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We developed an automated system for registering computed tomography (CT) images of the chest temporally. Our system detects anatomical landmarks, in particular, the trachea, sternum and spine, using an attenuation-based template matching approach. It computes the optimal rigid-body transformation that aligns the corresponding landmarks in two CT scans of(More)
A real-time vision system has been developed that analyzes color videos taken from a forward-looking video camera in a car driving on a highway. The system uses a combination of color, edge, and motion information to recognize and track the road boundaries, lane markings and other vehicles on the road. Cars are recognized by matching templates that are(More)
We describe an eecient method for localizing a mobile robot in an environment with landmarks. We assume that the robot can identify these landmarks and measure their bearings relative to each other. Given such noisy input, the algorithm estimates the robot's position and orientation with respect to the map of the environment. The algorithm makes eecient use(More)
Three-dimensional methods for quantifying pulmonary nodule volume at computed tomography (CT) and the effect of imaging variables were studied by using a realistic phantom. Two fixed-threshold methods, a partial-volume method (PVM) and a variable method, were used to calculate volumes of 40 plastic nodules (largest dimension, <5 mm: 20 nodules with solid(More)
T hroughout the world, humans compete with a multitude of pest species for food, fiber, and timber, although natural predators greatly reduce the densities of many of these pests. Loss of natural pest control services could have important economic, environmental, and human health consequences (Daily 1997). The Brazilian free-tailed bat (Tadarida(More)
The "Camera Mouse" system has been developed to provide computer access for people with severe disabilities. The system tracks the computer user's movements with a video camera and translates them into the movements of the mouse pointer on the screen. Body features such as the tip of the user's nose or finger can be tracked. The visual tracking algorithm is(More)
Using data collected with thermal imaging technology, we found a major reduction in population estimates of colony size in the Brazilian free-tailed bat (Tadarida brasiliensis) from 54 million, obtained in 1957 without this technology, to 4 million in 6 major cave colonies in the southwestern United States. The 1957 census was based on human visual(More)
The problem of recognizing objects subject to affine transformation in images is examined from a physical perspective using the theory of statistical estimation. Focusing first on objects that occlude zero-mean scenes with additive noise, we derive the Cramer-Rao lower bound on the mean-square error in an estimate of the six-dimensional parameter vector(More)