Infrared Flight Simulation Using Computer Generated Imagery

Abstract

A sophisticated deterministic interactive software model for computer generation of three -dimensionally projected infrared scenes has been developed. Scenes can be produced using either a self-emission or near infrared reflectance model. The software allows for generation of flight paths through a data base consisting of both feature and topography and near real -time display of stored precomputed images.The emphasis in the model development has been in computer generation of infrared scenes which accurately reproduce the characteristics of real -world imagery. The software combines computer graphics and infrared physics to produce synthetic scenes with the statistical properties of real scenes. Options exist for generation of images in near -infrared, 3 -5 or 8 -12 micron spectral bands including atmospheric attenuation effects. The threedimensional projection algorithms allow for viewing of the scenes from any geometry and include concave and convex surfaces as well as hidden objects. Features exist for insertion of additional objects into the three -dimensional scenes.Thus targets, buildings, and other natural or man -made objects can be inserted with any orientation anywhere in the scenes. This allows full simulation of varying depression angles, range closure, and fly -over.The three -dimensional infrared background clutter model is an evaluation tool capable of both assessing system performance in clutter and increasing our understanding of clutter itself. The model in its current form represents a powerful tool for the fundamental understanding of infrared clutter. Possible applications include, but are most certainly not limited to, sensor operator training in the area of target discrimination with dynamic imagery, evaluation of automatic target recognizer (ATR) algorithms, and simulations allowing pilots to pre -fly missions. Model descriptionA variety of internally and externally funded tasks have contributed to the threedimensional background clutter model in its current state. The Advanced Sensors and Guidance and Controls Directorates at USAMICOM have to date been the primary sponsors of this work. Reports [1,2] on previous model developments document the algorithmic techniques during stages of complexity to both backgrounds and inserted objects. The most recent model developments discussed herein involve further development of the scene simulation software. A model improvement has been added which allows for computation of near -infrared radiance maps through a solar reflectance model utilizing a point source and associated class object Lambertian reflectivities.A further improvement to the exisiting three-dimensional background clutter model is incorporation of a flight path generation algorithm which is highly interactive and uses inputs from the cursor of the image processing system. In addition, an atmospheric attenuation model has been incorporated into the three -dimensional projection code with the user specifying an extinction coefficient. All of the various models described above have been...