Methodology to Evaluate the Performance of Portable Photogrammetry for Large-Volume Metrology

Abstract

The increased relevance of large-volume metrology (LVM) in industrial applications entails certain challenges: measurements must be cost-efficient and the technologies must be easy to use while ensuring accuracy and reliability. Portable photogrammetry shows great potential to overcome such challenges, but industrial users do not yet rely on its accuracy for large scenarios (3 to 64 m), especially when mass-market cameras are not conceived of as industrial metrology instruments. Furthermore, the measurement results might also depend on the operator’s skills and knowledge of the key process variables. In this work, a methodology was designed so that the measurement uncertainty of portable photogrammetry can be evaluated under controlled conditions for LVM. To do so, PTB’s reference wall, which was designed to assess laser-based methods applied to large volumes, was used as a reference artefact to study the measurement performance under different conditions, enabling an analysis of the relative influence of two process variables: the spatial arrangement of the optical instruments on the scene, and the relative camera poses for an accurate triangulation. According to these variables, different measuring conditions were designed (Monte Carlo analysis), and experimentally evaluated and reported (LME, length measuring errors), analysing the performance figures expected from both unskilled and expert users.

Fast and accurate Zero-defect manufacturing using collaborative real-time photogrammetry

“…The use of these components, along with optical targets placed on the object for reconstructing their accurate position via closerange photogrammetry, has had a crucial role in measuring largevolume raw parts that must be machined with high-level precisions. (Puerto et al, 2022). Through the calibration and orientation of multi-camera systems for LVM, it is possible to highly increase accuracy, reaching levels of precision that come close to those of a laser tracker (LT), which also makes use of spherically mounted retroreflectors (SMRs) to achieve low measurement uncertainties for large volumes, but with a much smaller financial impact and with increased levels of automation, reducing the need of human intervention (Leizea et al, 2023).…”

Industrial photogrammetry for the optical mechanical truss of the China Survey Space Telescope

“…Its high-precision deformation measurement network has been introduced. The accuracy evaluation methods and standards of photogrammetry are still an area that has not been completely determined, especially in large-scale measurement applications, whose accuracy has not been relied on by industrial users [11]. This paper provides a successful case of industrial photogrammetry in the case of large size objects, which can provide a reference for the measurement of industrial photogrammetry accuracy.…”

Optical Characterization of Materials for Precision Reference Spheres for Use with Structured Light Sensors

“…These spheres are intended for the calibration of coordinate metrology equipment [41] and reverse engineering. Additionally, for digitized oriented systems, these spheres can also be used as registration targets in digitizing large objects or groups of objects that require high accuracy [43][44][45][46].…”