Department of Computational Science and Engineering, Yonsei University, Seoul 120-749, Republic of Korea.
Comput Math Methods Med. 2013;2013:974027. doi: 10.1155/2013/974027. Epub 2013 Mar 11.
This paper proposes a robust real-time myocardial border tracking algorithm for echocardiography. Commonly, after an initial contour of LV border is traced at one or two frames from the entire cardiac cycle, LV contour tracking is performed over the remaining frames. Among a variety of tracking techniques, optical flow method is the most widely used for motion estimation of moving objects. However, when echocardiography data is heavily corrupted in some local regions, the errors bring the tracking point out of the endocardial border, resulting in distorted LV contours. This shape distortion often occurs in practice since the data acquisition is affected by ultrasound artifacts, dropouts, or shadowing phenomena of cardiac walls. The proposed method is designed to deal with this shape distortion problem by integrating local optical flow motion and global deformation into a variational framework. The proposed descent method controls the individual tracking points to follow the local motions of a specific speckle pattern, while their overall motions are confined to the global motion constraint being approximately an affine transform of the initial tracking points. Many real experiments show that the proposed method achieves better overall performance than conventional methods.
本文提出了一种用于超声心动图的稳健实时心肌边界跟踪算法。通常，在整个心动周期的一到两帧上跟踪 LV 边界的初始轮廓后，在剩余的帧上进行 LV 轮廓跟踪。在各种跟踪技术中，光流法是最常用于运动目标的运动估计的方法。然而，当超声心动图数据在某些局部区域受到严重干扰时，这些误差会将跟踪点带出心内膜边界，导致 LV 轮廓变形。这种形状失真在实践中经常发生，因为数据采集受到超声伪影、丢失或心脏壁阴影现象的影响。所提出的方法旨在通过将局部光流运动和全局变形集成到一个变分框架中来处理这个形状失真问题。所提出的下降方法控制各个跟踪点跟随特定斑点图案的局部运动，而它们的整体运动则限制在全局运动约束中，该约束近似为初始跟踪点的仿射变换。许多实际实验表明，所提出的方法比传统方法具有更好的整体性能。
