Comparison of speckle reduction diversity tools for active millimeter-wave imaging This publication appears in: Journal of the Optical Society of America A: Optics and Image Science, and Vision Authors: I. Jäger, J. Stiens, L. Zhang, S. Islam, G. Koers and R. Vounckx Volume: 25 Issue: 7 Pages: 1716-1721 Publication Date: Jul. 2008
Abstract: Imaging concealed objects with millimeter-wave coherent radiation is accompanied with speckle. Like all interference phenomena speckle depends on three light parameters of the mm-wave laser beam: phase, wavelength and angle of incidence and could be reduced by the diversity of these three parameters. Diversity tools have been compared to improve images of concealed objects. We report measurements, simulations and image reconstruction results over the whole W-band (75뀶 GHz) and demonstrate where each tool works the best. Multi-phase diversity is successful to reduce speckle contrast multi-angle - to improve the image quality multi-spectral - to recognizes small object's features. A simple post-processing eliminates the areas, still covered by interference.
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