Laser scanning module with large sending aperture and inherent high angular position accuracy for 3D LiDAR

Jürgen Hasselbach; Siegwart Bogatscher; Christian Rembe

doi:10.1117/12.2520351

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11 April 2019 Laser scanning module with large sending aperture and inherent high angular position accuracy for 3D LiDAR

Jürgen Hasselbach, Siegwart Bogatscher, Christian Rembe

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Proceedings Volume 11028, Optical Sensors 2019; 1102804 (2019) https://doi.org/10.1117/12.2520351
Event: SPIE Optics + Optoelectronics, 2019, Prague, Czech Republic

Abstract

One design of state of the art laser scanner systems in automotive applications is based on oscillating mirror modules. The requirement of a large mirror surface for eye-safe transmission beams is a major drawback for fast and reproducible scanning. Tolerances of angular positioning, position sensing as well as vibrational perturbations limit the position accuracy of such a mirror and thus, the accuracy of the transmission spot position in the field of view (FoV). In contrast to scanner modules, Flash LiDAR systems provide high accuracy of spot positions. However, due to simultaneous illumination of the entire FoV, the maximum measurable range degrades. Our approach for a scanner module, presented in this paper, combines a micro lens array (MLA) with an objective lens for generating one optical telescope assembly for each angular scan position exclusively. The consequence is a maximum transmission beam diameter without angular FoV reduction along with minimum mirror dimensions. In order to avoid shadings between adjacent scan spots in the target distance, created by beam cut-offs at the aperture-stop of the objective lens, an array of optimized optical elements is provided additionally to the MLA. With adequate design of the MLA, the reliability of the scanner module regarding the angular positioning accuracy increases significantly. We demonstrate that the noise of the spot position is suppressed in dependence on the aperture-stop dimensions of the MLA. In conclusion, we present a new solution for a 3D LiDAR scanner module with a reliable spot-position accuracy comparable to 3D-camera/Flash LiDAR systems but with higher distance measurement range.

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Jürgen Hasselbach, Siegwart Bogatscher, and Christian Rembe "Laser scanning module with large sending aperture and inherent high angular position accuracy for 3D LiDAR", Proc. SPIE 11028, Optical Sensors 2019, 1102804 (11 April 2019); https://doi.org/10.1117/12.2520351

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