ISO/FDIS 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

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 part 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.

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

L'ISO 14096-1:2005 spécifie les procédures d'évaluation des paramètres de performance de base du processus de numérisation des films radiographiques tels que la résolution et la linéarité spatiales, la plage de densité, la sensibilité au contraste de densité et la courbe de transfert caractéristique. Ils peuvent être intégrés au logiciel du système ainsi qu'au film de référence normalisé utilisé pour le contrôle qualité du processus de numérisation. Ce film de référence comporte une série de cibles de contrôle pour l'évaluation de la performance. Ces cibles de contrôle permettent une évaluation du système de numérisation présentant une résolution spatiale allant jusqu'à 25 µm, une sensibilité au contraste de densité avec jusqu'à 0,02 de densité optique, une plage de densité comprise entre 0,5 et 4,5 et un format de film d'une capacité de (350 x 430) mm2 (14 x 17 pouces). L'ISO 14096-1:2005 ne s'adresse pas au traitement du signal et à l'affichage des données numérisées.

General Information

• Status: Not Published
• ICS: 37.040.25 - Radiographic films
• Technical Committee: ISO/TC 135/SC 5 - Radiographic testing
• Drafting Committee: ISO/TC 135/SC 5 - Radiographic testing
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 26-May-2026
• Completion Date: 26-May-2026

Relations

• Consolidates: FprEN ISO 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/FDIS 14096-1:2026)
• Effective Date: 12-Feb-2026
• Consolidates: ISO 29469:2022 - Thermal insulating products for building applications — Determination of compression behaviour
• Effective Date: 22-Jul-2023
• Revises: ISO 14096-1:2005 - Non-destructive testing — Qualification of radiographic film digitisation systems — Part 1: Definitions, quantitative measurements of image quality parameters, standard reference film and qualitative control
• Effective Date: 15-Jul-2023

Overview

ISO/FDIS 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 specifies standardized procedures for evaluating the performance of radiographic film digitisation systems. Published by the International Organization for Standardization (ISO), this document establishes a framework for assessing key parameters such as spatial resolution, spatial linearity, density range, density contrast sensitivity, and characteristic transfer curve. Using a standard reference film with a series of test targets, these procedures support consistent and reliable quality control across non-destructive testing (NDT) environments.

Key Topics

• Radiographic Film Digitisation Process: Assessment of how analog radiographic films are converted to digital format, ensuring accurate reporting and traceability for industrial inspections.
• Image Quality Parameters: Standardized measurement of critical characteristics, including:
  • Spatial resolution and spatial linearity: Evaluating the system’s ability to distinguish fine details and maintain accurate geometry during digitisation.
  • Density range: Verifying the measurable optical density range (typically from 0.5 to 4.5) for comprehensive film evaluation.
  • Density contrast sensitivity: Confirming the digitiser’s capability to detect fine differences down to 0.02 optical density.
  • Characteristic transfer curve: Establishing the relationship between input film density and digital output, ensuring consistent digital representation.
• Standard Reference Film: Utilization of a film with specific test targets, as defined in Annex B, to verify system accuracy and stability.
  • Suitable for film sizes up to 350 × 430 mm², spatial resolution to 10 µm, and low film noise.
• Quality Control Integration: Procedures designed to be incorporated into digitisation system software for ongoing, automated performance monitoring and long-term system stability checks.

Applications

ISO/FDIS 14096-1 provides high value in several industrial and technical fields by enabling:

• Industrial Radiography Quality Assurance: Ensuring radiographic film digitizers meet stringent performance criteria, contributing to reliable component inspection in sectors like aerospace, automotive, energy, and manufacturing.
• Data Traceability and Archiving: Facilitating the accurate digitization and long-term storage of radiographic test data for auditing, regulatory compliance, and ongoing process improvement.
• Calibration and Maintenance: Offering repeatable procedures for system calibration and preventive maintenance to detect drift or failures in digitisation performance early.
• Interlaboratory Comparability: Enabling different organizations or laboratories to align on image quality standards for global harmonization in non-destructive testing.

The standard is not intended to address signal processing or visual display aspects of digitised images, instead focusing on the initial capture and conversion process.

Related Standards

For full compliance and comprehensive application, users should consult the following related ISO standards:

• 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

These documents collectively provide a robust foundation for radiographic digitisation system qualification, operational reliability, and quality control in non-destructive testing.

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Keywords: ISO 14096-1, non-destructive testing, radiographic film digitisation, image quality, spatial resolution, density range, quality control, standard reference film, NDT, industrial radiography, calibration, measurement procedures, digitizer qualification, spatial linearity, density contrast sensitivity

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/TC 135/SC 5
Non-destructive testing —
Secretariat: DIN
Qualification of radiographic film
Voting begins on:
digitisation systems —
2026-05-26
Part 1:
Voting terminates on:
2026-07-21
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 de l’image, film de référence normalisé et contrôle
qualitatif
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
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 de l’image, film de référence normalisé et contrôle
qualitatif
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 SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .vi
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 .8
5.2.1 General .8
5.2.2 Spatial frequency maximum value ( f ) .8
C
5.2.3 Digitiser unsharpness (U ) .8
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 .8
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 (normative) Standard reference film . 14
Bibliography . 17

iii
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 document 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 (a)
patent(s) 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, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 138, Non-destructive testing, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
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 5.1.3, details added on digitisers capable to capture densities D > 4,5;
— in 5.1.5, details on the calculation of the standard deviation σ of the calibrated density D(gl) and Note 2
D
added;
D
— determination of the basic spatial resolution of the digitiser (SR ) added in the new subclause 5.2.5;
b
— clause 6 "Presentation of results” with a new Figure 2 added;
— Table 2 with quality numbers for representation of results in Figure 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 revision.
A list of all parts in the ISO 14096 series can be found on the ISO website.

iv
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.

v
Introduction
Radiographic film systems are used for industrial inspection by X- and gamma rays. For computer-supported
analysis, transmission and storage, the information stored in the radiographic film is converted into digital
data (digitisation). This document provides quantitative evaluation procedures which form the basis for
minimum requirements specified in ISO 14096-2.

vi
FINAL DRAFT International Standard ISO/FDIS 14096-1:2026(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, 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) 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);
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
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 (3.2), scattered light, flare or electronic bandwidth
Note 1 to entry: The basic spatial resolution SRbD (3.13) of the digitiser in mm is the half of the value of U or the
D
inverse of 2∙f approximately the spatial frequency value at 10 % MTF
M, .
Note 2 to entry: Internal device algorithms for smoothing or interpolation influence U ), thus the use of raw scan is
D
often recommended.
3.7
spatial frequency
f
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):
fP12/ (2)

c
Note 1 to entry: In practice, the scanning aperture, the mechanics, and the electronics of the digitiser reduce this
theoretical value.
3.9
modulation transfer function
MTF
normalised magnitude of the Fourier-transform (FT) of the differentiated spatial optical density edge
response function (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, where the digitiser
guarantees a minimum density contrast sensitivity (3.14)
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 digitiser unsharpness (3.6)U measured in a row (horizontal) and in a column (vertical)
D
of the scanned image, which corresponds to the effective pixel size and to the larger of both of the two
measured values
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, can 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.
3.15
working range
D
WR
range of optical densities, where the digitiser guarantees a minimum density contrast sensitivity (3.14) in
one single acquisition (3.16)
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 specified 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 that is 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 grey level gl
n n
D(gl ) calibrated optical density according to the CTC at grey level gl
m m
range of maximum and minimum optical densities, which can be measured by the digitis-
D
R
er with a guaranteed minimum density contrast sensitivity
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 (grey levels) for an area of (15 × 15) pixels
j,i
TTaabblle 1 e 1 ((ccoonnttiinnueuedd))
Symbol or abbreviated
Definition
term
I diffuse light intensity in front of the radiographic film
I diffuse light intensity behind the radiographic film
D
image
iSR interpolated basic spatial image resolution, see ISO 19232-5
b
LSF Line spread function
m modulation
MTF modulation transfer function
MTF 10 % magnitude value of the modulation transfer function
10 %
P pixel size
P horizontal pitch
h
P vertical pitch
v
S scanning aperture
A
D
basic spatial resolution of the digitiser
SR
b
standard deviation of optical densities
σ
D
U digitiser unsharpness
D
5 Evaluation procedures
5.1 Evaluation of the characteristic transfer curve, density range, pixel size and density
contrast sensitivity
5.1.1 Stepped density target
For the measurement of the characteristic transfer curve, the density range and the density contrast
s
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standard reference film and qualitative control
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Foreword . iv
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Introduction . vi
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1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 4
5 Evaluation procedures . 6
6 Presentation of results . 11
7 Qualitative control and long-term stability of the digitisation system . 12
Annex A (informative) MTF calculation . 14
Annex B (normative) Standard reference film . 17
Bibliography . 22

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MUST BE USED
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FOR FINAL
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iii
ISO14096ISO/FDIS 14096-1:2025(E2026(en) Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold
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Foreword
spacing: single
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ISO (the International Organization for Standardization) is a worldwide federation of national standards
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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 document 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).
Formatted: English (United Kingdom)
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 (a) patent(s)
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.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.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee ISO/TC 135, Non-destructive testing, Subcommittee
Formatted: Adjust space between Latin and Asian text,
SC 5, Radiation methods, in collaboration with the European Committee for Standardization (CEN) Technical Adjust space between Asian text and numbers
Committee CEN/TC 138, Non-destructive testing, in accordance with the Agreement on technical cooperation
Formatted: Font: Not Italic
between ISO and CEN (Vienna Agreement).
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This second edition cancels and replaces the first edition (ISO 14096--1:2005), which has been technically
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revised.
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The main changes are as follows:
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— — definitions of terms 3.2, 3.6, 3.7, 3.13, 3.163.2, 3.6, 3.7, 3.13, 3.16 and 3.173.17 updated;
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— — Clause 44 symbols and abbreviations added;
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— — in 5.1.3,5.1.3, details added on digitisers capable to capture densities D > 4,5;
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
— — in 5.1.5,in 5.1.5, details on the calculation of the standard deviation σ of the calibrated density D(gl)
D
and Note 2 added;
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D D
— — determination of the basic spatial resolution of the digitiser ( SR )(𝑆𝑅 ) added in the new
Formatted: Font: 10 pt
b b
clausesubclause 5.2.5;
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— — clause 66 "Presentation of results” with a new Figure 2Figure 2 added;
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iv © ISO 2024 2026 – All rights reserved
iv
ISO/DISFDIS 14096-1:20252026(en) Formatted: Font: 11 pt
Formatted: Font: 11 pt
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— — Table 2Table 2 with quality numbers for representation of results in Figure 2Figure 2 added;
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— — new Figure 1Error! Reference source not found. presents examples of line pair test pattern for
D
D
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direct evaluation of SR ;𝑆𝑅 ;
b b
— — “MTF calculation” moved to Annex AAnnex A and “standard reference film” description moved to
Annex B;Annex B;
— — editorial revision.
A list of all parts in the ISO 14096 series can be found on the ISO website.
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Any feedback or questions on this document should be directed to the user’s national standards body. A
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complete listing of these bodies can be found at www.iso.org/members.html.
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Formatted: English (United Kingdom)
Formatted: English (United Kingdom)
Field Code Changed
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MUST BE USED
Tab stops: Not at 17.2 cm
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FOR FINAL
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v
ISO14096ISO/FDIS 14096-1:2025(E2026(en) Formatted: Font: 11 pt, Bold
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Introduction
spacing: single
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Radiographic film systems are used for industrial inspection by X- and gamma rays. To apply means ofFor
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computer support for-supported analysis, transmission and storage, the information stored in the
radiographic film is converted into digital data (digitisation). This document provides quantitative evaluation
procedures which form the basis for minimum requirements specified in ISO 14096-2.
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vi © ISO 2024 2026 – All rights reserved
vi
DRAFT International Standard ISO/DIS 14096-1:2025(en)

Formatted: Left
Non-destructive testing — Qualification of radiographic film
digitisation systems —
Formatted: Main Title 2, Space After: 0 pt, Adjust
Part 1:
space between Latin and Asian text, Adjust space
Definitions, quantitative measurements of image quality parameters,
between Asian text and numbers
standard reference film and qualitative control Formatted: Right: 1.5 cm, Bottom: 1 cm, Gutter: 0 cm,
Section start: New page, Header distance from edge:
1.27 cm, Footer distance from edge: 0.5 cm
1 Scope
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This document specifies procedures for the evaluation of basic performance parameters of the radiographic Adjust space between Asian text and numbers
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 part -2. These procedures can be
integrated into the system software, and together with a standard reference film (see Annex B)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 .
Formatted: English (United Kingdom)
This document does not address signal processing and display of the digitised data.
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2 Normative references
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The following documents are referred to in the text in such a way that some or all of their content constitutes
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requirements of this document. For dated references, only the edition cited applies. For undated references,
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the latest edition of the referenced document (including any amendments) applies.
Adjust space between Asian text and numbers, Tab
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
ISO 11699--1, Non-destructive testing — Industrial radiographic film — Part 1: Classification of film systems
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
for industrial radiography
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ISO 14096--2, Non-destructive testing — Qualification of radiographic film digitisation systems — Part 2:
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Minimum requirements
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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
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3 Terms and definitions
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For the purposes of this document, the following terms and definitions apply.
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ISO and IEC maintain terminology databases for use in standardization at the following addresses:
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— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
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— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
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3.1 3.1
Formatted: TermNum2, Adjust space between Latin
radiographic film digitisation system and Asian text, Adjust space between Asian text and
digitiser numbers
sequential application of the two functions below:
Formatted: Regular
a) a) detection of the diffuse transmittance of a small unit area of the film (pixel, picture element)
Formatted: Numbered + Level: 1 + Numbering Style: a,
by means of an optical detector, giving an electric output signal (geometrical digitisation); b, c, … + Start at: 1 + Alignment: Left + Aligned at: 0
cm + Indent at: 0 cm, Adjust space between Latin and
b) b) conversion of the above electrical signal into a numerical value (densitometrical digitisation) Asian text, Adjust space between Asian text and
numbers, Tab stops: Not at 0.7 cm + 1.4 cm + 2.1 cm
3.2 3.2 + 2.8 cm + 3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3
scanning aperture cm + 7 cm
S
A
Formatted: TermNum2, Adjust space between Latin
spatial extension (area) on the radiographic film through which the digitiser performs the scanning of one
and Asian text, Adjust space between Asian text and
pixel for geometrical digitisation
numbers
Formatted: Regular Italic, Font: Bold, Not Italic
Note 1 to entry: The size of the scanning aperture corresponds:
Formatted: Regular Sub, Font: Bold, Not Superscript/
Subscript
a) a) in the case of rectangular aperture, to the longer side;
Formatted: Font: Bold
b) b) in the case of circular aperture, to the diameter.
Formatted
...
Note 2 to entry: The scanning aperture limits the basic spatial resolution of the digitiser.
Formatted
...
Formatted
...
3.3 3.3
pixel size
Formatted
...
P
Formatted: Regular Italic, Font: Bold, Not Italic
geometrical centre-to-centre distance between adjacent pixels in a row (horizontal pitch P ) or column
h
Formatted: Font: Bold
(vertical pitch P ) of the scanned image
v
D
D
Formatted
Note 1 to entry: The pixel size is the limiting value of the basic spatial resolution SR 𝑆𝑅 of the .
b
b
digitization system.
3.4 3.4
Formatted
...
optical density
D
Formatted: Regular Italic, Font: Bold, Not Italic
logarithmic value to the base 10 of the diffuse light intensity ratio in front of (I ) and behind (I ) the
0 D
Formatted: Font: Bold
radiographic film according to Formula (1):(1):
Formatted: label
I
𝐼 Formatted: label
0 0
D= lg 𝐷 = lg (1)
𝐼
D
I
D Formatted
...
3.5 3.5 Formatted
...
edge response function
Formatted: Regular Italic, Font: Bold, Not Italic
ERF
Formatted
...
resulting profile across a step function after digitisation into optical density values
Formatted: Font: Bold
3.6 3.6
Formatted
...
digitiser unsharpness
Formatted: Not Superscript/ Subscript
U
D
blurring of sharp edges by the scanning aperture (3.2),(3.2), scattered light, flare or electronic bandwidth
Formatted: Font: 10 pt
Formatted: Font: 10 pt
D
Note 1 to entry: The basic spatial resolution SR (3.13)SRbD (3.13) of the digitiser in mm is the half of
b
Formatted: Font: 11 pt
the value of U or the inverse of 2∙f approximately the spatial frequency value at 10 % MTF
D M, .
Formatted
...
2 © ISO 2025 2026 – All rights reserved
ISO/DISFDIS 14096-1:20252026(en) Formatted: Font: 11 pt
Formatted: Font: 11 pt
Formatted: Font: 11 pt
Note 2 to entry: Internal device algorithms for smoothing or interpolation influence U ), thus the use
D
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of raw scan is often recommended.
Line spacing: single, Tab stops: Not at 0.71 cm
3.7 3.7
Formatted: TermNum2, Adjust space between Latin
spatial frequency
and Asian text, Adjust space between Asian text and
f
numbers
measure of how often sinusoidal components of the structure repeat per unit of distance
Formatted: Regular Italic, Font: Bold, Not Italic
Note 1 to entry: The period of this function is measured in number of line pairs per millimetre (lp/mm). Formatted: Font: Bold
Formatted: Adjust space between Latin and Asian text,
3.8 3.8
Adjust space between Asian text and numbers, Tab
spatial frequency maximum value
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
f
c
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
value in number of line pairs per millimetre given by the Nyquist sampling theorem, see Formula (2):(2):
Formatted: TermNum2, Adjust space between Latin
and Asian text, Adjust space between Asian text and
fP=1/(2 ) 𝑓 = 1/(2 ⋅ 𝑃) (2)
c 𝑐
numbers
Formatted: Regular Italic, Font: Bold, Not Italic
Note 1 to entry: In practice, the scanning aperture, the mechanics, and the electronics of the digitiser
reduce this theoretical value.
Formatted: Regular Sub, Font: Bold, Not Superscript/
Subscript
3.9 3.9
Formatted: Font: Bold
modulation transfer function
MTF Formatted: label
normalised magnitude of the Fourier-transform (FT) of the differentiated spatial optical density edge response
Formatted: label
function (3.5)(3.5) describing the unsharpness function of the digitiser (contrast transmission as a function of
Formatted: Adjust space between Latin and Asian text,
the object size)
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stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
Note 1 to entry: The principle of determining the MTF is visualised in Figure A.1.Figure A.1 .
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
Note 2 to entry: This MTF calculation is based on optical densities, which correspond to the X-ray dose. Formatted: TermNum2, Adjust space between Latin
and Asian text, Adjust space between Asian text and
3.10 3.10
numbers
density range
Formatted
...
D
R
Formatted
...
range of maximum and minimum optical densities measurable with the digitiser, where the digitiser
guarantees a minimum density contrast sensitivity (3.14)(3.14)
Formatted: Regular Italic, Font: Bold, Not Italic
Formatted
...
Note 1 to entry: Depending on the construction of the digitiser, this density range can be split into
several working ranges (3.15),(3.15), e.g., by a different illumination power and/or a different detector integration time. Formatted: Font: Bold
Formatted
...
3.11 3.11
Formatted
characteristic transfer curve .
CTC
relationship between the optical density of the film and the digitised data
3.12 3.12
digital resolution
number of bits provided by the analogue-to-digital converter of the digitiser used for densitometrical
Formatted
...
digitisation
Formatted: Font: 10 pt
N
Note 1 to entry: A digital resolution of N bits corresponds to 2 digital values.
Formatted: Font: 10 pt
Formatted
MUST BE USED .
Formatted: Font: 11 pt
Formatted: Font: 11 pt, Not Bold
FOR FINAL
Formatted
...
Formatted: Font: Bold
Formatted: HeaderCentered
3.13 3.13
Formatted: TermNum2, Adjust space between Latin
basic spatial resolution of the digitisation system and Asian text, Adjust space between Asian text and
D
numbers
SR
b
D
𝑺𝑹
b
half of the measured digitiser unsharpness (3.6) (3.6)U measured in a row (horizontal) and in a column
D Formatted: Adjust space between Latin and Asian text,
(vertical) of the scanned image, which corresponds to the effective pixel size and to the larger of both of the Adjust space between Asian text and numbers
two measured values
D
D Formatted: Default Paragraph Font
Note 1 to entry: For the measurement of SR ,𝑆𝑅 , a duplex wire IQI according to ISO 19232-5 is exposed directly on the
b b
Formatted: Default Paragraph Font
film or a film print with sufficient resolution, can be used (see Figure 1Error! Reference source not found. a and b for
examples).
Formatted: Default Paragraph Font
Formatted: Adjust space between Latin and Asian text,
D image image
D
Note 2 to entry: The measurement of SR 𝑆𝑅 is described in ISO 19232-5:2018, as iSR 𝑖𝑆𝑅 measurement,
b
b b
b Adjust space between Asian text and numbers, Tab
illustrated in Figure B.1.Figure B.1 . stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
Note 3 to entry: See also 3.6, 5.2.43.6, 5.2.4 and 5.2.5Error! Reference source not found. for an alternative
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measurement using a sharp edge target and the 10 % value of the Modulation Transfer Function (3.9)(3.9) of this edge
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target (MTF10 %,), see Annexes AAnnex A and B.Annex B.
Formatted: Default Paragraph Font
3.14 3.14
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density contrast sensitivity
ΔD
CS Formatted: Default Paragraph Font
minimum density variation of the film, which is resolved by the digitiser
Formatted: TermNum2, Adjust space between Latin
and Asian text, Adjust space between Asian text and
Note 1 to entry: ΔDCS is mainly determined by the digitisation noise of the digitiser (noise of the light source and
numbers
detector), if the film noise can be neglected.
Formatted: Regular, Font: Bold
3.15 3.15
Formatted: Regular Italic, Font: Bold, Not Italic
working range
Formatted: Regular Sub, Font: Bold, Not Superscript/
D
WR
Subscript
range of optical densities, where the digitiser guarantees a minimum density contrast sensitivity (3.14)(3.14)
Formatted: Font: Bold
in one single acquisition (3.16)(3.16)
Formatted: Adjust space between Latin and Asian text,
Note 1 to entry: Only in this density range the digitised data can be used for evaluation. Depending on the digitiser
Adjust space between Asian text and numbers, Tab
construction there can be more than one working range, e.g. for brighter or darker films.
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
3.16 3.16
Formatted: TermNum2, Adjust space between Latin
single acquisition
and Asian text, Adjust space between Asian text and
digitisation of one radiographic film performed in one single process
numbers
Note 1 to entry: The result of a single acquisition is a collection of data without any further processing. A specified and
Formatted: Regular Italic, Font: Bold, Not Italic
unique set of parameters of the digitisation system is used for this acquisition.
Formatted
...
3.17 3.17 Formatted: Font: Bold
standard reference film
Formatted
...
photographic image on an industrial radiographic film containing most of the reference targets described in
Formatted
...
this document
Formatted
...
3.18 3.18
Formatted
...
target
Formatted: Font: 10 pt
physical pattern on a radiograph that is used to evaluate the digitiser
Formatted: Font: 10 pt
Formatted: Font: 11 pt
Formatted
...
4 © ISO 2025 2026 – All rights reserved
Formatted
...
Formatted
...
ISO/DISFDIS 14096-1:20252026(en)
Formatted
...
Formatted
...
Formatted Table
...
4 Symbols and abbreviated terms
Formatted
...
For the purposes of this document, the symbols and abbreviated terms given in Table 1Table 1 apply.
Formatted
...
Formatted
...
Table 1 — Symbols and abbreviated terms
Formatted
...
Symbol or
Definition
Formatted
...
abbreviated term
Formatted
...
CTC characteristic transfer curve of the digitiser
Formatted
...
D optical density of film
Formatted
...
D constant optical density of an additional film
A
Formatted
...
D(gl) calibrated optical density according to the CTC at grey level gl
Formatted
...
D(gl ) calibrated optical density according to the CTC at graygrey level gl
n n
Formatted
...
D(glm) calibrated optical density according to the CTC at graygrey level glm
Formatted
...
range of maximum and minimum optical densities, which can be measured by the
Formatted
D
R .
digitiser with a guaranteed minimum density contrast sensitivity
Formatted
...
ΔD density contrast sensitivity
CS
Formatted
...
DWR working range, optical density range in a single acquisition
Formatted
...
ERF edge response function
Formatted
...
f spatial frequency
Formatted
...
fc spatial frequency maximum value
Formatted
...
f spatial frequency value at 10 % MTF
M
Formatted
...
glj,i digitised data values (graygrey levels) for an area of (15 × 15) pixels
Formatted
...
I diffuse light intensity in front of the radiographic film
0 Formatted
...
ID diffuse light intensity behind the radiographic film Formatted
...
image
Formatted
iSRb interpolated basic spatial image resolution, see ISO 19232-5
...
Formatted
LSF Line spread function .
Formatted
...
m modulation
Formatted
...
MTF modulation transfer function
Formatted
...
MTF10 % 10 % magnitude value of the modulation transfer function
Formatted
...
P pixel size
Formatted
...
Ph horizontal pitch
Formatted
...
Pv vertical pitch
Formatted
...
S scanning aperture
A
Formatted
...
D
D
SR basic spatial resolution of the digitiser
𝑆𝑅
b b
Formatted
...
Formatted
 𝜎 standard deviation of optical densities .
𝐷
D
Formatted
...
U digitiser unsharpness
D
Formatted
...
MUST BE USED
Formatted
...
Formatted
...
FOR FINAL
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted
...
Formatted: Font: Bold
Formatted: HeaderCentered
5 Evaluation procedures
Formatted: Space Before: 12 pt, Adjust space between
Latin and Asian text, Adjust space between Asian text
5.1 Evaluation of the characteristic transfer curve, density range, pixel size and density and numbers
contrast sensitivity
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers, Tab
5.1.1 Stepped density target
stops: Not at 0.71 cm
Formatted: Adjust space between Latin and Asian text,
For the measurement of the characteristic transfer curve, the density range and the density contrast sensitivity
Adjust space between Asian text and numbers, Tab
of the digitiser, a stepped density target on a reference radiograph (standard reference film) shall be used with
stops: Not at 0.71 cm + 0.99 cm + 1.27 cm
the following requirements:
Formatted: Adjust space between Latin and Asian text,
— — to cover the optical density interval between D = 0,5 and D = 4,5; Adjust space between Asian text and numbers
Formatted: Adjust space between Latin and Asian text,
— — the optical density spacing between 2 adjacent steps is not greater than D = 0,5;
Adjust space between Asian text and numbers, Tab
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
— — the area of each step is at least 100 mm ;
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
— — a fine grain type film (maximum system class C2 in accordance with ISO 11699-1) with light exposure
Formatted: Default Paragraph Font
shall be used to achieve a fine granularity resulting into a film noise less than ∆D ≤ 0,01.
Formatted: Default Paragraph Font
5.1.2 Characteristic transfer curve (CTC) Formatted: Default Paragraph Font
Formatted
...
For a unique set of digitiser parameters, an acquisition of the stepped density target on the reference film is
Formatted
...
¯
performed. For each density step Di the arithmetic mean value 𝑔𝑙 𝑔𝑙 of the digitised data values glj,i for an
𝑖
𝑖
area of (15 × 15) pixels shall be determined according to Formula (3):Error! Reference source not found.:
1 Formatted
...
¯
𝑔𝑙 𝑔𝑙 = · 𝑔𝑙 (3)
𝑖 ∑ 𝑖,𝑗
𝑖
𝑗=1
Formatted: Font: (Intl) Cambria Math
Formatted: Font: (Intl) Cambria Math
¯
The characteristic transfer curve of the digitiser is constructed from a table of Di versus 𝑔𝑙 𝑔𝑙 of all steps i of
𝑖
𝑖
Formatted: Font: (Intl) Cambria Math
the stepped density target.
Formatted: English (United Kingdom)
Missing density values between the measured density steps D can be interpolated in conformance with the
i
Formatted: Font: (Intl) Cambria Math
following conditions:
Formatted: Font: (Intl) Cambria Math
a) a) for linear systems (digital data proportional to light intensity), the curve shall be logarithmic;
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b) b) for logarithmic systems (digital data proportional to optical film density (logarithm of light
intensity, see Formula 1),(1)), provided by electronic log-amplifiers or digital LUT), the curve shall be
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linear.
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¯ .
The digital data 𝑔𝑙 𝑔𝑙 provided by the digitiser and the corresponding optical density values D shall be
i
𝑖
𝑖
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reported in a table and/or a diagram.
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The discrete density values expressed by the digital data shall be named D(gl).
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Depending on the construction of the digitiser, the CTC may be different for the stepped density target in
scanning direction and perpendicular to it.
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5.1.3 Density range (DR)
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The density range of the digitiser is determined by the characteristic transfer curve. It is the difference
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between the minimum and maximum optical density, which can be resolved by the digitiser with the required
minimum density contrast sensitivity. The minimum and maximum optical density for a given parameter set
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of the digitiser is assigned from the corresponding characteristic transfer curve. But there can be digitiser
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6 © ISO 2025 2026 – All rights reserved
ISO/DISFDIS 14096-1:20252026(en) Formatted: Font: 11 pt
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parameters which select a different CTC. Then the density range is calculated from the maximum and
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minimum optical density values of all possible CTC’s.
Line spacing: single, Tab stops: Not at 0.71 cm
In the case that the digitiser is able to capture densities D > 4,5, the reference film shall be covered by a
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homogenous film with known density DA in the region of the stepped density target – but without the step
D = 0,5, which should be used as reference for the lowest density. The evaluation will then range from D = 0,5
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to D = 4,5 + DA.
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Example: With an additional film of homogenous density DA = 1 the step with D = 4,5 will have in the scanned image Formatted: Font: Not Italic
a D = 5,5. If the step with D = 0,5 and the step with D=5,5 are visible in the same image, the density range extends from
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0,5 to 5,5. If the last step is missing, the density range is from 0,5 to 5,0.
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5.1.4 Pixel size (P)
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The pixel size is determined by evaluating the spatial linearity targets of the standard reference film. By
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
dividing the known distance of these targets by the number of pixels found in the digitised image the pixel size
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
P can be calculated. This shall be performed in row and column direction of the image.
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D D
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SR
The pixel size P is the limit of the basic spatial resolution 𝑆𝑅 of the digitizer achievable, i.e. the value of
b b
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D D
SR 𝑆𝑅 is equal or larger than P, never smaller than P. stops: Not at 0.71 cm + 0.99 cm + 1.27 cm
b b
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5.1.5 Density contrast sensitivity (ΔD )
CS Adjust space between Asian text and numbers
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The evaluation of the density contrast sensitivity ΔD is based on a calculation of the standard deviation σ of
CS D
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adjacent pixels in a film region with constant optical density. This calculation shall be performed on the
stops: Not at 0.71 cm + 0.99 cm + 1.27 cm
digitised values of the calibrated optical film density D(gl).
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For convenience, it is specified that at least a neighbourhood of 225 pixels is considered for all following cases.
The standard deviation σ of the calibrated optical density D(gl ) shall be calculated for these 225 values at a
D i
given density step according to Formula (4):Error! Reference source not found.:
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𝜎
D
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1 1 1
225 225
𝜎 = ⋅ √ 𝐷 𝑔𝑙 − ⋅ 𝐷 𝑔𝑙 [𝐷(𝑔𝑙 ) − ⋅ { (𝐷(𝑔𝑙 ))}] (4)
∑ [ ( ) {∑ ( ( ))}] √∑ ∑
D 𝑛=1 𝑛 𝑚=1 𝑚 𝑛 𝑚
224 225 225 𝑚=1
√
𝑛=1 Formatted: Font: (Intl) Cambria Math
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where
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 𝜎 is the standard deviation of optical densities;
D D
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
𝐷 𝑔𝑙 (𝑔𝑙 ) is the calibrated optical density at graygrey level gl ;
( ) n
𝑛 𝑛 3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
𝐷(𝑔𝑙 )(𝑔𝑙 ) is the calibrated optical density at graygrey level glm;
𝑚 𝑚
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As the density steps of the reference film contains several artefacts e.g. dust or scratches, it is usefullyusefull
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to calculate the standard deviation σ of the steps from a difference image of two successive scanned images,
D
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if the film digitisation system allows a pixel correctly repeated scanning. The calibrated density D(gl ) shall be
i
taken from the mean value of the two scanned images. This is a similar procedure as described for efficiency
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measurements in [1].Error! Reference source not found.
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The σ represents the noise of the digitiser itself at the density value considered. The density contrast Formatted: Font: 10 pt
D
D D
sensitivity (scaled to 88,6 µm basic spatial resolution, SR ,𝑆𝑅 , actual basic spatial resolution of the digitiser)
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MUST BE USED .
b b
is calculated according to Formula (5):Error! Reference source not found.:
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FOR FINAL
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D D
𝑆𝑅 𝑆𝑅
b b
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Δ𝛥𝐷 = 2 ⋅ 𝜎 · ( ) 𝜎 · ( ) (5)
CS D D
𝑐 𝑐
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where
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 𝜎 is the standard deviation of optical densities;
D
D
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D 𝛥𝐷 is the density contrast sensitivity;
CS
CS
text, Adjust space between Asian text and numbers, Tab
D D
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
𝑆𝑅 𝑅 is the basic spatial resolution of the digitiser in mm;
b b
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
c is the size of the quadratic reference aperture (0,088 6 mm).
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To compare the density contrast sensitivity of digitisers with different pixel sizes, the value of D is referred
CS
D
D
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to a square SR 𝑆𝑅 size of c = 88,6 µm. This corresponds to the 100 µm diameter of the microdensitometer
b b
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aperture used for film granularity measurements in ISO 11699--1.
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The practical determination of the standard deviation should be carried out as follows:
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For every density step of the stepped density target of the standard reference film a square matrix of 15 × 15
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neighbouring pixels can be evaluated. The standard deviation of the calibrated density D(gli) of this set of
225 values can be calculated as above, giving the noise of the digitiser itself at this density value. This method
gives only correct results when the film noise of the stepped density target is lower than the digitisation noise
from the scanner.
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It shall be checked visually, by display of the evaluated regions, that no dust or scratches of the standard
reference film disturb this evaluation.
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NOTE In ISO 11699-1, an improved procedure is described for calculation of film granularity values (i.e. film noise)
using a more sophisticated procedure based on median calculations to reduce the disturbing influence of dust and
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scratches on the sensitivity calculation.
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stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
5.2 Evaluation of the spatial frequency maximum value, digitiser unsharpness, basic spatial
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
resolution of the digitiser and modulation transfer function
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5.2.1 General
stops: Not at 0.71 cm
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The spatial resolution of the digitiser is affected by the optical aperture of the system, the response of the
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electronics and the accuracy of the mechanical system. The optical aperture gives generally a linear, space
stops: Not at 0.71 cm + 0.99 cm + 1.27 cm
invariant response whose total effect is image blurring. This blurring is independent of the density. Some
equipment, like uncorrected flying spot flatbed scanners, have a spatial resolution depending on the position Formatted: Adjust space between Latin and Asian text,
on the film. Adjust space between Asian text and numbers
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5.2.2 Spatial frequency maximum value (f )
C
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stops: Not at 0.71 cm + 0.99 cm + 1.27 cm
Using the converging line pairs or parallel line pair test targets (see B.2.1B.2.1 for description) the highest
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indicated spatial frequency in line pairs per millimetre (lp/mm) can be determined, where all of the lighter
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lines are seen to be separated by the darker lines.
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It is important to note that, because of digitisation artefacts (aliasing)), it can be difficult to distinguish the Adjust space between Asian text and numbers, Tab
correct maximum value especially for the parallel line pair test target. A small misalignment of the test pattern stops: Not at 0.71 cm + 0.99 cm + 1.27 cm
to the scanning direction c
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