QAID # 10933 Published
Question / Problem:
How does the Standard Bar Code (SBC) algorithm search engine work?
Answer / Solution:
The Standard Bar Code driver searches for 1D bar codes in bitonal images in a linear fashion, probing the search area for potential bar codes. For horizontal bar codes with an orientation of 0, for example, it works down the image starting on the left edge and probing toward the right edge. For vertical bar codes, it works across the image starting on the top edge and probing top to bottom.
The distance between probes is calculated by dividing the specified bar code height by the specified quality (BarHeight/BarQuality) as follows:
|Quality||Number of Probes|
|Good||Ensures 1 probe per height of bar code.|
|Normal||Ensures 4 - 5 probes per height of bar code.|
|Poor||Ensures 1 probe for every DPI/50 lines.
When enabled with the selected search direction setting, the SBC engine is capable of reading bar codes that are skewed on either side of the search path. Skew detection is built into the engine and occurs automatically. Each selected direction covers a 90 degree window (45 degrees on either side of the search path).
For example, if the search direction is 90 degrees, bar codes can be read in the range 90 degrees +/- 45 degrees (resulting in a range from 45° to 135°.)
If all search directions are set, the bar code driver can read bar codes oriented from 0 to 360 degrees on the image.