IEEE Ultrasonics Symposium, 2005.最新文献

{"title":"Derivation of the impulse response of ultrasonic transducers by experimental system identification","authors":"T. Gehrke, F. Cheikhrouhou, H. M. Overhoff","doi":"10.1109/ULTSYM.2005.1602866","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602866","url":null,"abstract":"An important stage in realistic simulations of ul- trasound imaging systems is the employment of a model for the electroacoustic behaviour of the transducer. State of the art models based on equivalent circuits, finite element modelling or measured impulse responses suffer from miscellaneous practical deficiencies. A method for an experimental estimation of the impulse response based on linear parametric system identification and carefully chosen input signals is presented. Appropriate measurement conditions are derived from numerical simulations of diffraction effects. The approach is shown to provide a way to accurately determine the impulse response of a transducer without any advance information about the physical properties of the piezoelectric crystal. I. INTRODUCTION A piezoelectric ultrasound transducer in pulse echo imaging is used to transform an electrical signal produced by some driving circuit into an acoustical wave and vice versa to transform a pressure wave which impinges onto the transducer into an electrical signal. Simulation of ultrasound pulse echo systems thus require a realistic description of the relation be- tween electric and acoustic signals of the simulated transducer. The electromechanical behaviour can either be included into the simulation by the application of some kind of analytic model for the coupling between electrical and acoustical quantities or it can be treated as a black box within the system model whose behaviour is derived from measurements prior to the simulation. Within the analytic approach most frequently simple linear models have been employed which assume either proportionality between the acoustic and electric quantities (1) or relate them by an impulse response which has the form of a modulated sine function (2). While this might be sufficient for a coarse analysis of ultrasound systems it lacks the capability to simulate real systems thus making comparisons between simulations and experiments impossible. Equivalent circuits or finite element simulations have suc- cessfully been used to acquire more realistic models for the electromechanical behaviour of piezoelectric transducers (3), (4). These approaches require knowledge of the geometry and material properties of the piezoelectric crystals, their backing and matching layers. Moreover, in many cases these models are either not very accurate or they involve high numerical effort. Linear models based on measured impulse responses avoid problems associated with analytical approaches and are precise enough to be successfully included into pulse echo simulations (5)-(8). The impulse response of a piezoelectric ultrasound trans- ducer is most commonly been measured from reflections of a flat metal plane due to an excitation of the piezoelectric element with an electric pulse signal. It is well known that for non focussing transducers even a single point scatterer gives rise to a complex echo signal with overlapping contributions from plane and edge w","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133721628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High resolution quantification of myocardial motion in mice using 2d speckle tracking","authors":"Yinbo Li, C. Garson, B. A. French, J. Hossack","doi":"10.1109/ULTSYM.2005.1602871","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602871","url":null,"abstract":"Mid-ventricular myocardial tissue motion in mice was examined using high resolution ultrasound B- mode images. The mouse heart was imaged at 35MHz, with approximately 40μm axial resolution and 100μm lateral resolution. Over 100 image frames per cardiac cycle were used in the analysis. Myocardial motion was tracked between successive image frames using a 2D minimum sum of absolute differences (MSAD) applied to 2D pixel kernels. The method is computationally efficient and a processing speed of 0.11 second per tracked image frame was achieved on a 2.9GHz Pentium IV PC, nearly 100X faster than in MATLAB. In the normal mouse heart, physiologically typical values for left ventricular myocardial deformation were obtained: the peak radial strain was approximately 40%, the peak rate of systolic wall endocardial velocity was 23 mm/s and the peak rate of diastolic wall velocity was 39 mm/s in the lateral wall. The preliminary mouse results correlate well with human MRI results.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"179 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115761489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The temperature influence on the piezoelectric transducer noise, measurements and modeling","authors":"F. Coutard, E. Tisserand, P. Schweitzer","doi":"10.1109/ULTSYM.2005.1603180","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603180","url":null,"abstract":"In many case, the SNR limit the performance of a transducer. The understanding of the nature and the behavior of the noise allow to increase this SNR. First, we present the noise and impedance real part measurement results in air and in water. We show the link between them. The second part is a temperature study which confirms this influence. We show the little evolution of the total output noise in a conditioning chain. Finally, we use a derivate of Redwood electro-acoustical model to estimate the noise. The measurement results agreed with this one.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115907199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthetic aperture flow angle estimation on in-vivo data from the carotid artery","authors":"N. Oddershede, J. Jensen","doi":"10.1109/ULTSYM.2005.1603099","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603099","url":null,"abstract":"In conventional ultrasound velocity estimation sys- tems only the velocity projected onto the direction of the steered ultrasound beam is found. It has previously been shown how true blood flow velocity magnitudes can be found using synthetic transmit aperture imaging. The method is based on cross- correlation between lines beamformed along the flow direction. This method assumes the direction of flow is known. Jensen (2004) presented a method for estimating the direction of flow (1). The angle determination method is based on a search for the maximum normalized cross-correlation as a function of angle. It assumes the largest correlation is seen for the angle of flow. Previously, this method has only been validated using data from a circulating flow rig. This paper presents an In-Vivo investigation of the method. Real time data covering 2.2 seconds of the carotid artery of a healthy 30-year old male volunteer is acquired and then processed off-line using a large computer cluster. Data are acquired using our RASMUS experimental ul- trasound scanner and a 128 element 6.2 MHz linear array transducer. A 20 µs chirp was used during emission and virtual transmit sources were created behind the transducer using 11 transmitting elements. Data from 8 transmissions with each 64 receiving elements are beamformed and coherently summed to create high resolution lines at different angles for a set of points within the region of flow. The pulse repetition frequency was set to 10 kHz. The direction of flow is estimated using the above mentioned method. It is compared to the flow angle of 106 ◦ with respect to the axial direction, determined visually from the B-mode image. For a point in the center of the common carotid artery, 76 % of the flow angle estimates over the 2.2 seconds were within ±10 ◦ of the visually determined flow angle. The standard deviation of these estimates was below 2.7 ◦ .","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114482823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Droplet ejector using surface acoustic waves","authors":"J. Bennes, S. Alzuaga, S. Ballandras, F. Chérioux, F. Bastien, J. Manceau","doi":"10.1109/ULTSYM.2005.1602976","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602976","url":null,"abstract":"The present study aims to investigate droplet ejection using Surface Acoustic Waves (SAW). The interests in droplet ejection microsystems have dramatically grown in recent years due to inkjet printhead demand (Drop-On-Demand). Among several actuating methods (thermal, piezoelectric, etc.), the thermally driven inkjet printhead is the most successful (low cost, easy fabrication and high printing quality). Almost all of the current ink jet printers eject ink droplets through nozzles, with a direction of ejection always perpendicular to the nozzle surface. Surface acoustic waves devices are widely used for frequency filtering and are mainly devoted to cellular phones and telecommunication handset. Nowadays, recently published works have demonstrated the interest of SAW for guiding and positioning small liquid droplet atop a flat surface. This paper describes a new way to eject droplets (water, ink, etc...) using SAW. The surface acoustic waves devices used to eject droplets are carried out on lithium niobate substrates (LiNbO3 cut Y+128°, X propagation). The Rayleigh waves are excited using classical inter-digital transducers (IDT). The design of IDT has been simulated with finite element analysis and boundary element methods. The computations on the design of the IDT have been compared with measurements. The vibration amplitude of the wave necessary to droplet ejection is measured using a heterodyne laser probe. The range of the droplets volume ejected is between 100nl and 1μl. The influence of the supply voltage on the ejection is described.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114748632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amplitude and phase measurement of surface acoustic waves within a saw filter having fan-shaped transducers and numerical simulations","authors":"T. Chiba","doi":"10.1109/ULTSYM.2005.1603163","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603163","url":null,"abstract":".� A new method of laser heterodyne interferometry is applied to the phase measurement of surface acoustic waves within a SAW filter having fan-shaped transducers on a 128Y-X LiNbO3 substrate. As a result, it is clarified that the standing waves inside the fan-shaped transducer move towards the open end of the fan, resulting in several diffraction beams. Furthermore, a simple numerical simulation concerning the wave propagation and electrical characteristics of a SAW filter","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116786931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical prototyping of piezocomposite arrays: from material characterization to array performances","authors":"G. Férin, D. Certon, F. Patat, R. Dufait, N. Felix","doi":"10.1109/ULTSYM.2005.1602865","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602865","url":null,"abstract":"The numerical prototyping and optimization of ultrasound arrays for medical imaging applications enable probe designers to perform efficient and thorough studies. The efficiency of such methods directly depends on the characterization of probe's constitutive materials. Whatever the model used: numerical, analytical or FEM/BEM model, accurate input data are required to predict properly the final performances of the probe. This work presents two complementary methods for ultrasound transducer arrays numerical prototyping. Different studies point out the flexibility, and the enhanced value of such a tool for 1-3 piezocomposite ultrasound transducers arrays design and development.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117270669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calibrated tomographic schlieren system for characterization of medical probes","authors":"J. Le Floch, P. Gatta, G. Caliano, R. Carotenuto, M. Pappalardo","doi":"10.1109/ULTSYM.2005.1602939","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602939","url":null,"abstract":"Ultrasound (US) probes in the MHz range used in the medical field must comply with specific rules. Traditionally, calibrated hydrophones measure the pressure of the US field within a given volume but this procedure is time consuming. More recently, the Schlieren system has been demonstrated a fast and accurate technique for the quantification of the ultrasonic field characteristics (beam width and average acoustic intensity in function of the gray level). However, a relationship between the video gray level and the peak pressure was not determined, and only a small number of medical probes could be studied in real time due to a limited field of view. In this paper, the realization of an experimental set-up based on the Schlieren effect, allowing real time imaging, and a quantitative tomographic reconstruction of the US field of a wide range of medical probes, driven with continuous waves, is reported. We also investigated the relationship between pressure measurements and tomographic luminance values, in order to calibrate our Schlieren system. The results demonstrate that this new Schlieren system of compact dimension, 40 cm x 100 cm x 40 cm, is a time efficient method to characterize several medical probes in the frequency range 1-40 MHz. A non-linear relationship between the gray level of the tomographic reconstruction and the peak pressure was experimentally found. Once the system has been calibrated, it allows the quantitative reconstruction of tomographic views at any depth. Our future work is to quantify the video of the US field in real time and to obtain a 3D visualization.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117338681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of low light absorption material by photoacoustic microscope","authors":"A. Minamide, Y. Tokunaga, N. Naoe","doi":"10.1109/ULTSYM.2005.1603143","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1603143","url":null,"abstract":"New methods of evaluating low light absorption materials by a photoacoustic (PA) microscope with a low laser power were proposed. For an optically transparent material, laser light was absorbed by an opaque substrate under a transparent material, and a heat source was generated. The thermal wave was reverse-propagated in a transparent material. For an optically reflectivity material, surface plasmon was used. From experimental results of a thin film of silver, the new method was about 20 times more effective than conventional methods for observing PA signals.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123680032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Forward-looking IVUS imaging using an annular-ring CMUT array","authors":"F. Degertekin, M. Karaman, R. Guldiken","doi":"10.1109/ULTSYM.2005.1602813","DOIUrl":"https://doi.org/10.1109/ULTSYM.2005.1602813","url":null,"abstract":"A 64-element, 1.15mm diameter annular-ring CMUT array was characterized and used for forward- looking IVUS imaging tests. The array was manufactured using low temperature processes suitable for CMOS electronics integration on a single chip. The 43×140µm 2 array element has suitable view angle for forward looking imaging around 15MHz center frequency and pulse-echo measurements show nearly 100% fractional bandwidth around 17MHz. For imaging and SNR measurements, RF A-scan data sets from various targets were collected using an interconnect scheme forming a 32-element array configuration. The results demonstrate that annular-ring CMUT arrays fabricated with CMOS compatible processes are capable of forward-looking IVUS imaging.","PeriodicalId":302030,"journal":{"name":"IEEE Ultrasonics Symposium, 2005.","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121885997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}