In retinal optical coherence tomography (OCT), it is significant to focus the scan beam on the retina layers of the human eye fast to acquire high-quality OCT images. The refractive errors of the human eye are usually compensated by shifting the optical lens in the sample arm manually or electrically. Otherwise, refractive errors of the human eye will cause axial focal shift of the scanning beam and blur the OCT images. We propose a fast automatic focus method using the interference fringes magnitudes of the whole retinal layers to determine the best refractive correction position of motor-driven optical compensation lens without the aid of optical fundus imaging or OCT B-scan imaging. Also, the optical path difference between the sample arm and reference arm is adjusted in the spectral-domain OCT (SD-OCT) to reduce the effects of sensitivity roll-off. The experiments in the lab-built SD-OCT show that the average running time of the method is 15.2 s and the mean absolute deviation of each imaging is within 1 mm. The method is independent of extra optical setup and requires less computational consumption, which is suitable for low-cost and automatic retinal OCT devices.

中文翻译：

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视网膜光学相干断层扫描中使用干涉条纹幅度的自动聚焦方法

在视网膜光学相干断层扫描 (OCT) 中，将扫描光束快速聚焦在人眼的视网膜层上以获取高质量的 OCT 图像具有重要意义。人眼的屈光不正通常通过手动或电动移动样品臂中的光学透镜来补偿。否则，人眼的屈光不正会导致扫描光束的轴向焦距偏移并模糊 OCT 图像。我们提出了一种快速自动对焦方法，利用整个视网膜层的干涉条纹大小来确定电机驱动光学补偿镜片的最佳屈光矫正位置，而无需借助光学眼底成像或 OCT B 扫描成像。还，在谱域 OCT (SD-OCT) 中调整样品臂和参考臂之间的光程差，以减少灵敏度滚降的影响。实验室构建的SD-OCT实验表明，该方法的平均运行时间为15.2 s，每次成像的平均绝对偏差在1 mm以内。该方法独立于额外的光学设置，需要较少的计算消耗，适用于低成本和自动视网膜 OCT 设备。