{"title":"The use of correlation systems for real-time ultrasonic imaging","authors":"B. B. Lee, E. S. Furgason","doi":"10.1109/ULTSYM.1985.198618","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198618","url":null,"abstract":"In previous studies, we have shown that correlation systems can overcome the peak-power limitations of conventional pulse-echo systems in non-moving target applications. This study examines the applicability of correlation systems to practical real-time imaging situations involving moving targets and clutter. The study was carried out through simulations of the generalized ambiguity function and a derived system signal-to-noise ratio formula. Results indicate that whether a correlation system is better than a conventional system depends on the target velocity and the clutter-to-noise ratio, and that special pseudo-random Golay codes provide the best overall- .correlation system performance. Although the special Golay code properties of self-noise and crosscorrelation cancellation are diminished as the velocity of a target increases, the degradation of system performance was found to be minimal for all but the fastest moving targets in medical imaging applications.","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129824825","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":"Resolution Issues in Medical Ultrasound","authors":"J. Wright","doi":"10.1109/ULTSYM.1985.198620","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198620","url":null,"abstract":"A common figure of merit for imaging systems is resolution--the ability to differentiate two or more closely spaced point targets. When applied to ultrasonic images for medical applications, however, it is not an adequate measure of performance. The clinical user is also concerned with differentiating subtle textural changes in tissue. We refer to this figure of merit as contrast resolution. This paper reviews basic principles of ultrasonic beam formation in a tutorial fashion, and explores the systematic requirements and trade-offs necessary to achieve good contrast resolution along with good detail resolution. Simulation results are presented.","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128450990","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":"Polarization Dependence of the Direct Electromagnetic Generation of Ultrasound in Potassium","authors":"D. Kubinski, J. Trivisonno","doi":"10.1109/ULTSYM.1985.198687","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198687","url":null,"abstract":"","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129086615","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":"Acousto-Electro-Optic Effects in SAW Devices","authors":"A. Scholtz, P. Das","doi":"10.1109/ULTSYM.1985.198541","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198541","url":null,"abstract":"Both acoustooptic (AO) and electrooptic (EO) interactions can be generated simultaneously in piezoelectric crystals to produce an acousto-electrooptic (AEO) effect. AO devices have been developed for performing convolution, correlation, and matched filtering; EO devices may be used for pulse compression and matrix processing, as well as many other applications. An AEO effect can give not only an additional port for information, but also overcome individual limitations and be used for all the above applications. A theoretical description of AEO interaction in the Bragg regime, based on superposition of surface acoustic waves (SAW) and EO interdigital transducers was reported previously.1 Longitudinal and transverse components of the propagating SAW and applied electric field were considered separately to account for the anisotropy of the crystals. Coupled mode theory was then applied to predict features of the resulting diffraction.","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124644175","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":"Measurement of the Biot Structural Factor δ: for Sintered Bronze Spheres","authors":"S. R. Bakert, I. Rudnick","doi":"10.1109/ULTSYM.1985.198673","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198673","url":null,"abstract":"We have extracted the Biot structural factor 6 [11 for three samples of sintered bronze spheres (nom. dia. 7511, 11011, 50011, porosity 0.4 to 0.5) from measurements of the speed and attenuation of first and second sound in superfluid helium contained in these samples. We find 1 to lie in the range 3.3 to 4.5, about 1+ to 2 times larger than Stoll has estimated for typical marine sediments 121 (we take 6 to be defined by x=6 (awk/vP)', where is the argument of Biot's universal correction function F(K), a is the tortuosity, is the angular frequency, k is the permeability, v is the kinematic viscosity, and P is the porosity). If 6 is the normalfluid viscous p&&ration depth and a is a characteristic pore size, the range of /a covered by these measurements is ximately 0.01 to 1.","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124500237","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 Influence of a Chrome Film Bonding Layer on SAW Resonator Performance","authors":"W. Tanski","doi":"10.1109/ULTSYM.1985.198513","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198513","url":null,"abstract":"We have been working to make low aging rate, low phase noise SAW resonator oscillators for systems applications. These resonators are normally made using A1 electrodes, frequently including a Cr film bonding layer, and the resonators are often secured to a header u sing an adhesive. Here we report the results of tests to determine the i nfluence of a Cr bonding layer on device n oise levels and the effect of the high temperature bake (needed for adhesive cure) on a resonator frequency r esponse. It was found that a Cr film bonding caused an increase in the single side band phase noise (measured and the 1Hz intercept) of 15 dBc on average. High temperature b aking (35OoC) resulted in a significant and variable frequency shift as well a small changes in loss and Q. Physical analyses show Cr to be highly mobile, and significant oxidation of the A1 occurs when heated in air.","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"581 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134304221","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":"Imaging with Higher Order Diffraction Tomography","authors":"M. Slaney, A. Kak","doi":"10.1109/ULTSYM.1985.198623","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198623","url":null,"abstract":"This paper describes several higher order models for the fields scattered by an object and the computational techniques involved. The Born and the Rytov approximations are easily extended to include higher order terms but like most series their range of convergence is limited. Another technique to be described is based on algebraic techniques and can be shown to always converge. Unfortunately, numerical instabilities limit this approach to objects with a refractive index change of less than 20-30%. This paper will describe numerical approaches for each of these higher order models It reports the region of convergence for the Born and Rytov series and objects that lead to stable solutions for the algebraic approach.","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132995883","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":"Characterisation of Surface Breaking Cracks in Alumina Using Scanning Acoustic Microscopy","authors":"E. Almond, M. Gee, M. Nikoonahad, Graham C. Smith","doi":"10.1109/ULTSYM.1985.198608","DOIUrl":"https://doi.org/10.1109/ULTSYM.1985.198608","url":null,"abstract":"Images o f c r a c k s i n p o l y c r y s t a l l i n e a luminas were s t u d i e d by a c o u s t i c microscopy a t 750 MHz i n spec imens w i t h v a r i o u s s u r f a c e f i n i s h e s . The advan tages of a c o u s t i c microscopy o v e r o p t i c a l microscopy are demonst ra ted f o r d e t e c t i n g c r a c k s , and f o r d e t e r m i n i n g t h e c r a c k p a t h r e l a t i v e t o t h e m i c r o s t r u c t u r e . I . I n t r o d u c t i o n The i n c r e a s i n g u s e o f ce ramics i n l o a d b e a r i n g a p p l i c a t i o n s h a s c r e a t e d a concomi tan t r equ i r emen t f o r methods o f d e t e c t i n g s u r f a c e c r a c k s which are a major s o u r c e of mechanica l weakness. Such d e f e c t s are u s u a l l y d e t e c t a b l e by o p t i c a l microscopy b u t t h e s u r f a c e f i n i s h r e q u i r e d for examinat ion i s far s u p e r i o r t o t h a t needed f o r t h e component i n i ts s e r v i c e envi ronment . Fur thermore , w i th p a r t l y t r a n s l u c e n t ceramics such a s a lumina , o p t i c a l imaging o f s u r f a c e d e f e c t s i s d i f f i c u l t and i t is o f t e n n e c e s s a r y t o r e s o r t t o c o a t i n g t h e s u r f a c e o r t o s c a n n i n g e l e c t r o n microscopy i n o r d e r t o r e s o l v e c r a c k s and d i f f e r e n t i a t e between them and m i c r o s t r u c t u r a l f e a t u r e s . C l e a r l y , a l t e r n a t i v e methods f o r d e t e c t i n g d e f e c t s merit e v a l u a t i o n , and r e f l e c t i o n scann ing a c o u s t i c microscopy ( S A M ) i s a t t r a c t i n g i n c r e a s i n g a t t e n t i o n as a p o t e n t i a l non-des t ruc t ive -eva lua t ion (NDE) t echn ique f o r t h i s a p p l i c a t i o n . The t h e o r y and mechanics o f t h e t e c h n i q u e a r e wel l documented ( 1 , 2 ) . B r i e f l y , when imaging t h e s u r f a c e wi th a scann ing a c o u s t i c microscope a t i g h t l y focussed u l t r a s o n i c beam is raster scanned on t h e s u r f a c e of t h e specimen. Any s u r f a c e ( o r n e a r s u r f a c e ) e las t ic d i s c o n t i n u i t y c a u s e s a modu la t ion of t h e phase and ampl i tude of t h e a c o u s t i c s i g n a l which is r e f l e c t e d back from t h e spec imen. It is t h i s modula t ion which p r o v i d e s t h e c o n t r a s t i n t h e SAM. I n p a r t i c u l a r , the v a r i a t i o n cf t r a n s d u c e r o u t p u t a s a f u n c t i o n of d e f o c u s d i s t a n c e i n t h e a c o u s t i c microscope the (*) Formerly with Department of Electronic & Electrical Engineering, University College London, Torrington Place, London WClE 73E, UK 736 1985 ULTRASONICS SYMPOSIUM V(z) e f f e c t may be used t o enhance the d e t e c t a b i l i t y o f p a r t l y embedded mic roc racks and d i s c o n t i n u i t i e s (3,4). I n t h e p r e s e n t work i t was dec ided t o i n v e s t i g a t e p o t e n t i a ","PeriodicalId":240321,"journal":{"name":"IEEE 1985 Ultrasonics Symposium","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115238065","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}
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