ISO 11698-2:2000

INTERNATIONAL ISO
STANDARD 11698-2
First edition
2000-08-01
Micrographics — Methods of measuring
image quality produced by aperture card
scanners —
Part 2:
Quality criteria and control
Micrographie — Méthodes de mesurage de la qualité de l'image produite
par les numériseurs de cartes à fenêtre —
Partie 2: Critères et contrôle de qualité
Reference number
ISO 11698-2:2000(E)
©
ISO 2000

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ISO 11698-2:2000(E)
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ISO 11698-2:2000(E)
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 3.
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 part of ISO 11698 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 11698-2 was prepared by Technical Committee ISO/TC 171, Document imaging
applications, Subcommittee SC 1, Quality.
ISO 11698 consists of the following parts, under the general title Micrographics — Methods of measuring image
quality produced by aperture card scanners:
� Part 1: Characteristics of the test images
� Part 2: Quality criteria and control
Annexes A and B of this part of ISO 11698 are for information only.
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ISO 11698-2:2000(E)
Introduction
Scanning of microimages in aperture cards for use in CAD and electronic information systems is of great
importance. This International Standard provides means of evaluating the output quality of images resulting from
scanning of aperture card microimages. The procedures may be used to establish and maintain image quality
achieved by a scanner.
The specification of the test microimages can be found in ISO 11698-1.
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INTERNATIONAL STANDARD ISO 11698-2:2000(E)
Micrographics — Methods of measuring image quality produced
by aperture card scanners —
Part 2:
Quality criteria and control
1 Scope
This part of ISO 11698 specifies methods for using the test images specified in ISO 11698-1 to check the quality of
images produced by aperture card scanners.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 11698. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 11698 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 3272-1:1983, Microfilming of technical drawings and other drawing office documents — Part 1: Operating
procedures.
ISO 5457:1999, Technical product documentation — Sizes and layout of drawing sheets.
ISO 6196-1:1993, Micrographics — Vocabulary — Part 1: General terms.
ISO 6196-4:1998, Micrographics — Vocabulary — Part 4: Materials and packaging.
ISO 6196-5:1987, Micrographics — Vocabulary — Part 5: Quality of images, legibility, inspection.
ISO 6196-6:1992, Micrographics — Vocabulary — Part 6: Equipment.
ISO 6428:1982, Technical drawings — Requirements for microcopying.
ISO 12651:1999, Electronic imaging — Vocabulary.
3 Terms and definitions
For the purposes of this part of ISO 11698, the terms and definitions in ISO 6196 and ISO 12651 apply. Where a
term appears in both of these standards it is essential that the definition used is appropriate to the context of the
term. The following terms and definitions also apply.
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ISO 11698-2:2000(E)
3.1
barrel distortion
distortion in an image in which a specific point within the image is relatively farther from its optical axis than the
corresponding point on the original, typified by a rectangle having one of its sides bowed outward
3.2
image offsets
adjustment device of a scanner that allows the capture size area to be moved relative to the nominal position that is
specified in the relative International Standard for the aperture of an aperture card
3.3
pincushion distortion
distortion in an image in which a specific point within the image is relatively closer to its optical axis than the
corresponding point on the original, typified by a rectangle having one of its sides bowed inward
3.4
resolving power
numerical expression of the limit of resolution of an imaging system, expressed as the number of lines per
millimetre discernible in an image of a test chart
3.5
scaling error
relationship between the nominal and actual numbers of pixels or dots per length in an output electronic image
3.6
scanner offsets
adjustments of the scanner system that calibrate the position of the capture area to be centralized over the
standard card aperture area when image offsets are set to zero
3.7
test card
aperture card or piece of photographic film having the same dimensions, containing a test image in the aperture or
equivalent area
3.8
test image
area of a test card that contains test targets, patterns, etc., intended for measuring quality of image produced by an
aperture scanner
3.9
test target
target comprising elements such as test charts, patterns and characters, used for assessing the quality of output
from an imaging system
4 Methods of use
4.1 General
Because of its impact on the accuracy of other tests, evaluation of focus shall be made first. Other tests may be
made in any order, taking account of interdependence of results as indicated in the method.
Test images shall be scanned into an electronic imaging system. Output images, on screen or as hard copy, shall
be examined to assess quality level of characteristics. For a given bit-mapped image this may be different from its
ultimate image on screen or as hard copy. Some characteristics shall be assessed by visual inspection, others by
measurement.
For measurement of screen images, a calibrated electronic viewing system by which any pixel in view can be
displayed as an X direction and Y direction pixel count from a reference corner of an image shall be used. The lines
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ISO 11698-2:2000(E)
in the image shall be aligned within�����2° with the corresponding axis of the measuring device of the viewing system.
Errors in alignment greater than two degrees are likely to affect the accuracy of scaling and capture size tests.
For measurement of hard copy images, appropriate allowance shall be made for error introduced by the printer and
it is essential that the magnitude of any printer error be determined by separate calibration of the printer.
Either or both methods may be used for evaluation but an electronic viewing measurement system is usually
capable of producing more accurate results. No criteria for characteristics are specified. These are for the user to
decide.
4.2 Establishing a quality reference
To establish the quality reference the system shall be working at optimum level for all types of material to be
1)
scanned. Each of the test images specified in ISO 11698-1 and any other test image made by the user shall be
scanned, regenerated as hard copy print of corresponding A size and evaluated. If the quality of the printed output
is acceptable the prints shall be retained for reference and the reference bit-mapped images securely retained on a
separate disk. All scanner adjustment settings and all other system settings used to make the reference prints shall
be recorded.
5 Test methods
5.1 Focus
5.1.1 Set the scanner for the highest resolution and reduction ratio, and allows the full test image area to be
scanned.
5.1.2 Scan a type 4 test image and display the resulting image on a monitor screen or print it.
5.1.3 Examine the test targets and record the letter of smallest pattern that can be resolved in each set of patterns
in all the test targets.
5.1.4 Check that the lines ruled in the background area are clearly separate over the complete image area.
NOTE Adjusting the focus of a scanner may require a special tool and proc
...