TAV-IR: a visible and near-IR radiometric analysis code which operates with an off-the-shelf computer animation package

Abstract

This paper describes a new image generation software code for creating radiometrically accurate images in the visible and near-infrared wavelength band. It was developed to evaluate pilot vision through aircraft windscreens and was written to operate in conjunction with an off- the-shelf computer animation software package. This capability allows the user to take advantage of the geometric modeling and motion generation capabilities inherent within the computer animation software for scene and scenario generation while using the new image generation codes for sensor modeling. The code, called TAV-IR, uses spectral reflectance and transmittance data as a function of incidence angle to describe surface material properties and spectral illumination data to model light sources. Once the operator selects the wavelength band of interest, the spectral sampling rate and the image size, the code produces an `image cube' consisting of floating point radiometric values for each pixel and each wavelength bin modeled. This image cube is then post-processed for sensor modeling purposes and image display. The code also reads an output file from a thin-film optical coating analysis package so that the reflective and transmissive properties of coated windscreens can be modeled. An interactive image inspection and display tool with a graphical user interface was also developed. This interactive tool, called SPEC, allows image pan and zoom and permits the operator to select pixels in the scene and view the spectral data contained in the selected pixels.