ISO/IEC 15415:2004(E)
© ISO/IEC 2004 – All rights reserved v
Introduction
The technology of bar coding is based on the recognition of patterns encoded, in bars and spaces or in a
matrix of modules of defined dimensions, according to rules defining the translation of characters into such
patterns, known as the symbology specification. Symbology specifications may be categorized into those for
linear symbols, on the one hand, and two-dimensional symbols on the other; the latter may in turn be sub-
divided into «multi-row bar code symbols» sometimes referred to as «stacked bar code symbols», and «two-
dimensional matrix symbols». In addition there is a hybrid group of symbologies known as «composite
symbologies»; these symbols consist of two components carrying a single message or related data, one of
which is usually a linear symbol and the other a two-dimensional symbol positioned in a defined relationship
with the linear symbol.
Multi-row bar code symbols are constructed graphically as a series of rows of symbol characters, representing
data and overhead components, placed in a defined vertical arrangement to form a (normally) rectangular
symbol, which contains a single data message. Each symbol character has the characteristics of a linear bar
code symbol character and each row has those of a linear bar code symbol; each row, therefore, may be read
by linear symbol scanning techniques, but the data from all the rows in the symbol must be read before the
message can be transferred to the application software.
Two-dimensional matrix symbols are normally square or rectangular arrangements of dark and light modules,
the centres of which are placed at the intersections of a grid of two (sometimes more) axes; the coordinates of
each module need to be known in order to determine its significance, and the symbol must therefore be
analysed two-dimensionally before it can be decoded. Dot codes are a subset of matrix codes in which the
individual modules do not directly touch their neighbours but are separated from them by a clear space.
Unless the context requires otherwise, the term “symbol” in this International Standard may refer to either type
of symbology.
The bar code symbol must be produced in such a way as to be reliably decoded at the point of use, if it is to
fulfil its basic objective as a machine-readable data carrier.
Manufacturers of bar code equipment and the producers and users of bar code symbols therefore require
publicly available standard test specifications for the objective assessment of the quality of bar code symbols
(a process known as verification), to which they can refer when developing equipment and application
standards or determining the quality of the symbols. Such test specifications form the basis for the
development of measuring equipment for process control and quality assurance purposes during symbol
production as well as afterwards.
The performance of measuring equipment for the verification of symbols (verifiers) is the subject of a separate
International Standard (ISO/IEC 15426, Parts 1 and 2).
This International Standard is intended to achieve comparable results to the linear bar code symbol quality
standard ISO/IEC 15416, the general principles of which it has followed. It should be read in conjunction with
the symbology specification applicable to the bar code symbol being tested, which provides symbology-
specific detail necessary for its application. Two-dimensional multi-row bar code symbols are verified
according to the ISO/IEC 15416 methodology, with the modifications described in Clause 6; different
parameters and methodologies are applicable to two-dimensional matrix symbols.
There are currently many methods of assessing bar code quality at different stages of symbol production. The
methodologies described in this specification are not intended as a replacement for any current process
control methods. They provide symbol producers and their trading partners with universally standardized
means for communicating about the quality of multi-row bar code and two-dimensional matrix symbols after
they have been printed. The procedures described in this International Standard must necessarily be
augmented by the reference decode algorithm and other measurement details within the applicable
