SHIPIR: a model for simulating infrared images of ships at sea

SHIPIR is a model which simulates infrared images of ships at sea. The model is divided in five main modules. The ship model definition module defines the ship geometry, the thermal plates, the radiative surfaces, and the user-specified thermal boundary conditions. The simulation condition definition module gathers all necessary inputs to simulate a specific IR image. The background irradiance computation module runs Lowtran7 to compute atmospheric transmittance and radiance, direct solar irradiance and sea irradiance on the ship and the observer. The heat transfer solution is then computed with a steady-state algorithm, generating the ship surface temperatures. The infrared scene generation module creates the scene as viewed by an observer in a predefined waveband and at a position that can be changed interactively. A simple IR plume image is also generated at this stage. This paper describes the different modules that are part of the model. Examples of the outputs generated with a baseline scenario are given. The steps and results of a validation experiment performed with data from two instrumented plates are highlighted.