WO2002082106A1 - Procede et dispositif d'analyse d'un signal audio numerique - Google Patents
Procede et dispositif d'analyse d'un signal audio numerique Download PDFInfo
- Publication number
- WO2002082106A1 WO2002082106A1 PCT/FR2002/001107 FR0201107W WO02082106A1 WO 2002082106 A1 WO2002082106 A1 WO 2002082106A1 FR 0201107 W FR0201107 W FR 0201107W WO 02082106 A1 WO02082106 A1 WO 02082106A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- frequency
- digital audio
- audio signal
- filter
- signal
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/16—Spectrum analysis; Fourier analysis
- G01R23/165—Spectrum analysis; Fourier analysis using filters
- G01R23/167—Spectrum analysis; Fourier analysis using filters with digital filters
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H17/00—Networks using digital techniques
- H03H17/02—Frequency selective networks
- H03H17/0248—Filters characterised by a particular frequency response or filtering method
- H03H17/0264—Filter sets with mutual related characteristics
- H03H17/0266—Filter banks
Definitions
- the present invention relates to a method and a device for the analysis of a digital audio signal usable for the recognition of musical notes present in a sound, audio or musical signal.
- Document FR-A-2,648,566 discloses a method and a device for measuring frequency peaks contained in the spectrum of an analog signal, by threshold comparator.
- the instants of passage of the signal are determined and stored by a given threshold value using a threshold comparator, a clock and a random access memory.
- the location of the frequency peaks contained in the spectrum of the analyzed signal is determined.
- a filter bank is produced for a very wide frequency range, for example a bandwidth of a octave or higher.
- Music notes are located by detecting their frequency, using the so-called PITCH TRACKING method.
- This technique has the problem of having a low reliability in particular by the fact that the additional step of PITCH TRACKING is present.
- the present invention overcomes the drawbacks of the techniques known up to now, and has the advantage for this of presenting a method and a device provided with high reliability.
- Another advantage of the invention is to be adaptable to any type of musical instrument, since the frequency range to be analyzed can be adapted according to the range of the instrument. This implementation is also done in real time.
- the present invention relates to a method for analyzing a digital audio signal usable for recognizing musical notes present in a sound, audio or musical signal, characterized by the fact that: - filters with bandwidth widths are created distinct, each corresponding to a frequency interval including the frequency of a single musical note to be recognized, the whole covering the frequency range to be analyzed;
- the digital audio signal is filtered using the filters created organized in a bank to break down the digital audio signal into as many output signals as there are filters present in the bank, each of the output signals corresponding to a musical note to be recognized in order to project the digital audio signal in a time-frequency basis.
- each filter corresponds to a frequency interval symmetrical with the frequency of the musical note to be recognized.
- a preliminary filtering of the digital audio signal is carried out by a finite impulse response filter - a digital audio signal is sub-sampled to reduce its bit rate, the sub-sampling being a function of the frequency range to be analyzed.
- the digital audio signal is obtained by acquisition of a sound signal by microphone and sampling.
- the group time of each filter is compensated by a pure delay filter of suitable value.
- the invention also relates to a device for analyzing a digital audio signal usable for recognizing musical notes present in a sound, audio or musical signal, characterized in that it comprises a bank of filters in each of which the digital audio signal is injected at the input, said filters having different bandwidths but covering the entire frequency range to be analyzed, each bandwidth including the frequency of a single musical note, to decompose the audio signal digital in as many output signals as musical notes to be recognized, in order to carry out a projection of the digital audio signal in a time-frequency basis.
- It includes a quantizer for determining the width of the passband of each filter in the bench so that each filter corresponds to one and only one musical note.
- the quantizer is made up of means for calculating the frequency of each musical note in the frequency range to be analyzed and frequency thresholds separating two consecutive notes to assign to each filter a bandwidth between two consecutive frequency thresholds and including the frequency of a note
- the subsampler for the prior reduction of the audio-digital signal bit rate, the subsampling being a function of the frequency range to be analyzed,
- Figure 1 is a block diagram of the device according to the invention in a particular embodiment.
- FIG. 2 illustrates the distribution of the passbands of the bank filters in the frequency range to be analyzed.
- FIG. 3 shows the frequency representation of the filtering device according to the invention.
- FIG. 4 shows an example of an audio signal evolving over time, then, successively, two output signals corresponding to two filtering channels each revealing a musical note.
- the method according to the invention begins with an acquisition of a sound signal A by means of a microphone 1, then with a digitization of the audio electrical signal B thus obtained by means of a sampler 2 .
- the sampler 2 delivers a digital audio signal C.
- the digital signal C can be obtained from other sources and in particular from a compact digital disk, a computer file or any other source. .
- sampling frequency of sampler 2 may be the standard frequency for audio compact discs, that is to say 44.1 kHz.
- the digital audio signal C is then filtered using a finite impulse response filter constituting anti-aliasing filtering (known by the term anti-aliasing).
- This first processing of the signal C is followed by the filter 3 by a sub-sampling at the level of a sub-sampler marked 4 in FIG. 1.
- sub-sampling is to reduce the bit rate of the signal to be processed and its parameters depend on the range of the musical instrument or the range of frequencies to be analyzed, in order to respect the frequency of NYQUIST.
- the impulse response of filter 3 depends on the sub-sampling rate used, and therefore on the range of frequencies to be analyzed.
- E is called the signal coming from the sub-sampler 4 which is the working signal usable for the step of filtering by filter bank which will be described below.
- the working signal E is then processed by a filter bank 5 composed by a plurality of filters 7 whose bandwidth is distinct and predetermined, and adapted to cover the entire frequency range to be analyzed.
- the frequency range to be analyzed corresponds to the range of the instrument.
- the passband widths of each filter 7 they are determined to include the frequency fi of a note without interfering with the frequency of other notes.
- each filter 7 is associated with a note in the frequency range to be analyzed.
- the working signal E is decomposed or projected through the filter bank 5, in order to obtain output signals Fi each revealing the time and frequency location of a musical note.
- each filter 7 is important and is achieved by determining the order of each of the filters 7.
- the bandwidth of each filter 7 is determined by a chromatic quantizer 6 capable of fixing the terminals of the bandwidth of the filter 7.
- the bandwidth of a filter 7 includes the frequency fi of the musical note associated with it. It is constructed by a quarter-tone interval on either side of the frequency fi for recognition of 12 notes per octave. More specifically, Figure 2 gives an illustration of bandwidths as a function of frequency.
- the thresholds of each filter are determined by arithmetic mean of the frequencies of two successive notes.
- the thresholds are then defined by: fi + fi + l
- y ⁇ is a threshold of rank i and fj and f i + 1 the frequencies of two successive notes of rank i and i + 1.
- the quantizer determines the thresholds up to the maximum frequency of the frequency range to be analyzed.
- These two octaves include 24 notes requiring the calculation of the parameters of 24 filters whose bandwidths are obtained by the chromatic quantizer 6.
- the filters 7 are CHEBYCHEV type I filters of order 10.
- the order of the filter is adapted as a function of the instrument and of the sub-sampling rate.
- This type of filter is by analog origin and it is therefore necessary to calculate its digital equivalent for a software implementation, which does not exclude 0 a hardware implementation.
- the index j indicates the channel number, that is to say the note to be analyzed and a and b are the coefficients of the filters.
- a decomposition of the digital audio signal C is obtained into a wavelet packet, each channel obtained corresponding to a musical note.
- This delay compensation is carried out by means of a delay compensator filter 80 positioned after the filter bank 5.
- the value of the pure delay filter 8 corresponding to each filter 7 is determined as a function of the theoretical group time of the filter 7.
- FIG. 3 An example of frequency representation of the device according to the invention is given in FIG. 3.
- the first graph is an illustration of the evolution of the amplitude of the signal (in decibel) as a function of frequency.
- the second graph is an illustration of the evolution of the phase (in degrees) as a function of frequency.
- the number and the parameters of the filters 7 are adapted to the frequency range to be analyzed.
Landscapes
- Physics & Mathematics (AREA)
- Mathematical Physics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Peptides Or Proteins (AREA)
- Auxiliary Devices For Music (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP02720088A EP1373908A1 (fr) | 2001-04-05 | 2002-03-29 | Procede et dispositif d'analyse d'un signal audio numerique |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR0104619A FR2823386B1 (fr) | 2001-04-05 | 2001-04-05 | Procede et dispositif d'analyse d'un signal audio numerique |
FR01/04619 | 2001-04-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2002082106A1 true WO2002082106A1 (fr) | 2002-10-17 |
Family
ID=8861966
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR2002/001107 WO2002082106A1 (fr) | 2001-04-05 | 2002-03-29 | Procede et dispositif d'analyse d'un signal audio numerique |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1373908A1 (fr) |
FR (1) | FR2823386B1 (fr) |
WO (1) | WO2002082106A1 (fr) |
-
2001
- 2001-04-05 FR FR0104619A patent/FR2823386B1/fr not_active Expired - Lifetime
-
2002
- 2002-03-29 EP EP02720088A patent/EP1373908A1/fr not_active Withdrawn
- 2002-03-29 WO PCT/FR2002/001107 patent/WO2002082106A1/fr not_active Application Discontinuation
Non-Patent Citations (2)
Title |
---|
FERNANDEZ-CID ET AL: "Multi-pitch estimation for polyphonic musical signals", ACOUSTICS, SPEECH AND SIGNAL PROCESSING, 1998. PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL CONFERENCE ON SEATTLE, WA, USA 12-15 MAY 1998, NEW YORK, NY, USA,IEEE, US, 12 May 1998 (1998-05-12), pages 3565 - 3568, XP010279575, ISBN: 0-7803-4428-6 * |
KUHN W B: "A REAL-TIME PITCH RECOGNITION ALGORITHM FOR MUSIC APPLICATIONS", COMPUTER MUSIC JOURNAL, CAMBRIDGE, MA, US, vol. 14, no. 3, 1990, pages 60 - 71, XP000783866 * |
Also Published As
Publication number | Publication date |
---|---|
FR2823386A1 (fr) | 2002-10-11 |
FR2823386B1 (fr) | 2003-08-08 |
EP1373908A1 (fr) | 2004-01-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0103257B1 (fr) | Procédé et dispositifs d'atténuation de bruits parasites | |
BE1019445A3 (fr) | Procede d'extraction d'information audio. | |
CA2266654C (fr) | Procede et dispositif d'egalisation aveugle des effets d'un canal de transmission sur un signal de parole numerique | |
EP3238210B1 (fr) | Procede de traitement et d'analyse d'un signal, et dispositif mettant en oeuvre ledit procede | |
EP3899701B1 (fr) | Mesure temporelle a haute precision d'evenements vibro-acoustiques en synchronisation avec un signal sonore sur dispositif a ecran tactile | |
CA1225745A (fr) | Procede et installation d'analyse et de restitution de signal a echantillonnage et interpolation | |
EP0312463B1 (fr) | Dispositif de filtrage numérique, et radar comportant un tel dispositif | |
EP1782536B1 (fr) | Procede de generation d'un signal numerique representatif des erreurs d'appariement d'un systeme de conversion analogique numerique a entrelacement temporel, et un convertisseur analogique numerique a entrelacement temporel l'utilisant | |
EP1373908A1 (fr) | Procede et dispositif d'analyse d'un signal audio numerique | |
EP0616315A1 (fr) | Dispositif de codage et de décodage numérique de la parole, procédé d'exploration d'un dictionnaire pseudo-logarithmique de délais LTP, et procédé d'analyse LTP | |
EP0989544A1 (fr) | Dispositif et procédé de filtrage d'un signal de parole, récepteur et système de communications téléphonique | |
EP0821345B1 (fr) | Procédé d'extraction de la fréquence fondamentale d'un signal de parole | |
EP1459214B1 (fr) | Procede de caracterisation d un signal sonore | |
WO2013053631A1 (fr) | Procédé et dispositif pour séparer des signaux par filtrage spatial itératif | |
EP2901447B1 (fr) | Procédé et dispositif pour séparer des signaux par filtrage spatial à variance minimum sous contrainte linéaire | |
EP0740414A1 (fr) | Dispositif de retard programmable d'un signal analogique et antenne acoustique programmable correspondante | |
EP0140396A1 (fr) | Procédé et dispositif de reconstitution d'un signal analogique | |
FR2478355A1 (fr) | Analyseur de spectre notamment pour reconnaissance de la parole dans un appareil telephonique commande par la voix | |
WO2022263773A1 (fr) | Procédé/dispositif pour la validation d'un titre de transport basé sur une localisation d'un utilisateur relativement à un premier porteur d'un premier moyen d'acquisition | |
CN117935851A (zh) | 一种声音信号分离方法、系统、介质及设备 | |
BE1020218A3 (fr) | Procede pour ameliorer la resolution temporelle des informations fournies par un filtre compose et dispositif correspondant. | |
FR3032553A1 (fr) | Procede de generation d'une empreinte audio reduite a partir d'un signal sonore et procede d'identification d'un signal sonore en utilisant une telle empreinte audio reduite | |
FR2561808A1 (fr) | Procede et systeme de traitement de signal visant a l'extraction d'une information phonematique et filtre de phase lineaire | |
WO2002082424A1 (fr) | Procede et dispositif d'extraction de parametres acoustiques d'un signal vocal | |
EP1233521A1 (fr) | Procédé de synchronisation d'un signal d'horloge avec un signal de référence |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VN YU ZA ZM ZW |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 2002720088 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 2002720088 Country of ref document: EP |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
NENP | Non-entry into the national phase |
Ref country code: JP |
|
WWW | Wipo information: withdrawn in national office |
Country of ref document: JP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 2002720088 Country of ref document: EP |