Advancing plenoptic / lightfield imaging for optical diagnostics

在学术和工业应用中，对流体运动、空气动力学和微尺度流动的实验研究现在由数字技术主导。照相机用于拍摄示踪粒子的图像，这些示踪粒子被播种到流动中以跟踪它们的运动，从而推断流体运动。这项基于粒子图像测速（PIV）和粒子跟踪测速（PTV）的技术在过去的30年里已经发展到现在甚至可以与最详细的计算机模拟兼容。重要的是，这些实验技术包括所有的物理流动问题。然而，它们可能是昂贵的，需要大量的专业知识来设置和操作。将研究、调查和开发一种从单个相机收集三维（3D）颗粒位置图像的新方法，作为我开发光学仪器的持续研究计划的一部分。它是基于收集相机看到的整个光场，而不仅仅是由主透镜聚焦的光场。被称为光场或全光成像，相机在传感器前面具有微透镜阵列，其允许颗粒位置的小角度透视观察。在很多方面，这与有复眼的昆虫看待世界的方式相似。这种类型的成像系统，仅使用一个摄像头，有望在流动系统中更容易安装和设置，特别是在查看访问受限的情况下。它还将允许，第一次，在微观尺度上的三维流动，如在多孔介质和微观生物流动的透视观察是非常有限的流动的现实测量。水滴在表面上的蒸发已经引起了很多学术兴趣，并且在其中进行测量极具挑战性，将用于测试其使用的技术和理论的局限性。该计划将继续开发这种类型的相机系统，通过解决一些基本问题，其中有有限的研究文献中的实验使用。这些措施包括开发一个通用的校准程序，一个通用的光学模型的基础上，光线跟踪描述成像过程，图像数据的处理，以确定对象在三维空间和先进的方法的基础上PTV和粒子运动的数值模型，以提供高质量的流量测量。能够收集高质量的微尺度流动数据，目前有有限的方法，将在学术界和工业界产生重大影响，使人们能够理解重要问题的性质和科学，如扩散和蒸发。该计划还将培养学生在机械工程，光学仪器和流体力学领域，开发新的知识和科学。学生将在专业的环境中工作，接受补充培训，使他们受到业界和学术界的高度追捧。

Experimental research into the motion of fluids, aerodynamics and microscale flows in academic and industrial applications is now dominated by digital techniques. Cameras are used to take images of tracer particles seeded into the flow to track their movement, inferring fluid motion. This technology, based on particle image velocimetry (PIV) and particle tracking velocimetry (PTV) has been developed over the last 30 years to a point where it is now compatible with even the most detailed computer simulations. Importantly, these experimental techniques include all of the physics of the flow problem. However, they can be costly and require significant expertise to set up and operate. _A new approach to collect images of particle locations over three dimensions (3D) from a single camera will be researched, investigated and developed, as part of my continuing research program developing optical instrumentation. It is based on collecting the entire light field seen by the camera, not just what is brought into focus by the main lens. Termed light-field or plenoptic imaging, the camera has a microlens array in front of the sensor that allows small angle perspective viewing of particle locations. In many ways, this is similar to how insects with compound eyes view the world. This type of imaging system, using only a single camera, promises to be significantly easier to install and setup in a flow system, especially where viewing access is limited. It will also allow, for the first time, realistic measurement of three-dimensional flows at the microscale such as the flow in porous media and microscale biological flows where perspective viewing is extremely limited. The evaporation of a water droplet on a surface, which has received much academic interest and is extremely challenging within which to take measurements, will be used to test the limits of the technique and theory of its use. The program will continue to develop this type of camera system for experimental use by addressing a number of fundamental question for which there is limited research available in the literature. These include developing a general calibration procedure, a general optical model based on ray tracing to describe the imaging process, processing of image data to define objects in 3-D space and advanced approaches based on PTV and numerical models of particle motion to provide high-quality flow measurement. Being able to collect high quality data at the microscale flows, for which there are currently limited approaches, will have significant impact both in academia and industry, allowing understanding of the nature and science of important problems such as diffusion and evaporation. The program will also train students in the areas of mechanical engineering, optical instrumentation and fluid mechanics, developing new knowledge and science. Students will work in a professional environment, receiving supplementary training making them highly sought after by industry and academia.