Design and manufacturing of an optimized retro reflective marker for photogrammetric pose estimation in ITER

TL;DR

This paper presents the design, optimization, and testing of a new retro reflective marker based on the cat's eye principle, significantly improving photogrammetric pose estimation in the challenging environment of ITER.

Contribution

It introduces a novel methodology for optimizing retro reflector design for ITER, overcoming environmental constraints and doubling performance over previous solutions.

Findings

Achieved around 100% performance gain in the targeted range.

Developed a marker fulfilling all ITER application requirements.

Validated the design through modeling, manufacturing, and testing.

Abstract

Retro reflective markers can remarkably aid photogrammetry tasks in challenging visual environments. They have been demonstrated to be key enablers of pose estimation for remote handling in ITER. However, the strict requirements of the ITER environment have previously markedly constrained the design of such elements and limited their performance. In this work, we identify several retro reflector designs based on the cat's eye principle that are applicable to the ITER usecase and propose a methodology for optimizing their performance. We circumvent some of the environmental constraints by changing the curvature radius and distance to the reflective surface. We model, manufacture and test a marker that fulfils all the application requirements while achieving a gain of around 100\% in performance over the previous solution in the targeted working range.