Method for indexing and searching handwritten documents in a database
Patent 5553284 Issued on September 3, 1996. Estimated Expiration Date: June 6, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
A method for indexing electronic handwritten documents is provided. Each document includes a plurality of output symbols in an output sequence, and is modeled by a respective Hidden Markov Model (HMM). The HMMs share a common alphabet and a common sequence length. A tree is established, having linked nodes stored in a memory. Each node has n pointers, each identifying a different node in the next level of the tree. Each path from the root to a different one of the leaf nodes defines a respective sequence of pointers. An indexing procedure is performed, for each of a subset of the nodes in one of the levels of the tree. The procedure includes: (1) determining the probability that a subset of one of the sequences of pointers leading from the root to that node represents a subset of the output symbols in one of the documents; (2) invoking the procedure for the next level, if the determined probability exceeds the minimum probability value of that level; and (3) adding a pointer to that document in the list of pointers of the leaf node associated with that sequence of pointers, if the next level is the last level and the probability is greater than the threshold value. The procedure is repeated for each other document.
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June 6, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
