SIST ISO 16067-2:2011

SLOVENSKI STANDARD
01-julij-2011
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Photography - Electronic scanners for photographic images - Spatial resolution
measurements - Part 2: Film scanners
Photographie - Scanners électroniques pour images photographiques - Mesurages de la
résolution spatiale - Partie 2: Scanners pour films
Ta slovenski standard je istoveten z: ISO 16067-2:2004
ICS:
37.040.10 Fotografska oprema. Photographic equipment.
Projektorji Projectors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 16067-2
First edition
2004-10-15
Photography — Electronic scanners for
photographic images — Spatial
resolution measurements —
Part 2:
Film scanners
Photographie — Scanners électroniques pour images
photographiques — Mesurages de la résolution spatiale —
Partie 2: Scanners pour films
Reference number
©
ISO 2004
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©  ISO 2004
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ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Terms and definitions. 1
4 Test chart . 4
4.1 Representation and recommended size .4
4.2 General characteristics of the test chart . 4
4.3 Test chart elements . 6
5 Test conditions. 7
5.1 General. 7
5.2 Temperature and relative humidity . 8
5.3 Luminance and colour measurements .8
5.4 Linearization . 8
5.5 Scanner settings . 8
6 Measuring the scanner OECF. 8
7 Limiting visual resolution and its relation to SFR . 8
8 Edge SFR test measurement . 9
9 Presentation of results . 9
9.1 General. 9
9.2 Scanner OECF . 10
9.3 Resolution Measurements . 11
Annex A (normative) Scanner OECF test patches. 13
Annex B (informative) SFR algorithm. 14
Annex C (informative) Using slanted edge analysis for colour spatial registration measurement . 17
Bibliography . 19

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 16067-2 was prepared by Technical Committee ISO/TC 42, Photography.
ISO 16067 consists of the following parts, under the general title Photography — Electronic scanners for
photographic images — Spatial resolution measurements:
 Part 1: Scanners for reflective media
 Part 2: Film scanners
iv © ISO 2004 – All rights reserved

Introduction
One of the most important characteristics of an electronic film scanner is the ability to capture the fine detail
found in the original film. This ability to resolve detail is determined by a number of factors, including the
performance of the scanner lens, the number of addressable photoelements in the image sensor(s) used in
the scanner, and the electrical circuits in the scanner. Different measurement methods can yield different
metrics that quantify the ability of the scanner to capture fine details.
This International Standard specifies methods for measuring the limiting visual resolution, and spatial
frequency response calculated from a slanted edge (Edge SFR) imaged by a film scanner. The scanner
measurements described in this International Standard are performed in the digital domain, using digital
analysis techniques. A test chart of appropriate size and characteristics is scanned and the resulting data is
analysed. The test chart described in this International Standard is designed specifically to evaluate
continuous tone film scanners. It is not designed for evaluating electronic still-picture cameras, video cameras,
or bi-tonal document scanners.
The edge SFR measurement method described in this International Standard uses a computer algorithm to
analyse digital image data from the film scanner. Pixel values near slanted vertical and horizontal edges are
used to compute the SFR values. The use of a slanted edge allows the edge gradient to be measured at
many phases relative to the image sensor photoelements, so that the SFR can be determined at spatial
frequencies higher than the half sampling frequency, sometimes called the Nyquist limit. This technique is
mathematically equivalent to a moving knife-edge measurement.
Part 1 of this International Standard deals with reflective media.
INTERNATIONAL STANDARD ISO 16067-2:2004(E)

Photography — Electronic scanners for photographic
images — Spatial resolution measurements —
Part 2:
Film scanners
1 Scope
This International Standard specifies methods for measuring and reporting the spatial resolution of electronic
scanners for continuous tone photographic negatives and reversal (e.g. slide) films. The International
Standard applies to both monochrome and colour film scanners.
2 Normative references
The following referenced documents are indispensable for the application 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 5-2, Photography — Density Measurements — Part 2: Geometric conditions for transmission density
ISO 554, Standard atmospheres for conditioning and/or testing — Specifications
ISO 12231, Photography — Electronic still-picture cameras — Terminology
ISO 12233, Photography — Electronic still-picture cameras — Resolution Measurements
ISO 14524, Photography — Electronic still-picture cameras — Methods for measuring opto-electronic
conversion functions (OECFs)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12231 and the following apply.
3.1
addressable photoelements
number of active photoelements in an image sensor
NOTE This is equal to the number of active lines of photoelements, multiplied by the number of active photoelements
per line.
3.2
aliasing
reconstructed image artefacts in sampled imaging systems where the combined spatial frequency energy of
the input image and scanner combination is significant beyond the half-sampling frequency of the scanner
NOTE These artefacts usually manifest themselves as moiré patterns in repetitive image features or as jagged stair
stepping at edge transitions.
3.3
digital output level
numerical value assigned to a particular output level, also known as the digital code value
3.4
edge spread function
ESF
normalized spatial signal distribution in the linearized output of an imaging system resulting from imaging a
theoretical infinitely sharp edge
3.5
effectively spectrally neutral
having spectral characteristics that result in a specific imaging system producing the same output as for a
spectrally neutral object
3.6
electronic scanner for photographic films
scanner incorporating an image sensor that outputs a digital signal representing a still film image
3.7
fast scan direction
scan direction corresponding to the direction of the alignment of the addressable photoelements in a linear
array image sensor
3.8
gamma correction
process that alters the image data in order to modify the tone reproduction
3.9
image sensor
electronic device that converts incident electromagnetic radiation into an electronic signal; e.g. a charge
coupled device (CCD) array
3.10
resolution
measure of the ability of a digital image capture system, or a component of a digital image capture system, to
capture fine spatial detail
NOTE Resolution measurement metrics include resolving power, limiting visual resolution, SFR, MTF and CTF.
3.11
sampled imaging system
imaging system or device which generates an image signal by sampling an image at an array of discrete
points, or along a set of discrete lines, rather than a continuum of points
NOTE The sampling at each point is done using a finite size sampling aperture or area.
3.12
sample spacing
physical distance between sampling points or sampling lines, measured in units of distance (e.g. µm, mm)
NOTE The sample spacing may be different in the two orthogonal sampling directions.
3.13
sampling frequency
reciprocal of sample spacing
NOTE Expressed in samples per unit distance (e.g. dots per inch).
2 © ISO 2004 – All rights reserved

3.14
scanner
electronic device that converts a fixed image, such as a film or film transparency, into an electronic signal
3.15
scanner opto-electronic conversion function
scanner OECF
relationship between the input density and the digital output levels for an opto-electronic digital capture system
3.16
slow scan direction
direction in which the scanner moves the photoelements (perpendicular to the lines of active photoelements in
a linear array image sensor)
3.17
spatial frequency response
SFR
R
SFR
measured amplitude response of an imaging system as a function of relative input spatial frequency
NOTE 1 The SFR is normally represented by a curve of the output response to an input sinusoidal spatial luminance
distribution of unit amplitude, over a range of spatial frequencies. The SFR is normalized to yield a value of 1,0 at a spatial
frequency of 0.
NOTE 2 In equations, the symbol R rather than the abbreviation SFR is used for clarity.
SFR
3.18
spectrally neutral
test chart in which the relative spectral power distributions of the incident and reflected (or transmitted) light
are equal
3.19
test chart
arrangement of test patterns designed to test particular aspects of an imaging system
3.20
test pattern
specified arrangement of spectral reflectance or transmittance characteristics used in measuring an image
quality attribute
3.21
test pattern types
3.21.1
bi-tonal patterns
patterns that are spectrally neutral or effectively spectrally neutral, and consist exclusively of two reflectance
or transmittance values in a prescribed spatial arrangement
NOTE Bi-tonal patterns are typically used to measure resolving power, limiting resolution and SFR.
3.21.2
grey scale patterns
patterns that are spectrally neutral or effectively spectrally neutral, and consist of a large number of different
reflectance or transmittance values in a prescribed spatial arrangement
NOTE Grey scale patterns are typically used to measure opto-electronic conversion functions.
3.21.3
spectral patterns
patterns that are specified by the spatial arrangement of features with differing spectral reflectance or
transmittance values
NOTE Spectral patterns are typically used to measure colour reproduction.
4 Test chart
4.1 Representation and recommended size
This clause defines the type and specifications of the test chart depicted in Figure 1. This test chart can be
made at various sizes to correspond to popular film sizes. The recommended size is 24 mm × 36 mm, which
corresponds to the 35 mm film format.

Figure 1 — Representation of the test chart

4.2 General characteristics of the test chart
4.2.1 The test chart shall be a transmission test chart based on a current monochrome photographic film
material. The film material shall be spectrally neutral with tolerances as specified in ISO 14524, and resistant
to fading.
4.2.2 The active height and width of the reflection test chart should be no less than 16,7 mm. Additional
white space may be added to the width or height to include target management data or other test chart
elements not defined by this International Standard.
4 © ISO 2004 – All rights reserved

4.2.3 The test chart shall include grey scale patterns and should include bitonal elements. Grey scale
patches are necessary to measure the opto-electronic transfer function of the scanner. The bitonal elements
may be used to assess limiting visual resolution and aliasing. (See Clause 7.)
4.2.4 The density values of the grey patches shall be in accordance with Annex A. The densities shall be
measured as specified in ISO 5-2.
4.2.5 The target manufacturer should state the spatial frequency at which the target’s frequency content is
0,2. These declarations should be cited in both cycles per millimetre (cycles/mm) and equivalent dots-per-inch
(DPI), where the DPI value equals 50,8 times the spatial frequency in cycles/mm. Suggested wording is, “This
target suitable for SFR measurements to XXX cycles per millimetre (xxx dpi)”.
The spatial frequency content of the edge features should be the same for both near horizontal, near-vertical,
and near-45º edge features, and should be indicated as a graph (Figure 2), or should be characterized with a
closed form equation or equations up to the frequency having a 0,2 modulation response.
An example equation corresponding to Figure 2 is the N-th order polynomial:
1 2 3 4 5 6 7
Target Modulation = C + C ν + C ν + C ν + C ν + C ν + C ν + C ν (1)
0 1 2 3 4 5 6 7
Where ν = spatial frequency in terms of line pairs per millimetre
th
C = polynomial coefficients associated with the i term
i
0 −2 −3 −4
C = × 10 C = −1,0161e × 10 C = −5,9389e × 10 C = 5,6116e × 10
0 1,0000e 1 2 3
−5 −7 −9 −11
C = −2,3443e × 10  C = 5,0997e × 10 C = −5,6120e × 10 C = 2,4681e × 10
4 5 6 7
The above-mentioned 7th order polynomial is only valid, as an example frequency response characteristic, for
spatial frequencies in the range DC to approximately 58,154 1 cycles/mm.

Key
X frequency (cycles/mm)
Y modulation
Figure 2 — Frequency content of a transmission edge’s spatial derivative
4.3 Test chart elements
4.3.1 General
For testing purposes, the test chart shall include elements to measure the scanner opto-electronic conversion
function, and SFR in the fast scan and slow scan directions. (See Figure 3.)

Figure 3 — Test chart elements labelled by section number

4.3.2 Grey scale patches for measuring the scanner OECF
The test chart shall include 20 neutral grey scale patches with specified visual densities. The maximum patch
density shall be at least 1,5 times the maximum density of the central slanted square (4.2.2). The minimum
patch density shall be equal to the transmissive media minimum density. The spatial arrangement of the
patches shall be designed to minimize flare between adjacent patches as depicted in Figure 1. A suggested
spatial arrangement is given in Annex A.
4.3.3 Near-vertical and near-horizontal slanted edges to measure the vertical and horizontal edge
SFR
The test chart shall include a slanted (approximately 5º) square feature used to measure vertical and
horizontal edge SFR. The density of the square shall exceed that of the immediate surrounding area. The
central square’s surround density shall have a visual diffuse density of greater than or equal to 0,40 and less
than or equal to 0,60. The square patch density shall have a visual diffuse density of greater than or equal to
1,5 and less than or equal to 2,4.
NOTE These values insure sufficiently low edge transition contrasts to aid robust SFR measurements.
6 © ISO 2004 – All rights reserved

4.3.4 Near-45º edges to measure 45º SFR
The test chart should include a diamond shaped feature (approximately 50º from vertical) to measure the SFR
at 45º. The density of this feature should match that of the surround area defined in 4.3.2.
4.3.5 Vertical and horizontal square wave features
The test chart shall include horizontal and vertical square wave features of extended length to aid in the visual
detection of aliasing. These features shall have a spatial frequency of 25, 33,3, 50, 100, and 166,7 cycles/mm.
The minimum and maximum densities should nominally match the D and D of the grey scale patches.
max min
NOTE The square wave features have a spatial frequency corresponding to approximately 1200, 1600, 2400, 5000
and 8400 DPI.
4.3.6 Near-vertical and near-horizontal square features
The test chart shall include horizontal and vertical square wave features of extended length to aid in the
detection of aliasing. These features shall have the same frequencies as indicated in 4.3.4. The minimum and
maximum densities should nominally match the D and D of the grey scale patches.
max min
NOTE These slanted lines eliminate the ambiguity of phase-induced patterns in resolution measurements.
4.3.7 Fiducial marks to aid in automatic SFR and scanner OECF measurement
The test chart should include fiducial marks in the corners of the central target features. These marks can aid
in the automatic analysis of grey patch and slanted edge features for scanner OECF and SFR measurements.
NOTE The vertical and horizontal distance between fiducial marks in Figure 1 is 12,19 mm. This distance can be
used to verify scanner sampling frequency.
4.3.8 Slightly Slanted Extended Lines to check scan linearity, “stair stepping” and cyclical scan
artefacts
The test chart should include horizontal and vertical slightly slanted lines to check scan linearity, and cyclical
scanner behaviours such as colour channel misregistration.
4.3.9 Bi-tonal spatial resolution elements
The test chart should include bi-tonal spatial patterns to aid in evaluating limiting visual resolution. These
elements should be of high contrast (D and D ) and accompanied with numbered groups that are keyed
max min
to know spatial frequencies.
4.3.10 Administrative elements
The test chart should include administrative elements to aid in tracking the genealogy and characteris
...