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Images are different in terms of DPI, scanner setting and barcode label quality. The controls in AX-4 serve as a means to fine-tune the recognition process so that it matches individual image characteristics. Properly used, these controls allow AX-4 to obtain the best possible speed and recognition rate.
Granularity.
With a default value of "9" the engine reads through a page in coarse mode. Reading is extremely fast and typically over 96% of all barcodes are located. Set the value to "1" and retry if a read operation fails to locate a barcode symbol.
Minimum length.
The customer defines this value. Normally it is set to match the expected string length. In special situations text and graphics pattern may appear to the recognition engine as short barcode strings. This feature suppresses the reporting of all strings that are shorter than expected.
Search location / size.
These four values define a window within an image. The search for barcode symbols is confined to that window. When all four values are set to zero the entire image is the window. Under normal conditions there is no significant time saving associated with searching less than the entire image.
Search types.
Used to enable the search engine for individual barcode types. Engine speed is best if only one barcode type is enabled. Detection of barcode type is automatic.
Read multiple.
When enabled the AX-4 engine keeps reading after finding the first barcode symbol. When arriving at the end of the image the engine reports back all barcode symbols.
Read direction.
The engine is capable of reading barcodes in all four basic directions:left to right, right to left, top to bottom, and bottom to top. Reading from the left to the right is the fastest algorithm. Searching an image in more than one direction is possible but slow.
Read skewed.
This control is only effective when reading barcodes from left to right is enabled. It allows barcode symbols to be badly skewed. A badly skewed barcode is defined as a symbol where not a single scan-line passes through both the beginning and end of the symbol.
Error check.
With error check enabled the AX-4 engine calculates the check character for a barcode symbol and compares it with the string. The engine reports back a status of OK (40h) or not OK. Normally the customer defines if error check is enabled or not. However, for some barcode types, the use of a check character is mandatory if one intends to comply with public standards. When necessary, AX-4 overwrites customer settings to comply with the standard.
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