Physically-based Model for Accurate Rendering of Atmospheric Laser Scattering

The off-axis detection and characterization of laser scatter in the atmosphere has been demonstrated and modeled to different degrees of complexity and for varied applications. High-fidelity modeling of the laser-atmosphere interaction is central to detection capability. We present the requirements for a fully physically-based model to synthetically render radiometrically accurate images of a laser scattering in the atmosphere by implementing a system that simulates light physics in relation to a camera and a particle system. The system uses ambient lighting in conjunction with a laser system to simulate light transfer in a participating medium; photons from the source are modeled using a photon mapping procedure. The physically-based modeling system also includes relevant solid objects along with their material properties, e.g., object color and albedo. Additionally, the system includes the effect of a microscopic particle system that affects the lighting of the solid objects. Since physically-based scene rendering is time consuming, we make use of high performance computing resources to ensure the accuracy in the generated scenes. To increase the speed of model development, we utilize lower-fidelity preview displays in WebGL to determine the energy stored in solid objects and particulates in the scene prior to submitting software to run on high performance computing resources. The final output from the model includes a water system and an open sky in addition to the laser and atmosphere.