A customizable digital holographic microscope

We propose a low-cost, compact, and portable holographic microscope designed for the characterization of micrometric particles suspended in a liquid.
This system is built around a commercial optical microscope by substituting its illumination source (a light-emitting diode) with a collimated laser beam. Similarly, a quartz flow cell replaces the microscope glass slide using 3D-printed custom mounting.
With the hardware presented in this paper, the holographic imaging of the electromagnetic fields emitted by the objects that intercept the laser beam achieves a resolution close to that achieved with optical microscopes, but with a much larger depth of field.
Once a hologram is recorded, a variety of morphological and optical features, including particle projected section, aspect ratio, and extinction cross-section can be extracted.
Additionally, we introduce a remote system control that enables users to process the acquired holograms to a remote computational device.
This work encompasses a comprehensive description of the methodology of the image processing in holographic microscopy, and a series of validation measurements conducted using calibrated particles. This technique is suitable for the characterization of airborne particles found in snow, firn and ice; here we report experimental results obtained from Alpine ice cores.

We include the 3d printer design files, the Holography tutorial in jupyter, and the files to control remotely the camera, the Pycamera project in python

本研究提出一款低成本、紧凑型且便携的全息显微镜（holographic microscope），用于表征悬浮于液体中的微米级颗粒。
该系统以商用光学显微镜为核心架构，将其照明光源（发光二极管，light-emitting diode）替换为准直激光束（collimated laser beam）；同理，采用3D打印定制支架的石英流通池（quartz flow cell）替代了显微镜载玻片。
依托本文提出的硬件方案，对拦截激光束的物体所辐射的电磁场进行全息成像，可获得与光学显微镜相近的分辨率，同时拥有显著更大的景深（depth of field）。
在记录得到全息图后，可提取出多种形态学与光学特征，包括颗粒投影截面、长径比（aspect ratio）以及消光截面（extinction cross-section）。
此外，本研究还引入了远程系统控制功能，支持用户将采集到的全息图传输至远程计算设备进行处理。
本研究全面阐述了全息显微镜图像处理的方法学流程，并开展了一系列使用校准颗粒的验证测试。该技术可用于表征雪、粒雪（firn）与冰中的大气悬浮颗粒，本文报告了取自阿尔卑斯冰芯的实验结果。
本研究附带3D打印机设计文件、Jupyter格式的全息学教程，以及用于远程控制相机的相关文件与Python语言编写的Pycamera项目。