SIST ISO 15739:2014

INTERNATIONAL ISO
STANDARD 15739
Second edition
2013-06-15
Photography — Electronic still-picture
imaging — Noise measurements
Photographie — Imagerie des prises de vue électroniques —
Mesurages du bruit
Reference number
©
ISO 2013
© ISO 2013
All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions . 3
4.1 General . 3
4.2 Illumination . 3
4.3 Temperature and relative humidity . 4
4.4 White balance. 4
4.5 Infrared (IR) blocking filter. 4
4.6 Photosite integration time . 4
4.7 Colour noise weighting . 4
4.8 Compression . 5
5 Noise measurement procedures . 5
5.1 General . 5
5.2 Measurement of a DSC having a removable lens . 6
5.3 Measurement of a DSC having manual exposure control . 7
5.4 Measurement of a DSC using a test chart . 7
6 Calculation and reporting of results . 9
6.1 General . 9
6.2 Signal-to-noise ratios — large area . 9
6.3 DSC dynamic range .12
Annex A (normative) Noise component analysis .14
Annex B (normative) Visual noise measurements .18
Annex C (informative) Removing low frequency variations from the image data .27
Annex D (informative) Recommended procedure for determining signal to noise ratio .29
Annex E (informative) Recommended practical viewing conditions for various output media .30
Bibliography .31
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. 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. 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.
The committee responsible for this document is ISO/TC 42, Photography.
This second edition cancels and replaces the first edition (ISO 15739:2003), which has been
technically revised.
iv © ISO 2013 – All rights reserved

Introduction
Noise is an important attribute of electronic photographic systems. The camera noise measurements
described in this International Standard are performed in the digital domain, using digital analysis
techniques. Since the noise performance of an image sensor may vary significantly with exposure time
and operating temperature, these operating conditions are specified. The visibility of noise to human
observers depends on the magnitude of the noise, the apparent tone of the area containing the noise
and the spatial frequency of the noise. The magnitude of the noise present in an output representation
depends on the noise present in the stored image data and the contrast amplification or gain applied to
the data in producing the output. The noise visibility is different for the luminance (or monochrome)
channel and the colour (or colour difference) channels. Therefore, this International Standard accounts
for these factors in measuring and reporting the camera noise measurements. Annex A specifies the
method for determining the components of the digital camera noise from a number of samples. The
perceptibility of noise in an image can vary depending on the viewing distance, spatial frequency,
density, colour and viewing conditions. Annex B describes a procedure for measuring the visual noise
level using a human visual model as a method for weighting the spectral components of the noise. A
method for removing low frequency variations in the patch data resulting, for example, from luminance
shading is given in Annex C. A recommended step-by-step procedure for determining the signal to noise
ratio and incremental gain is provided in Annex D. In Annex E recommendations for practical viewing
conditions for various output media are given.
INTERNATIONAL STANDARD ISO 15739:2013(E)
Photography — Electronic still-picture imaging — Noise
measurements
1 Scope
This International Standard specifies methods for measuring and reporting the noise versus signal level
and dynamic range of digital still cameras. It applies to both monochrome and colour electronic digital
still cameras.
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.
ISO 7589:2002, Photography — Illuminants for sensitometry — Specifications for daylight, incandescent
tungsten and printer
ISO 12232:2006, Photography — Digital still cameras — Determination of exposure index, ISO speed
ratings, standard output sensitivity, and recommended exposure index
ISO 14524:2009, Photography — Electronic still-picture cameras — Methods for measuring opto-electronic
conversion functions (OECFs)
ITU-R BT.709-5, Parameter values for the HDTV Standards for production and International programme
exchange
CIE 15:2004, Colorimetry, 3rd edition
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
camera opto-electronic conversion function
camera OECF
relationship between the input scene log luminances and the pixel values for an opto-electronic digital
capture system
Note 1 to entry: The units of measurement for this function are log candelas per square metre.
3.2
clipping value
pixel value that remains constant for further increases in exposure (highlight clipping value) or for
further decreases in exposure (dark clipping value)
3.3
digital still camera
DSC
camera that produces a digital still image from the digitized output of a solid-state photo sensor and
records the digital still image using a digital memory, such as a removable memory card
3.4
image sensor
electronic device which converts incident electromagnetic radiation into an electronic signal
Note 1 to entry: A charge coupled device (CCD) array is an example of an image sensor.
3.5
incremental gain function
incremental gain
change in the pixel values of the DSC divided by the change in the exposure values
Note 1 to entry: For the determination of incremental gain values, log input values are not used.
Note 2 to entry: If the input exposure points are very finely spaced and the output noise is small compared to
the quantization interval, the incremental gain function can have a jagged shape. Such behaviour is an artefact
of the quantization process and is removed by using an appropriate smoothing algorithm, or by fitting a smooth
curve to the data. In some cases, it may be desirable to fit a curve to the input-output data and then determine the
incremental gain function by taking the first derivative of the function used for the curve fit.
3.6
incremental output signal
exposure level multiplied by the incremental gain at that particular exposure level
3.7
incremental signal-to-noise ratio
ratio of the incremental output signal to the root mean square (rms) noise level, at a particular signal level
Note 1 to entry: This is typically expressed as a graph or Table showing the incremental signal-to-noise ratio
versus input signal level for the full range of input signal levels.
3.8
DSC dynamic range
ratio of the maximum exposure level that provides a pixel value below the highlight clipping value to the
minimum exposure level that can be captured with an incremental signal-to-temporal-noise ratio of at
least 1, as determined in accordance with ISO 15739
3.9
noise
unwanted variations in the response of an imaging system
3.9.1
total noise
all the unwanted variations, consisting of pattern noise and temporal noise, of the values in the digitized
output captured by a single exposure
Note 1 to entry: The procedure in this International Standard for calculating the total noise requires multiple frames.
3.9.2
fixed pattern noise
unwanted variations of the values in the digitized output which remain constant between exposures
3.9.3
temporally varying noise
unwanted variation in the values of the digitized output that changes from one exposure to the next due
to sensor dark current, photon shot noise, analogue processing and quantization
3.10
noise spectrum
curve or equation which expresses the
...