The Digital Imaging and Remote Sensing Image Generation (DIRSIG) model was developed to create synthetic images of remotely sensed scenes (Schott et al. 1999). It is a quantitative model based on first principles that calculates the radiance reaching the sensor from the visible region of the spectrum through to the long-wave. DIRSIG generates a very accurate representation of what a sensor would see by modeling all processes involved in the imaging chain. Currently, DIRSIG only models light from passive sources such as the sun, blackbody radiation due to the temperature of an object, and local incoherent illuminants. Active systems allow the user to tailor the illumination source for specific applications. Remote sensing Laser Detection and Ranging (LADAR) systems that use a laser as the active source have existed for almost 40 years (Fiocco and Smullin 1963). LADAR systems are used to locate the position of an object. Light Detection and Ranging (LIDAR) systems are used to derive the properties of an object, such as density or chemical composition. Recently, advances in tunable lasers and infrared detectors have allowed much more sophisticated and accurate work to be done, but a comprehensive spectral LADAR/LIDAR modelhas yet to be developed. To provide a tool to assist in LADAR/LIDAR development, this research incorporates a first-principle-based elastic LADAR/LIDAR model into DIRSIG. It calculates the spectral irradiance at the focal plane for both the atmospheric and topographic return, based on the system characteristics and the assumed atmosphere. The model accounts for the geometrical form factor, a measure of the overlap between the sensor and receiver field of view, in both the monostatic and bistatic cases. The model includes the effect of multiple bounces from topographical targets. Currently, only direct detection systems are modeled. Several sources of noise are extensively modeled, such as speckle from rough surfaces and atmospheric turbulence phase effects.
Library of Congress Subject Headings
Optical radar; Remote sensing--Data processing; Imaging systems--Digital techniques
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Burton, Robin, "Elastic LADAR modeling for synthetic imaging applications" (2002). Thesis. Rochester Institute of Technology. Accessed from
RIT – Main Campus