Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Electrical signal parameter measurement system
Reexamination Certificate
2002-07-10
2004-01-06
Assouad, Patrick (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Electrical signal parameter measurement system
C381S071140, C702S189000, C704S216000
Reexamination Certificate
active
06675114
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a system and a method for evaluating noise and sound, and more particularly, relates to a system and a method for evaluating noise and sound based on an autocorrelation function (hereinafter called “ACF”) and an interaural crosscorrelation function (hereinafter referred to as “IACF”).
The present invention also relates to a system and a method for measuring and subjectively evaluating environmental noise such as automobile noise and aircraft noise, and more particularly, relates to a system and a method for measuring and subjectively evaluating noise on the basis of a binaural system.
BACKGROUND ART
Environmental noise such as atrafic noise and aircraft noise has been discussed previously with a sound pressure level and its frequency characteristic measured by using a noise level meter in monaural. However, it has been recognized that only the physical factors measured by the noise level meter in monaural mentioned above could not express sufficiently and appropriately the subjective response of the human beings. In the field of concert hall acoustics, it has been revealed that physical data of the hall in a binaural system has relevance to psychological (subjective) evaluation, whereas, in the field of the research of environmental noise, only physical data such as spectrum information in the monaural system has been dealt with.
Up to now, in the music field, in order to tune instruments as well as to evaluate tone, at first sound spectrum has been analyzed, and then ceptsrum analyzing has been effected.
For many years, the environmental noise has been evaluated in terms of the statistical sound pressure level (SPL), represented as L
x
or L
eq
and its power spectrum measured by a monaural sound level meter. The SPL and power spectrum alone, however, do not provide a description that matches subjective evaluations of the environmental noise.
Also, it is difficult to express appropriately psychological responses to sound by the conventional method for evaluating timble and for tuning tone.
It is an object of the present invention to provide a system, a method and a storage media for identifying a category of a noise source by using physical factors derived from an autocorrelation function ACF which always changes in the time domain as well as from an interaural crosscorrelation function IACF of a binaural signal on the basis of the human auditory-brain system.
It is another object of the present invention to provide a system, a method and a storage media for subjectively evaluating more precisely timbre, scale, loudness, pitch, tone color, perception of duration, subjective diffuseness, apparent source width for the sound field by using physical factors derived from ACF and IACF which are ever changing in the time domain based on the human auditory brain function system.
SUMMARY OF THE INVENTION
In order to attain the above mentioned objects, a method for evaluating noise and sound according to the present invention comprises the steps of:
capturing the sound and converting the captured sound into an acoustic signal;
calculating an autocorrelation function ACF by processing the acoustic signal with the aid of a computing means;
calculating at least one autocorrelation function factor (ACF factor) from the calculated ACF with the aid of the computing means; and
evaluating the sound in accordance with said at least one ACF factor and a preestablished database with the aid of the computing means, said database storing at least one of the following data; tone data associating tones with ACF factors, prosodic data associating prosodic elements with ACF factors and subjective evaluation data associating subjective evaluation values with ACF factors.
According to the invention, the sound can objectively be evaluated by reading data from said preestablished database (storing data that associate various kinds of information of various musical instruments which have been evaluated to generate good sounds (scale values of, for instance, tone color, prosodic element, timbre and subjective diffuseness, scale values of apparent source width ASW and subjective evaluation values) with ACF factors and IACF factors); and by comparing the readout data with the ACF factor extracted from the acoustic signal of the target sound to derive a difference therebetween, numerical value of the difference or a degree of the difference. When the sound evaluating method according to the present invention is applied to manufacturing of musical instruments, adjustment of tone color or timbre and tuning of tonal scale, it is objectively and appropriately possible to attain an instrument which would be evaluated subjectively to have good tone color. Also, an instrument can objectively and appropriately be tuned. In other words, according to the invention, instruments which have been manufactured in accordance with craftsman's intuition could be manufactured in accordance with the objective data.
In an embodiment of the sound evaluating method according to the invention, said step of calculating at least one ACF factor comprises calculating at least one of the following ACF factors: energy &PHgr;(0) represented at the origin of the delay (i.e. delay time is zero); an effective duration &tgr;
e
; a delay time of a maximum peak &tgr;
1
; an amplitude of the maximum peak of the normalized ACF &phgr;
1
; and information of respective peaks within the delay time (from zero to &tgr;
1
) &tgr;
n
′, &phgr;
n
′ (n=1, 2, 3, . . . , N (N is an integer less than approximately 10)).
According to this embodiment, a musical instrument having a subjective evaluation denoting better tone color can be more objectively and more appropriately manufactured based on the various ACF factors mentioned above and the instrument is also more objectively and more appropriately tuned.
Another embodiment of the sound evaluating method according to the invention further comprises the steps of:
calculating a pitch frequency based on the delay time &tgr;
1
of the ACF; and
comparing the calculated pitch frequency with data of a predetermined tonal scale database to derive a difference therebetween to perform tuning.
According to this embodiment, under favor of the phenomenon such that an inverse number of the &tgr;
1
calculated from the sound signal correlates the pitch frequency, the musical scale of the intended instrument can appropriately be tuned. In this connection, it is possible that the predetermined tonal scale database may be superseded by the said predetermined database.
Another embodiment of the sound evaluating method according to the invention further comprises the steps of:
capturing the sound in a binaural manner and converting the captured sound into an acoustic binaural signal;
calculating an interaural crosscorrelation function IACF between left and right channels from the acoustic binaural signal with the aid of computing means;
calculating at least one interaural crosscorrelation function factors from the calculated interaural crosscorrelation function IACF with the aid of the computing means; and
evaluating the sound or evaluating subjectively the sound based on the IACF factors and/or the ACF factors and the said preestablished database with the aid of the computing means.
According this embodiment, the sound evaluation and the subjective sound evaluation can objectively and appropriately be accomplished by comparing evaluation values of spatial subjective sensations such as a subjective diffuseness extracted from the IACF with data stored read out of the database to derive differences between them.
The principal conception of the present invention may be realized not only as the method mentioned above but also as a system.
For instance, a sound evaluation system according to the invention comprises:
sound capturing means for capturing a sound and converting the captured sound into an acoustic signal;
ACF calculating means for calculating an autocorrelation function ACF from the acoustic signal;
ACF factor calculating means for calculating
Ando Yoichi
Sakai Hiroyuki
Assouad Patrick
Kobe University
Oliff & Berridg,e PLC
LandOfFree
Method for evaluating sound and system for carrying out the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for evaluating sound and system for carrying out the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for evaluating sound and system for carrying out the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3246285