Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Claas Derboven

Markus Kurt Cremer

Sebastian Streich

Markus Cremer

Martin Weis

Frank Streitenberger

The apparatus for converting an information signal from a time to a variable spectral representation includes a means for windowing the information signal, a means for converting the windowed information signal to a spectral representation, and a means for weighting a set of information signal spectral coefficients with several sets of complex base function coefficients provided from a means for providing the sets of base function coefficients. The sets of base function coefficients are derived from base functions of various frequencies by windowing and transform, wherein several sets of base function coefficients are provided for one and the same base function for base functions of higher frequencies, wherein the windows for providing these sets are related to various time portions of the base function. The variable spectral representation exhibits variable bandwidth of the variable spectral coefficients, which are efficient and accurate to calculate and especially suited for music analysis purposes.

Apparatus and method for converting an information signal to a spectral representation with variable resolution

An apparatus for determining a type of chord has a means for providing a reference vector for the type of chord, a means for providing a reference vector from a test signal, and a means for comparing the reference vector with the test signal vector. The means for providing a reference vector is configured to provide, for the type of chord, a reference vector from a plurality of different reference vectors. In addition, the means for providing a test signal vector from the test signal is configured to provide the test signal vector having a plurality of test signal vector elements. In addition, the means for comparing the reference vector with the test signal vector is configured to compare the reference vector and the test vector or versions of the test signal vector which are cyclically shifted by different shift values, in order to obtain various comparison results which are allocated to the test signal vector or shift values, so as to determine the type of chord on the basis of an extreme comparison result and the shift value associated with same.

Apparatus and method for determining a type of chord underlying a test signal

A tone smoothing is performed such that to each time section of a melody line segment a number is associated such that for all groups of directly neighboring time sections, to which the same spectral component is associated by the melody line segment, the numbers associated with the directly neighboring time sections are different numbers from one to the number of the directly neighboring time sections, for each spectral component that is associated with one of the time sections of the melody line segment, the numbers of those groups are added up to which time sections of the same the respective spectral component is associated by the melody line segment, a smoothing spectral component is determined as the spectral component for which the greatest summing-up results, and the melody line segment is changed, by associating the determined smoothing spectral component to each time section of the melody line segment. By this, in particular the inadequacy of monophonic audio signals is considered, usually comprising a transient process at beginnings of notes, so that only to the end of the notes the desired note pitch is achieved.

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Ilmenau, Germany

Claas Derboven