光场显微成像微尺度流动可视化及三维流场测量方法研究

Microfluidic flow dynamics is one of fundamental research subjects in the field of microfluidics. Investigation into the new measurement techniques for microfluidic flow is one of important directions in engineering thermodynamics and energy utilization field and is also a pressing problem to be solved in the experiments of microfluidic flow. The objective of the project is to investigate a novel method for visualization and three-dimensional velocity field measurement of microfluidic flows using light field microscope in microfluidic devices. Through the combination of conventional microscope and micro-lens array, the multi-perspective views of three-dimensional microfluidic flow can be captured in a single photograph, and the useful perspective views represent a new way to look at microscopic flow. In this project, light field microscopy for semi-transparent media will be proposed, and the imaging model of light field microscope will then be integrated including microscopic lens and micro-lens array and its performance such as depth of field and axial and angular resolutions will be tested. Tomographic and three-dimensional deconvolution algorithms for reconstructing the micro-scale flow structure will be studied numerically and experimentally, and further a modified cross-correlation method is used to derive the three-dimensional velocity field, considering the microfluidic flow characteristics such as low reynolds number. Finally a light field Micro-PIV system based on a single camera and light field microscope will be built and evaluated experimentally under laboratory conditions. The project is expected to break through the mutual constraints between measurement volume, the axial resolution and lateral resolution of the conventional micro-particle imaging velocimetry for three-dimensional flow field measurement. Based on the ultimate research results of this project, a measurement method for three-dimensional velocity field using light field microscope will be presented, which will provide a novel measurement technique for improving the research of the microfluidic flow dynamics.

微尺度流动是微流控系统研究的基础性问题，探索其测试分析新方法是工程热物理领域的重要基础研究内容之一，也是当前国际上微流动特性实验研究的前沿和难点问题。本项目提出一种单相机光场显微成像微尺度流动可视化及三维流场测量方法，通过常规显微成像系统与微透镜阵列相结合，单次曝光可获得大景深、多视角的三维流动光场信息，提供了一种新的微流动可视化方法。项目将具体开展半透明介质光场显微成像模型、显微镜与微透镜阵列相结合的光场显微成像系统、层析/三维反卷积算法重构微尺度流动三维结构与速度场计算方法、单相机光场Micro-PIV系统集成与性能评价及优化等方面的研究。该项目有望突破微流动三维流场测量技术存在的测量体体积、轴向分辨率和横向分辨率之间相互制约的矛盾，建立一套较完整的微尺度三维流场测量方法，丰富研究手段，提高对微尺度流动过程的认识水平。

微尺度流动是微流控系统研究的基础性问题，探索其测试分析新方法是工程热物理领域的重要基础研究内容之一，也是当前国际上微流动特性实验研究的前沿和难点问题。本项目开展了单相机光场显微成像微尺度流动可视化及三维流场测量方法研究，通过常规显微成像系统与微透镜阵列相结合，单次曝光可获得大景深、多视角的三维流动光场信息，进而发展了一种新的微流动可视化方法。项目具体开展了半透明介质光场显微成像模型、显微镜与微透镜阵列相结合的光场显微成像系统、层析/三维反卷积算法重构微尺度流动三维结构与速度场计算方法、单相机光场Micro-PIV系统集成与性能评价及优化等方面的研究。构建的光场Micro-PIV在硬件上高度集成，结构紧凑、易于标定，降低了系统同步控制和标定等技术的复杂程度，突破了传统三维流场PIV测量技术存在的测量体体积小、轴向分辨率和平面分辨率之间矛盾，为三维流场测试提供了新方法。项目执行期间，构建并开发了光场Micro-PIV系统；国内外期刊发表论文33篇，国内外会议论文12篇，其中SCI收录20篇，EI收录13篇；应邀在国内学术会议上做大会报告/邀请报告4次；授权中国发明专利4项，申请中国发明专利5项。培养博士生2名、硕士生4名；项目负责人许传龙教授获2020度中国颗粒学会青年颗粒学奖，并入选2018年江苏省“333高层次人才培养工程”培养计划。