Chen Min, Gee James C, Prince Jerry L, Aguirre Geoffrey K
Department of Radiology, University of Pennsylvania, Philadelphia PA 19104, USA.
Department of ECE, Johns Hopkins University, Baltimore M D 21218, USA.
Comput Pathol Ophthalmic Med Image Anal (2018). 2018 Sep;11039:328-335. doi: 10.1007/978-3-030-00949-6_39. Epub 2018 Sep 14.
A-scan acquisitions in OCT images are acquired in a fan-beam pattern, but saved and displayed in a rectangular space. This results in an inaccurate representation of the scan geometry of OCT images, which introduces systematic distortions that can greatly impact shape and morphology based analysis of the retina. Correction of OCT scan geometry has proven to be a challenging task due to a lack of information regarding the true angle of entry of each A-scan through the pupil and the location of the A-scan nodal points. In this work, we present a preliminary model that solves for the OCT scan geometry in a restricted 2D setting. Our approach uses two repeat scans with corresponding landmarks to estimate the necessary parameters to correctly restore the fan-beam geometry of the input B-scans. Our results show accurate estimation of the ground truth geometry from simulated B-scans, and we found qualitatively promising result when the correction was applied to longitudinal B-scans of the same subject. We establish a robust 2D framework that can potentially be expanded for full 3D estimation and correction of OCT scan geometries.
光学相干断层扫描（OCT）图像中的A扫描采集采用扇形光束模式，但保存和显示在矩形空间中。这导致OCT图像扫描几何形状的表示不准确，从而引入系统失真，这可能会极大地影响基于视网膜形状和形态的分析。由于缺乏关于每个A扫描通过瞳孔的真实入射角和A扫描节点位置的信息，OCT扫描几何形状的校正已被证明是一项具有挑战性的任务。在这项工作中，我们提出了一个初步模型，该模型在受限的二维设置中求解OCT扫描几何形状。我们的方法使用两次带有相应地标的重复扫描来估计必要参数，以正确恢复输入B扫描的扇形光束几何形状。我们的结果表明，从模拟B扫描中可以准确估计真实几何形状，并且当将校正应用于同一受试者的纵向B扫描时，我们发现了定性上有前景的结果。我们建立了一个强大的二维框架，该框架有可能扩展用于OCT扫描几何形状的全三维估计和校正。
