Publications

Research into the use of multiframe superresolution has led to the development of algorithms for providing images with enhanced resolution using several lower resolution copies. An integral component of these algorithms is the determination of the registration of each of the low resolution images to a reference image. Without this information, no resolution enhancement can be attained. We have endeavored to find a suitable method for registering severely undersampled images by comparing several approaches. To test the algorithms, an ideal image is input to a simulated image formation program, creating several undersampled images with known geometric transformations. The registration algorithms are then applied to the set of low resolution images and the estimated registration parameters compared to the actual values. This investigation is limited to monochromatic images (extension to color images is not difficult) and only considers global geometric transformations. Each registration approach will be reviewed and evaluated with respect to the accuracy of the estimated registration parameters as well as the computational complexity required. In addition, the effects of image content, specifically spatial frequency content, as well as the immunity of the registration algorithms to noise will be discussed.

With increased terrorist threats in the past few years, it is no longer feasible to feel confident that a facility is well protected with a static security system. Potential adversaries often research their targets, examining procedural and system changes, in order to attack at a vulnerable time. Such system changes may include scheduled sensor maintenance, scheduled or unscheduled changes in the guard force, facility alert level changes, sensor failures or degradation, etc. All of these changes impact the system effectiveness and can make a facility more vulnerable. Currently, a standard analysis of system effectiveness is performed approximately every six months using a vulnerability assessment tool called ASSESS (Analytical Systems and Software for Evaluating Safeguards and Systems). New standards for determining a facility's system effectiveness will be defined by tools that are currently under development, such as ATLAS (Adversary Time-line Analysis System) and NextGen (Next Generation Security Simulation). Although these tools are useful to model analyses at different spatial resolutions and can support some sensor dynamics using statistical models, they are limited in that they require a static system state as input. They cannot account for the dynamics of the system through day-to-day operations. The emphasis of this project was to determine the feasibility of dynamically monitoring the facility security system and performing an analysis as changes occur. Hence, the system effectiveness is known at all times, greatly assisting time-critical decisions in response to a threat or a potential threat.