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Vol.1 , No. 1, Publication Date: Jan. 27, 2015, Page: 1-8
 and high side-lobe about -13dB down from the maximum on axis value (the contrast of ultrasound imaging).The result for that is one of a famous artifact in medical ultrasound that the anatomy of the organ outside the main beam to be mapped into the main beam. In this work we used eleven windowing functions to rounded edges of the aperture that taper toward zero at the ends of the aperture to create low side-lobes level and reduce the false echo. Windowing functions used (hamming, hanning, Blackman, Bartlett, Nuttall, Kaiser (β=4,8,12 and 16), Parzen and Bohman) as apodization functions. Images are reconstructed by linear array image reconstruction and raster point technique. To evaluate these eleven windowing functions the SNR is calculated and also the sidelobe and mainlobe in dB are calculated for each window. The results showed that there is trade-off in selecting these function: the main lobe of the beam broadens as the side-lobes lower. However, Nutall, Kaiser (β =12) and Kaiser (β =16) have the best main-lobe, side-lobe and SNR. These windowing functions improve the resolution, contrast of the ultrasound image.&picture=http://www.aascit.org/aascit/decorators/img/journal/893.jpg)
| [1] | Mawia A. Hassan, Biomedical Engineering Department, Sudan University of Science & Technology, Khartoum, Sudan. |
Ultrasound imaging is one of the important noninvasive technique that using in medical diagnosis. Unfortunately the far field beam pattern in ultrasound is a sinc function which has a better main-lobe (the resolution of ultrasound imaging) and high side-lobe about -13dB down from the maximum on axis value (the contrast of ultrasound imaging).The result for that is one of a famous artifact in medical ultrasound that the anatomy of the organ outside the main beam to be mapped into the main beam. In this work we used eleven windowing functions to rounded edges of the aperture that taper toward zero at the ends of the aperture to create low side-lobes level and reduce the false echo. Windowing functions used (hamming, hanning, Blackman, Bartlett, Nuttall, Kaiser (β=4,8,12 and 16), Parzen and Bohman) as apodization functions. Images are reconstructed by linear array image reconstruction and raster point technique. To evaluate these eleven windowing functions the SNR is calculated and also the sidelobe and mainlobe in dB are calculated for each window. The results showed that there is trade-off in selecting these function: the main lobe of the beam broadens as the side-lobes lower. However, Nutall, Kaiser (β =12) and Kaiser (β =16) have the best main-lobe, side-lobe and SNR. These windowing functions improve the resolution, contrast of the ultrasound image.
Keywords
Medical Ultrasound, Apodization, Windowing Functions, Linear Array Image Reconstruction, Phase Array Image Reconstruction
Reference
| [01] | Desser TS, Jedrzejewicz T, Bradley C (2000) Native tissue harmonic imaging: basic principles and clinical applications. Ultrasound Quarterly, 16, 40 –8. |
| [02] | Dickinson RJ (1986). Refl ection and scattering. In CR Hill, ed., Physical Principles of Medical Ultrasonics . |
| [03] | Chichester: Ellis Horwood. Duck FA (1990). Physical Properties Of Tissue – A Comprehensive Reference Book. London: Academic Press. |
| [04] | Duck FA (2002). Nonlinear acoustics in diagnostic ultrasound. Ultrasound in Medicine and Biology, 28, 1 –18. |
| [05] | Humphrey VF (2000). Nonlinear propagation in ultrasonic fields: measurements, modeling and harmonic imaging. Ultrasonics, 38, 267 –72. |
| [06] | J. A Zagzebski, Essentials of ultrasound physics, St Louis, Mo: Mosby, (1996). |
| [07] | R. Reeder, C. Petersen, The AD9271-A Revolutionary Solution for Portable Ultrasound, Analog Dialogue, Analog Devices. (2007). |
| [08] | C. Fritsch, M. Parrilla, T. Sanchez, O. Martinez, “Beamforming with a reduced sampling rate,” Ultrasonics, vol. 40, pp. 599–604, 2002. |
| [09] | B. D. Steinberg, “Digital beamforming in ultrasound,” IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, vol. 39, pp. 716–721, 1992. |
| [10] | Th omenius KE (1996). Evolution of ultrasound beamformers. IEEE Ultrasonic Symposium Proceedings, 1615 –22. |
| [11] | Shattuck DP, Weinshenker MD, Smith SW, von Ramm OT (1984). Explososcan: a parallel processing technique for high speed ultrasound imaging with linear phased arrays. Journal of the Acoustical Society of America, 75, 1273 –82. |
| [12] | The Gale Encyclopedia of Medicine, 2nd Edition, Vol. 1 A-B. p. 4, Cobbold, Richard S. C. (2007). Foundations of Biomedical Ultrasound. Oxford University Press. pp. 422–423. ISBN 978-0-19-516831-0. |
| [13] | Chi Hyung Seo,"Improved contrast in ultrasound imaging using dual apodization with cross-correlation", presented to the faculty of the viterbi school of engineering university of southern California, December 2008. |
| [14] | Eric W. Weisstein (2003). CRC Concise Encyclopedia of Mathematics. CRC Press. ISBN 1-58488-347-2. |
| [15] | Hoskins PR, Th rush A, Martin K, Whittingham TA. (2003). Diagnostic ultrasound physics and equipment. London: Greenwich Medical Media. |
| [16] | M. Ali, D. Magee and U. Dasgupta, “Signal Processing Overview of Ultrasound Systems for Medical Imaging,” SPRAB12, Texas Instruments, Texas, November 2008. |
| [17] | J. O. Smith, Mathematics of the Discrete Fourier Transform (DFT), Center for Computer Research in Music and Acoustics (CCRMA), Department of Music, Stanford University, Stanford, California, 2002. |
| [18] | A. V. Oppenheim and R. W. Schafer, Discrete-Time Signal Processing. NJ: Prentice-Hall, Englewood Cliffs, 1989. |
| [19] | Mawia A. Hassan and Yasser M. Kadah, “Digital Signal Processing Methodologies for Conventional Digital Medical Ultrasound Imaging System,” Proc. American Journal of Biomedical Engineering, vol. 3(1), pp. 14-30, USA, 2013 |
| [20] | M. O’Donnell and S.W. Flax, “Phase-aberration correction using signals from point reflectors and diffuse scatterers: measurements,” IEEE Trans. Ultrason., Ferroelect., and Freq. Contr. 35, no. 6, pp. 768-774, 1988 |
