Tenenbaum et al. (1) presented an algorithm , Isomap, for computing a quasi-isomet-ric, low-dimensional embedding of a set of high-dimensional data points. Two issues need to be raised concerning this work. First, the basic approach presented by Tenenbaum et al. is not new, having been described in the context of flattening cortical surfaces using geodesic… (More)
Previous studies demonstrated substantial variability of the location of primary visual cortex (V1) in stereotaxic coordinates when linear volume-based registration is used to match volumetric image intensities [Amunts, K., Malikovic, A., Mohlberg, H., Schormann, T., and Zilles, K. (2000). Brodmann's areas 17 and 18 brought into stereotaxic space-where and… (More)
Spectral graph partitioning provides a powerful approach to image segmentation. We introduce an alternate idea that finds partitions with a small isoperimetric constant, requiring solution to a linear system rather than an eigenvector problem. This approach produces the high quality segmentations of spectral methods, but with improved speed and stability.
Inferior temporal cortex plays an important role in shape recognition. To study the shape selectivity of single inferior temporal neurons, we recorded their responses to a set of shapes systematically varying in boundary curvature. Many inferior temporal neurons were selective for stimuli of specific boundary curvature and maintained this selectivity over… (More)
The term space-variant vision was introduced in the late 1980s to refer to sensor architectures based on a smooth variation of resolution across the workspace, like that of the human visual system. The use of such sensor architectures is rapidly becoming an important factor in machine vision in which the constraints of size, weight, cost and performance… (More)
The primary visual cortex (V1) can be delineated both functionally by its topographic map of the visual field and anatomically by its distinct pattern of laminar myelination. Although it is commonly assumed that the specialized anatomy V1 exhibits corresponds in location with functionally defined V1, demonstrating this in human has not been possible thus… (More)
The mapping function w = k log(z + a) is a widely accepted approximation to the topographic structure of primate V1 foveal and parafoveal regions. A better model, at the cost of an additional parameter, captures the full field topographic map in terms of the dipole map function w = k log[(z + a)/(z + b)]. However, neither model describes topographic shear… (More)
3 Introduction The achievements of the ear are indeed fabulous. While I am writing, my elder son rattles the fire rake in the stove, the infant babbles contentedly in his baby carriage, the church clock strikes the hour, … … In the vibrations of air striking my ear, all these sounds are superimposed into a single extremely complex stream of pressure waves.… (More)