Single-shot structured light with diffractive optic elements for real-time 3D imaging for collaborative logistic scenarios

Single-shot structured light with diffractive optic elements for real-time 3D imaging for collaborative logistic scenarios

We present a novel concept for 3D or multimodal imaging based on the principle of structured light to be used in collaborative scenarios with mobile transport robots. The system consists of a standard CMOS camera and a projector that generates a single coded light pattern using a diffractive optical element (DOE). The sensor is intended to enable the design of dynamic and adaptive logistics processes that are characterised by diverse and unpredictable events. The novelty of the proposed system for triangulation-based 3D reconstruction is the special coding of the light patterns, which ensures high robustness and efficiency of 3D data generation. The pattern is based on a perfect submap, a matrix of pseudorandomly distributed dots in which each submatrix of fixed size is different from the others. Given the size of the working space and known geometrical parameters of the optical components, we derive important design constraints such as uniqueness window size and min.minimal Hamming distance for an optimal pattern. We examine practically how the pattern constraints affect the quality of the 3D data and compare our proposed encoding with single-shot patterns that are known from the literature. Furthermore, we propose a real-time processing pipeline that converts an image of the captured dot pattern into a high-resolution 3D point cloud using an algorithmically efficient pattern decoding approach. Finally, we show how we overcame challenges of the application such as eye safety, large horizontal field of view, high point dot density, and corresponding large number of points dots in when designing and fabricating the DOE.

Fulltext Access

https://doi.org/10.1117/12.2675818

Citing

@inproceedings{vehar2023singleshot,
  author    = {Darko Vehar and Andreas Hermerschmidt and Rico Nestler and Karl-Heinz Franke},
  title     = {Single-shot structured light with diffractive optic elements for real-time 3D imaging for collaborative logistic scenarios},
  booktitle = {Digital Optical Technologies 2023},
  series    = {Proceedings of SPIE},
  volume    = {12624},
  pages     = {126240V},
  year      = {2023},
  note      = {Proc. SPIE 12624, Digital Optical Technologies 2023, 126240V (7 August 2023)}
}