UmUTracker: A versatile MATLAB program for automated particle tracking of 2D light microscopy or 3D digital holography data

We present a versatile and fast MATLAB program (UmUTracker) that automatically detects and tracks particles by analyzing video sequences acquired by either light microscopy or digital in-line holographic microscopy. Our program detects the 2D lateral positions of particles with an algorithm based on the isosceles triangle transform, and reconstructs their 3D axial positions by a fast implementation of the Rayleigh-Sommerfeld model using a radial intensity profile. To validate the accuracy and performance of our program, we first track the 2D position of polystyrene particles using bright field and digital holographic microscopy. Second, we determine the 3D particle position by analyzing synthetic and experimentally acquired holograms. Finally, to highlight the full program features, we profile the microfluidic flow in a 100μm high flow chamber. This result agrees with computational fluid dynamic simulations. On a regular desktop computer UmUTracker can detect, analyze, and track multiple particles at 5 frames per second for a template size of 201 × 201 in a 1024 × 1024 image. To enhance usability and to make it easy to implement new functions we used object-oriented programming. UmUTracker is suitable for studies related to: particle dynamics, cell localization, colloids and microfluidic flow measurement.

本报告推出一款多功能且高效的 MATLAB 程序（UmUTracker），该程序能够通过分析由光学显微镜或数字在线全息显微镜获取的视频序列，自动检测和追踪粒子。程序采用等腰三角形变换算法检测粒子的二维横向位置，并通过快速实现的瑞利-索末菲尔德模型，利用径向强度分布重建其三维轴向位置。为确保本程序精度与性能，我们首先利用明场和数字全息显微镜追踪聚苯乙烯粒子的二维位置；其次，通过分析合成和实验获取的全息图确定粒子的三维位置；最后，为彰显程序全面特性，我们对100μm高流量室内的微流体流动进行了分析。该结果与计算流体动力学模拟相符。在常规台式计算机上，UmUTracker 能够以每秒5帧的速度检测、分析和追踪模板大小为201 × 201像素的多个粒子，图像分辨率为1024 × 1024像素。为提升易用性并便于实现新功能，我们采用了面向对象编程。UmUTracker适用于与粒子动力学、细胞定位、胶体以及微流体流动测量相关的各项研究。