Sensor Array Overview; Core Components - Geodesic Sensor Net Technical Manual

1: GSN Introduction

Sensor Array Overview

The Geodesic Advantage
If tension is distributed evenly across the surface of a sphere,
such as occurs with a soap bubble, the surface tension is balanced
by compression directed from all points on the surface toward
the sphere center.
If a single quantity of tension is exerted between all pairs of a network of sensors, the
network will adjust the spatial location of each sensor until a single distance spans all
pairs. For accurate control of this tension, it must be applied in direct lines between
the sensor pairs, and only along those lines. Each line is a geodesic , the shortest
distance between two points on the surface of a sphere.
An accurate geodesic tessellation of the head surface optimizes the sampling of the
electrical field. Accurate surface sampling is essential for the integration of advanced
EEG methods, such as electrical source localization, with anatomical magnetic
resonance images (MRIs), and with other neuroimaging data, such as functional MRI.
The GSN Role in a Geodesic EEG System
All GES configurations have a common set of core components: at least one Geodesic
Sensor Net, one amplifier, and a data-acquisition computer running EEG acquisition
software (Figure 1-2).
Geodesic Sensor Net Amplifier
Data-acquisition computer
Figure 1-2. Core components
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Geodesic Sensor Net Technical Manual
S-MAN-200-GSNR-001 • January 31, 2007