CN103369428A - Detection and estimation method for background subtraction of environment noise - Google Patents
Detection and estimation method for background subtraction of environment noise Download PDFInfo
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- CN103369428A CN103369428A CN2013102346762A CN201310234676A CN103369428A CN 103369428 A CN103369428 A CN 103369428A CN 2013102346762 A CN2013102346762 A CN 2013102346762A CN 201310234676 A CN201310234676 A CN 201310234676A CN 103369428 A CN103369428 A CN 103369428A
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Abstract
The invention discloses a detection and estimation method for background subtraction of environment noise, relates to the technical field of environment noise detection, and aims to overcome the technical defects of complex means and devices, large light power loss, low sensitivity and high construction cost of the existing band-pass audio filtering optical fiber microphone. The method comprises the steps of performing synchronous collecting on two microphones with the same model according to the frequency range of the detected noise, wherein one microphone is packaged by a sound adsorption material to be isolated from the high frequency in the external environment and used as a low-frequency signal background, and the other microphone is directly communicated with the external environment to collect a full-frequency band sound signal; and using a processor to subtract the low-frequency signal in the full-frequency band sound signal to realize the detection on the intensity of high-frequency noise. The detection and estimation method for the background subtraction of the environment noise solves the technical problems of complex means and devices, large light power loss, low sensitivity and high construction cost of the existing band-pass audio filtering optical fiber microphone.
Description
Technical field
The present invention relates to a kind of ambient noise background subtraction and detect and method of estimation, belong to the industrial measurement and control technology, the environment noise test technical field.
Background technology
Noise pollution is the fourth-largest environmental hazard after air pollution, water pollution and solid waste pollution, is occupied the first place of all kinds of environmental pollutions complaint events by the complaint event number of its initiation, serious threat people's normal operation, life and healthy always; The implementation environment noise measuring is to hold the noise pollution present situation, carries out the basic demand of ambient noise scientific and effective control.
Microphone is a kind of energy transducer that voice signal is converted to the signal of telecommunication, is divided into resistance-type, inductance type, electrostatic, piezoelectric type Four types in the transducing mode; The carbon electrode microphone is the earliest way of realization of resistance-type microphone, utilizes the mode of resistance transducing, and principle is to utilize carbon Contact resistance changed by the acoustic pressure effect, obtains the signal of telecommunication of respective change with this; After 20th century, along with the development of sensor technology, inductance and electrostatic transducing components and parts have replaced the main transducing tie that resistance becomes microphone; Utilize the inductance phenomenon, and derived moving-coil type and aluminium band type two class microphones on the basis of inductance principle; It is voice coil loudspeaker voice coil that moving-coil microphone adopts enamelled wire usually, link to each other with microphone diaphragm back, hang in the magnetic field, when being subject to extraneous acoustic pressure effect, diaphragm produces vibration, can drive simultaneously the voice coil loudspeaker voice coil vibration and do cutting magnetic line movement in magnetic field, the induced electromotive force that this moment, voice coil loudspeaker voice coil wire two ends produced is identical with the sound source sound that causes the vibration of microphone diaphragm; Tape microphone was developed in early 1930s, it has identical electromagnetic principle with moving-coil microphone, different is, aluminium strip namely is the diaphragm of microphone, is again the voice coil loudspeaker voice coil that moves in magnetic field, is usually formed by the aluminium foil manufacturing, has good transient response ability, quite responsive to various wind noises or mechanical conductive noise, very easily cause the infringement of microphone diaphragm, thereby unsuitable outdoor application; Condenser microphone is a kind of of electrostatic microphone, usually formed by electric capacity transducing components and parts and prime amplifier two parts, the movable part of condenser microphone is the frivolous vibrating diaphragm of a slice, simultaneously also be (another is the microphone backplane) in two electrodes of capacitor, when vibrating diaphragm during along with acoustic vibration, capacitance stored between electric capacity also changes, and will obtain the alternating voltage with sound pressure variations at the two ends of load resistance, finishes the process of acoustic-electric conversion; Electret microphone is the another kind of electrostatic microphone, and the phenomenon that electret claims again " electret " to utilize dielectric can obtain electret under the effect of highfield is made; Operation principle and the condenser microphone of electret microphone are similar, its vibrating diaphragm and backplane have used the electret material that can possess permanent charge to make as material, this class microphone does not need the capacitor power supply, and having saved provides the polarizing voltage of cartridge work power supply; The material that piezoelectric microphone utilizes some to have piezoelectric effect is made, and crystal formula, ceramic-type and high polymer formula etc. are arranged; Take crystal formula microphone as example, when a certain amount of lattice
30Occur, crystal produces distortion by mechanism, and crystal just face produces electric charge, realizes the conversion of acoustic energy; In recent years, after optical-fibre communications succeeded, fiber microphone occurred, it is a kind of optical signalling that the acoustic vibration signal is converted to modulation, and by Optical Fiber Transmission, the light signal of modulation is demodulated to the device of the signal of telecommunication again; Fiber microphone mainly contains based on the Y type microphone of reflecting film structure and interfere type microphone.
Patent " Zhang Faxiang; Zhang Wentao; Li Fang etc. have the fiber microphone ［ P ］ of the logical sound of band filter function. China: 201110067714.0 " a kind of fiber microphone with the logical sound of band filter function is disclosed, comprising: cylinder, as the main body of this fiber microphone; Be installed on the diaphragm in the cylinder, deformation occurs when being used for existing acoustic pressure poor in both sides; Be installed in respectively the first dividing plate and the second partition of diaphragm both sides, the high frequency sound signal that is respectively applied to filter different frequency range makes the diaphragm both sides exist acoustic pressure poor; Be installed on the axis and the sensor fibre that is connected with diaphragm, be used for the deformation of perception diaphragm; Open the first sound penetrating hole and the second sound penetrating hole on the sidewall at cylinder two ends, be used for sound wave is entered in the cylinder; Open in the first filtering hole on the dividing plate and open the second filtering hole on dividing plate, be used for making dividing plate to have the function of filtering high frequency sound wave; And open the first tail optical fiber hole and the second tail optical fiber hole in the cylinder two ends, be used for drawing and the fixing tail optical fiber of sensing light; The upper and lower bound of the mode change sound frequency filtering that changes filtering bore dia and length is adopted in this invention, makes fiber microphone only responsive to the acoustical signal of characteristic frequency, has realized band-pass filtering function.
Although existing fiber microphone can realize being with logical sound filter function, only responsive to the acoustical signal in the characteristic frequency band, but present fiber microphone is very high to reflectivity and the elastic membrane quality requirement of reflectance coating, exist measurement means and device complicated, optical power loss is large, the technical problem that sensitivity is low and cost is high.
Summary of the invention
Complicated with device in order to overcome the logical sound of existing band filtering fiber microphone measurement means, optical power loss is large, the technological deficiency that sensitivity is low and cost is high, the invention provides a kind of ambient noise background subtraction detects and method of estimation, the method is according to the frequency range of detection noise, two same model microphones are carried out synchronous acquisition, one of them microphone adopts sound-absorbing material to seal and extraneous high-frequency isolation, as the low frequency signal background, another road microphone directly communicates with external environment and gathers the full frequency band voice signal, processor is to the low frequency signal background subtraction in the full frequency band voice signal, realize the detection of high-frequency noise intensity, solved the logical sound of existing band filtering fiber microphone measurement means complicated with device, optical power loss is large, the technical problem that sensitivity is low and cost is high.
The technical solution adopted for the present invention to solve the technical problems: a kind of ambient noise background subtraction detects and method of estimation, has following characteristics:
(1) selects two same model microphones, the porous material composite construction that adopts high frequency to absorb sound is sealed with external environment a microphone and is carried out high-frequency isolation, another microphone directly communicates with external environment without any frequency range isolation, by two microphone signals of two-way same model A/D synchronous acquisition;
(2) processor is by carrying out respectively power spectrum statistical computation noise intensity to two-way A/D signal, and the two-way noise intensity carried out difference, with the low frequency signal background subtraction in the microphone A/D collection signal that directly communicates with external environment, do not comprised the high-frequency noise intensity of external environment low-frequency noise;
(3) determine that according to the frequency range of detection noise carrying out the high-frequency isolation microphone with external environment seals the surface density of sound-absorbing material, aperture, porosity, thickness and composite construction.
The invention has the beneficial effects as follows: according to the frequency range of detection noise, two same model microphones are carried out synchronous acquisition, one of them microphone adopts sound-absorbing material to seal and extraneous high-frequency isolation, as the low frequency signal background, another road microphone directly communicates with external environment and gathers the full frequency band voice signal, processor is to the low frequency signal background subtraction in the full frequency band voice signal, realize the detection of high-frequency noise intensity, solved the logical sound of existing band filtering fiber microphone measurement means complicated with device, optical power loss is large, the technical problem that sensitivity is low and cost is high.
Below in conjunction with drawings and Examples the present invention is elaborated.
Description of drawings
Fig. 1 is the overall construction drawing of ambient noise background subtraction detection of the present invention and method of estimation;
Fig. 2 is the specific embodiment schematic diagram of ambient noise background subtraction detection of the present invention and method of estimation;
Fig. 3 be in the specific embodiment of the invention with the structure chart of external environment high-frequency isolation microphone, wherein 301 is the microphone schematic diagram, 302 for carrying out the sound-absorbing material of sealing of high-frequency isolation with external environment;
Fig. 4 is microphone outer envelope material structure figure, wherein L in the specific embodiment of the invention
sBe the thickness of porous metals, L
cThickness for cavity (air backing).
Embodiment
With reference to Fig. 2-Fig. 4.
(1) the single chip computer AT 89C52 chip of the processor adopting atmel corp of specific embodiment of the invention production, adopt 16 AD7655 to finish the synchronous acquisition of two-way microphone audio frequency signal, be used in two same model microphones with external environment carry out high-frequency isolation the microphone outside seal the porous material composite construction that sound-absorbing material is selected the high frequency sound absorption, AD7655 has two-way sampling and holding circuit, allow two-way microphone signal synchronized sampling, can guarantee the synchronous of two-way microphone signal sampling, AD7655 carries out Collect conversion according to the sample rate of 1MHz to voice signal and becomes 16 position digital signals, and single chip computer AT 89C52 reads respectively synchronization two-way A/D signal by P0 mouth and P1 mouth;
(2) single chip computer AT 89C52 carries out respectively power spectrum statistical computation noise intensity by the two-way A/D signal to synchronous acquisition, obtains external environment low-frequency noise intensity B
1With external environment noise intensity B
2, the two-way noise intensity is proportionally subtracted each other formula: B=k
1B
2-k
2B
1Obtain the high-frequency noise intensity B in the external environment, wherein k
1And k
2Be proportionality coefficient, k
1And k
2According to external environment noise intensity B
2In contain low-frequency noise intensity B
1Size determine;
(3) with reference to accompanying drawing 3, in the specific embodiment of the invention with external environment high-frequency isolation microphone construction figure, microphone 301 and outer envelope sound-absorbing material 302 are configured for detecting the new microphone of external environment low-frequency sound signal background jointly, the described porous metals composite structural design of sealing sound-absorbing material 302 employing high frequency sound absorptions, can be in the noise measuring process, realize filtering the function of high frequency noise, with reference to accompanying drawing 4 microphone outer envelope material structure figure, the composite construction of porous metals is by rigidity backing (selecting metallic plate), cavity (air backing) enough becomes with porous metallic layers (selecting the foamed aluminium metallic plate) three parts, the thickness of rigidity backing (0.5-1mm) and porous metallic layers (20-40mm) is determined, by regulating the thickness (L of cavity
c) realize the sound absorption function to different detection noise frequency ranges, in the detection of high frequency, set the thickness (L of cavity
c=0).
Claims (1)
1. an ambient noise background subtraction detects and method of estimation, has following characteristics:
(1) selects two same model microphones, the porous material composite construction that adopts high frequency to absorb sound is sealed with external environment a microphone and is carried out high-frequency isolation, another microphone directly communicates with external environment without any frequency range isolation, by two microphone signals of two-way same model A/D synchronous acquisition;
(2) processor is by carrying out respectively power spectrum statistical computation noise intensity to two-way A/D signal, and the two-way noise intensity carried out difference, with the low frequency signal background subtraction in the microphone A/D collection signal that directly communicates with external environment, do not comprised the high-frequency noise intensity of external environment low-frequency noise;
(3) determine that according to the frequency range of detection noise carrying out the high-frequency isolation microphone with external environment seals the surface density of sound-absorbing material, aperture, porosity, thickness and composite construction.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107169970A (en) * | 2017-05-13 | 2017-09-15 | 西安费斯达自动化工程有限公司 | Panoramic picture/precise image/spherical crown electret chirm integrative detection system |
| CN110970052A (en) * | 2019-12-31 | 2020-04-07 | 歌尔科技有限公司 | Noise reduction method and device, head-mounted display equipment and readable storage medium |
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| US5398286A (en) * | 1991-01-11 | 1995-03-14 | Booz-Allen & Hamilton, Inc. | System for enhancing an analog signal |
| CN2429985Y (en) * | 2000-06-09 | 2001-05-09 | 程滋颐 | Open active noiseless microphone |
| CN1350747A (en) * | 2000-01-13 | 2002-05-22 | 皇家菲利浦电子有限公司 | Noise reduction |
| CN101685630A (en) * | 2009-06-30 | 2010-03-31 | 广州华纸节能科技有限公司 | Anti-noise fiber material cushion and preparation method thereof |
| CN101848288A (en) * | 2010-04-19 | 2010-09-29 | 北京东微世纪科技有限公司 | Simulation noise reduction system and method for microphone |
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4672674A (en) * | 1982-01-27 | 1987-06-09 | Clough Patrick V F | Communications systems |
| US5398286A (en) * | 1991-01-11 | 1995-03-14 | Booz-Allen & Hamilton, Inc. | System for enhancing an analog signal |
| CN1350747A (en) * | 2000-01-13 | 2002-05-22 | 皇家菲利浦电子有限公司 | Noise reduction |
| CN2429985Y (en) * | 2000-06-09 | 2001-05-09 | 程滋颐 | Open active noiseless microphone |
| CN101685630A (en) * | 2009-06-30 | 2010-03-31 | 广州华纸节能科技有限公司 | Anti-noise fiber material cushion and preparation method thereof |
| CN101848288A (en) * | 2010-04-19 | 2010-09-29 | 北京东微世纪科技有限公司 | Simulation noise reduction system and method for microphone |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107169970A (en) * | 2017-05-13 | 2017-09-15 | 西安费斯达自动化工程有限公司 | Panoramic picture/precise image/spherical crown electret chirm integrative detection system |
| CN107169970B (en) * | 2017-05-13 | 2020-09-29 | 西安费斯达自动化工程有限公司 | Integrated automatic monitoring and tracking method for bird song of panoramic image, accurate image and spherical crown electret |
| CN110970052A (en) * | 2019-12-31 | 2020-04-07 | 歌尔科技有限公司 | Noise reduction method and device, head-mounted display equipment and readable storage medium |
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Application publication date: 20131023 |