The virtual reality based motion simulation of the guide wire and the catheter inside specific vascular structures can benefit a lot for the endovascular intervention. A fast and well-performed collision cancellation ...The virtual reality based motion simulation of the guide wire and the catheter inside specific vascular structures can benefit a lot for the endovascular intervention. A fast and well-performed collision cancellation algorithm is proposed based on the geometric analysis and the angular propagation （AP）, and a 3-D real-time interactive system is developed for the motion simulation of the guide wire and the catheter inside the specific patient vascular. The guide wire or the catheter is modeled as the ＂multi-body＂ representation and properties are defined by its intrinsic characteristics. The motion of the guide wire or the catheter inside the vascular is guided by the collision detection and the collision cancellation algorithm. Finally, a relaxation procedure is used to achieve more realistic status. Experimental results show that the behavior of the guide wire or the catheter depends on the defined parameters. The real-time simulation can be achieved. The result shows that the simulation system is effective and promising.展开更多
在磁共振成像过程中由于患者的运动会在图像中造成运动伪影,从而造成图像的退化,严重影响临床诊断.本文对M R I图像刚性平移运动伪影提出了一个改进的后处理方法:首先用谱平移理论消除频率编码方向平移运动;然后建立模糊模型表示图像的...在磁共振成像过程中由于患者的运动会在图像中造成运动伪影,从而造成图像的退化,严重影响临床诊断.本文对M R I图像刚性平移运动伪影提出了一个改进的后处理方法:首先用谱平移理论消除频率编码方向平移运动;然后建立模糊模型表示图像的背景并对其进行抑制,用数学形态学的方法确定图像的支撑域;最后以能量熵为收敛准则,用相位恢复算法对频率编码方向残余的子像素移动造成的伪影和相位编码方向的伪影进行消除.实验表明,应用本研究提出的方法能够明显地消除图像空间运动造成的伪影.展开更多
为了更好的了解血管生理形态,常需要从医学图像中分割出血管。采用传统的单阈值区域生长算法进行血管分割,如果选取的阈值太高可能导致血管末梢的丢失,而如果选取的阈值太低则可能会导致一些不属于血管的点被生长到血管区域中。因此,提...为了更好的了解血管生理形态,常需要从医学图像中分割出血管。采用传统的单阈值区域生长算法进行血管分割,如果选取的阈值太高可能导致血管末梢的丢失,而如果选取的阈值太低则可能会导致一些不属于血管的点被生长到血管区域中。因此,提出了一种基于Ordered Region Growing(ORG)算法的双阈值区域生长算法来克服这个缺点,实验证明这种算法能够获得较好的血管分割效果。展开更多
文摘The virtual reality based motion simulation of the guide wire and the catheter inside specific vascular structures can benefit a lot for the endovascular intervention. A fast and well-performed collision cancellation algorithm is proposed based on the geometric analysis and the angular propagation （AP）, and a 3-D real-time interactive system is developed for the motion simulation of the guide wire and the catheter inside the specific patient vascular. The guide wire or the catheter is modeled as the ＂multi-body＂ representation and properties are defined by its intrinsic characteristics. The motion of the guide wire or the catheter inside the vascular is guided by the collision detection and the collision cancellation algorithm. Finally, a relaxation procedure is used to achieve more realistic status. Experimental results show that the behavior of the guide wire or the catheter depends on the defined parameters. The real-time simulation can be achieved. The result shows that the simulation system is effective and promising.
文摘在临床的实际应用中,基于小波变换的单模态的医学图像中的计算机断层造影术(CT)和核磁共振图像(MRI)之间的数据融合提供了更丰富的信息.融合图像的3D(three dimensional)重建采用表面绘制方式,所用的一种体数据遍历算法,既提高计算效果,又能进行真实感曲面的显示,并可实现对感兴趣区域(Region of interest, ROI)的分割提取、三维重建和显示,提高医学诊断的准确性和可靠性.
文摘在磁共振成像过程中由于患者的运动会在图像中造成运动伪影,从而造成图像的退化,严重影响临床诊断.本文对M R I图像刚性平移运动伪影提出了一个改进的后处理方法:首先用谱平移理论消除频率编码方向平移运动;然后建立模糊模型表示图像的背景并对其进行抑制,用数学形态学的方法确定图像的支撑域;最后以能量熵为收敛准则,用相位恢复算法对频率编码方向残余的子像素移动造成的伪影和相位编码方向的伪影进行消除.实验表明,应用本研究提出的方法能够明显地消除图像空间运动造成的伪影.
文摘为了更好的了解血管生理形态,常需要从医学图像中分割出血管。采用传统的单阈值区域生长算法进行血管分割,如果选取的阈值太高可能导致血管末梢的丢失,而如果选取的阈值太低则可能会导致一些不属于血管的点被生长到血管区域中。因此,提出了一种基于Ordered Region Growing(ORG)算法的双阈值区域生长算法来克服这个缺点,实验证明这种算法能够获得较好的血管分割效果。
