Correlating Intrinsic Parameters and Sharpness for Condition Monitoring of Automotive Imaging Sensors

Kettelgerdes, Marcel; Bohm, Lena; Elger, Gordon

doi:10.1109/icsrs53853.2021.9660665

Cited by 7 publications

(1 citation statement)

References 16 publications

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“…Literature [2][3][4][5] shows that temperature fluctuations result in performance degradation by defocusing due to housing deformation and lens expansion, imaging errors due to thermal mismatch between lens and lens carrier and interconnects, creep in solder joints, and adhesive shrinkage, among others. Authors in [6][7][8] report about the various aberrations introduced into the system by the tilt and decentering of the lens elements.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of thermally-induced change in sharpness of automotive cameras by coupled thermo-mechanical and optical simulation

Pandey,

Unruh,

Kettelgerdes

et al. 2023

SPIE Future Sensing Technologies 2023

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This paper investigates the change in optical performance in a multi-element lens objective from a series production automotive camera, due to elevated temperature. The change in optical performance is evaluated by a coupled thermomechanical and optical finite element (FE) simulation. The change in the overall geometry of the objective at 85°C is calculated by thermo-mechanical simulation and caused by the expansion of individual elements. In addition, the change in the surface geometry of the lenses is obtained after smoothening the distorted FE mesh. Optical simulations are performed afterward on the deformed objective to evaluate the optical parameters including MTF (modulation transfer function) at 60 line pairs per millimeter (lp/mm). A shift of the best focus position of the lens is observed. Simulated MTF values are validated by measuring the MTF at 60 lp/mm of 10 lens samples by heating it in-situ on the measurement system. It is seen that change in MTF is about 10 percent when the lens is heated from room temperature to 85°C. Coupled optical simulations indicate the presence of astigmatism and coma, implying the asymmetric change in lens geometry at elevated temperature and tilt in one or more lens elements.

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