Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/122354
Title: NON-LINEAR REGULARIZATION FOR IMAGING THROUGH TURBID MEDIA
Authors: CHEN WENSHENG
Keywords: digital holography, compressive sensing, compressive imaging, 3D imaging, bubble dynamics, regularization
Issue Date: 21-Aug-2015
Citation: CHEN WENSHENG (2015-08-21). NON-LINEAR REGULARIZATION FOR IMAGING THROUGH TURBID MEDIA. ScholarBank@NUS Repository.
Abstract: Over the last decade, compressive imaging has emerged as a new imaging paradigm by adoption of compressive sensing theory and algorithm in computational imaging systems. A well?behaved compressive imaging system requires careful system design with optimal forward operator and proper regularization in image reconstruction with prior information about the object under observation. In many compressive imaging systems, free?space propagation is widely used as a forward operator to mix information of the object field. In this thesis, we first defined and compared two free?space propagation based compressive imaging systems with different subsampling mechanisms: random subsampling and deterministic subsampling. The importance of randomization in subsampling was highlighted. As a natural compressive imaging system, compressive holography was applied for spherical particle imaging and demonstrated superior performance in removing twin images and artifacts from defocused particles. More importantly, an empirical concentration bound of particles for accurate compressive reconstruction was provided based on numerical simulation with a physically rigorous Mie scattering model. Based on above theories and simulations, in?line digital holography was used to experimentally study the dynamics of bubbles within a high-intensity-focused-ultrasound beam. Digital holography was demonstrated as a powerful tool in bubble dynamics study by successful observation of a few important phenomena. Lastly, a new hybrid imaging method was proposed for imaging through turbid media and was validated numerically. The method incorporates two complementary holograms filtered by a Bragg grating in the compressive reconstruction.
URI: http://scholarbank.nus.edu.sg/handle/10635/122354
Appears in Collections:Ph.D Theses (Open)

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