التفاصيل البيبلوغرافية
| العنوان: |
Sound signal processing apparatus and method |
| Document Number: |
20090216354 |
| تاريخ النشر: |
August 27, 2009 |
| Appl. No: |
12/378719 |
| Application Filed: |
February 19, 2009 |
| مستخلص: |
Character value of a sound signal is extracted for each unit portion, and degrees of similarity between the character values of the individual unit portions are calculated and arranged in a matrix configuration. The matrix has arranged in each column the degrees of similarity acquired by comparing, for each of the unit portions, the sound signal and a delayed sound signal obtained by delaying the sound signal by a time difference equal to an integral multiple of a time length of the unit portion, and it has a plurality of the columns in association with different time differences. Repetition probability is calculated for each of the columns corresponding to the different time differences in the matrix. A plurality of peaks in a distribution of the repetition probabilities are identified. The loop region in the sound signal is identified by collating a reference matrix with the degree of similarity matrix. |
| Inventors: |
Ong, Bee Suan (Delft, NL); Streich, Sebastian (Delft, NL); Fujishima, Takuya (Hamamatsu-shi, JP); Arimoto, Keita (Hamamatsu-shi, JP) |
| Assignees: |
Yamaha Corporation (Hamamatsu-shi, JP) |
| Claim: |
1. A sound signal processing apparatus for identifying a loop region where a similar musical character is repeated in a sound signal, said sound signal processing apparatus comprising: a character extraction section that divides the sound signal into a plurality of unit portions and extracts a character value of the sound signal for each of the unit portions; a degree of similarity calculation section that calculates degrees of similarity between the character values of individual ones of the unit portions; a first matrix generation section that generates a degree of similarity matrix by arranging the degrees of similarity between the character values of the individual unit portions, calculated by said degree of similarity calculation section, in a matrix configuration, said degree of similarity matrix having arranged in each column thereof the degrees of similarity acquired by comparing, for each of the unit portions, the sound signal and a delayed sound signal obtained by delaying the sound signal by a time difference equal to an integral multiple of a time length of the unit portion, said degree of similarity matrix having a plurality of the columns in association with different time differences equal to different integral multiples of the time length of the unit portion; a probability calculation section that, for each of the columns corresponding to the different time differences in the degree of similarity matrix, calculates a repetition probability indicative of a level of similarity on the basis of the degree of similarity; a peak identification section that identifies a plurality of peaks in a distribution of the repetition probabilities calculated by said probability calculation section; a second matrix generation section that generates a reference matrix having a plurality of columns corresponding to different time differences equal to different integral multiples of the time length of the unit portion and having predetermined reference values arranged in the columns associated with positions of the time differences where the plurality of peaks identified by said peak identification section are located; and a collation section that identifies the loop region in the sound signal by collating the reference matrix with the degree of similarity matrix. |
| Claim: |
2. The sound signal processing apparatus as claimed in claim 1 wherein said collation section includes: a correlation calculation section that calculates correlation values along a time axis of the sound signal by applying the reference matrix to the degree of similarity matrix, and a sound signal portion identification section that identifies the loop region on the basis of peaks in a distribution of the correlation values calculated by said correlation calculation section. |
| Claim: |
3. The sound signal processing apparatus as claimed in claim 1 wherein said peak identification section includes: a period identification section that identifies a period of the peaks in the distribution of the repetition probabilities; and a peak selection section that selects a plurality of peaks appearing with the period, identified by said period identification section, in the distribution of the repetition probabilities. |
| Claim: |
4. The sound signal processing apparatus as claimed in claim 1 wherein said peak identification section limits, to within a predetermined range, a total number of the peaks to be identified from the distribution of the repetition probabilities. |
| Claim: |
5. The sound signal processing apparatus as claimed in claim 2 wherein said portion identification section identifies, as a loop region, a sound signal portion running from a time point of a peak in the distribution of the correlation values to a time point when a reference length corresponding to a size of the reference matrix terminates. |
| Claim: |
6. The sound signal processing apparatus as claimed in claim 2 wherein, when a peak having a flat top is detected in a distribution of the correlation values, said portion identification section identifies, as a loop region, a sound signal portion having a start point that coincides with a leading edge of the peak and an end point that coincides with a time point located a reference length, corresponding to a size of the reference matrix, from a trailing edge of the peak. |
| Claim: |
7. The sound signal processing apparatus as claimed in claim 1 wherein said degree of similarity calculation section compares the character value of each of the unit portions and the character value of each individual one of other unit portions and calculates a degree of similarity between the compared character values. |
| Claim: |
8. The sound signal processing apparatus as claimed in claim 1 wherein the musical character is a phrase of a music piece. |
| Claim: |
9. The sound signal processing apparatus as claimed in claim 1 wherein said character extraction section extracts the character value on the basis of a pitch of the sound signal. |
| Claim: |
10. A computer-implemented method for identifying a loop region where a similar musical character is repeated in a sound signal, comprising: a step of dividing the sound signal into a plurality of unit portions and extracting a character value of the sound signal for each of the unit portions; a degree of similarity calculation step of calculating degrees of similarity between the character values of individual ones of the unit portions; a step of generating a degree of similarity matrix by arranging the degrees of similarity between the character values of the individual unit portions, calculated by said degree of similarity calculation step, in a matrix configuration, said degree of similarity matrix having arranged in each column thereof the degrees of similarity acquired by comparing, for each of the unit portions, the sound signal and a delayed sound signal obtained by delaying the sound signal by a time difference equal to an integral multiple of a time length of the unit portion, said degree of similarity matrix having a plurality of the columns in association with different time differences equal to different integral multiples of the time length of the unit portion; a probability calculation step of, for each of the columns corresponding to the different time differences in the degree of similarity matrix, calculating a repetition probability indicative of a level of similarity on the basis of the degree of similarity; a peak identification step of identifying a plurality of peaks in a distribution of the repetition probabilities calculated by said probability calculation step; a step of generating a reference matrix having a plurality of columns corresponding to different time differences equal to different integral multiples of the time length of the unit portion and having predetermined reference values arranged in the columns associated with positions of the time differences where the plurality of peaks identified by said peak identification step are located; and a loop identification step of identifying the loop region in the sound signal by collating the reference matrix with the degree of similarity matrix. |
| Claim: |
11. The computer-implemented. method as claimed in claim 10 wherein said loop identification step includes: a correlation calculation step of calculating correlation values along a time axis of the sound signal by applying the reference matrix to the degree of similarity matrix, and a step of identifying the loop region on the basis of peaks in a distribution of the correlation values calculated by said correlation calculation step. |
| Claim: |
12. A computer-readable storage medium storing a program causing a computer to perform a process for identifying a loop region where a similar musical character is repeated in a sound signal, said program comprising: a step of dividing the sound signal into a plurality of unit portions and extracting a character value of the sound signal for each of the unit portions; a degree of similarity calculation step of calculating degrees of similarity between the character values of individual ones of the unit portions; a step of generating a degree of similarity matrix by arranging the degrees of similarity between the character values of the individual unit portions, calculated by said degree of similarity calculation step, in a matrix configuration, said degree of similarity matrix having arranged in each column thereof the degrees of similarity acquired by comparing, for each of the unit portions, the sound signal and a delayed sound signal obtained by delaying the sound signal by a time difference equal to an integral multiple of a time length of the unit portion, said degree of similarity matrix having a plurality of the columns in association with different time differences equal to different integral multiples of the time length of the unit portion; a probability calculation step of, for each of the columns corresponding to the different time differences in the degree of similarity matrix, calculating a repetition probability indicative of a level of similarity on the basis of the degree of similarity; a peak identification step of identifying a plurality of peaks in a distribution of the repetition probabilities calculated by said probability calculation step; a step of generating a reference matrix having a plurality of columns corresponding to different time differences equal to different integral multiples of the time length of the unit portion and having predetermined reference values arranged in the columns associated with positions of the time differences where the plurality of peaks identified by said peak identification step are located; and a loop identification step of identifying the loop region in the sound signal by collating the reference matrix with the degree of similarity matrix. |
| Claim: |
13. The computer-readable storage medium as claimed in claim 12 wherein said loop identification step includes: a correlation calculation step of calculating correlation values along a time axis of the sound signal by applying the reference matrix to the degree of similarity matrix, and a step of identifying the loop region on the basis of peaks in a distribution of the correlation values calculated by said correlation calculation step. |
| Current U.S. Class: |
700/94 |
| Current International Class: |
06 |
| رقم الانضمام: |
edspap.20090216354 |
| قاعدة البيانات: |
USPTO Patent Applications |