高强度聚焦超声图像斑点解相关特性分析

摘要

斑点解相关原理广泛应用于超声导航和超声图像三维重建等领域.高强度聚焦超声系统中超声图像的斑点解相关特性是本文研究重点,通过对高强度聚焦超声图像中纹理方向不同的斑点区域在横向和层间的解相关规律分析,针对纹理方向对解相关特性造成干扰的问题,基于傅里叶变换的方向检测和方向矫正算法被提出.首先根据斑点区域的频谱亮度分布计算纹理的主控方向,然后对矫正后的频谱进行傅里叶反变换,得到新的斑点区域.实验结果显示,提出的方法取得良好的效果,新斑点区域在横向和层间的解相关曲线呈现一致的规律,提出的方法可用于斑点检测、纹理特征提取、超声图像层间定位和三维重建.%Speckle decorrelation principle is widely used in ultrasound navigation and three-dimensional reconstruction of ultrasound images,etc.In this study,we discussed the speckle decorrelation characteristics in the ultrasound images from highintensity focused ultrasound system,and analyzed the decorrelation rules of speckle area with different texture orientations at elevational direction and lateral direction,and finally proposed a novel Fourier transform-based algorithm to detect and correct the texture orientation.We calculated the main orientation of speckle texture according to the distribution of Fourier spectrum in speckle area,and obtained a new speckle area after Fourier inverse transform for the corrected spectrum.The experimental results show that the novel Fourier transform-based algorithm performs well,and that the decorrelation curves of new speckle area in lateral direction and elevational direction exhibit a consistent rule,which indicate that the novel algorithm can be used for speckle detection,texture feature extraction,distance estimation between successive images,and three-dimensional reconstruction of ultrasound images.