ISO 19262:2015

INTERNATIONAL ISO
STANDARD 19262
First edition
2015-11-15
Photography — Archiving Systems —
Vocabulary
Photographie — Systèmes d’archivage — Vocabulaire
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
Bibliography .44
Foreword
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The committee responsible for this document is ISO/TC 42, Photography.
iv © ISO 2015 – All rights reserved

Introduction
This International Standard provides a vocabulary which standardizes the use and meaning of
terms associated with archiving systems for photography. These terms are drawn from traditional
photography, digital photography, image permanence and information technology.
This International Standard is organized alphabetically and follows natural (English) word order
wherever possible. The source documents for many of the definitions are International Standards
developed by ISO/TC 42. Where possible, users are advised to verify if a more recent edition of the
source document has been published, which contains an updated version of the term and definition.
Future revisions of this International Standard will include updated terms and definitions consistent
with the source documents at the time the revision is prepared.
INTERNATIONAL STANDARD ISO 19262:2015(E)
Photography — Archiving Systems — Vocabulary
1 Scope
This International Standard defines terms used in the area of imaging system capability qualification
for archival recording and approval.
Only terms related to this area are included. These terms are relevant to the current tasks or are of
general interest in imaging system capability qualification for archival recording and approval.
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.
There are no normative references cited in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
acutance
numerical value that correlates to some extent with subjective image sharpness
3.2
automatic document feeder
ADF
powered device to feed microforms, films or paper into a scanner for capture
[SOURCE: ISO 12651-1:2012, 4.10]
3.3
Adobe RGB 1998
three-component colour image encoding defined in Adobe RGB (1998) colour image encoding
[SOURCE: ISO 12640-4:2011, 3.1]
3.4
aliasing
output image artefacts that occur in a digital imaging system for input images having significant energy
at frequencies higher than the Nyquist frequency of the system
Note 1 to entry: These artefacts usually manifest themselves as moiré patterns in repetitive image features or as
jagged “stairstepping” at edge transitions.
[SOURCE: ISO 16067-1:2003, 3.2]
3.5
ambient light
illumination that remains present in an area when some indicated light source (such as a specialized
light, projector, or self-luminous display) is turned off
Note 1 to entry: Ambient light can be natural or artificial light. Ambient light is generally uncontrolled and can be
highly variable, posing a possible risk to image quality. The level of ambient light should be minimized in relation
to the level of light produced by the imaging system.
[SOURCE: ISO 4246:1994, 15]
3.6
array (imaging)
orderly arrangement of individual sensor elements in image capture devices
Note 1 to entry: In digital imaging, there are primarily three array types: two dimensional or area arrays, one
dimensional or linear arrays, and tri-linear arrays consisting of three consecutive linear arrays of red, green, and
blue sensitive sensor elements.
3.7
artifact
general term to describe a broad range of undesirable flaws or distortions in digital reproductions
produced during capture or data processing
Note 1 to entry: Some common forms of image artifacts include noise, chromatic aberration, blooming,
interpolation, and imperfections created by compression, among others.
3.8
aspect ratio
ratio of length to width of an object
[SOURCE: ISO 13794:1999, 2.10]
3.8.1
image aspect ratio
ratio of the image width to the image height
[SOURCE: ISO 15740:2008, 3.16]
3.8.2
pixel aspect ratio
ratio of the distance between sampling points in the two orthogonal sampling directions
Note 1 to entry: If the distances are equal, the pixel aspect ratio equals 1:1, and is said to be “square”.
Note 2 to entry: See also image aspect ratio (3.8.1).
[SOURCE: ISO 12231:2005, 2.6.2]
3.8.3
sampling aspect ratio
ratio of the sample spacing in the two orthogonal sampling directions
[SOURCE: ISO 12231:2012, 3.155]
3.9
banding (imaging)
unwanted stripes or bands that occur in a digital image
Note 1 to entry: Bands are usually caused by fixed pattern noise of linear sensors in scanners or interference
problems between electronic parts of a camera.
2 © ISO 2015 – All rights reserved

3.10
binary image
digitized image consisting of an array of pixels, each of which has a value of 0 or 1, whose values are
normally represented by dark and bright regions on the display screen or by the use of two distinct colours
[SOURCE: ISO 13322-1:2004, 3.1.3]
3.11
bit depth
maximum number of discrete levels available for the digitized representation of the signal intensity,
represented as a power of two
Note 1 to entry: The term can be confusing since it is sometimes used to represent bits per pixel and at other
times, the total number of bits used multiplied by the number of total channels. For example, a typical colour
image using 8 bits per channel is often referred to as a 24-bit colour image (8 bits × 3 channels). Colour scanners
and digital cameras typically produce 24 bit (8 bits × 3 channels) or 36 bit (12 bits × 3 channels) images, and
high-end devices can produce 48 bit (16 bit × 3 channels) images. A grayscale scanner would generally be 1 bit for
monochrome or 8 bit for grayscale (producing 256 shades of gray). Bit depth is also referred to as colour depth.
[SOURCE: ISO 22493:2008, 5.2.2.2.1]
3.12
bit rate
number of bits transmitted per second
[SOURCE: ISO/IEC 18000-2:2009, 4.2]
3.13
bitonal (digital) image
see binary image
3.14
black point
neutral colour with the lowest luminance that can be produced by an imaging medium in normal use,
measured using the specified measurement geometry
[SOURCE: ISO 12231:2012, 3.104]
3.15
blooming
phenomenon which occurs when a pixel of the solid-state imaging device is so illuminated that the
number of generated electrons is greater than can be stored
Note 1 to entry: This excess of electrons can spread into neighbouring cells. As a result, the highlight areas of the
scene appear increased in size on the television screen.
[SOURCE: IEC 808-04-03]
3.16
bits per pixel
see bit depth
3.17
brightness
attribute of a visual sensation according to which an area appears to emit more or less light
Note 1 to entry: Brightness is among the three attributes that specify colour. The other two attributes are hue
and saturation.
[SOURCE: ISO/IEC 8613-2:1995]
3.18
checkerboard
regular squared dark and bright structure on a surface like the one used on a chess board
3.19
chroma
C*
chromatic
chromaticiness, colourfulness, of an area judged as a proportion of the brightness of a similarly
illuminated area that appears white or hrightly transmitting
[SOURCE: ISO/IEC 8613-2:1995]
3.20
chromatic aberration
image defect caused when different wavelengths of light are focused at different distances from a lens
(longitudinal chromatic aberration) or when the scale of the image at different wavelengths is different
(lateral chromatic aberration)
Note 1 to entry: This results in varying degrees of sharp focus at the image sensor or shifted objects in an image
depending on the colour or wavelength of light. Chromatic aberration is seen as “colour fringing,” and is most
noticeable in an image at edges with high contrast.
3.21
chromaticity
attribute of a colour stimulus defined by its trichromatic coordinates or by its dominant or
complementary wavelength and purity characteristics taken together
[SOURCE: IEC 723-08-33]
3.22
chromaticity coodinates
ratios of each of the members of a set of CIE tristimulus values to their sum
[SOURCE: ISO 105-A08:2001, 2.4]
3.23
CIELAB colour space
three-dimensional, approximately uniform colour space, produced by plotting, in rectangular
coordinates the component values are L*, a*, b*
[SOURCE: ISO 5631-1:2009, 3.5]
[SOURCE: CIELAB colour space is specified in CIE Publication 15]
3.24
clipping
abrupt truncation of a signal when the signal exceeds a system’s ability to differentiate signal values
above or below a particular level
Note 1 to entry: In the case of images, the result is that there is no differentiation of light tones when the clipping
is at the high end of signal amplitude and no differentiation of dark tones when clipping occurs at the low end of
signal amplitude. For digital audio, clipping occurs when the signal is restricted by the selected bit depth (which
represents amplitude). In a system using 16-bit signed integers, 32 767 is the largest positive value that can be
represented. If input levels are set so that excursions above that are permitted, then clipping will result and some
information will be lost.
Note 2 to entry: If clipping occurs in only one or two channels of an RGB image, the hue will change instantly. For
example, Caucasian skin tones can go reddish yellow when highlight clipping occurs in the red channel only.
4 © ISO 2015 – All rights reserved

3.24.1
clipping (black)
truncation of a signal when the signal represents a tone darker than the system’s ability to differentiate
Note 1 to entry: Excessive black clipping tends to result in “blocked-up” or featureless shadows in an image.
3.24.2
clipping (highlights)
truncation of a signal when the signal represents a tone lighter than the system’s ability to differentiate
Note 1 to entry: Excessive highlight clipping tends to result in “blown-out” or featureless highlights in an image.
3.25
codec
device or algorithm used to perform encoding/decoding and compression/decompression of the digital
data
Note 1 to entry: This may be combined with converting analog signals into digital (and vice versa).
[SOURCE: ISO/TR 16056-1:2004, 3.16]
3.26
colorimeter
instrument for measuring colorimetric quantities, such as the tristimulus values of a colour stimulus
[SOURCE: IEC 845-05-18]
Note 1 to entry: Colorimeters are the primary device used to evaluate the colour qualities of display monitors.
There are two basic types of colorimeters: tristimulus colorimeter and spectrocolorimeters.
3.27
colorimetry
measurement of colours based on a set of conventions
[SOURCE: IEC 845-05-10]
3.28
colour
sensation resulting from the visual perception of radiation of a given spectral composition
[SOURCE: ISO 4618:2006, 2.57]
3.29
colour accuracy
ability of an imaging system to reproduce the colours of some intended object, as specified using some
colour difference metric
Note 1 to entry: The reference object against which the colour accuracy is measured can be, for example, an
original scene, the colorimetry of an original scene chromatically adapted to some different adopted white, or an
image file describing a reproduction on some reference medium.
3.30
colour cast
tint of a particular colour, usually unwanted, which affects the whole of a photographic image
3.31
colour channel
data channel that represents some specific aspect relating to colour in an image
Note 1 to entry: A colour channel stores the colour information for one colour component of a colour model. For
example, the RGB colour model has three separate colour channels; one for red, one for green and one for blue.
3.32
colour constancy
high level of invariance of the visual system relative to changes in the spectral qualities of the
illumination to the perception of reflective colours
3.33
colour depth
here usually being the bit depth per colour channel but sometimes also used for the sum of the bit
depth’s for all colour channels
Note 1 to entry: See bit depth.
3.34
colour difference metric
metric based on some specified mathematical difference between the points representing a test
specimen and its reference in an appropriate colour space
3.35
colour distance
see colour difference
3.36
colour encoding
quantized digital encoding of a colour space, encompassing both colour space encodings and colour
image encodings
[SOURCE: ISO/TS 22028-3:2006, 3.5]
3.37
colour filter array
mosaic or stripe layer of coloured transmissive filters fabricated on top of an imager in order to obtain
a colour image from a single image sensor
[SOURCE: ISO 12231:2005, 2.8]
3.38
colour fringing
existence of coloured fringes in the area of high contrast structures in images
Note 1 to entry: One of the sources for these is lateral and longitudinal chromatic aberration.
3.39
colour gamut
solid in a colour space, consisting of all those colours that are either: present in a specific scene, artwork,
photograph, photomechanical, or other reproduction; or capable of being created using a particular
output device and/or medium.
Note 1 to entry: See also luminance ratio (3.155).
[SOURCE: ISO/TS 22028-3:2006, 3.6]
3.40
colour image encoding
digital encoding of the colour values for a digital image, including the specification of a colour space
encoding, together with any information necessary to properly interpret the colour values, such as the
image state, the intended image viewing environment and the reference medium
Note 1 to entry: In some cases, the intended image viewing environment will be explicitly defined for the colour
image encoding. In other cases, the intended image viewing environment may be specified on an image-by-image
basis using metadata associated with the digital image.
6 © ISO 2015 – All rights reserved

Note 2 to entry: Some colour image encodings will indicate particular reference medium characteristics, such as
a reflection print with a specified density range. In other cases, the reference medium will not be applicable, such
as with a scene-referred colour image encoding, or will be specified using image metadata.
Note 3 to entry: Colour image encodings are not limited to pictorial digital images that originate from an original
scene, but are also applicable to digital images with content, such as text, line art, vector graphics and other
forms of original artwork.
[SOURCE: ISO/TS 22028-3:2006, 3.7]
3.41
colour management
communication of the associated data required for unambiguous interpretation of colour content data
and application of colour data conversions, as required, to produce the intended reproductions
[SOURCE: ISO 15076-1:2010, 3.1.11]
3.42
colour misregistration
colour-to-colour spatial dislocation of otherwise spatially coincident colour features of an imaged object
3.43
colour model
way of specifying or describing a colour numerically
EXAMPLE In the 24-bit-deep RGB colour model, the intensity of each of the red, green and blue components
of the model (8 bits for each channel) are represented on a scale from 0 to 255.
Note 1 to entry: Common examples include RGB, HSV and CMYK.
Note 2 to entry: The lowest intensity of any colour is represented by 0 and the highest intensity by 255.
Note 3 to entry: There are two main categories of colour models: additive and subtractive. Additive colour
models (such as RGB) are based on transmitted light while subtractive colour models (such as CMYK) are based
on reflected light.
3.44
colour rendering
mapping of image data representing the colour-space coordinates of the elements of a scene to output-
referred image data representing the colour-space coordinates of the elements of a reproduction
Note 1 to entry: Colour rendering generally consists of one or more of the following: compensating for differences
in the input and output viewing conditions, tone scale and gamut mapping to map the scene colours onto the
dynamic range and colour gamut of the reproduction, and applying preference adjustments.
[SOURCE: ISO/TS 22028-3:2006, 3.8]
3.45
colour re-rendering
mapping of picture-referred image data appropriate for one specified real or virtual imaging medium
and viewing conditions to picture-referred image data appropriate for a different real or virtual
imaging medium and/or viewing conditions
Note 1 to entry: Colour re-rendering generally consists of one or more of the following: compensating for
differences in the viewing conditions, compensating for differences in the dynamic range and/or colour gamut of
the imaging media, and applying preference adjustments.
[SOURCE: ISO 22028-1:2004, 3.12]
3.46
colour space
geometric representation of colours in space, usually of three dimensions
[SOURCE: CIE Publication 17.4 (845-03-25) and ISO 22028-1]
3.47
colour space encoding
digital encoding of a colour space, including the specification of a digital encoding method, and a colour
space value range
Note 1 to entry: Multiple colour space encodings can be defined based on a single colour space where the different
colour space encodings have different digital encoding methods and/or colour space value ranges. (For example,
8-bit sRGB and 10 bit e-sRGB are different colour space encodings based on a particular RGB colour space.)
Note 2 to entry: This term is also defined in ISO 22028-1, ISO/TS 22028-2 and ISO/TS 22028-3.
3.48
colour space (colorimetric)
colour space having an exact and simple relationship to CIE colorimetric values
Note 1 to entry: Colorimetric colour spaces include those defined by CIE (e.g. CIE XYZ, CIELAB, CIELUV, etc.), as
well as colour spaces that are simple transformations of those colour spaces (e.g. additive RGB colour spaces).
[SOURCE: ISO 22028-1]
3.49
colour space white point
colour stimulus to which colour space values are normalized
Note 1 to entry: It is not necessary that the colour space white point correspond to the assumed adapted white
point and/or the reference medium white point for a colour image encoding.
[SOURCE: ISO 22028-1]
3.50
colour temperature
temperature of a Planckian radiator whose radiation has the same chromaticity as that of a given stimulus
[SOURCE: ISO 9241-302:2008, 3.2.13]
3.51
compression (lossless, visually lossless, lossy)
3.51.1
image compression
process that alters the way digital image data is encoded in order to reduce the size of an image file
[SOURCE: ISO 12233:2000, 3.11]
3.51.2
lossless compression
data file compression technique where the decompressed image is identical to the original
uncompressed image
[SOURCE: ISO 12651:1999, 4.79]
3.51.3
lossy compression
data file compression technique where the decompressed image may not be identical to the original
uncompressed image
[SOURCE: ISO 12651:1999, 4.80]
8 © ISO 2015 – All rights reserved

3.51.4
visually lossless compression
form or manner of lossy compression where the data that is lost after the file is compressed
and decompressed is not detectable to the eye; the compressed data appearing identical to the
uncompressed data
Note 1 to entry: Visually lossless compression according to this definition is independent of the viewing condition
meaning that even at highest magnification levels the difference to uncompressed data is visually imperceptible.
3.52
compression ratio
relationship of the file size before compression to the file size after compression
[SOURCE: ISO 12651-1:2012, 4.32]
3.53
continuous tone (image)
image represented using a large enough number of potential tonal levels per pixel so that the differences
between adjacent tonal levels are visually imperceptible in the intended use condition
Note 1 to entry: It is an image that has not undergone a graphic arts halftone screening process.
Note 2 to entry: Generally referring to pictorial images, where there is a non-broken range of tones from white
to black that may have every shade of gray represented. There are theoretically an infinite number of tones.
Traditional photography (photochemical photography) produces continuous tone images. When reformatting
pictorial items, it is important to distinguish continuous tone originals from printed halftones, since these two
classes are likely to require different strategies and methods for making the digital images.
3.54
contrast
difference between the grey levels of two specified parts of the image
[SOURCE: ISO 21227-1:2003, 3.5.4]
3.55
contrast sensitivity function
CSF
functional description of the human visual systems sensitivity to peak-to-peak luminance differences
(i.e. contrast) of a range of sine wave spatial frequencies
Note 1 to entry: The CSF varies with colour and viewing conditions.
Note 2 to entry: While the CSF is dependent on the average luminance viewing conditions, a single one is usually
adopted for typical conditions.
3.56
correlated colour temperature
temperature of the Planckian radiator whose perceived colour most closely resembles that of a given
stimulus at the same brightness and under specified viewing conditions
[SOURCE: ISO 3664:2009, 3.3]
3.57
D50
D65
standard illuminants specified by CIE publication 15
EXAMPLE A, D50, D65, F series.
[SOURCE: ISO 3664]
3.58
data rate
number of bits that are conveyed or processed per unit of time, most often (but not exclusively)
employed when discussing time-based media like sound or video
Note 1 to entry: The data rate is often expressed in units of kilobits per second (kbit/s or kbps, 10 to the third
power), megabits per second (Mbit/s or Mbps, 10 to the sixth power), or gigabits per second (Gbit/s or Gbps, 10 to
the ninth power).
3.59
decibel
dB
one-tenth of the bel
Note 1 to entry: The decibel is more often used than the bel as a unit of level.
Note 2 to entry: The decibel can be defined as a unit of level of a power-like quantity when the base of the
logarithm is the tenth root of 10. Also, the decibel is the unit of level of a field quantity when the base of the
logarithm is the 20th root of 10.
[SOURCE: IEC 801-22-03]
3.60
decoder
equipment, application, or algorithm for decoding signals, which may include decompression of data
previously compressed by an encoder
Note 1 to entry: This definition is derived from the IEC 723-07-47 definition for broadcasting, sound and
television and was altered to be applicable to imaging and archiving in general.
3.61
defect
event or shortcoming that does not conform to specification
Note 1 to entry: Defects are generally classed by severity, with class one being the highest severity.
3.62
defect pixel
pixel or subpixel that operates in a way other than the one in which it is driven
[SOURCE: ISO 9241-302:2008, 3.4.30]
3.63
delta E
see colour difference
3.64
de-mosaicing
calculation of missing colors at every position of an image generated by a sensor with a colour filter array
3.65
densitometer
instrument for measuring optical densities by transmission or by reflection under standardized
geometrical and spectral conditions
[SOURCE: ISO 6196-6:1992, 06.06.03]
10 © ISO 2015 – All rights reserved

3.66
density
degree of light absorption, reflection, or scattering characteristics of a photographic image, expressed
as the logarithm to the base 10 of the ratio of incident radiant flux to the transmitted, reflected, or
scattered flux
[SOURCE: SOURCE; ISO 18913:2003, 3.26]
3.67
depth of field
axial depth of the space on both sides of the object plane within which the object can be moved without
detectable loss of sharpness in the image, while the positions of the image plane and of the objective
are maintained
[SOURCE: ISO 10934-1:2002, 2.36]
3.68
depth of focus
axial depth of the space on both sides of the image within which the image appears acceptably sharp,
while the positions of the object plane and of the objective are maintained
[SOURCE: ISO 10934-1:2002, 2.37]
3.69
device level target
DLT
test chart designed and used to test the performance and characteristics of an imaging device or an
imaging system
3.70
device-dependent colour space
colour space defined by the characteristics of a real or idealized imaging device
Note 1 to entry: Device-dependent colour spaces having a simple functional relationship to CIE colorimetry can
also be categorized as colorimetric colour spaces. For example, additive RGB colour spaces corresponding to real
or idealized CRT displays can be treated as colorimetric colour spaces.
[SOURCE: ISO 22028-1:2004, 3.17]
3.71
digital code value [digital output level]
numerical value assigned to a particular output level
[SOURCE: ISO 16067-1:2003, 3.3]
3.72
digital file
set of related digital records held in a tightly bound relationship within the business system and
managed as a single object
Note 1 to entry: At a high level of abstraction, a digital or computer file is a stored segment or block of information
that is available to a computer program. Files are so named because they are the counterparts of the paper
documents traditionally kept in file folders, usually stored in a file cabinet. Computer operating systems consider
files as a sequence of bytes, while application software interprets the binary data as, say, text characters, image
pixels, or audio samples.
[SOURCE: ISO 16175-2:2011, 3.10]
3.73
digital image
digital file consisting of picture elements (pixels) with one or more digital code values per pixel that
represent a colour or tonal value
Note 1 to entry: A digital image can represent a natural scene or any kind of object.
3.74
digital imaging
process of creating digital images
Note 1 to entry: The term may also be used more generally to include digital image processing.
3.75
digital imaging system
system that records and/or produces images using digital data
[SOURCE: ISO/TS 22028-3:2006, 3.13]
3.76
digital master
raw, partially processed, or fully processed digital reference image in mostly a scene referred state that
may require additional processing for output and display
3.77
digital negative
DNG
digital image file format designed by Adobe Systems
Note 1 to entry: DNG is a file format that wraps camera sensor data (“camera RAW data”) plus metadata to support
image reconstruction, adjustment, and display based on the TIFF/EP (ISO 12234-2) International Standard.
3.78
digital output level
numerical value assigned to a particular output level
Note 1 to entry: This term is also defined in ISO 16067-2 and ISO 21550.
[SOURCE: ISO 14524:2009, 3.2]
3.79
digital still camera
DSC
device which incorporates an image sensor and produces a digital signal representing a still picture
Note 1 to entry: A digital still camera is typically a portable, hand-held device. The digital signal is usually
recorded on a removable memory, such as a solid-state memory card or magnetic disk.
Note 2 to entry: This term is also defined in ISO 12232, ISO 15739 and ISO 17321-1.
3.80
digitization
act of generating a digital (quantized) representation of a continuous signal
[SOURCE: ISO 20998-1:2006, 2.7]
3.81
display white point
chromaticity of a computer display’s nominal white value
[SOURCE: ISO/IEC 15948:2004, 3.1.52]
12 © ISO 2015 – All rights reserved

3.82
distortion (geometric distortion, TV distortion)
displacement from the ideal shape of a subject (lying on a plane parallel to the image plane) in the
recorded image
Note 1 to entry: It basically derives from variation of lateral magnification in the image field of a camera lens
and results in straight lines being rendered as curves. There are other factors to induce geometric distortion,
for example, rotational asymmetricity of a camera lens or position shift processing in a camera imaging process.
[SOURCE: ISO 17850]
3.83
dither
intentionally applied noise that is intended to randomize quantization error
Note 1 to entry: This can have the effect of preventing visible or audible patterns in images and sounds, such as
contouring that are more objectionable than random noise. Dither is routinely used in processing of both digital
audio and digital images.
3.84
Dmax
Dmin
see maximum density, minimum density
Note 1 to entry: Dmax is an abbreviation for maximum density and Dmin for minimum density.
Note 2 to entry: The abbreviations are used both in describing the characteristics of an image or an imaging
device such as a scanner.
3.85
dots per inch
DPI
unit for the number of spots that a scanner (printer) can divide an image into (scan, print) per inch both
horizontally or vertically
Note 1 to entry: See sampling rate.
3.86
downsampling
reduction of samples in data where the sampling rate is reduced with reference to the original
sampling rate
3.87
dynamic range
difference, over a given period of time, between maximum and minimum signal levels, expressed in
decibels, contrast ratios or f-stops
Note 1 to entry: The minimum signal level must be greater than a specified usable signal level.
Note 2 to entry: This definition is derived from IEC 702-04-23, but was altered to match the imaging and
archiving application.
3.87.1
ISO 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
[SOURCE: ISO 12231:2012, 3.86]
3.87.2
ISO scanner dynamic range
difference of the maximum density where the incremental gain is higher than 0,5, as determined
according to ISO 21550 to the minimum density that appears unclipped
[SOURCE: ISO 21550:2004, 3.13]
3.88
eciRGB v2
RGB colour encoding specified in ISO 22028-4
3.89
edge spread function
ESF
normalized spatial signal distribution in the linearized output of an imaging system resulting from
imaging a theoretical infinitely sharp edge
Note 1 to entry: See also line spread function (3.150), point spread function (3.195).
[SOURCE: ISO 16067-2:2004, 3.4]
3.90
effectively spectrally neutral
having spectral characteristics which result in a specific imaging system producing the same output as
for a spectrally neutral object
Note 1 to entry: See also spectrally neutral (3.241).
[SOURCE: ISO 16067-2:2004, 3.5]
3.91
electronic scanner for photographic films
scanner incorporating an image sensor that outputs a digital signal representing a still film image
[SOURCE: ISO 16067-2:2004, 3.6]
3.92
electronic scanner for photographic prints
scanner incorporating an image sensor that outputs a digital signal representing a still print image
[SOURCE: ISO 16067-1:2003, 3.6]
3.93
electronic still-picture camera
camera incorporating an image sensor that outputs an analogue or digital signal representing a still-
picture, or records an analog or digital signal representing a still picture on a removable media, such as
a memory card or magnetic disk
[SOURCE: ISO 12233:2000, 3.7]
3.94
encoder
device, application, or algorithm that encodes data, often used for data compression
Note 1 to entry: A decoder is used to play the data, which often entails decompression.
14 © ISO 2015 – All rights reserved

3.95
exchangeable image file format
EXIF
metadata set to accompany TIFF, JPEG, and RIFF WAV formatted image files
Note 1 to entry: Exif was prepared by the Technical Standardization Committee on AV & IT Storage Systems
and Equipment and is Published by the Japan Electronics and Information Technology Industries Association
(JEITA). The Exif 2.2 specification (JEITA CP-3451) is in nearly universal use by camera manufacturers. The Exif
data structure is based on the TIFF tags and there is significant overlap between TIFF and Exif metadata. While,
the Exif standard is almost exclusively focused on image data, it does stipulate a method of writing audio data in
files. Also specified is the relational information indicating the relation between image files and audio files.
3.96
exposure (H) (photographic)
total quantity of light allowed to fall upon a photosensitive emulsion or an imaging sensor (measured
in lux seconds)
[SOURCE: ISO 10934-1:2002, 2.50]
3.96.1
colour sequential exposure
acquisition of a picture by combining repeated exposures to capture different colour components
[SOURCE: ISO 12231:2012, 3.52.2]
3.97
exposure index
EI
numerical value that is inversely proportional to the exposure provided to an image sensor to
obtain an image
Note 1 to entry: Images obtained from a DSC using a range of exposure index values will normally provide a
range of image quality levels.
[SOURCE: ISO 12232:2006, 3.2]
3.98
exposure latitude
acceptable exposure variation without losing highlight or shadow detail
Note 1 to entry: The exposure latitude depends on the degree to which the dynamic range of the imaging system
exceeds that of the scene or original to be digitized.
3.99
exposure process
various methods to capture images in the electronic still picture camera
[SOURCE: ISO 12231:2005, 2.38]
3.100
exposure series
series of images of the same subject taken using different exposure index values
[SOURCE: ISO 12232:2006, 3.3]
3.100.1
single exposure
acquisition of a picture by a single exposure, with one or more image sensors, that exposes all sensor
pixels, all colours, and all image locations at the same time
[SOURCE: ISO 12231:2012, 3.52.1]
3.100.2
time sequential exposure
acquisition of a picture by combining repeated exposures to capture different spatial components
[SOURCE: ISO 12231:2012, 3.52.3]
Note 1 to entry: Time sequential exposure can be with a line array (line scanning) or an area array. With a line array,
the picture is acquired by optical or physical sub-scanning with an image sensor in one dimension. With an area
array, repeated exposures may integrate smaller pictures into a larger picture by means of image sensor shifting.
3.101
extended gamut
colour gamut extending outside that of the standard sRGB CRT display as defined by IEC 61966-2-1
[SOURCE: ISO/TS 22028-3:2006, 3.14]
3.102
fast scan direction
scan direction corresponding to the direction of the alignment of the addressable photoelements in a
linear array image sensor.
[SOURCE: ISO 21550:2004, 3.7]
3.103
fiducial mark
index mark on a test system that allows automatic geometric identification and orientation detection of
an object using imaging systems
3.104
file format (image)
processing method to encode the image information for storage in a computer file
Note 1 to entry: Typical file formats in archiving are Tiff, JPEG, JPEG 2000, and PNG.
Note 2 to entry: Set of structural conventions that define a wrapper, formatted data, and embedded metadata,
and that can be followed to represent images, audiovisual waveforms, texts, etc., in a digital object. The wrapper
component on its own is often colloquially called a file format. The formatted data may consist of one or more
encoded binary bitstreams, for such entities as images or waveforms, and/or textually-encoded data, often
marked up with XML or HTML, for texts. The embedded metadata may be skeletal or extensive.
[SOURCE: ISO 29301:2010, 3.15]
3.105
flare
light falling on an image, in an imaging system, which does not emanate from the subject point
Note 1 to entry: See also image flare, veiling flare, veiling glare.
Note 2 to entry: Flare is also sometimes referred to as veiling glare.
3.105.1
image flare
unwanted increase in signal resulting from light incident on an image sensor that does not emanate
from the subject point
Note 1 to entry: While image flare can result from a variety of causes, the following four are common: internal
multiple reflections between lens surfaces, light diffusion at lens barrel, body, or edge of lens, leaking of light,
and the tails of the lens optical transfer function including spherical and comatic aberrations. Differentiation
between these four may be difficult once an image is captured, but it is more appropriate to evaluate the last
one with regard to the system resolution. Thus, care should be taken to minimize optical transfer function
contribution in the measurement of image flare.
Note 2 to entry: “Image flare” was defined in ISO 3664:2000 in another context but it was deleted in ISO 3664:2009.
16 © ISO 2015 – All rights reserved

3.106
flat field
area of uniform spectral radiance as measured from a specified position
3.107
focus bracketing, focus series
see focus stacking
[SOURCE: ISO 10934-2:2007, 2.28.2]
3.108
focus stacking
image stack acquired at different focal positions
[SOURCE: ISO 10934-2:2007, 2.28.2]
Note 1 to entry: A digital imaging process that combines multiple images focused on different distances at parallel
planes on a three-dimensional object to produce an image with a greater depth of field than could be achieved
with a single image. The technique is most commonly used in macro photography and photo microscopy.
3.109
gain
quantitative expression of a power increase by the ratio of the values at two points of a power or of a
quantity related to power in a well defined manner
Note 1 to entry: By extension, the word “gain” may represent the ratio of powers in a given situation and in a
reference condition; for example, the “gain of an antenna”.
Note 2 to entry: Gain is generally expressed in logarithmic units by a positive or negative value. When a gain has
a negative value in logarithmic units, attenuation may be used instead of gain.
[SOURCE: IEC 702-02-11]
3.110
gain modulation
variation of the gain over the signal level.
Note 1 to entry: One example for a gain modulation is the application of a gamma to an image.
3.111
gamma
exponent that describes approximations to certain non-linear transfer functions encountered in image
capture and reproduction
Note 1 to entry: Within this International Standard, gamma is the exponent in the transfer function from display_
output to image_sample. Image_sample = display_output gamma where both display_output and image_sample
are scaled to the range 0 to 1.
[SOURCE: ISO/IEC 15948:2004, 3.1.20]
3.112
gamma correction
process that alters the image data in order to modify the tone reproduction
Note 1 to entry: Gamma correction is performed in part to correct for the nonlinear light-output versus signal
input characteristic of the display. The relationship between the light input level and the output signal level,
called the OECF, provides the gamma correction curveshape for an image capture device.
Note 2 to entry: The gamma correction is usually an algorithm, lookup table, or circuit which operates separately
on each colour component of an image.
Note 3 to entry: This term is also defined in ISO 12233, ISO 16067-1, ISO 16067-2 and ISO 21550.
3.113
gamut, colour
see colour gamut
3.114
gamut mapping
mapping of the colour-space coordinates of the elements of a source image to colour-space coordinates
of the elements of a reproduction to compensate for differences in the source and output medium colour
gamut capability
Note 1 to entry: The term “gamut mapping” is somewhat more restrictive than the term “colour rendering”
because gamut mapping is performed on colorimetry that has already been adjusted to co
...