Vision Sensor SBSI/SBSC-EN, 8062650 - 1607b - 13/09/2016
Page 149
Vision Sensor Manual
As data codes are redundant codes, errors in the modules or code words can be
corrected. The amount of error correcting capacities which is not already used by the
present data code symbol is expressed in the unused error correction quality. In a way,
this grade reflects the reliability of the decoding process. Note, that even codes with an
unused error correction grading of 0, which could possibly mean a false decoding result,
can be decoded in a reliable way, because the implemented decoding functionality is more
sophisticated and robust compared to the reference decode algorithm proposed by the
standard.
In order to achieve an evaluation according to the norm, there are defined minimum
requirements for the size of the code inside the camera image (resolution) and mounting
of camera and illumination. These requirements are specified inside the norm.
Quality parameters according to AIM DPM-1-2006 are a extension to ISO/IEC 15415
Standard, which define the requirements of the grey value conditions oft he image oft he
data code, and so improves the reproducibility of the quality evaluation of different
manufacturers.
Quality parameters according to AIM consist of one value more than quality parameters
according to ISO/IEC 15415. This value is called „Mean Light“. „Mean light“ is not a
quality value of the code, it shows the quality of the image by calculating the average grey
value of the bright data code modules. „Mean light“ can vary from 0.0 to 1.0. A image has
the required grey value conditions if the „mean light“ value is between 70% and 86%
(0.70 to 0.86).
Quality type
There are existing two possibilities, to display quality parameters. Both are according to
the norm. The grades can be given in values from A to F or from 4 to 0. A and 4 are the
best possible grades. This setting determines how the grades should be displayed. It
affects the display on screen as well as the output over the interfaces.
The assignment is the following:
A B C D F
4 3 2 1 0
4.6.3.11.4 2D Code detector, tab Advanced
2D Code detector, tab Quality (Page 147)
2D Code detector, tab Symbols (Page 150)
Fig. 143: Detector 2D Code, tab Advanced
Summary of Contents for SBSC-EN
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