# Fielding

Fielding is an optional process where the OCRMax tool attempts to classify a particular character against a known subset of all the characters in the trained font. Fielding can improve the overall performance of the tool by allowing it to disregard some or much of the trained font from consideration when classifying any character.

To use fielding you must specify a field string to indicate which characters from the trained font can occur for any given position in the character string. You can specify a literal character such as "C" or "$" in the field string, or use any of the following field definitions supported by the OCRMax tool:

- * represents any character (including spaces)
- N represent any numeric character
- A represents any alphabetic character (upper and lower case)

For example, the following figure shows a variety of character strings that can be classified by the defined field string:

In addition to the field definitions supplied by default, an OCRMax tool allows you to specify your own field definitions. You could, for example, define the field definition U to represent the subset of numeric characters "0123", and then refine the field string in the previous figure to be Date: UN/UN/20UN.

Be aware that fielding can generate more reliable results at the cost of increased execution time.