I-Corps: Fringe Projection Profilometry for Precision Surface Metrology

这个i-Corps项目的更广泛的影响/商业潜力是开发一种精密曲面的快速测量系统。拟议的技术旨在设计和制造亚毫米射电望远镜和卫星通信天线，这些望远镜和卫星通信天线需要严格的表面公差，并根据严格的表面精度要求大量生产面板。目前，用于高精度测量表面的方法有很多。然而，它们在大小、空间分辨率和对接触的敏感度方面都受到限制。其他方法，如坐标测量机(CMM)和激光跟踪器，涉及单点测量，因此非常慢。这项拟议的技术旨在以亚毫米的空间分辨率和极高的精度在几分钟内测量米级面积。此外，所提出的技术可用于最终组装的反射盘的对准，这通常是使用全息照相术或具有手动基准的商业摄影测量系统来完成的。在全息照相法的情况下，这两种应用都需要大量的准备时间、硬件和可用的卫星信标信号。未来的射电望远镜将需要更高的精度、更大的碟子和更大的数量。这个I-Corps项目是基于条纹投影摄影测量的发展。该技术使用廉价的现成硬件来快速测量高分辨率的自由曲面。这项技术的工作原理是将一系列条纹图案投射到待测量的曲面上。两个摄像头使用立体视觉在三维空间中对投影图案中的特征位置进行三角测量。专有算法处理摄像头记录的图像，以生成具有三维坐标的密集点云，这些点云绘制出表面的形状。整个过程只需要几分钟，不需要根据要测量的形状定制光学元件或硬件。这使得建议的技术对于大批量、大规模定制制造过程来说是最优的。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this I-Corps project is the development of a rapid measuring system for precision curved surfaces. The proposed technology is aimed at the design and fabrication of submillimeter radio telescopes and satellite communication antennas, which require tight surface tolerances, with panels produced in large quantities according to strict surface accuracy requirements. There are currently many methods used for measuring surfaces with high accuracy. However, they are limited on size, spatial resolution, and sensitivity to contact. Other methods such as coordinate measuring machines (CMM) and laser trackers, involve single point measurements and, therefore, are very slow. The proposed technology is designed to measure meter-scale areas with sub-millimeter spatial resolution and with extreme accuracy in a few minutes. In addition, the proposed technology may be used the alignment of a final assembled reflector dish, which is generally done using holography or commercial photogrammetry systems with manual fiducials. Both applications require significant preparation time, hardware, and an available satellite beacon signal in the case of the holography method. Radio telescopes of the future will require higher accuracy, larger dishes, and in higher quantities. This I-Corps project is based on the development of fringe projection photogrammetry. The proposed technology uses inexpensive, off-the-shelf hardware to rapidly measure freeform curved surfaces in high resolution. The technology works by projecting a series of fringe patterns onto the curved surface to be measured. Two cameras use stereo vision to triangulate the location of features in the projected patterns in three-dimensional space. Proprietary algorithms process images recorded by the cameras to generate a dense cloud of points with three dimensional coordinates that map the shape of the surface. This entire process takes only a few minutes and does not require custom optics or hardware based on the shape to be measured. This makes the proposed technology optimal for high volume, mass customization fabrication processes.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.