DIFFUSIVE EDGE ENHANCEMENT IN IMAGING
DIFFUSIVE EDGE ENHANCEMENT IN IMAGING
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DOI：
10.1006/jmrb.1995.1141
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发表时间：
1995-10-01
期刊：
影响因子：
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通讯作者：
DESWIET, TM
中科院分区：
文献类型：
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作者：
DESWIET, TM
一个定量的理论扩散的影响在快速和缓慢的交换制度的有界区域的图像。在快速交换机制中，图像运动地变窄为简单的峰值形状，与对象的形状无关。对于相位编码，峰值是高斯的，对于频率编码，峰值是洛伦兹的。在慢交换机制中，对于相位和频率编码，预计图像的边缘增强。对于频率编码，边缘峰的形状在长回波时间是洛伦兹的，而在短回波时间是“不对称洛伦兹”的。相位编码的边缘峰值的一些特征可以用随机游走的简单性质来理解。(C)出版社：Academic Press
A quantitative theory of the effect of diffusion on images of a bounded region in the fast- and slow-exchange regimes is presented. In the fast-exchange regime, the image is motionally narrowed to a simple peaked shape, independent of the shape of the object. The peak is Gaussian for phase encoding and Lorentzian for frequency encoding. In the slow-exchange regime, it is shown that edge enhancement of images is expected, for both phase and frequency encoding. For frequency encoding, the shape of the edge peaks is Lorentzian at long echo times and an ''asymmetric Lorentzian'' for short echo times. Some features of the edge peaks for phase encoding can be understood in terms of simple properties of random walks. (C) 1995 Academic Press, Inc.