Optical Signature Modeling of Transmissive Materials

The purpose of this effort is to demonstrate the viability of algorithms for calculating the temperatures and optical (visible and infrared) signatures of objects (e.g., targets) containing transmissive and partially transmissive materials. Industry-standard codes such as the Optical Signatures Code (OSC) and OPTISIG assume that all materials are opaque, which can lead to substantial errors in the calculation of the signatures of these targets. Though measurements of material transmissivity exist, these codes cannot properly use the measurements. Proven first principles techniques, such as ray-tracing, can be used to account for the complex thermal and optical phenomenology, but require parallelization and methodologies for balancing computational times and accuracy. In this Phase I effort, multiple algorithms for calculating the thermal (emitted) component of the signature (e.g., ray tracing, modified radiosity) and the reflected component of the signature (forward and backward ray-tracing, photon mapping) will be evaluated for computational speed and compared to existing high-fidelity codes. The result will be candidate algorithms for augmenting existing OSC/OPTISIG methodologies which will more accurately predict the optical signatures of future complex targets and countermeasures. Approved for Public Release | 16-MDA-8917 (15 November 16)