Phenomenological investigations for understanding spectral and polarimetric signatures of landmines J. Michael Cathcart *a , Boris Mizaikoff c , Thomas Orlando c , Robert Bock b , Manfred Karlowatz c , Ricardo Campbell a a School of Physics, b Georgia Tech Research Institute, c School of Chemistry, Georgia Institute of Technology, Atlanta, Georgia 30332 Keywords: thermal signatures, hyperspectral signatures, landmines, soil models, polarimetry, physics-based models ABSTRACT Georgia Tech is in the second year of a Multi-University Research Initiative designed to study the impact of environmental processes on optical signatures. In particular, this program is conducting phenomenological studies on hyperspectral and polarimetric signatures of various target classes in the visible and infrared wavebands. Initial research studies have focused on landmines and the impact of various environmental factors and processes (e.g., subsurface processes) on the resultant spectral infrared signatures. A variety of approaches have been employed in this research to gain a better understanding of the impact of the environment on the spectral and polarimetric characteristics of soil and landmine signatures. These approaches include theoretical analyses, physics-based signature modeling, field measurements, and laboratory studies. Results from these studies will be presented that underscore the importance of incorporating the subsurface processes into the signature analyses. The results of these analyses have been propagated to algorithm developers to permit the creation of more robust processing techniques based on these physical analyses and models. This paper will present an overview of the program, a review of the research investigations initiated over the past year, and a summary of the results from these initial investigations. 1. INTRODUCTION Development of new and improving existing techniques to aid in the detection of landmines, particularly buried ones, relies on a detailed understanding of the phenomenology related to their signatures. Discrimination features for landmine (and other buried objects) derived from electro-optical signatures represent one aspect of this difficult problem. Understanding the origins of these features and how they are impacted by the local environmental conditions is the subject of this paper. Extensive research efforts over the past several years have focused on defining the utility of electro-optical signatures for this application; specific features have been identified which validate the use of electro- optical signatures for landmine detection. In particular, hyperspectral signatures in both the visible-short wave infrared and long wave infrared bands have shown utility in addressing this detection problem. Despite these accomplishments, issues and questions have naturally arisen as these techniques have been extended to other regimes and conditions (e.g., different soil conditions, weather conditions, etc.). The utility of other types of optical signatures like polarimetry is also of concern. In addition, sensor-related questions have been raised as to exactly what is required in the sensor to maximize detectability while minimizing sensor complexity – for example, questions related to the number of spectral samples, sensor bands, data processing requirements have still not been fully resolved. These questions are of particular importance to the development of deployable, operational sensor systems. All of these issues and questions form the basis for the research program initiated at Georgia Tech under a Multi- University Research Initiative program sponsored by the Army Research Office. Under this program, now in its second year, Georgia Tech has initiated a research program to conduct detailed studies of the phenomenology underlying electro-optical signatures (particularly hyperspectral) and the environmental factors (e.g., water, weathering, etc.) that impact the characteristics of these signatures. A five-member university team composed of the Georgia Institute of Technology, University of Hawaii, University of Maryland, University of Florida, Clark Atlanta University and Rochester Institute of Technology was assembled to address these areas. In addition to a focus on the specific physics of * michael.cathcart@gtri.gatech.edu 404-894-3471 Detection and Remediation Technologies for Mines and Minelike Targets IX, edited by Russell S. Harmon, J. Thomas Broach, John H. Holloway, Jr., Proceedings of SPIE Vol. 5415 (SPIE, Bellingham, WA, 2004) 0277-786X/04/$15 · doi: 10.1117/12.547515 230 Downloaded From: http://spiedigitallibrary.org/ on 08/15/2013 Terms of Use: http://spiedl.org/terms