Stray light analysis: image quality of camera system in 3D scene

Stray light analysis is crucial to mitigate the contribution from unwanted light and address issues such as lens flare, light leakage, scattered light or ghosting in high-quality optical systems like camera systems. Stray light can be analyzed using physical prototypes or with simulation. Traditional simulation approaches to analyze stray light can be complicated to setup and time-consuming. In addition, it is important to evaluate the contribution of stray light within the final application environment. The mitigation of stray light done by the lens and mechanical designer can be different depending on the end application. To overcome these challenges, we describe how you can evaluate the image quality of a camera system for a specific application with an acceptable simulation time considering the impact of stray light. The use case consists of taking a picture of a landscape from a cellphone camera with sunlight. The analysis considers stray light from both optical and non-optical components within a 3D-scene under realistic illumination conditions. In this case study, we will highlight the method to converge efficiently and quickly to the final image quality result. The cellphone camera lens is designed with Ansys Zemax OpticStudio®. The mechanical components and the optical properties of the imager are imported into Ansys Speos® for system level analysis in the 3D scene. Leveraging GPU computation and specific functionalities to improve simulation efficiency, we can converge toward a highly detailed result in a reasonable simulation time.