System and method for finding desired results by incremental search using an ambiguous keypad with the input containing orthographic and typographic errors

1. A computer-implemented user-interface system for incrementally finding and presenting one or more content items in response to keystrokes entered by a user on an input device having a known layout of overloaded keys selected from a set of key layouts, each overloaded key having a corresponding set of alphanumeric symbols, the system comprising:

a database stored in a computer memory, the database containing content items and corresponding descriptive terms that characterize the content items;

a computer memory comprising instructions for causing a computer system to:

receive keystrokes from the user and build a string corresponding to incremental entries by the user, each item in the string having the set of alphanumeric symbols associated with a corresponding keystroke;

map the string to the database to find the most likely content items corresponding to the incremental entries, the mapping being in accordance with a defined error model, the error model corresponding to the known layout of overloaded keys of the input device;

wherein the error model associates the string with:

(i) suggested corrections for typographic errors corresponding to incremental user entries, wherein suggested corrections are derived by replacing characters in the string resulting from one or more accidently pressed adjacent keys;

(ii) suggested corrections for orthographic errors corresponding to incremental user entries, wherein suggested corrections are derived by replacing one or more characters in the string resulting from phonetic substitutions; and

wherein the most likely content items are ordered and presented on a display device in accordance with defined ordering criteria;

such that the user-interface system receives ambiguous entries from the user and presents the most likely matching content items.

2. The system of claim 1 , wherein the error model includes generating typographic variants of the descriptive terms that characterize the content items.

3. The system of claim 1 , wherein the error model includes generating orthographic variants of the descriptive terms that characterize the content items.

4. The system of claim 1 , wherein the error model includes generating variants based on at least one of inserting, deleting, substituting, and transposing one or more characters of the descriptive terms that characterize the content items.

5. The system of claim 1 , wherein the error model includes generating N-gram variants of the descriptive terms that characterize the content items, the N-gram variants including variants based on nonadjacent characters of the descriptive terms.

6. The system of claim 1 , wherein the error model includes distance functions to assign error penalties to errors occurring in the string.

7. The system of claim 1 , wherein the database contains pre-computed variants of the descriptive terms that characterize the content items and the mapping logic maps the incremental entries to the pre-computed variants.

8. The system of claim 7 , wherein the pre-computed variants are encoded according to the known layout of overloaded keys of the input device.

9. The system of claim 1 , wherein mapping the string to the database generates variants based on the incremental entries and uses the variants to find the most likely content items corresponding to the incremental entries.

10. The system of claim 1 , wherein the instructions for mapping the string to the database further cause the computer system to:

identify a first set of content items corresponding to a first set of alphanumeric symbols in the string;

identify a second set of content items corresponding to a second set of alphanumeric symbols in the string; and

include content items appearing in both the first and second set of content items in the most likely content items corresponding to the incremental entries.

11. The system of claim 10 , wherein the identifying the first set of content items, identifying the second set of content items, and including the content items appearing in both the first and second set of content items in the most likely content items is invoked when the number of most likely content items returned by mapping the string to the database to find the most likely content items corresponding to the incremental entries alone is below a predetermined threshold.

12. The system of claim 1 , wherein the defined ordering criteria includes at least one of personalized user preferences, popularity of the content items, temporal relevance of the content items, location relevance of the content items, recency of the content items, and relevance of the descriptive terms to the content items.

13. The system of claim 1 , wherein the string is mapped to the database according to a trie descend.

14. The system of claim 1 , wherein the input device is an input constrained device.

15. The system of claim 1 , wherein the input device is a wireless communication device, a mobile phone, a PDA, a personal media player, or a television remote control.

16. The system of claim 1 , wherein the display device is a display constrained device.

17. The system of claim 1 , wherein the display device is a wireless communication device, a mobile phone, a PDA, a personal media player, or a television.

18. The system of claim 1 , wherein the input device and the display device are the same device.