How does vision determine the size, shape and boundaries of objects in our environment? Research in my lab centers on various aspects of visual perception and the visual control of action. Recent research on the visual system has grown into an exciting collaboration among psychologists, physiologists, computer scientists, and mathematicians. My research continues to blur the lines between these fields in two ways. First, traditional psychophysical methods are enhanced using advanced computer graphics and image processing techniques for stimulus generation and analysis. Second, both mathematical methods and computer simulations are used to model the psychophysical results. The simulation models attempt to reflect a feasible physiological implementation, as I have a strong interest in neural network models of vision.