Back to results
US 7,923,621 B2Granted
Tempo analysis device and tempo analysis method
AssigneeSony Corporation
InventorsGoro Shiraishi, Chie Sekine, Kumiko Masuda, Kuniharu Mori
Life of this patent
Estimating the term…
Abstract
A tempo analyzer to analyze the tempo of sound such as a musical composition or the like is provided in which a controller (9) takes, based on level information on a sound signal from an analysis data extraction unit (62), a frame which is a predetermined unit-time interval as a unit of process, detects positions of peaks of the level of the sound signal (apex of the change in level) higher than a predetermined level to find a time interval (peak-to-peak interval) between the peak positions in the frame, and determines a peak-to-peak time interval having occurred frequently as a tempo.
Claims12
A tempo analyzing apparatus comprising:
- a frequency band extracting means for extracting a sound signal of a frequency in a predetermined frequency band from an input sound signal;
- a volume calculating means for calculating a volume of the sound signal extracted by the frequency band extracting means;
- a threshold setting means for setting a threshold used to detect a peak of change in level with reference to the volume calculated by the volume calculating means;
- a peak detecting means for detecting positions of a plurality of ones, higher than a predetermined threshold, of peaks of change in level of the sound signal extracted by the frequency band extracting means, the peaks of change in level being detected in accordance with the threshold set by the threshold setting means, the positions including at least one reference position;
- a time interval detecting means for detecting a time interval between the at least one reference position and one or more others of the positions detected by the peak detecting means in a predetermined unit-time interval;
- an interval frequency detecting means for identifying a frequently occurring one of the time intervals detected by the time interval detecting means;
- an identifying means for accumulating a frequency of occurrence of each time interval between the positions of peaks detected in a plurality of unit-time intervals and identifying the tempo of the sound to be reproduced with the input sound signal on the basis of a maximum one among all the accumulated frequencies of time interval occurrence, wherein when the identifying means determines that a frequency of occurrence for a time interval exceeds a value, the identifying means reduces frequency of occurrence for at least one time interval;
- an image display device;
- and
- a display controlling means for causing an image to be displayed on the image display device, the image corresponding to the tempo identified by the identifying means and not to a tempo identified using any auto-correlation calculation or beat structure analysis.
7 more elements
A tempo analyzing method comprising steps of:
- extracting a sound signal of a frequency included in a predetermined frequency band from the input sound signal;
- and
- calculating a volume of the extracted sound signal;
- setting a threshold used to detect a peak position with reference to the calculated volume;
- detecting positions of a plurality of ones, higher than a predetermined threshold, of peaks of change in level of the extracted sound signal, the peaks of change in level being detected in accordance with the set threshold, the positions including at least one reference position;
- detecting a time interval between the at least one reference position and one or more others of the detected positions in a predetermined unit-time interval;
- identifying a frequently occurring one of the detected time intervals;
- accumulating a frequency of occurrence of each time interval between the peak positions detected in a plurality of the unit-time intervals;
- when a frequency of occurrence for a time interval exceeds a value, reducing a frequency of occurrence for at least one time interval;
- identifying the tempo of the sound to be reproduced on a basis of a maximum one among all the accumulated frequencies of time interval occurrence;
- and
- displaying an image on an image display device corresponding to the identified tempo and not to a tempo identified using any autocorrelation calculation or beat structure analysis.
9 more elements
Dependencies are inferred from the claim text.