Couëdel Lénaïc, Nosenko Vladimir
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, SK S7N 5E2, Canada.
CNRS, Aix-Marseille Université, PIIM, UMR 7345, 13397 Marseille CEDEX 20, France.
J Imaging. 2019 Mar 16;5(3):41. doi: 10.3390/jimaging5030041.
In this article, a strategy to track microparticles and link their trajectories adapted to the study of the melting of a quasi two-dimensional complex plasma crystal induced by the mode-coupling instability is presented. Because of the three-dimensional nature of the microparticle motions and the inhomogeneities of the illuminating laser light sheet, the scattered light intensity can change significantly between two frames, making the detection of the microparticles and the linking of their trajectories quite challenging. Thanks to a two-pass noise removal process based on Gaussian blurring of the original frames using two different kernel widths, the signal-to-noise ratio was increased to a level that allowed a better intensity thresholding of different regions of the images and, therefore, the tracking of the poorly illuminated microparticles. Then, by predicting the positions of the microparticles based on their previous positions, long particle trajectories could be reconstructed, allowing accurate measurement of the evolution of the microparticle energies and the evolution of the monolayer properties.
在本文中，我们提出了一种追踪微粒并连接其轨迹的策略，该策略适用于研究由模式耦合不稳定性引起的准二维复杂等离子体晶体的熔化。由于微粒运动的三维特性以及照明激光片的不均匀性，两帧之间散射光强度可能会发生显著变化，这使得微粒的检测及其轨迹的连接极具挑战性。借助基于使用两种不同内核宽度对原始帧进行高斯模糊处理的两遍噪声去除过程，信噪比提高到了一个水平，使得能够对图像的不同区域进行更好的强度阈值处理，从而能够追踪照明不佳的微粒。然后，通过根据微粒的先前位置预测其位置，可以重建较长的微粒轨迹，从而能够准确测量微粒能量的演化以及单层特性的演化。
