ISO/TS 19567-1:2016

TECHNICAL ISO/TS
SPECIFICATION 19567-1
First edition
2016-04-01
Photography — Digital cameras
— Texture reproduction
measurements —
Part 1:
Frequency characteristics
measurements using cyclic pattern
Photographie — Caméras numériques — Mesurages de la
reproduction de la texture —
Partie 1: Mesurages des caractéristiques de fréquence en utlisant un
modèle cyclique
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions . 1
4.1 General . 1
4.2 Environments for measurement . 2
4.3 Apparatus and hardware . 2
4.4 Arrangement of measuring equipment . 2
4.4.1 Reflective test chart . 2
4.4.2 Transmissive test chart . 2
4.5 Lighting . 3
4.6 Camera settings . 3
5 Texture reproduction measurement procedure . 4
5.1 General . 4
5.2 Multiburst measurement . 5
5.2.1 Low contrast multiburst chart . 5
5.2.2 Measurement method . 6
5.3 Siemens star measurement . 7
5.3.1 Low contrast sine siemens star chart . 7
5.3.2 Measurement method . 7
6 Presentations of results . 8
6.1 General . 8
6.2 Multiburst measurement . 8
6.3 Siemens star measurements . 8
Annex A (informative) Categorization of texture.10
Annex B (informative) Exposure condition for the measurement .11
Annex C (informative) Interpretation of measurement results .14
Annex D (informative) Measurement results of multiburst and siemens star .16
Bibliography .20
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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The committee responsible for this document is ISO/TC 42, Photography.
iv © ISO 2016 – All rights reserved

Introduction
Texture generally means the visual and tactile surface quality derived from the physicality of the
material and the roughness or graininess of the surface. For digital still cameras, texture is of course
the visual surface quality and the characteristic of texture reproduction in the captured image is
interpreted into the reproduction of the low contrast fine details. This Technical Specification specifies
the measurement of how cameras reproduce texture defined as low contrast fine details.
The tendency to utilize small sensors with high pixel counts in some cameras leaves a very small amount
of light reaching the individual pixel. With the signal getting smaller and the noise level remaining at
a certain level, it is necessary to reduce the noise in the image processing after capturing the image.
Although the algorithms used for noise reduction have been developed over time, they are still not able
to differentiate texture in the actual scene from the unwanted noise introduced by the capturing system.
This decreases the image quality and it is therefore helpful to have a method to measure the loss of
texture. Texture can also be enhanced to increase the acutance of the image. The texture reproduction
is dependent on frequency and contrast because the noise reduction and the acutance enhancement,
etc. are nonlinearly dependent on the pixel value and the difference among the surrounding pixels.
This part of ISO 19567 specifies methods to measure texture reproduction using test charts with cyclic
patterns. The test charts are based on the established measurement methods, multiburst (IEC 61146-
1) and siemens star (ISO 12233). This part of ISO 19567 newly defines the density of the test charts
and exposure setting of measured cameras. The measurement results are presented in the spatial
frequency response (SFR) curves.
If one SFR is larger than the other in all frequency range, larger amount of texture is reproduced in the
corresponding image. If two SFRs have a cross point and the larger SFR depends on the frequency range,
the superior image in the subjective evaluation is dependent on the dominant frequency of the image.
Comparison of the measurement result provides important information in the texture comparison of
the captured images.
Texture in a real scene consists mostly of non-structured or random patterns as shown in Annex A.
Although it has been confirmed by experiments (Annex C and Annex D) that the texture reproduction
characteristics of most cameras are well represented by the measurements in this Technical
Specification, some cameras are found to indicate different characteristics for structured patterns
compared to those for non-structured patterns. Measurement methods using non-structured or
random patterns are under study and are expected to be included in consequent parts to this Technical
Specification.
TECHNICAL SPECIFICATION ISO/TS 19567-1:2016(E)
Photography — Digital cameras — Texture reproduction
measurements —
Part 1:
Frequency characteristics measurements using cyclic
pattern
1 Scope
This part of ISO 19567 specifies a protocol to measure the texture reproduction in the images captured
and processed by digital cameras including cameras in other devices, e.g. in camera phones.
This part of ISO 19567 specifies protocols for the measurement of the texture reproduction using test
charts with cyclic pattern.
This part of ISO 19567 excludes the acceptable range of value for texture reproduction.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
IEC 61966-2-1:1999, Multimedia systems and equipment — Colour measurement and management —
Part 2-1: Colour management — Default RGB colour space —sRGB
IEC 61966-2-1/Amd 1:2003, Multimedia systems and equipment — Colour measurement and
management — Part 2-1: Colour management — Default RGB colour space —sRGB
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
texture
low contrast fine details, which appear in objects
EXAMPLE Low contrast fine details, which is visible in foliage, fur, sand, textiles, grass, or masonry surfaces.
3.2
texture reproduction
response in the output image of cameras to the texture of the object in the scene
4 Test conditions
4.1 General
The following measurement conditions should be used as nominal conditions when measuring the
texture reproduction of a digital camera.
4.2 Environments for measurement
The measurement shall be carried out in the following environment unless otherwise stated:
— Temperature: 23 °C ± 3 °C
4.3 Apparatus and hardware
Either a reflective chart or a transmissive chart may be used. The light flux from the target shall be
diffused and shall not include any specular component.
4.4 Arrangement of measuring equipment
4.4.1 Reflective test chart
The arrangement of the measuring equipment for a reflective test chart shall be set up as shown in
Figure 1. The camera shall be positioned so that it casts no shadow on the chart. The lamps shall be
positioned at an angle which avoids direct specular reflection from the test chart entering the camera.
f
Figure 1
...