EAGER: A Novel Hybrid Light-Field and High-Energy Pulse Color and Depth Encoded Illumination PIV Technique for Unsteady Flow Analyses

粒子图像测速技术（PIV）经常用于研究随时间变化的流体流动，如空气动力流动和生理流动。三十多年来，这一直是黄金标准，也是获取二维流动信息的有效技术。层析PIV作为一种流量测量技术，在复杂的流体流动情况下获得三维流动信息。然而，这种方法是昂贵的，因为它需要多个相机设置（通常是4到6个昂贵的相机），复杂的流图像重建技术，结果通常限于相机对准，这往往导致轴向分辨率差。最近的工作表明，使用单光场相机设置可以获得3D PIV测量。然而，轴向分辨率仍然有限。因此，本研究项目旨在通过开发和验证一种新型3D PIV技术来解决这些限制，该技术结合了一个单光场彩色相机，一个高能脉冲彩虹照明光束，用于生成颜色编码和粒子深度信息，以及一个内部开发的粒子和流重建算法。该方法将改善轴向分辨率的限制，并将显著提高学术界、工业界和国家实验室流体流量测量系统的能力。粒子和流算法和验证将传播给广泛的潜在用户。本研究的教育部分将把工程分析研究转化为课堂，并通过针对社区学院和大学本科生的学生来提高工程招聘和保留。本研究项目旨在开发一种新的3D PIV技术，该技术包括单光场相机，高能脉冲色深编码光束，交替方向乘法器（ADMM）和用于粒子位置和流重建的改进的Horn-Schunck光流算法。基本上，光场相机将捕获高能光束照射下粒子的二维（2D）角度、空间和颜色深度编码信息，与目前的3D PIV方法相比，提供更高分辨率的粒子重建。这项研究工作将解决与系统开发、系统校准、测量验证相关的问题，并检查该技术在复杂流动实验中实现三维流动测量的能力，并提高轴向分辨率。如果成功，这项新技术将为从航空到生物医学等所有领域的研究人员和工程师提供高3D轴向分辨率测量能力，从而对国家的工业和研究基础设施产生间接但非常广泛的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Time dependent fluid flow such as aerodynamic and physiological flow are often studied experimentally using particle image velocimetry (PIV). This has been the gold standard for over three decades and has been an effective technique to acquire two-dimensional flow information. Tomographic PIV emerged as a flow measurement technique to obtain three-dimensional (3D) flow information in complex fluid flow scenarios. However, this method is costly as it requires a multiple camera setup (typically 4 to 6 expensive cameras), a complex flow image reconstruction technique and the results are typically limited to the camera alignment which often results in poor axial resolution. Recent work has shown that it is possible to obtain 3D PIV measurements using a single light field camera setup. However, the axial resolution remains limited. As a result, this research project aims to address these limitations by developing and validating a novel 3D PIV technique that incorporates a single light field color camera, a high energy pulsed rainbow illumination beam for generating color coded and particle depth information, and an in-house developed particle and flow reconstruction algorithm. This method will improve limitations in axial resolution and will significantly advance capabilities of fluid flow measurement systems in academia, industry, and national laboratories. The particle and flow algorithms and validations will be disseminated to a wide range of potential users. The educational component of this research will translate engineering analysis research to the classroom and enhance engineering recruitment and retention by targeting students from community colleges and university undergraduate students.This research project aims to develop a novel technique for 3D PIV that incorporates a single light-field camera, a high-energy pulse color-depth encoded beam, an alternating direction of multipliers (ADMM) and modified Horn-Schunck optical flow algorithm for particle position and flow reconstruction. Fundamentally, the light field camera will capture two-dimensional (2D) angular, spatial, and color-depth encoded information of particles illuminated by the high-energy beam, providing higher resolution particle reconstruction compared to current 3D PIV approaches. This research effort will address issues related to system development, system calibration, validation of measurements, and examining the technique’s ability to achieve 3D flow measurements in complex flow experiments with improved axial resolution. If successful, this novel technique will provide high 3D axial resolution measurement capabilities to researchers and engineers in all areas ranging from aeronautics to biomedical, thus having an indirect yet very broad impact on the nation’s industrial and research infrastructure.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.