DIRS Laboratory 76-3215
July 12, 2019 at 10:00am
Keegan McCoy
Ph.D. Thesis Defense
Abstract: 

Abstract

 

Stray light, any unwanted radiation that reaches the focal plane of an optical system, reduces image contrast, creates false signals or obscures faint ones, and ultimately degrades radiometric accuracy. These detrimental effects can have a profound impact on the usability of collected remote sensing data, which must be radiometrically calibrated to be useful for scientific applications (e.g. Landsat imagery).  Understanding the full impact of stray light on data scientific utility is of particular concern for lower cost, more compact imaging systems, which inherently provide fewer opportunities for stray light control. To address these concerns, this research presents a general methodology for integrating point spread function (PSF) and stray light performance data from optomechanical system models in optical engineering software with a physics-based image and data simulation model.  This integration method effectively emulates the PSF and stray light performance of a detailed system model within a high-fidelity scene, thus producing realistic simulated imagery.  This novel capability enables system trade studies and sensitivity analyses to be conducted on parameters of interest, including those that influence stray light, by analyzing their quantitative impact on user applications when imaging realistic operational scenes, while also informing the writing of system requirements.  In addition to detailing the methodology’s radiometric framework, we describe the collection of necessary raytrace data from an optomechanical system model (in this case, using FRED Optical Engineering Software), and present PSF and stray light component validation tests through imaging Digital Imaging and Remote Sensing Image Generation (DIRSIG) model test scenes.  The integration method’s ability to produce quantitative metrics to assess the impact of stray light-focused system trade studies on user applications is then demonstrated using a Cassegrain telescope model and stray light-stressing coastal scene under various system and scene conditions.