Advanced applications in wide-area impedance sensing

Abstract

In this thesis a wide-area impedance sensor used in hyperspectral imaging for a wide variety of applications is presented. Building on previous work, this sensor is decoupled from fluorescent lamps and thus is used to passively detect independent sources such as fluorescent lamps and laptop control signals. The active sensing electrodes with common-mode feedback are used with a spectrum analyzer and synchronous demodulator for source and material detection respectively. A setup for active source multiplexing is described and used in image reconstruction and material detection. Algorithms for image reconstruction from such ill-posed inverse problems are discussed and improvements are made. Hyperspectral techniques for extracting the occupancy values of various materials are shown. Finally, future experiments using this sensor for gesture sensing and as a purely digital demodulator for passive imaging are described.