MRI: Development of an Intensified KHz Rate Plenoptic Camera System for 3D Flow Diagnostics

从血液流经人工心脏瓣膜到现代喷气发动机中燃料和空气的混合和燃烧，许多流动都是不稳定的和三维的。然而，用于研究、测试和评估这些流场的现代诊断方法是缓慢的和二维的，或者在多摄像机3D诊断的情况下，昂贵和复杂。在这个项目中，研究团队将开发一种新的成像系统，能够仅使用一台相机在实际流场中进行高速3D测量。开发的系统将比复杂的多摄像头系统更便宜、更紧凑、更容易安装，从而为世界各地的研究人员提供了一种可访问和负担得起的工具来进行高速3D流动测量。该成像系统将用于了解心脑血管流动，推进高速车辆设计研究，并提高发动机和发电燃烧系统的燃烧效率。此外，这里开发的技术将与更广泛的研究社区公开分享，以确保美国政府机构和行业的学生和研究人员获得信息。如此广泛的分布确保了开发的系统影响到最广泛的应用，涉及非稳定的3D流体流动。这种诊断的基础是增强型全光成像系统，能够以每秒1000帧以上的成帧速率测量3D标量和速度场。该系统由三个基本要素组成：(1)千赫兹增强型全光学摄像机和针对三维流动测量进行优化的照明源；(2)图像重建和速度估计算法，以渲染体积图像和估计速度场；(3)在可接受的时间框架内处理数据的计算平台。该系统的开发将使时间分辨的三维流动测量成为可能，包括粒子图像测速、化学发光成像、激光诱导荧光和背景定向纹影成像。拟议中的仪器是基于奥本大学研究人员建造的低帧频原型，该原型已被证明是一种简单、紧凑、健壮和有效的3D成像系统。该系统的模块化将使该系统能够针对不同的设施和技术进行优化，包括立体全光诊断，有可能显著提高体积测量的空间分辨率。

From blood flow through artificial heart valves to mixing and combustion of fuel and air in a modern jet engine, many flows are both unsteady and three-dimensional. Modern diagnostics used to study, test and evaluate these flow fields, however, are slow and two-dimensional or, in the case of multi-camera 3D diagnostics, expensive and complex. In this project, the research team will develop a new imaging system capable of making high-speed 3D measurements in practical flow fields using only a single camera. The developed system will be significantly cheaper, more compact, and easier to set up than complex multi-camera systems, thus providing researchers around the world with an accessible and affordable tool to make high-speed 3D flow measurements. This imaging system will be used to understand cardio- and cerebro-vascular flows, advance high speed vehicle design research, and improve combustion efficiency in engines and combustion systems for power generation. In addition, the technology developed here will be openly shared with the broader research community to ensure access for students and researchers across the U.S. government agencies and industries. Such wide distribution ensures that the developed system impacts the widest possible range of applications involving unsteady, 3D fluid flows.The basis for this diagnostic is an intensified plenoptic imaging system capable of measuring 3D scalar and velocity fields at framing rates in excess of 1,000 frames per second. The system consists of three essential elements: (1) a kHz rate intensified plenoptic camera and illumination source optimized for 3D flow measurements; (2) image reconstruction and velocity estimation algorithms to render volumetric images and estimate velocity fields; and (3) a computing platform that processes the data in an acceptable time frame. The development of this system will enable time-resolved, 3D flow measurements, including particle image velocimetry, chemiluminiscence imaging, laser induced fluorescence, and background oriented Schlieren imaging. The proposed instrument is based on a low frame-rate prototype built by investigators at Auburn University that has been demonstrated as a simple, compact, robust and effective 3D imaging system. The modularity of the system will allow the system to be optimized for different facilities and techniques, including stereo-plenoptic diagnostics with the potential to dramatically improve spatial resolution of volumetric measurements.