Requirements For Pdf417 Codes - Siemens SIMATIC Vision Sensor VS 130-2 Manual

1.7.3

Requirements for PDF417 codes

General Requirements for PDF417 Codes and Legibility
The requirements are as follows:
•
Codes with a bar width of at least 3 pixels and in which the height of a single
row of symbols is at least 9 pixels can be read.
•
The width of the black and white bars must be uniform over the entire code
field.
• The view angle of the sensor to the surface must be greater than 70 °.
•
The code should not make contact with any other objects in the image (keep
the quiet zone free: twice the column width).
•
Within the code, the ratio of contrast (difference between black and white) to
noise should be at least three and should be very similar over the entire code
field.
•
The image background must have a homogeneous brightness (no textures
such as stripes or grooves etc.).
•
The code must be positioned in the sensor image so that the entire code
(including start and stop pattern) always has a clearance of at least 3 pixels to
the edge of the image.
•
The error correction codes (the lower part of the bar code) must not be
covered.
•
The following code types are not supported: Truncated PDF417,
Macro PDF417, Micro PDF417
•
At the minimum bar width, each symbol column requires 51 pixels. Along with
the four start and stop patterns, the width of the code with n code columns is:
Width = 51 * (n + 4) pixels. Due to the limited image resolution, codes with up
to a maximum of 40 code rows and up to a maximum of 6 code columns (for all
sensor heads except 6GF2002-8GB) or up to 60 code rows and up to 12 code
columns (for sensor head 6GF2002-8GB) can be read.
Vision Sensor SIMATIC VS 130-2/VS 130-2vcr
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