Cuartas-Vélez Carlos, Restrepo René, Bouma Brett E, Uribe-Patarroyo Néstor
Applied Optics Group, Universidad EAFIT, Carrera 49 # 7 Sur-50, Medellín, Colombia.
Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, MA 02114, USA.
Biomed Opt Express. 2018 Jun 26;9(7):3354-3372. doi: 10.1364/BOE.9.003354. eCollection 2018 Jul 1.
We present a novel tomographic non-local-means based despeckling technique, TNode, for optical coherence tomography. TNode is built upon a weighting similarity criterion derived for speckle in a three-dimensional similarity window. We present an implementation using a two-dimensional search window, enabling the despeckling of volumes in the presence of motion artifacts, and an implementation using a three-dimensional window with improved performance in motion-free volumes. We show that our technique provides effective speckle reduction, comparable with B-scan compounding or out-of-plane averaging, while preserving isotropic resolution, even to the level of speckle-sized structures. We demonstrate its superior despeckling performance in a phantom data set, and in an ophthalmic data set we show that small, speckle-sized retinal vessels are clearly preserved in intensity images and in two orthogonal, cross-sectional views. TNode does not rely on dictionaries or segmentation and therefore can readily be applied to arbitrary optical coherence tomography volumes. We show that despeckled esophageal volumes exhibit improved image quality and detail, even in the presence of significant motion artifacts.
我们提出了一种用于光学相干断层扫描的基于断层非局部均值的新型去斑技术TNode。TNode基于在三维相似性窗口中为散斑导出的加权相似性准则构建。我们展示了一种使用二维搜索窗口的实现方式，能够在存在运动伪影的情况下对体数据进行去斑，以及一种使用三维窗口的实现方式，在无运动的体数据中具有更高的性能。我们表明，我们的技术能有效减少散斑，与B扫描复合或平面外平均相当，同时保持各向同性分辨率，甚至达到散斑大小结构的水平。我们在体模数据集中展示了其卓越的去斑性能，并且在眼科数据集中表明，在强度图像以及两个正交的横截面视图中，散斑大小的小视网膜血管清晰可见。TNode不依赖于字典或分割，因此可以很容易地应用于任意光学相干断层扫描体数据。我们表明，即使存在明显的运动伪影，去斑后的食管体数据也能展现出更高的图像质量和细节。
