Search

This paper reports on advances in mathematical models of observer-ensemble performance in narrow-field- of-view visual search and target discrimination for ground vehicles in natural terrain. Three developments are presented. We show that the distribution of search time follows a log normal distribution. We show that search outcome is the result of a race between scene parsing and target detection. Scene parsing guides and focuses search, but also leads to quitting without detection. Quitting is not simply the consequence of having exhausted the supply of suspect locations. We present a refined target signature metric and computational method that emulates human perceptual organization of the target into component regions. This is significant not only because it improves the ease-of-use and reduces subjective user input, but also because it is potentially applicable to thermal images. The refined metric provides reasonably accurate prediction of probability of detection for cued detection and uncued search experiments., Presented at the Ground Target Modeling and Validation Conference (13th) held in Houghton, MI on 5-8 Aug 2002. Published in the Proceedings of the Ground Target Modeling and Validation Conference (13th), 247-256, 2002. This article is from ADA459530 Proceedings of the Ground Target Modeling and Validation Conference (13th) Held in Houghton, MI on 5-8 August 2002

This paper presents a mathematical model, which includes a closed-form equation (the ABCt law) that generates the entire Blackwell-McCready (BM) threshold data set. It derives relationships among the four fundamental parameters of foveal vision: target area A, background luminance B, threshold contrast C and stimulus presentation time t. It shows that graphs of log (t) as a function of log (ABC) are hyperbolas whose asymptotic regions are related to the well known laws of Weber- Fechner and Bloch. It unifies important relationships associated with target/background scene parameters as they relate to the human foveal vision process. The constants associated with the simple empirical laws of Ricco, Blackwell, Weber-Fechner and Bloch can easily be obtained for a large range of target `background conditions and stimulus presentation times. Conditions for the most efficient stimulation of the human visual system are quantified and expressed in terms of the total energy for specific detection tasks.

TACOM's Thermal Imaging Model (TTIM) is capable of processing measured or modeled infrared scenes so as to account for FLIR sensor effects, natural atmospheric effects, and battlefield environment effects. This allows the operator to relate surface temperatures on the vehicle to image grey levels and vice-versa. The importance of the image simulation procedure is that the concept vehicle designer for the first time will have simulated imagery of his vehicle concept as seen through some threat sensor configuration. The relative survivability criteria for various concept vehicle designs can then be evaluated in a systematic manner. This report outlines the basic function and architecture of the TACOM Thermal Imaging Model. Typical use of the simulation model are given as well as examples of output imagery generated from the model.