Biomedical subjects

Fabio Solari

Publications and source records attributed to Fabio Solari.

3 recordsLinked to original sources

PubMed2006

A phase-based stereo vision system-on-a-chip.

A simple and fast technique for depth estimation based on phase measurement has been adopted for the implementation of a real-time stereo system with sub-pixel resolution on an FPGA device. The technique avoids the attendant problem of phase warping. The designed system takes full advantage of the inherent processing parallelism and segmentation capabilities of FPGA devices to achieve a computation speed of 65megapixels/s, which can be arranged with a customized frame-grabber module to process 211frames/s at a size of 640x480 pixels. The processing speed achieved is higher than conventional camera frame rates, thus allowing the system to extract multiple estimations and be used as a platform to evaluate integration schemes of a population of neurons without increasing hardware resource demands.

Biomedical Engineering↗

PubMed2003

Centric-minded templates for self-motion perception.

We propose a two-layer neuromorphic architecture by which motion field pattern, generated during locomotion, are processed by template detectors specialized for gaze-directed self-motion (expansion and rotation). The templates provide a gaze-centered computation for analyzing motion field in terms of how it is related to the fixation point (i.e., the fovea). The analysis is performed by relating the vectorial components of the act of motion to variations (i.e., asymmetries) of the local structure of the motion field. Notwithstanding their limited extension in space, such centric-minded templates extract, as a whole, global information from the input flow field, being sensitive to different local instances of the same global property of the vector field with respect to the fixation point; a quantitative analysis, in terms of vectorial operators, evidences this property as tuning curves for heading direction. Model performances, evaluated in several situations characterized by conditions of absence and presence of pursuit eye movements, validate the approach. We observe that the gaze-centered model provides an explicit testable hypothesis that can guide further explorations of visual motion processing in extrastriate cortical areas.

Computational Biology↗

PubMedDate not supplied

Emergence of oscillations and spatio-temporal coherence states in a continuum-model of excitatory and inhibitory neurons.

A neural field model of the reaction-diffusion type for the emergence of oscillatory phenomena in visual cortices is proposed. To investigate the joint spatio-temporal oscillatory dynamics in a continuous distribution of excitatory and inhibitory neurons, the coupling among oscillators is modelled as a diffusion process, combined with non-linear point interactions. The model exhibits cooperative activation properties in both time and space, by reacting to volleys of activations at multiple cortical sites with ordered spatio-temporal oscillatory states, similar to those found in the physiological experiments on slow-wave field potentials. The possible use of the resulting spatial distributions of coherent states, as a flexible medium to establish feature association, is discussed.

Models, Neurological↗