Method and apparatus for capitalizing text using maximum entropy

• US 20060020448A1
• Filed: 10/29/2004
• Published: 01/26/2006
• Est. Priority Date: 07/21/2004
• Status: Abandoned Application

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Acero, Alejandro, Chelba, Ciprian I.
• Application Number:
  US10/977,870
• Publication Number:
  US 20060020448A1
• Time in Patent Office: Days
• US Class Current: 704/10
• CPC Class Codes: G06F 40/232 Orthographic correction, e.g. spell checking or vowelisation

Abstract

A method and apparatus are provided for selecting a form of capitalization for a text by determining a probability of a capitalization form for a word using a weighted sum of features. The features are based on the capitalization form and a context for the word.

Claims

1. A method of determining capitalization for text, the method comprising:

determining a probability of a capitalization form for a word using an exponentiated weighted sum of features that are based on the capitalization form and a context for the word; and

using the probability to select a capitalization form for the word.

2. The method of claim 1 wherein determining a probability comprises determining the probability using a maximum entropy model.

3. The method of claim 1 wherein determining a probability comprises determining the probability using a log-linear model.

4. The method of claim 1 wherein determining a probability comprises using an exponentiated weighted sum of features that is normalized such that it provides a proper probability assignment.

5. The method of claim 1 wherein determining a probability of a capitalization form for a word comprises determining the probability of a capitalization form for a current word in a sequence of words.

6. The method of claim 5 wherein the features comprise the identity of a previous word that occurs before the current word in the sequence of words.

7. The method of claim 5 wherein the features comprise the identity of a future word that occurs after the current word in the sequence of words.

8. The method of claim 5 wherein the features comprise the capitalization form for a previous word that occurs before the current word in the sequence of words.

9. The method of claim 5 wherein the features comprise the capitalization form for a second previous word that occurs two words before the current word in the sequence of words.

10. The method of claim 5 wherein the features comprise a portion of the word.

11. The method of claim 10 wherein the features comprise a prefix of the word.

12. The method of claim 10 wherein the features comprise a suffix of the word.

13. A computer-readable medium having computer-executable instructions for performing steps comprising:

determining a likelihood of a type of capitalization for a word by taking the exponent of a weighted sum of features; and

using the likelihood to identify a type of capitalization for the word.

14. The computer-readable medium of claim 13 wherein the features comprise the identity of the word.

15. The computer-readable medium of claim 13 wherein the features comprise the identity of a prior word that appears before the word in a sequence of words.

16. The computer-readable medium of claim 13 wherein the features comprise the identity of a next word that appears after the word in a sequence of words.

17. The computer-readable medium of claim 13 wherein the features comprise the type of capitalization applied to a prior word that appears before the word in a sequence of words.

18. The computer-readable medium of claim 13 wherein the features comprise the types of capitalization applied to two prior words that appear before the word in a sequence of words.

19. The computer-readable medium of claim 13 wherein the features comprise a prefix of the word.

20. The computer-readable medium of claim 13 wherein the features comprise a suffix of the word.

21. The computer-readable medium of claim 13 wherein determining a likelihood comprises determining a probability using a maximum entropy model.