for evaluation of the digital data is preserved during the film digitisation
process.
v
oSIST prEN ISO 14096-1:2025
oSIST prEN ISO 14096-1:2025
DRAFT International Standard ISO/DIS 14096-1:2025(en)
Non-destructive testing — Qualification of radiographic film
digitisation systems —
Part 1:
Definitions, quantitative measurements of image quality
parameters, standard reference film and qualitative control
1 Scope
This document specifies procedures for the evaluation of basic performance parameters of the radiographic
film digitisation process such as spatial resolution and spatial linearity, density range, density contrast
sensitivity and characteristic transfer curve. They can be integrated into the system software and together
with a standard reference film (see Annex B) used for quality control of the digitisation process. This
reference film provides a series of test targets for performance evaluation. The test targets are suitable for
evaluating a digitisation system with a basic spatial resolution down to 10 µm, a density contrast sensitivity
down to 0,02 optical density, a density range of 0,5 to 4,5 and a film size capacity of (350∙430) mm .
This document does not address signal processing and display of the digitised data.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 11699-1, Non-destructive testing — Industrial radiographic film — Part 1: Classification of film systems for
industrial radiography
ISO 14096-2, Non-destructive testing — Qualification of radiographic film digitisation systems — Part 2:
Minimum requirements
ISO 19232-5, Non-destructive testing — Image quality of radiographs — Part 5: Determination of the image
unsharpness and basic spatial resolution value using duplex wire-type image quality indicators
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
radiographic film digitisation system
digitiser
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 optical detector, giving an electric output signal (geometrical digitisation)
oSIST prEN ISO 14096-1:2025
ISO/DIS 14096-1:2025(en)
b) conversion of the above electrical signal into a numerical value (densitometrical digitisation)
3.2
scanning aperture
S
A
spatial extension (area) on the radiographic film through which the digitiser performs the scanning of one
pixel for geometrical digitisation
Note 1 to entry: The size of the scanning aperture corresponds a) in the case of rectangular aperture to the longer
side, b) in the case of circular aperture: to the diameter.
Note 2 to entry: The scanning aperture limits the basic spatial resolution of the digitiser.
3.3
pixel size
P
geometrical centre-to-centre distance between adjacent pixels in a row (horizontal pitch P ) or column
h
(vertical pitch P ) of the scanned image, the larger of both determines the pixel size P
v
D
Note 1 to entry: The pixel size is the limiting value of the basic spatial resolution SR of the digitization system.
b
3.4
optical density
D
logarithmic value to the base 10 of the diffuse light intensity ratio in front of (I ) and behind (I ) the
0 D
radiographic film according to Formula (1):
I
D=lg (1)
I
D
3.5
edge response function
ERF
resulting profile across a step function after digitisation into optical density values
3.6
digitiser unsharpness
U
D
blurring of sharp edges by the scanning aperture, scattered light, flare or electronic bandwidth
D
Note 1 to entry: The basic spatial resolution SR (3.13) of the digitiser in mm is the half of the value of U or the
D
b
inverse of 2∙f the spatial frequency value at 10 % MTF
M, .
3.7
spatial frequency
f
a measure of how often sinusoidal components of the structure repeat per unit of distance
Note 1 to entry: The period of this function is measured in number of line pairs per millimetre (lp/mm).
3.8
spatial frequency maximum value
f
c
value in number of line pairs per millimetre given by the Nyquist sampling theorem, see Formula (2):
fP=⋅12/() (2)
c
Note 1 to entry: In practice, the scanning aperture, the mechanics, and the electronics of the digitiser reduce this
theoretical value.
oSIST prEN ISO 14096-1:2025
ISO/DIS 14096-1:2025(en)
3.9
modulation transfer function
MTF
normalised magnitude of the Fourier-transform (FT) of the differentiated spatial optical density edge
response function (ERF, see 3.5) describing the unsharpness function of the digitiser (contrast transmission
as a function of the object size)
Note 1 to entry: The principle of determining the MTF is visualised in Figure A.1.
Note 2 to entry: This MTF calculation is based on optical densities, which correspond to the X-ray dose.
3.10
density range
D
R
range of maximum and minimum optical densities measurable with the digitiser
Note 1 to entry: Depending on the construction of the digitiser, this density range can be split into several working
ranges (3.15), e.g., by a different illumination power and/or a different detector integration time.
3.11
characteristic transfer curve
CTC
relationship between the optical density of the film and the digitised data
3.12
digital resolution
number of bits provided by the analogue-to-digital converter of the digitiser used for densitometrical
digitisation
N
Note 1 to entry: A digital resolution of N bits corresponds to 2 digital values.
3.13
basic spatial resolution of the digitisation system
D
SR
b
half of the measured unsharpness of the digitiser U in a digital image, which corresponds to the effective
D
pixel size
D
Note 1 to entry: For the measurement of SR , a duplex wire IQI according to ISO 19232-5 is exposed directly on the
b
film or a film print with sufficient resolution, may be used (see Figure 1 a and b for examples).
D image
Note 2 to entry: The measurement of SR is described in ISO 19232-5:2018, as iSR measurement, illustrated in
b
b
Figure B.1.
Note 3 to entry: See also 3.6, 5.2.4 and 5.2.5 for an alternative measurement using a sharp edge target and the 10 %
value of the Modulation Transfer Function (3.9) of this edge target (MTF ), see Annexes A and B.
10 %,
3.14
density contrast sensitivity
ΔD
CS
minimum density variation of the film, which is resolved by the digitiser
Note 1 to entry: ΔD is mainly determined by the digitisation noise of the digitiser (noise of the light source and
CS
detector), if the film noise can be neglected.
oSIST prEN ISO 14096-1:2025
ISO/DIS 14096-1:2025(en)
3.15
working range
D
WR
range of optical densities, where the digitiser guarantees a minimum density contrast sensitivity in one
single acquisition
Note 1 to entry: Only in this density range the digitised data can be used for evaluation. Depending on the digitiser
construction there can be more than one working range, e.g. for brighter or darker films.
3.16
single acquisition
digitisation of one radiographic film performed in one single process
Note 1 to entry: The result of a single acquisition is a collection of data without any further processing. A defined and
unique set of parameters of the digitisation system is used for this acquisition.
3.17
standard reference film
photographic image on an industrial radiographic film containing most of the reference targets described in
this document
3.18
target
physical pattern on a radiograph which are used to evaluate the digitiser
4 Symbols and abbreviated terms
For the purposes of this document, the symbols and abbreviated terms given in Table 1 apply.
Table 1 — Symbols and abbreviated terms
Symbol or abbreviated
Definition
term
CTC characteristic transfer curve of the digitiser
D optical density of film
D constant optical density of an additional film
A
D(gl) calibrated optical density according to the CTC at grey level gl
D(gl ) calibrated optical density according to the CTC at gray level gl
n n
D(gl ) calibrated optical density according to the CTC at gray level gl
m m
range of maximum and minimum optical densities, which can be measured by the digit-
D
R
iser
ΔD density contrast sensitivity
CS
D working range, optical density range in a single acquisition
WR
ERF edge response function
f spatial frequency
f spatial frequency maximum value
c
f spatial frequency value at 10 % MTF
M
gl digitised data values (gray levels) for an area of (15 × 15) pixels
j,i
I diffuse light intensity in front of the radiographic film
I diffuse light intensity behind the radiographic film
D
image
iSR interpolated bas
...