Pattern Recognition Lab, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany.
Siemens Healthcare GmbH, Forchheim, Germany.
Int J Comput Assist Radiol Surg. 2019 Sep;14(9):1541-1551. doi: 10.1007/s11548-019-02027-8. Epub 2019 Jul 12.
For a perfectly plane symmetric object, we can find two views-mirrored at the plane of symmetry-that will yield the exact same image of that object. In consequence, having one image of a plane symmetric object and a calibrated camera, we automatically have a second, virtual image of that object if the 3-D location of the symmetry plane is known.
We propose a method for estimating the symmetry plane from a set of projection images as the solution of a consistency maximization based on epipolar consistency. With the known symmetry plane, we can exploit symmetry to estimate in-plane motion by introducing the X-trajectory that can be acquired with a conventional short-scan trajectory by simply tilting the acquisition plane relative to the plane of symmetry.
We inspect the symmetry plane estimation on a real scan of an anthropomorphic human head phantom and show the robustness using a synthetic dataset. Further, we demonstrate the advantage of the proposed method for estimating in-plane motion using the acquired projection data.
Symmetry breakers in the human body are widely used for the detection of tumors or strokes. We provide a fast estimation of the symmetry plane, robust to outliers, by computing it directly from a set of projections. Further, by coupling the symmetry prior with epipolar consistency, we overcome inherent limitations in the estimation of in-plane motion.
对于完全平面对称的物体，我们可以找到两个在对称面镜像的视图，这将产生该物体完全相同的图像。因此，如果知道对称面的三维位置，对于一个平面对称物体的一个图像和一个校准的相机，我们就可以自动获得该物体的第二个虚拟图像。
我们提出了一种从一组投影图像中估计对称面的方法，即基于极线一致性的一致性最大化的解。有了已知的对称面，我们可以通过引入 X 轨迹来利用对称性来估计平面内的运动，只需相对对称面倾斜采集平面即可获得 X 轨迹。
我们在人体头部模拟体的真实扫描中检查了对称面估计的效果，并使用合成数据集展示了其鲁棒性。此外，我们还展示了使用所获得的投影数据来估计平面内运动的所提出方法的优势。
人体中的对称破坏器被广泛用于检测肿瘤或中风。我们通过直接从一组投影中计算来快速估计对称面，该方法对离群值具有鲁棒性。此外，通过将对称先验与极线一致性相结合，我们克服了在平面内运动估计中的固有限制。
