Centre for Neuroscience, Indian Institute of Science, Bangalore, India.
Department of Electronic Systems Engineering, Indian Institute of Science, Bangalore, India.
Nat Nanotechnol. 2023 Apr;18(4):380-389. doi: 10.1038/s41565-022-01291-1. Epub 2023 Jan 23.
Neuromorphic cameras are a new class of dynamic-vision-inspired sensors that encode the rate of change of intensity as events. They can asynchronously record intensity changes as spikes, independent of the other pixels in the receptive field, resulting in sparse measurements. This recording of such sparse events makes them ideal for imaging dynamic processes, such as the stochastic emission of isolated single molecules. Here we show the application of neuromorphic detection to localize nanoscale fluorescent objects below the diffraction limit, with a precision below 20 nm. We demonstrate a combination of neuromorphic detection with segmentation and deep learning approaches to localize and track fluorescent particles below 50 nm with millisecond temporal resolution. Furthermore, we show that combining information from events resulting from the rate of change of intensities improves the classical limit of centroid estimation of single fluorescent objects by nearly a factor of two. Additionally, we validate that using post-processed data from the neuromorphic detector at defined windows of temporal integration allows a better evaluation of the fractalized diffusion of single particle trajectories. Our observations and analysis is useful for event sensing by nonlinear neuromorphic devices to ameliorate real-time particle localization approaches at the nanoscale.
神经形态相机是一类新的动态视觉启发式传感器,它将强度变化率编码为事件。它们可以异步地以尖峰的形式记录强度变化,而与视野中的其他像素无关,从而产生稀疏的测量结果。这种对稀疏事件的记录使它们非常适合成像动态过程,例如孤立单分子的随机发射。在这里,我们展示了神经形态检测在亚衍射极限下定位纳米级荧光物体的应用,精度低于 20nm。我们演示了神经形态检测与分割和深度学习方法的结合,以毫秒时间分辨率定位和跟踪小于 50nm 的荧光粒子。此外,我们表明,通过组合强度变化率产生的事件信息,可以将单个荧光物体的质心估计的经典极限提高近两倍。此外,我们验证了在定义的时间积分窗口中使用神经形态探测器的后处理数据可以更好地评估单个粒子轨迹的分形扩散。我们的观察和分析对于非线性神经形态器件的事件感应是有用的,以改善纳米尺度的实时粒子定位方法。