Some Useful Definitions

This section defines some terms and concepts used in this chapter.

acceptance threshold: If the matching score is below this level the character at the specified position fails verification.

character line: A spatial arrangement of characters you expect to find in your application. For example, a character string. Sometimes referred to as a line.

character position key set: A set of keys that define allowed characters for a single character position in a character line.

confidence threshold: If the difference between the matching score for the position and the highest scoring confusion character is greater than the confidence threshold, the position passes verification; otherwise, the verification status of the position is confused.

confusion score: A number in the range 0 through 1 that indicates the probability that two characters can be confused with one another during optical verification. A value of 0 means that the characters will never be confused with each other; and a value of 1 means that they will always be confused.

confusion threshold: If the computed confusion score for a character pairing is greater than the confusion threshold, the characters are easily confused with each other during optical verification.

current keys: A set of keys selected from the character position key set that are used with the current run-time image.

character line arrangement: A sequence of character lines in space. Sometimes referred to as a line arrangement.

matching score: The score generated when the OCV tool measures the match between the run-time character image for a position and the model image for a character expected to be in that position. A score is calculated for each of the current keys and the highest score is the matching score.

The OCV tool also reports score results for character lines and character line arrangements.

optical character verification (OCV): The process of verifying that the characters in a text area are the expected characters.