Code Quality
This group contains functions for quality assessment of various 1D and 2D codes. The assessment is based on international standards. The code quality check is intended to ensure that the corresponding code can be reliably decoded at the time of use.
In order to obtain comparable results, the standards define methods for measuring and evaluating specific attributes and for deriving an overall assessment of code quality. The aim is to predict, as far as possible, the expected readability of the codes, using different types of readers, in different applications, environments and under different conditions. A minimum acceptable quality level is therefore usually defined for each individual application.
On the one hand, the standards describe requirements that must be met by the systems used in order to obtain usable results. On the other hand, the standards provide recommendations such as illumination, lens settings and geometric structure in order to be able to compare the ratings with other systems. In order to set up a system that conforms to the standard, it is advisable to obtain the relevant quality assessment specifications and the codes to be tested.
The functions can also be used with non-standard systems. The only consequence of this is that the quality determined is not comparable with other systems. In general, minor differences in the individual evaluation categories are to be expected for different systems.
In accordance with the ISO/IEC 15416:2016 standard, the print quality of barcodes for the code types Code 39, Code 128, EAN 8, EAN 13, ITF, UPC-A, UPC-E can be determined using the following functions:
In accordance with the ISO/IEC 15415:2011 standard, the print quality of two-dimensional matrix symbols of the ECC200 Data Matrix code and QR code types can be determined using the following functions:
Interpretation of the HRESULT
For the Code Grading functions the HRESULT return values are used as follows:
Code | Name | Description |
|---|---|---|
0x000 | S_OK | Function was executed successfully and all evaluations were carried out in accordance with the standard. |
0x001 | S_FALSE | Function was executed successfully, not all scan lines could be decoded for 1D codes and not all checks could be performed according to the standard for 2D codes. The overall score was therefore set to 0, but the individual results can be evaluated. |
0x256 | S_WATCHDOGTIMEOUT | Function was aborted by the watchdog. Individual results can be evaluated depending on the time of termination |
0x70C | NOTFOUND | Function was not executed successfully, no scan line could be decoded for 1D codes and the code was not found or could not be decoded for 2D codes. |
0x7xx | All error codes | Function was not executed successfully. See: ADS Return Codes |