Image processing
4.1 Reading code (1D and 2D codes)
SIMATIC MV420 / SIMATIC MV440
Operating Instructions, 04/2013, A5E02371045-06
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Note
Changing the time-saving image acquisition with half resolution
If the cells are larger than 10 pixels, change to time-saving image acquisition at half
resolution. This change is also useful at high object speeds.
The self-adaptive recognition technique of the reader "ID-Genius" allows reliable and robust
reading of the most difficult codes. The most reliable recognition is reached by the reader
when you make adequate time available for the device to adapt itself by setting a high cycle
time limit.
Range of application
● Any alignment and position of the code in the image.
● The code can be printed both dark on a light background and light on a dark background.
● Reading codes even when cells overlap or are largely isolated.
● Reading of mirror-inverted codes.
● Tolerance of distortion due, for example, to inclined installation of the image sensor
(viewing angle down to a lower limit of approximately 40 degrees to the printed surface).
● Resistant to similar-looking foreign objects in the area of the code.
● Resistant to interference patterns (grooves, granularity) in the area of the code
● Wide tolerance of contrast fluctuations.
● Wide range of imaging sizes from 5 to 35 pixels per cell.
● Light shadows or shiny areas in cells are tolerated. The polarity of the cells compared
with the background must not, however, become inverted within a code.
● The ratio of the distance to the closest neighbor and the diameter of any cell can be
between 2 and 0.8.
● Although code dots must be printed according to a regular square grid pattern, individual
points can be displaced from their ideal position by up to 1/3 of the grid unit. Even slight
parallelogram-shaped distortions during printing are tolerated.
● With large-image but small-dimensioned codes, slight curves in the printed material
surface are tolerated. With larger dimension codes (for example, more than 14 x 14) or a
strongly inclined sensor axis, curves are not allowed.
● Large tolerance of background disturbances that cannot be described quantitatively
● Large tolerance of poor contrast conditions
● The reader reads codes with a maximum code dimension of 72 x 72 cells.
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