本文關鍵詞：基于水聽器空間平均效應修正的高頻聲場定征方法研究　出處：《哈爾濱工業(yè)大學》2017年博士論文　論文類型：學位論文

  更多相關文章： 空間平均效應 高頻水聽器校準 高頻聲功率 聲鑷輻射力

【摘要】：高頻聲場定征是先進醫(yī)療設備戰(zhàn)略新興產(chǎn)業(yè)發(fā)展的需要,水聽器是用于水聲聲壓探測的換能器件,廣泛應用于超聲醫(yī)療診斷設備的聲場測量。隨著高頻超聲醫(yī)療診斷設備應用中分辨率的提高和安全性指標的發(fā)展,對高頻聲場中聲壓、聲功率及輻射力的測量精度、測量頻率范圍提出了越來越高的要求。根據(jù)超聲醫(yī)療發(fā)展的要求,超聲頻率需至少達到幾十兆赫茲量級。隨頻率升高所需水聽器孔徑越小,需達到微米量級,進一步造成聲壓靈敏度降低和制作工藝難度的提高;而隨著頻率的升高,聲功率越微弱,接近現(xiàn)有溯源方法的本底噪聲無法計量輻射力,這對利用水聽器進行高頻聲場定征提出了新的挑戰(zhàn)。本課題“基于水聽器空間平均效應修正的高頻聲場定征方法研究”,在分析水聽器孔徑空間平均效應修正和聲壓靈敏度校準方法的基礎上,研究了高頻聲場中聲功率、輻射力定量方法,本文的主要工作如下:針對高頻聲場中水聽器孔徑空間平均效應引起聲壓低估愈發(fā)嚴重,而現(xiàn)有聲場定征修正模型不完善的問題,本文提出一種基于瑞利積分-菲涅爾近似的空間平均效應評估方法。該方法利用瑞利積分描述換能器輻射聲壓,通過在水聽器有效孔徑上積分,采用級數(shù)展開和菲涅耳近似得到水聽器空間平均作用下的聲壓解析解,并逐次分析了平面活塞換能器聲軸、垂直于聲軸平面上以及聚焦換能器聲軸、焦平面內的空間平均效應對聲壓、聲束寬度的影響。在此基礎上,將研究結果拓展至衰減介質中水聽器的空間平均效應分析,并對菲涅耳近似和聚焦聲場中瑞利積分聲壓表示的有效區(qū)間進行了討論。從而解決了高頻聲場探測中水聽器的孔徑空間平均效應修正模型不完善的問題,為實現(xiàn)動態(tài)位置反饋的高頻聲壓、聲束寬度的精密測量奠定基礎。針對水聽器聲壓靈敏度校準水環(huán)境中低頻大位移振動造成零差干涉校準系統(tǒng)工作點漂移引起信號衰落,無法穩(wěn)定開展40 MHz以上聲壓靈敏度校準的問題,本文提出一種基于外差干涉測量原理的水聽器校準方法。該方法在綜合分析了干涉儀中非線性誤差抑制、光電接收器頻率響應校準以及諧波場中水聽器空間平均效應修正等不確定度分量的基礎上,采用高頻聲光調制器進行光波移頻,對載波信號高速數(shù)據(jù)采樣后進行數(shù)字正交解調,避免了零差干涉校準中工作點漂移和鎖相反饋電路易振蕩的問題,將聲壓靈敏度校準頻率上限拓展至60MHz。該水聽器校準方法首先分析了水中質點振速與聲壓重建原理,揭示了質點振動位移/速度與聲壓之間的函數(shù)關系。然后對薄膜隨聲波運動跟隨性進行分析,建立薄膜厚度與聲壓衰減之間嚴格的數(shù)學模型,以修正薄膜厚度對各頻率點下聲壓測量的影響。將透聲反光薄膜放置于水面,利用外差干涉儀測量薄膜振動位移以復現(xiàn)水聲聲壓,該結構避免了聲光共路過程中聲光干涉效應的影響。針對微弱劑量高頻超聲功率接近現(xiàn)有測量方法本底噪聲,聲場參數(shù)中聲功率及輻射力缺乏有效計量手段的問題,本文在實現(xiàn)水聽器空間平均效應修正和聲壓靈敏度校準的基礎上,提出一種基于動態(tài)位置反饋的水聽器平面掃描聲功率測量和建模結合的輻射力評估方法。該方法首先應用外差干涉儀對水聽器進行聲壓靈敏度校準,考慮水聽器空間平均效應修正,利用射線聲學方法構建微粒在高頻聚焦聲場(單波束聲鑷)中三維受力模型,通過搭建聲場掃描裝置實測聲功率和聲束寬度,并將其帶入輻射力模型,解決了高頻聲場中聲功率和輻射力定量難題。在上述研究的基礎上,本文設計和搭建了聲場平面掃描系統(tǒng)和水聽器聲壓靈敏度外差干涉校準系統(tǒng),包括聲光移頻外差干涉儀、載波信號解調系統(tǒng)、光電二極管幅頻響應校準等單元,并在此基礎上對空間平均效應修正模型、水聽器聲壓靈敏度校準及聲功率測量等環(huán)節(jié)進行了實驗測試與分析。測試結果與分析表明,搭建的水聽器聲壓靈敏度外差干涉校準系統(tǒng)校準頻率上限高達60MHz,擴展不確定度優(yōu)于9.8%;搭建的聲場平面掃描系統(tǒng)聲束寬度測量分辨率可達0.1μm,在水聽器聲壓靈敏度校準頻率60 MHz范圍內開展聲功率測量,測量功率下限小于1 m W,可實現(xiàn)n N量級的輻射力定量研究。
[Abstract]:High frequency sound field identification is the need for the development of advanced medical equipment and strategic emerging industries. Hydrophone is a transducer for underwater acoustic pressure detection, and is widely applied to acoustic measurement of ultrasonic medical diagnostic equipment. With the improvement of the resolution and the development of safety index in the application of high frequency ultrasound medical diagnostic equipment, the measurement accuracy and frequency range of sound pressure, sound power and radiation force in high frequency sound field are increasingly demanding. According to the requirements of ultrasonic medical development, the ultrasonic frequency needs to be at least tens of megahertz orders. The hydrophone aperture is smaller with increasing frequency, required to achieve micron level, further decrease the difficulty of production technology and the pressure sensitivity increased; and with the increase of frequency, the sound power is weak, close to the existing tracing method is the background noise to measure radiation, the high frequency sound field characteristic has brought new challenges to the use of hydrophone. The sign method of "high frequency sound field hydrophone based on the effect of spatial average correction, based on the analysis of pore space average hydrophone effect correction and pressure sensitivity calibration method, study the quantitative methods of radiation acoustic power, high frequency sound field, the main work is as follows: according to the high frequency sound field space hydrophone aperture averaging effect the pressure caused by underestimation is increasingly serious, and the existing acoustic characterization of modified model problems, this paper puts forward a method for evaluating the Finel approximate Rayleigh integral - space based on average effect. The method described by Rayleigh integral transducer radiation pressure, the effective aperture integral in hydrophone, using Fresnel series expansion and approximate solution of pressure hydrophone under the action of analytical space averaging, and the successive analysis of plane piston transducer acoustic axis, perpendicular to the acoustic axis plane and focusing transducer axis and the focal plane space average the effect of sound pressure and sound beam width. Based on that, we extend the research results to the spatial mean effect analysis of the hydrophone in the attenuation medium, and discuss the effective interval between the Fresnel approximation and the Rayleigh integral acoustic pressure representation in the focused acoustic field. It solves the problem that the correction model of the aperture spatial mean effect of hydrophone is not perfect in the high frequency acoustic field detection, and lays the foundation for the precise measurement of the high frequency sound pressure and the beam width of the dynamic position feedback. For the low frequency acoustic pressure sensitivity of hydrophone calibration in the water environment caused by large displacement vibration calibration system working point zero differential interference drift caused by signal fading, unable to carry out more than 40 MHz stable pressure sensitivity calibration problem, this paper presents a calibration method of hydrophone heterodyne interferometry principle based on water. The method in the comprehensive analysis of the interferometer nonlinear error suppression, photoelectric receiver frequency response calibration and hydrophone space harmonic field average effect correction based on the degree of uncertainty component, wave frequency shift using high frequency acousto-optic modulator, the carrier signal high speed data sampling digital quadrature demodulation, avoiding the problem of interference point the calibration drift and PLL feedback circuit easy oscillation zero difference, the pressure sensitivity calibration frequency limit is extended to 60MHz. The calibration method of the hydrophone first analyzes the principle of the velocity of vibration and the sound pressure reconstruction in the water, and reveals the function relation between the vibration displacement / velocity of the particle and the sound pressure. Then we analyze the follower of the film with the sound wave motion, establish a strict mathematical model between the thickness of the film and the sound pressure attenuation, so as to correct the influence of the thickness of the film on the sound pressure measurement at all frequencies. The transonic reflective film is placed on the water surface. Heterodyne interferometer is used to measure the vibration displacement of the membrane to reproduce the underwater acoustic pressure. The structure avoids the influence of acousto-optic interference in the acousto-optic common path. According to the background noise of the existing measurement methods to high frequency ultrasonic power weak acoustic power and radiation dose, the acoustic parameters in the lack of effective means of measurement problems, based on the realization of the hydrophone space average effect correction and pressure sensitivity calibration, evaluation method is proposed with dynamic position feedback sensor plane scanning acoustic power measurement and modeling based on the radiation force. This method used the pressure sensitivity of hydrophone calibration of heterodyne interferometer, considering the hydrophone space average effect, construction of particles in high frequency focused sound field using ray method (single beam acoustic tweezers) in three-dimensional force model, through building a sound field scanning device the measured acoustic power and beam width, and brought it into the radiation force model to solve the acoustic power and radiation of high frequency sound field quantitative problem. On the basis of the above research, this paper design and build a sound field scanning system and acoustic pressure sensitivity of hydrophone heterodyne interferometric calibration system, including acousto optical frequency heterodyne interferometer, the carrier signal demodulation system, photodiode frequency response calibration unit, and based on the spatial averaging effect correction model, and the acoustic pressure sensitivity of hydrophone calibration power measurement and other aspects of the testing and analysis of experiments. Analysis and test results show that the acoustic pressure sensitivity of hydrophone heterodyne interferometer calibration frequency calibration system is up to 60MHz, the expanded uncertainty is less than 9.8%; to build the field of the plane beam scanning system for measuring the width of the resolution can reach 0.1 M, conduct sound power measurement in the frequency range of 60 MHz acoustic pressure sensitivity of hydrophone calibration, measurement of power limit less than 1 m W, radiation quantitative research can achieve n N level.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TB565.1

【參考文獻】

相關期刊論文 前7條

1 王林春;江月松;辛遙;桑峰;;頻率掃描干涉中參考干涉儀的非線性誤差分析[J];光電子.激光;2010年09期

2 張治國;張錫文;;紅細胞在微血管狹窄處的力學行為[J];中國科學:生命科學;2010年05期

3 陳洪芳;鐘志;丁雪梅;;激光外差干涉的非線性誤差補償[J];光學精密工程;2010年05期

4 黎永前,李曉瑩,朱名銓;納米精度外差式激光干涉儀非線性誤差修正方法研究[J];儀器儀表學報;2005年05期

5 周剛,何培忠,壽文德,夏榮民,黃小唯;超聲診斷設備的熱指數(shù)、機械指數(shù)的定義和測量方法[J];聲學技術;2004年S2期

6 趙慧潔,張廣軍;影響激光外差高精度計量的幾個關鍵因素[J];北京航空航天大學學報;2002年02期

7 趙慧潔;外差干涉儀頻率混疊誤差分析[J];計量學報;1999年03期

，

本文編號：1346411