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Nahamoo和Kak最近提出了一种综合孔径超声衍射断层图象技术。这种技术具有两个优点:一,为了获得重建物体截面声参数图象所需的散射数据,物体仅需作一次旋转;二,由于考虑了发射器和接收器的孔径函数,照射波原理上可采取任意形式而不限于平面波。本文给出此种图象系统图象重建的一种计算机实现方法,此法属于所谓“滤波-反传播”算法一类。它完全不需要内插,对于一幅N×N图象的重建,主要通过2N次FFT运算完成。文中并给出了计算机模拟的结果。 相似文献
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A new synthetic aperture imaging technique for reconstruction of ultrasonic parameters of an objectfrom its diffraction data has recently been suggested by Nahdmoo et al.The technique offers two mainadvantages.First,the object needs to be rotated only once by 90°in collecting the diffraction data sufficientfor the tomography reconstruction.Secondly,by taking into account the aperture function of transducers,the technique,in principle,permits the use of any type of insonification,as opposed to the plane wave type.These features facilitate the practical implementation of the technique.In this paper,a digitalimplementation for cross-sectional reconstruction is presented.The jmplementation,which is of the filteredback-propagation type Ref.[2],requires no interpolation in the frequency domain,and can be carried outwith only 2N FFT‘s for reconstructing an N×N image.Computer simulation results are included todemonstrate numerical accuracies of the algorithm. 相似文献
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X射线计算机层析造影,即现在为人们所熟知的X-CT(X-rag computered Tomography),曾是生物医学造影技术中的一个重大突破.凭借这种技术,医生们现在能够通过观察人体器官断面结构的图象来作出诊断.X-CT具有高灵敏度和高分辨率的优点,因此获得了广泛的临床应用.然而,在一些应用中,例如为诊断乳腺癌的女性乳房造影时,大剂量X射线的扫描对于人体的危害可能是不可忽视的.因此,近 相似文献
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