McEachen J C, Nehorai A, Duncan J S
Dept. of Electr. and Comput. Eng., Naval Postgraduate Sch., Monterey, CA 93943, USA.
IEEE Trans Image Process. 2000;9(4):651-65. doi: 10.1109/83.841941.
A robust, flexible system for tracking the point to point nonrigid motion of the left ventricular (LV) endocardial wall in image sequences has been developed. This system is unique in its ability to model motion trajectories across multiple frames. The foundation of this system is an adaptive transversal filter based on the recursive least-squares algorithm. This filter facilitates the integration of models for periodicity and proximal smoothness as appropriate using a contour-based description of the object's boundaries. A set of correspondences between contours and an associated set of correspondence quality measures comprise the input to the system. Frame-to-frame relationships from two different frames of reference are derived and analyzed using synthetic and actual images. Two multiframe temporal models, both based on a sum of sinusoids, are derived. Illustrative examples of the system's output are presented for quantitative analysis. Validation of the system is performed by comparing computed trajectory estimates with the trajectories of physical markers implanted in the LV wall. Sample case studies of marker trajectory comparisons are presented. Ensemble statistics from comparisons with 15 marker trajectories are acquired and analyzed. A multiframe temporal model without spatial periodicity constraints was determined to provide excellent performance with the least computational cost. A multiframe spatiotemporal model provided the best performance based on statistical standard deviation, although at significant computational expense.
已开发出一种强大、灵活的系统，用于跟踪图像序列中左心室（LV）心内膜壁的点对点非刚性运动。该系统在对多帧运动轨迹进行建模的能力方面独具特色。该系统的基础是基于递归最小二乘算法的自适应横向滤波器。此滤波器利用基于对象边界的轮廓描述，适当地促进周期性模型和近端平滑模型的整合。轮廓之间的一组对应关系以及一组相关的对应质量度量构成了系统的输入。使用合成图像和实际图像推导并分析来自两个不同参考系的帧间关系。推导了两个均基于正弦波之和的多帧时间模型。给出了系统输出的示例用于定量分析。通过将计算得到的轨迹估计与植入LV壁的物理标记的轨迹进行比较来对系统进行验证。给出了标记轨迹比较的样本案例研究。获取并分析了与15个标记轨迹比较的总体统计数据。确定了一个无空间周期性约束的多帧时间模型，其以最少的计算成本提供了出色的性能。一个多帧时空模型基于统计标准差提供了最佳性能，尽管计算成本很高。
