Comprehensive stray light (flare) testing: Lessons learned

Abstract

Stray light (also called flare) is any light that reaches the detector (i.e., the image sensor) other than through the designed optical path. Depending on the mechanism causing stray light, it can introduce phantom objects (ghosts) within the scene, reduce contrast over portions of the image, and effectively reduce system dynamic range. These factors can adversely affect the application performance of the camera and, therefore, stray light measurement is to be included in the upcoming IEEE-P2020 standard for measuring automotive image quality. The stray light of a camera can be measured by capturing images of a bright light source positioned at different angles in (or outside of) the camera’s field of view and then processing those captured images into metric images with associated summary statistics. However, the setup and light source can have a significant impact on the measurement. In this paper, we present lessons learned and various technical elements to consider for stray light (flare) testing of digital imaging systems. These elements include the radiometric (e.g., brightness) and geometric (e.g., size) qualities of the light source and setup. Results are to be presented at the conference.