similar in the parallel and perpendicular cases; so, in this situation, the precision of haptic estimates should not vary with orientation (see [3] for a counter example). Suppose the observer looks at and feels the surfaces simultaneously. The principle of maximum likelihood (ML) prescribes the strategy for combining visual and haptic estimates that produces the estimate of lowest variance [4–8]. If the visual and haptic estimates are independent and normally distributed, that strategy is weighted summation Vision and haptics have different limitations and advantages because they obtain information by different methods. If the brain combined information from the Sˆ VH � wVS ˆ V � wHS ˆ H, two senses optimally, it would rely more on the one

Abstract not found

The geometry of binocular projection is analyzed in relation to the primate visual system. An oculomotor parameterization, which includes the classical vergence and version angles, is defined. It is shown that the epipolar geometry of the system is constrained by binocular coordination of the eyes. A local model of the scene is adopted, in which depth is measured relative to a plane containing the fixation point. These constructions lead to an explicit parameterization of the binocular disparity field, involving the gaze angles as well as the scene structure. The representation of visual direction and depth is discussed, with reference to the relevant psychophysical and neurophysiological literature. 1