Confidence Reporting: OCR Professional

For some applications, it may be important to know the reliability of the recognized text generated by the engine. These applications may require having additional confidence information for the recognized characters and/or words.

The RECOGCHARS2.nConfidence field is a combined value. Its most significant bit is used to express the certainty/uncertainty of the word. (If this bit is set to 1, the word is uncertain.) The remaining bits express the certainty of the character recognition: ranging from 0 to 100.

Applications that examine the character confidence information can use a threshold value, above which the character value is treated as a suspicious result. A value of 64 is recommended for this purpose. A value less than 64 will indicate that the character was recognized with high confidence. A value of 64 or greater marks that the code is suspicious.

NOTE:

The confidence reporting system works best when all three recognition modules are used in the voting scheme (DOC2_RECOGMODULE_OMNIFONT_PLUS3W), but this is not the default value. If other machine print recognition modules are used (DOC2_RECOGMODULE_OMNIFONT_PLUS2W, DOC2_RECOGMODULE_MTEXT_OMNIFONT, etc) then confidence information is still available, but the ability of the system to properly report confidence will be reduced. This will result in a higher level of false negative and false positive reporting of suspicious recognition results.