Patent ID: 8554715

Claim:
A document classification apparatus, comprising a processor; a score computation module configured to compute a score value from information obtained for a document to be classified; a threshold comparator configured to perform a comparison to determine whether the score value is above a first threshold, below a second threshold or between the first and second threshold; a further processing module configured to process the document dependent on the result of the comparison, the further processing module being configured to single out the document for further inspection to assign a class if the score value is between the first and second threshold; a threshold determination module configured to determine the effective levels of the first and second threshold, based on an input minimum accuracy value and a set of training examples, by searching for a combination of effective thresholds levels that maximizes a yield over the training set while at least achieving said input minimum accuracy value, wherein the threshold determination module is configured to determine the yield according to yield=( TP+TN+FP+FN )/( TP+TN+FP+FN+M ) and the accuracy according to a function of TP and TN and/or FP and FN that increases with increasing TP and TN and/or decreases with increasing FP and FN, wherein TP and FP are counts of training patterns with a score value above the first threshold that are identified in the training pattern to belongs to a class and not to belong to the class respectively, wherein FN and TN are counts of training patterns with a score value below the second threshold that are identified in the training pattern to belongs to the class and not to belong to the class respectively, and M is a count of training patterns with a score value between the first and second threshold.