Opt Lett. 2020 Jul 15;45(14):4012-4015. doi: 10.1364/OL.393712.
Laser Doppler holography (LDH) is an interferometric blood flow imaging technique based on full-field measurements of the Doppler spectrum. LDH has so far been demonstrated in the retina with ultrafast cameras, typically at 75 kHz. We show here that a similar method can be implemented with camera frame rates 10 times slower than before. Due to energy conservation, low and high frequency local power Doppler signals have opposite variations, and a simple contrast inversion of the low frequency power Doppler reveals fast blood flow beyond the camera detection bandwidth for conventional laser Doppler measurements. Relevant blood flow variations and color composite power Doppler images can be obtained with camera frame rates down to a few kHz.
激光多普勒全息术（LDH）是一种基于多普勒光谱全场测量的干涉血流成像技术。迄今为止，超快相机已在视网膜中展示了 LDH，通常在 75 kHz。我们在这里表明，可以使用比以前慢 10 倍的相机帧率实现类似的方法。由于能量守恒，低频和高频局部功率多普勒信号具有相反的变化，并且低频功率多普勒的简单对比度反转揭示了传统激光多普勒测量的相机检测带宽之外的快速血流。通过将相机帧率降低到几 kHz，可以获得相关的血流变化和彩色复合功率多普勒图像。
