Presenter

M.Sc. Lixiao Zhang

Abstract

Millimeter wave imaging is a very promising technology for concealed weapon detection that is becoming a compulsory measure to enhance aviation security. Millimeter wave imaging has two fundamental realizations, passive and active. In indoor environments, such as the airports, active imaging has the advantage of high image contrast over passive imaging however it suffers from coherent artifacts of glint and speckle. In this work, we study material phenomenology, component technologies, quasi-optics design, and imaging system architectures, which need to be understood for building an imaging system. We present experimental imaging systems capable of providing multi-parameter, frequency, angle and phase, illumination. Through theoretical analyses and experiments, we investigate the cause of glint and speckle (interference noise), and show how multi-parameter illumination techniques can reduce these artifacts. As far as we know, this work is the first to experimentally prove the angle and phase diversity concepts for speckle reduction in millimeter wave imaging field. We also find that processing multispectral millimeter wave images can extract extra scene features and enhance object appearance, resulting in greatly improved image quality.