ISO/IEC TR 29158:2011

Information technology — Automatic identification and data capture techniques — Direct Part Mark (DPM) Quality Guideline

ISO/IEC TR 29158:2011 is an engineering document intended for verifier manufacturers and application specification developers. It describes modifications which are to be considered in conjunction with the symbol quality methodology defined in ISO/IEC 15415 and a symbology specification. It defines alternative illumination conditions, some new terms and parameters, modifications to the measurement and grading of certain parameters, and the reporting of the grading results. ISO/IEC TR 29158:2011 was developed to assess the symbol quality of direct marked parts, where the mark is applied directly to the surface of the item and the reading device is a two-dimensional imager. When application specifications allow, this method may also be applied to symbols produced by other methods. This is appropriate when direct part marked (DPM) symbols and non-DPM symbols are being scanned in the same scanning environment. The symbol grade is reported as a DPM grade rather than as an ISO/IEC 15415 grade.

Technologies de l'information — Techniques automatiques d'identification et de capture de données — Ligne directrice de qualité du marquage direct sur pièce (DPM)

General Information

• Status: Withdrawn
• Publication Date: 05-Oct-2011
• Withdrawal Date: 05-Oct-2011
• ICS: 35.040 - Information coding
• ICS: 35.040.50 - Automatic identification and data capture techniques
• Technical Committee: ISO/IEC JTC 1/SC 31 - Automatic identification and data capture techniques
• Drafting Committee: ISO/IEC JTC 1/SC 31/WG 1 - Data carrier
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 14-Dec-2020
• Completion Date: 14-Dec-2020

Relations

• Revised: ISO/IEC 29158:2020 - Information technology — Automatic identification and data capture techniques — Direct Part Mark (DPM) Quality Guideline
• Effective Date: 05-Nov-2015

Standards Content (Sample)

TECHNICAL ISO/IEC
REPORT TR
First edition
2011-10-15
Information technology — Automatic
identification and data capture
techniques — Direct Part Mark (DPM)
Quality Guideline
Technologies de l'information — Techniques automatiques
d'identification et de capture de données — Ligne directrice de qualité
du marquage direct sur pièce (DPM)

Reference number
©
ISO/IEC 2011
©  ISO/IEC 2011
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
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Published in Switzerland
ii © ISO/IEC 2011 – All rights reserved

Contents Page
Foreword . iv
Introduction . v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Abbreviated terms . 2
5  Overview of methodology . 3
5.1  Process differences from 15415 . 3
5.2  Lighting. 3
6  Obtaining the image . 3
6.1  Orientation of the symbol to the camera . 3
6.2  Lighting. 4
6.3  Image focus . 4
6.4  Reflectance calibration . 4
6.5  Initial image reflectance level of the symbol under test . 5
7  Obtaining the test image . 5
7.1  Binarize image . 5
7.2  Apply Reference Decode Algorithm . 5
7.3  Connect areas of the same colour . 6
7.4  Final image adjustment . 7
8  Determine contrast parameters . 7
8.1  Calculate Cell Contrast (CC) . 8
8.2  Calculate Cell Modulation (CM) . 8
8.3  Calculate % Reflectance of Symbol (Rtarget) . 8
9  Grading . 8
9.1  Cell Contrast (CC) . 8
9.2  Minimum Reflectance . 8
9.3  Cell Modulation (CM) . 8
9.4  Fixed pattern damage . 9
9.5  Final grade . 9
10  Communicating grade requirements and results . 9
10.1  Communication from Application to Verifier . 9
10.2  Communicating from Verifier to Application . 9
10.3  Communicating Lighting . 9
10.4  Communicating the use of a proprietary decode . 10
Annex A (normative) Threshold determination method . 11
Annex B (informative) Communicating the grade . 15
Annex C (informative) Cross-reference to ISO/IEC 15415 . 18

© ISO/IEC 2011 – All rights reserved iii

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national bodies casting a vote.
In exceptional circumstances, when the joint technical committee has collected data of a different kind from
that which is normally published as an International Standard (“state of the art”, for example) it may decide to
publish a Technical Report. A Technical Report is entirely informative in nature and shall be subject to review
every five years in the same manner as an International Standard.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC TR 29158 was prepared jointly by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 31, Automatic identification and data capture techniques.

iv © ISO/IEC 2011 – All rights reserved

Introduction
Direct Part Marking (DPM) is a technology whereby, generally, an item is physically altered to produce two
different surface conditions. This alteration can be accomplished by various means including, but not limited to,
dot peen, laser, ink jet, and electro-chemical etch. The area of the alteration is called “the mark”. The area that
includes the mark and background as a whole, when containing a pattern defined by a bar code symbology
specification, is called “a symbol”.
When light illuminates a symbol, it reflects differently depending on whether it impinges on the background of
the part or on the physical alteration. In most non-DPM bar code scanning environments, light is reflected off a
smooth surface that has been coloured to produce two different diffuse reflected states. The DPM
environment generally does not fit this model because the two different reflected states depend on at least
one of the states having material oriented to the lighting such that the angle of incidence is equal to the angle
of reflection. Sometimes the material so oriented produces a specular (mirror-like) reflectance that results in a
signal that is orders of magnitude greater than the signal from diffuse reflectance.
In addition, from the scanner point-of-view, some marking and printing methods generate dots and are not
capable of producing smooth lines.
Current specifications for matrix symbologies and two-dimensional print quality are not exactly suited to
reading situations that have either specular reflection or unconnected dots or both. This is intended to act as a
bridge between the existing specifications and the DPM environment in order to provide a standardized
image-based measurement method for DPM that is predictive of scanner performance.
As with all symbology and quality standards, it is the responsibility of the applicator to define the appropriate
parameters of this guideline for use in conjunction with a particular application.

© ISO/IEC 2011 – All rights reserved v

TECHNICAL REPORT ISO/IEC TR 29158:2011(E)

Information technology — Automatic identification and data
capture techniques — Direct Part Mark (DPM) Quality Guideline
1 Scope
This Technical Report is an engineering document intended for verifier manufacturers and application
specification developers.
This Technical Report describes modifications which are to be considered in conjunction with the symbol
quality methodology defined in ISO/IEC 15415 and a symbology specification. It defines alternative
illumination conditions, some new terms and parameters, modifications to the measurement and grading of
certain parameters, and the reporting of the grading results.
This Technical Report was developed to assess the symbol quality of direct marked parts, where the mark is
applied directly to the surface of the item and the reading device is a two-dimensional imager.
When application specifications allow, this method may also be applied to symbols produced by other
methods. This is appropriate when direct part marked (DPM) symbols and non-DPM symbols are being
scanned in the same scanning environment. The symbol grade is reported as a DPM grade rather than as an
ISO/IEC 15415 grade.
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/IEC 15415, Information technology — Automatic identification and data capture techniques — Bar code
print quality test specification — Two-dimensional symbols
ISO/IEC 15416, Information technology — Automatic identification and data capture techniques — Bar code
print quality test specification — Linear symbols
ISO/IEC 19762-1, Information technology — Automatic identification and data capture (AIDC) techniques —
Harmonized vocabulary — Part 1: General terms relating to AIDC
ISO/IEC 19762-2, Information technology — Automatic identification and data capture (AIDC) techniques —
Harmonized vocabulary — Part 2: Optically readable media (ORM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 15415, ISO/IEC 15416,
ISO/IEC 19762-1, ISO/IEC 19762-2 and the following apply.
3.1
MLcal
mean of the light lobe from a histogram of the calibrated standard
© ISO/IEC 2011 – All rights reserved 1

3.2
MLtarget
mean of the light lobe from the final grid-point histogram of the symbol under test
3.3
reference symbol
high-contrast printed calibration card
EXAMPLE The GS1 Data Matrix calibrated conformance standard test card.
3.4
Rcal
reported reflectance value, Rmax, from a calibration standard
3.5
Rtarget
measured percent reflectance of the light elements of the symbol under test relative to the calibrated standard
3.6
SRcal
system response parameters (such as exposure and/or gain) used to create an image of the calibration
standard
3.7
SRtarget
system response parameters (such as exposure and/or gain) used to create an image of the symbol under
test
3.8
stick
line segment comprised of image pixels that is used to connect areas of the same colour that are near to each
other
3.9
T1
threshold created using a histogram of the defined grey-scale pixel values in a circular area twenty times the
aperture size in diameter, centred on the image centre using the algorithm defined in Annex A
3.10
T2
threshold created using the histogram of the reference grey-scale image pixel values at each intersection
point of the grid using the method defined in Annex A
4 Abbreviated terms
CM Cell Modulation
CC
...