ISO/TS 19567-2:2019
(Main)Photography — Digital cameras — Part 2: Texture analysis using stochastic pattern
Photography — Digital cameras — Part 2: Texture analysis using stochastic pattern
This document specifies a protocol to measure the texture reproduction in images captured and processed by digital cameras including cameras in other devices e.g. in camera phones. This document specifies protocols for the measurement of texture reproduction using test charts with stochastic pattern. NOTE The measurement method specified in this document is for objective evaluations of texture reproduction, of which the results are sometimes inconsistent with subjective evaluations (See Annex C).
Photographie — Caméras numériques — Partie 2: Analyse de la texture en utilisant un modèle stochastique
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TECHNICAL ISO/TS
SPECIFICATION 19567-2
First edition
2019-07
Corrected version
2019-11
Photography — Digital cameras —
Part 2:
Texture analysis using stochastic
pattern
Photographie — Caméras numériques —
Partie 2: Analyse de la texture en utilisant un modèle stochastique
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions and methods . 1
4.1 General . 1
4.2 Environmental conditions . 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
4.4.3 Lighting . 3
4.4.4 Camera settings . 3
4.5 Test Chart . 4
4.5.1 General. 4
4.5.2 Chart generation . 4
5 Analytical approach. 5
5.1 General . 5
5.2 Measurement method . 6
6 Presentation of results . 8
6.1 SFR curve . 8
6.2 Single numerical values . 9
6.2.1 General. 9
6.2.2 SFR10 . 9
6.2.3 SFR50 .10
6.2.4 Texture acutance .10
Annex A (informative) Differentiation of cyclic pattern and stochastic pattern .12
Annex B (informative) Exposure condition for the measurement .14
Annex C (informative) Inconsistency between results of the measurement method specified
in this document and subjective evaluations .17
Bibliography .20
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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 jointly by Technical Committee ISO/TC 42, Photography.
A list of all parts in the ISO 19567 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.
This corrected version of ISO/TS 19567-2:2019 incorporates the following correction:
— The mention of the collaboration with IEC/TC 100, Audio, video and multimedia systems and
equipment, was removed from the Foreword.
iv © ISO 2019 – All rights reserved
Introduction
In a general context, texture refers to the visual and tactile surface quality derived from the physicality
of a material and the roughness or graininess of its surface. For digital still camera images, texture is
restricted to the visual surface quality and the characteristic of texture reproduction in the captured
image can be interpreted as the reproduction of the low contrast fine details. This document specifies
the measurement of how cameras reproduce texture defined as low contrast fine details.
The on going tendency to utilize smaller sensors with higher pixel counts in some cameras leaves
a very small amount of light reaching each 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 may 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 values of the surrounding pixels.
This document specifies methods to measure texture reproduction using test charts with a stochastic
pattern. Annex A talks about the differentiation of this document from ISO/TS 19567-1, which deals
with cyclic pattern. The test charts described here are based on randomly arranged circles of various
sizes and colour with a limited contrast. This provides a target with known structure and spatial
statistics similar to natural images. The measurement results are presented in SFR (Spatial Frequency
Response) curves from which a single value representing the overall texture content is derived.
In general if one measured SFR is greater than the other across all measured spatial frequencies, a
larger amount of texture is reproduced in the corresponding image. If two SFRs have a crossover point
and the larger SFR depends on the frequency range, relative ordering of texture preservation quality
is less clear. Comparison of the measurement results can provide important information about the
relative texture reproduction of the captured images.
While the measurement method specified in this document is for objective evaluations of texture
reproduction for images, their relationship to subjective evaluations of texture reproduction with visual
perception is important to give attention, since image quality for camera/photograph users generally
accords with subjective evaluation. Annex C explains possible inconsistency between measurement
results using the method described in this document and subjective evaluations, due to different
condition of noise, with experimental results for images.
TECHNICAL SPECIFICATION ISO/TS 19567-2:2019(E)
Photography — Digital cameras —
Part 2:
Texture analysis using stochastic pattern
1 Scope
This document specifies a protocol to measure the texture reproduction in images captured and
processed by digital cameras including cameras in other devices e.g. in camera phones.
This document specifies protocols for the measurement of texture reproduction using test charts with
stochastic pattern.
NOTE The measurement method specified in this document is for objective evaluations of texture
reproduction, of which the results are sometimes inconsistent with subjective evaluations (See Annex C).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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 and methods
4.1 General
The measurement shall be carried out using digital images of the texture test chart captured by a
digital still camera.
The following measurement conditions should be used as nominal conditions when measuring the
texture reproduction of a digital still camera. If it is not possible or appropriate to achieve these nominal
operating co
...
TECHNICAL ISO/TS
SPECIFICATION 19567-2
First edition
2019-07
Corrected version
2019-11
Photography — Digital cameras —
Part 2:
Texture analysis using stochastic
pattern
Photographie — Caméras numériques —
Partie 2: Analyse de la texture en utilisant un modèle stochastique
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions and methods . 1
4.1 General . 1
4.2 Environmental conditions . 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
4.4.3 Lighting . 3
4.4.4 Camera settings . 3
4.5 Test Chart . 4
4.5.1 General. 4
4.5.2 Chart generation . 4
5 Analytical approach. 5
5.1 General . 5
5.2 Measurement method . 6
6 Presentation of results . 8
6.1 SFR curve . 8
6.2 Single numerical values . 9
6.2.1 General. 9
6.2.2 SFR10 . 9
6.2.3 SFR50 .10
6.2.4 Texture acutance .10
Annex A (informative) Differentiation of cyclic pattern and stochastic pattern .12
Annex B (informative) Exposure condition for the measurement .14
Annex C (informative) Inconsistency between results of the measurement method specified
in this document and subjective evaluations .17
Bibliography .20
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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
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 jointly by Technical Committee ISO/TC 42, Photography.
A list of all parts in the ISO 19567 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.
This corrected version of ISO/TS 19567-2:2019 incorporates the following correction:
— The mention of the collaboration with IEC/TC 100, Audio, video and multimedia systems and
equipment, was removed from the Foreword.
iv © ISO 2019 – All rights reserved
Introduction
In a general context, texture refers to the visual and tactile surface quality derived from the physicality
of a material and the roughness or graininess of its surface. For digital still camera images, texture is
restricted to the visual surface quality and the characteristic of texture reproduction in the captured
image can be interpreted as the reproduction of the low contrast fine details. This document specifies
the measurement of how cameras reproduce texture defined as low contrast fine details.
The on going tendency to utilize smaller sensors with higher pixel counts in some cameras leaves
a very small amount of light reaching each 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 may 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 values of the surrounding pixels.
This document specifies methods to measure texture reproduction using test charts with a stochastic
pattern. Annex A talks about the differentiation of this document from ISO/TS 19567-1, which deals
with cyclic pattern. The test charts described here are based on randomly arranged circles of various
sizes and colour with a limited contrast. This provides a target with known structure and spatial
statistics similar to natural images. The measurement results are presented in SFR (Spatial Frequency
Response) curves from which a single value representing the overall texture content is derived.
In general if one measured SFR is greater than the other across all measured spatial frequencies, a
larger amount of texture is reproduced in the corresponding image. If two SFRs have a crossover point
and the larger SFR depends on the frequency range, relative ordering of texture preservation quality
is less clear. Comparison of the measurement results can provide important information about the
relative texture reproduction of the captured images.
While the measurement method specified in this document is for objective evaluations of texture
reproduction for images, their relationship to subjective evaluations of texture reproduction with visual
perception is important to give attention, since image quality for camera/photograph users generally
accords with subjective evaluation. Annex C explains possible inconsistency between measurement
results using the method described in this document and subjective evaluations, due to different
condition of noise, with experimental results for images.
TECHNICAL SPECIFICATION ISO/TS 19567-2:2019(E)
Photography — Digital cameras —
Part 2:
Texture analysis using stochastic pattern
1 Scope
This document specifies a protocol to measure the texture reproduction in images captured and
processed by digital cameras including cameras in other devices e.g. in camera phones.
This document specifies protocols for the measurement of texture reproduction using test charts with
stochastic pattern.
NOTE The measurement method specified in this document is for objective evaluations of texture
reproduction, of which the results are sometimes inconsistent with subjective evaluations (See Annex C).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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 and methods
4.1 General
The measurement shall be carried out using digital images of the texture test chart captured by a
digital still camera.
The following measurement conditions should be used as nominal conditions when measuring the
texture reproduction of a digital still camera. If it is not possible or appropriate to achieve these nominal
operating co
...
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