Method and apparatus for enhanced phonetic indexing and search

1. A method comprising:

receiving digital representations of audio signals, wherein the audio signals are produced by a suitable device;

producing phonetic indexes of the audio signals based on said digital representations thereof;

producing phonetic N-gram sequences from the phonetic indexes by segmenting the phonetic indexes into a plurality of phonetic N-grams;

producing inverted indexes of the plurality of phonetic N-grams;

obtaining a textual search term;

converting the textual search term into a phonetic search term;

searching the phonetic search term on the inverted indexes;

ranking the digital representations of the audio signals based on matching between the search query and detected events of the search in the inverted indexes such that a rank reflects the probability that the textual search term is found within any of the audio signals,

wherein the ranking is according to the following formula:

Rank

j

=

100

*

(

1

-

a

*

log

2

(

1

+

1

∑

i

=

0

N

-

1

⁢

C

i

)

)

where the rank is the rank level, j denotes the audio signal, Cj is the confidence score of i-th detected event that satisfy a query in the j-th signal, N is the number of detected events within the j-th signal that satisfy the search query, and a is a constant; and

based on the ranking, determining whether or not to automatically perform on each signal of the audio signals a second slower and more accurate phonetic search based on non-inverted indexing,

in case a determination to perform the second search is satisfied then the second slower and more accurate phonetic search based on non-inverted indexing is carried out;

responsive to performing the second slower and more accurate search, determining search results with respect to the textual search term; and

playing back, via a media player, the search results with respect to said digital representations of the audio signals.

2. The method according to claim 1 , wherein the plurality of phonetic N-grams are of the same N-gram length.

3. The method according to claim 1 , further comprises producing one or more segmented phonetic search terms from the phonetic search term, the segmented phonetic search terms having the same N-gram length as the plurality of phonetic N-grams;

producing a search query from the one or more segmented phonetic search terms; and

searching the search query on the inverted index.

4. The method according to claim 1 , wherein the plurality of phonetic N-grams are of variable lengths.

5. The method according to claim 1 , further comprises obtaining a limitation parameter; and limiting the number of audio signals that are used for phonetic search according to the limitation parameter.

6. The method according to claim 1 , further comprises determining whether to perform a phonetic search according to an accuracy estimation of the inverted index search.

7. The method according to claim 1 , further comprises determining whether to perform, a phonetic search according to the available processing resources of a device performing the search.

8. The method according to claim 1 , further comprises obtaining an enable/disable parameter; and determining whether to perform a phonetic search according to the enable/disable parameter.

9. The method according to claim 1 , further comprises storing search results of the inverted index in a storage device.

10. The method according to claim 1 , wherein segmenting the phonetic index into a plurality of phonetic N-grams comprises segmenting the phonetic index to sequences of consecutive phonemes with an overlap of a whole number of phonemes between the sequences.

11. The method according to claim 10 , wherein the whole number is zero, hence the plurality of phonetic N-grams do not overlap.

12. The method according to claim 10 , wherein the whole number is non-zero, hence the plurality of phonetic N-grams overlap therebetween.

13. The method according to claim 1 , wherein the second search would be performed only on audio signals that have a rank that is higher than a given threshold.

14. The method according to claim 1 , wherein determining whether or not to perform the second search is according to an accuracy estimation of the search based on inverted indexes.

15. The method according to claim 1 : wherein determining whether or not to perform the second search is according to load balance of the computerized apparatus performing the phonetic search.

16. The method according to claim 1 , wherein a is empirically determined.