SIST ISO 13322-1:2006

INTERNATIONAL ISO
STANDARD 13322-1
First edition
2004-12-01
Particle size analysis — Image analysis
methods —
Part 1:
Static image analysis methods
Analyse granulométrique — Méthodes par analyse d'images —
Partie 1: Méthodes par analyse d'images statiques

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, abbreviated terms, definitions, and symbols. 1
3.1 Terms, abbreviated terms and definitions. 1
3.2 Symbols . 3
4 Sample preparation demands for method description . 4
4.1 General recommendations. 4
4.2 Suggested preparation methods. 5
5 Image capture. 6
5.1 General. 6
5.2 Procedures . 7
5.3 Operating conditions for an image capture instrument. 7
6 Microscopy and image analysis . 8
6.1 General. 8
6.2 Size classes and magnification . 9
6.3 Counting procedure. 9
7 Calculation of the particle size results . 13
8 Test report. 13
Annex A (normative) Study on the sample size required for the estimation of mean particle
diameter . 15
Annex B (normative) Operating magnification. 34
Annex C (normative) Resolution and sizing limits for typical objective lenses . 35
Annex D (informative) Flow chart showing a typical image analysis method . 36
Annex E (informative) Statistical tests of mean and variance — Analysis of variance and multiple
comparisons. 37
Bibliography . 39

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 13322-1 was prepared by Technical Committee ISO/TC 24, Sieves, sieving and other sizing methods,
Subcommittee SC 4, Sizing by methods other than sieving.
ISO 13322 consists of the following parts, under the general title Particle size analysis — Image analysis
methods:
 Part 1: Static image analysis methods
 Part 2: Dynamic image analysis methods
iv © ISO 2004 – All rights reserved

Introduction
The purpose of this part of ISO 13322 is to give guidance for a measurement description and its validation
when determining particle size by image analysis.
Image analysis is a technique used in very different applications on image material with variations in material
properties. Hence, it is not relevant to describe an exact standard method for determination of particle size by
image analysis. The aim of this part of ISO 13322 is limited to give a standardized description of the technique
used and a standardized validation.
This part of ISO 13322 includes methods of calibration verification using a certified standard graticule as a
reference or by using certified standard particles. It is sensible to make some measurements on particles, or
other reference objects, of known size so that the likely systematic uncertainties introduced by the equipment
can be calculated.
This part of ISO 13322 gives a recommendation for a precise description of the distribution including the
number of analyzed particles and an analysis window to make sure that the obtained information is valid.
Measurement of particle-size distributions by microscopy methods is apparently simple, but because only a
small amount of sample is examined, considerable care has to be exercised in order to ensure that the
analysis is representative of the bulk sample. This can be demonstrated by splitting the original sample and
making measurements on three or more parts. Statistical analysis of the data, for example using the Student's
t-test, will reveal whether the samples are truly representative of the whole.
Errors introduced at all stages of the analysis from sub-division of the sample to generation of the final result
add to the total uncertainty of measurement and it is important to obtain estimates for the uncertainty arising
from each stage. Indications where this is required are given at the appropriate point in the method.
Because of the diverse range of equipment and sample preparation expertise available, it is not intended to
give a prescriptive procedure where use of individual methods does not jeopardize the validity of the data.
However, essential operations are identified to ensure that measurements made conform to this part of
ISO 13322 and are traceable.
INTERNATIONAL STANDARD ISO 13322-1:2004(E)

Particle size analysis — Image analysis methods —
Part 1:
Static image analysis methods
1 Scope
This part of ISO 13322 is applicable to the analysis of images for the purpose of determining particle size
distributions. The particles are appropriately dispersed and fixed on an optical or electron microscope sample
stage such as glass slides, stubs, filters, etc. Image analysis can recover particle images directly from
microscopes or from photomicrographs.
Even though automation of the analysis is possible, this technique is basically limited to narrow size
distributions of less than an order of magnitude. A standard deviation of 1,6 of a log-normal distribution
corresponds to a distribution of less than 10:1 in size. Such a narrow distribution requires that over 6 000
particles be measured in order to obtain a repeatable volume-mean diameter. If reliable values are required
for percentiles, e.g. D or other percentiles, at least 61 000 particles must be measured. This is described in

Annex A.
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 9276-1, Representation of results of particle size analysis — Part 1: Graphical representation
ISO 9276-2, Representation of results of particle size analysis — Part 2: Calculations of average particle
sizes/diameters and moments from particle size distributions
3 Terms, abbreviated terms, definitions and symbols
3.1 Terms, abbreviated terms and definitions
For the purposes of this document, the following definitions apply.
3.1.1
view field
field which is viewed by a viewing device, e.g. optical microscope or electron scanning microscope
3.1.2
measurement frame
field in a view field in which particles are counted for image analysis
NOTE The set of measurement frames composes the total measurement field.
3.1.3
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
3.1.4
edge finding
one of many edge detection methods used to detect transition between objects and background
3.1.5
Euler number
number of objects minus the number of holes inside the objects, which describes the connectedness of a
region, not its shape
NOTE A connected region is one in which all pairs of points can be connected by a curve lying entirely in the region.
If a complex two-dimensional object is considered to be a set of connected regions, where each one can have holes, the
Euler number for such an object is defined as the number of connected regions minus the number of holes. The number of
holes is one less than the connected regions in the set compliment of the object. It is important to report the Euler number
together with the connectivity applied, i.e., 4-connectivity or 8-connectivity.
3.1.6
Feret diameter
distance between two parallel tangents on opposite sides of the image of a particle
3.1.7
equivalent circular diameter
ecd
diameter of a circle having the same area as the projected image of the particle
NOTE It is also known as the Haywood Diameter.
3.1.8
grey image
image in which multiple grey level values are permitted for each pixel
3.1.9
image analysis
processing and data reduction operation which yields a numerical or logical result from an image
3.1.10
numerical aperture
NA
product of the refractive index of the object space and the sine of the semi-aperture of the cone of rays
entering the entrance pupil of the objective lens from the object point
3.1.11
pixel
picture element
individual sample in a digital image that has been formed by uniform sampling in both the horizontal and
vertical directions
3.1.12
segmentation
〈noun〉 part into which something can be divided; subdivision or section
3.1.13
segmentation
〈verb〉 act of dividing something into segments
2 © ISO 2004 – All rights reserved

3.1.14
threshold
grey level value which is set to discriminate objects of interest from background
3.2 Symbols
δ error
θ half-angle subtended by the particle at the objective lens
λ wavelength, expressed in micrometres
µ refractive index of the surrounding medium
ϕ shape factor
A projected area of particle i
i
d minimu
...