论文标题
视网膜血流成像的激光多普勒全息图中的时空滤波
Spatio-temporal filtering in laser Doppler holography for retinal blood flow imaging
论文作者
论文摘要
激光多普勒全息（LDH）是一种全场干涉成像技术，最近在眼科中应用，以测量血流，这是一个高临床兴趣的参数。从以超快框架速率获取的数字全息图的时间波动中，LDH揭示了带有几毫秒的时间分辨率的视网膜和脉络膜血流。然而，LDH遇到困难以检测较慢的血液流动，因为它需要使用低多普勒的频移频率，而多普勒频率转移会因眼运动而损坏。我们在这里证明了使用由多普勒超声改编的时空分解，该分解提供了适合于歧视血液流动的基础。单数值分解（SVD）可以用作一种简单，坚固且有效的方法，以将血流的多普勒波动与强烈的空间连贯性（例如眼运动）分开。我们表明，SVD优于常规的傅里叶滤波器，以显示较慢的血液流动，并大大提高了LDH揭示较小尺寸或病理学减少的血液流量的容器的能力。
Laser Doppler holography (LDH) is a full-field interferometric imaging technique recently applied in ophthalmology to measure blood flow, a parameter of high clinical interest. From the temporal fluctuations of digital holograms acquired at ultrafast frame rates, LDH reveals retinal and choroidal blood flow with a few milliseconds of temporal resolution. However LDH experiences difficulties to detect slower blood flow as it requires to work with low Doppler frequency shifts which are corrupted by eye motion. We here demonstrate the use of a spatio-temporal decomposition adapted from Doppler ultrasound that provides a basis appropriate to the discrimination of blood flow from eye motion. A singular value decomposition (SVD) can be used as a simple, robust, and efficient way to separate the Doppler fluctuations of blood flow from those of strong spatial coherence such as eye motion. We show that the SVD outperforms the conventional Fourier based filter to reveal slower blood flow, and dramatically improves the ability of LDH to reveal vessels of smaller size or with a pathologically reduced blood flow.
