Binocular fringe projection profilometry for the metrology of meter-scale optical surfaces

Abstract

Demand for better quality, larger quantity, and size of astronomical telescopes from visible to radio frequencies is increasing. More rapid, efficient, and adaptable manufacturing processes are needed to support the needs of growing science and engineering communities in these fields. To aid the development and execution of these new processes, a flexible, accurate, and low-cost metrology system is needed. This paper outlines a variety of fringe projection profilometry (FPP) that has demonstrated high accuracy over large areas, making it a critical tool for manufacturing steel molds for forming primary reflectors and shape verification of the reflectors themselves used for radio astronomy.

Systematic Radio Telescope Alignment Using Portable Fringe Projection Profilometry

“…Oftentimes, the use of multiple methods is required. In 2022, our research group developed a metrology technique based on binocular fringe projection profilometry for measuring radio telescope panels in a laboratory setting to assist our research into the rapid fabrication of radio telescope panels [27]. As a demonstration of the panel forming technique, our research team is constructing a 2.4 m × 3.2 m radio telescope, known as the Student Radio Telescope (SRT), using our own fabricated panels [28].…”

“…However, as panels approach one or even two meters in size, CMMs become more costly, and data collection becomes very slow. In 2022, our team developed a technique for measuring panels and panel molds with a modification to fringe projection profilometry (FPP) [27]. The method uses two calibrated cameras (using Zhang's method [29]) as a stereo pair and a DLP projector.…”