Barcode symbols must be readable by barcode scanners and therefore should be produced with appropriate precision. To determine whether a given code is correctly produced, its quality must be checked using specialized inspection devices called barcode verifiers.
Using such devices, it is possible to unambiguously assess whether a given barcode will be read by barcode scanners. The practice often used by printing houses of checking code readability with a barcode scanner does not guarantee that a code checked in this way has sufficient quality. Scanners differ from one another, for example, in the precision of their optics, resolution, number of scanning lines, and decoding software, and it is by no means certain that if one scanner reads a poor-quality code, a scanner from another manufacturer will also read it. The previously used method of verifying barcode quality, the so-called traditional “Dimensional” method, was based on examining the dimensions of barcodes (the width of individual bars and spaces, i.e., the light gaps between bars, the size of the left and right light margins of the code, the distance between similar edges of adjacent bars, the width of the data character, the height of the code bars) and the light reflectance coefficient of the bars and the code background (determining the correctness of the relative print contrast, the so-called PCS of the barcode). This method was never standardized. In the traditional method of barcode verification, the threshold point for locating bar edges and the points at which light reflectance coefficients from the background and bars are measured (used to calculate PCS, i.e., relative print contrast) were not standardized.
The article comes from the magazine “Logistyka” 2001/3.