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John Porrill

Researcher at University of Sheffield

Publications -  104
Citations -  3538

John Porrill is an academic researcher from University of Sheffield. The author has contributed to research in topics: Adaptive control & Motor learning. The author has an hindex of 31, co-authored 104 publications receiving 3377 citations.

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Optimal combination and constraints for geometrical sensor data

John Porrill
TL;DR: A formalism is described for the statistical combination of geometrical information from multiple sensors, including the com bination of multiple stereo views to increase the accuracy of a wire frame model and the consistent imposition of geometric constraints on such a model.
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Pooling of Vertical Disparities by the Human Visual System

TL;DR: The effects of scaling vertical disparities on the perceived amplitudes of dome-shaped surfaces depicted with horizontal disparities were examined, and the sizes of the scaling effects were less than those predicted by either theory, suggesting that other cues to fixation distance such as oculomotor information played an appreciable role.
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Deformable model of the human iris for measuring ocular torsion from video images

TL;DR: A deformable model of the human iris is described, which forms part of a system for accurate offline measurement of binocular eye movements, particularly cyclotorsion (torsion), from video image sequences, and measurements obtained are repeatable and accurate to within 0.1°.
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Where is the light? Bayesian perceptual priors for lighting direction

TL;DR: This work describes a non-parametric maximum-likelihood estimation method for finding the prior distribution for lighting direction, and suggests that each observer has a distinct prior distribution, with non-zero values in all directions, but with a peak which indicates observers are biased to expect light to come from above left.
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Optimal combination of multiple sensors including stereo vision

TL;DR: The statistical combination of information from multiple sources is considered for stereo vision formulation and the particular needs of the target application, stereo vision, require that the formulation be adequate to deal with highly correlated errors and constraints.