Digital Holography and Wavefront Sensing

Digital Holography and Wavefront Sensing
Title Digital Holography and Wavefront Sensing PDF eBook
Author Ulf Schnars
Publisher Springer
Pages 233
Release 2014-09-19
Genre Technology & Engineering
ISBN 3662446936

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This highly practical and self-contained guidebook explains the principles and major applications of digital hologram recording and numerical reconstruction (Digital Holography). A special chapter is designated to digital holographic interferometry with applications in deformation and shape measurement and refractive index determination. Applications in imaging and microscopy are also described. Spcial techniques such as digital light-in-flight holography, holographic endoscopy, information encrypting, comparative holography, and related techniques of speckle metrology are also treated

Wavefront Sensing the 3D Image Reconstruction in Deep Turbulence

Wavefront Sensing the 3D Image Reconstruction in Deep Turbulence
Title Wavefront Sensing the 3D Image Reconstruction in Deep Turbulence PDF eBook
Author Matthais Thomas Banet
Publisher
Pages 0
Release 2023
Genre
ISBN

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"The work presented in this dissertation explores the use of several unconventional imaging and wavefront sensing modalities in the presence of distributed-volume, or "deep," atmospheric turbulence. This dissertation focuses on the propagation of coherent light from laser sources through the atmosphere, and imaging/wavefront sensing at optical and infrared laser wavelengths. Such wavelengths are negatively affected by deep turbulence. We use a coherent detection method known as digital holography to (1) coherently image distant objects and (2) to sense and correct for aberrations due to turbulence along the propagation path. We showed that compensated-beacon adaptive optics can be used with a digital holographic wavefront sensor or a Shack-Hartmann wavefront sensor to improve the performance of beam projection to distant objects over uncompensated beacon adaptive optics. We saw performance gains of 17% for the Shack-Hartmann wavefront sensor and 26% for the digital holographic wavefront sensor on average for several turbulence scenarios. We explored multi-wavelength 3D imaging with digital holography along with two speckle decorrelation mechanisms that degrade 3D imaging performance in a theoretical framework. Upon establishing this framework, we simulated multi-wavelength 3D imaging of distant objects through deep turbulence and reconstructed the imagery using sharpness metric maximization for 3D data. The results showed that the reconstruction process was more successful if using more corrective phase screens along the digital propagation path. Additionally we showed that sharpness metric maximization suffered in performance in the presence of scintillated illumination patterns, also known as uplink scintillation. Finally we explored motion compensated, multi-wavelength 3D imaging with digital holography and a pilot tone in theory. Our theoretical framework predicted that one would see increased noise in range images, known as range chatter, over highly-sloped object facets relative to the optical axis, and simulations bore this out explicitly. We showed that range chatter increases as a function of object facet slope, optical illumination bandwidth, optical frequency spacing, and turbulence. Going further we used sharpness metric maximization to improve the range chatter that was brought about by turbulence."--Pages xiv-xv.

Predictive Dynamic Digital Holography

Predictive Dynamic Digital Holography
Title Predictive Dynamic Digital Holography PDF eBook
Author Sennan David Sulaiman
Publisher
Pages 100
Release 2017
Genre
ISBN

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Digital holography has received recent attention for many imaging and sensing applications, including imaging through turbulent and turbid media, adaptive optics, three-dimensional projective display technology and optical tweezing. It holds several advantages over conventional imaging and wavefront sensing, chief among these being significantly fewer and simpler optical components and the retrieval of complex field. A significant obstacle for digital holography in real-time applications, such as wavefront sensing for high-energy laser systems and high-speed imaging for target tracking, is the fact that digital holography is computationally intensive; it requires iterative virtual wavefront propagation and hill-climbing algorithms to optimize sharpness criteria. This research demonstrates real-time methods for digital holography based on approaches for optimal and adaptive identification, prediction, and control of optical wavefronts. The methods presented integrate minimum-variance wavefront prediction into dynamic digital holography schemes to accelerate the wavefront correction and image sharpening algorithms. Further gains in computational efficiency are demonstrated in this work with a variant of localized sharpening in conjunction with predictive dynamic digital holography for real-time applications. This "subspace correction" method optimizes sharpness of local regions in a detector plane by parallel independent wavefront correction on reduced-dimension subspaces of the complex field in a spectral plane.

Digital Holography for MEMS and Microsystem Metrology

Digital Holography for MEMS and Microsystem Metrology
Title Digital Holography for MEMS and Microsystem Metrology PDF eBook
Author Anand Asundi
Publisher John Wiley & Sons
Pages 189
Release 2011-07-05
Genre Technology & Engineering
ISBN 1119972787

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Approaching the topic of digital holography from the practical perspective of industrial inspection, Digital Holography for MEMS and Microsystem Metrology describes the process of digital holography and its growing applications for MEMS characterization, residual stress measurement, design and evaluation, and device testing and inspection. Asundi also provides a thorough theoretical grounding that enables the reader to understand basic concepts and thus identify areas where this technique can be adopted. This combination of both practical and theoretical approach will ensure the book's relevance and appeal to both researchers and engineers keen to evaluate the potential of digital holography for integration into their existing machines and processes. Addresses particle characterization where digital holography has proven capability for dynamic measurement of particles in 3D for sizing and shape characterization, with applications in microfluidics as well as crystallization and aerosol detection studies. Discusses digital reflection holography, digital transmission holography, digital in-line holography, and digital holographic tomography and applications. Covers other applications including micro-optical and diffractive optical systems and the testing of these components, and bio-imaging.

Digital Holography

Digital Holography
Title Digital Holography PDF eBook
Author Ulf Schnars
Publisher Springer Science & Business Media
Pages 165
Release 2005-12-08
Genre Science
ISBN 3540269118

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This highly practical and self-contained guidebook explains the principles and major applications of digital hologram recording and numerical reconstruction (Digital Holography). A special chapter is designated to digital holographic interferometry with applications in deformation and shape measurement and refractive index determination. Applications in imaging and microscopy are also described. Spcial techniques such as digital light-in-flight holography, holographic endoscopy, information encrypting, comparative holography, and related techniques of speckle metrology are also treated

Analog and Digital Holography with MATLAB

Analog and Digital Holography with MATLAB
Title Analog and Digital Holography with MATLAB PDF eBook
Author Georges T. Nehmetallah
Publisher SPIE-International Society for Optical Engineering
Pages 0
Release 2015
Genre Compressed sensing (Telecommunication).
ISBN 9781628416923

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Holography is the only truly three-dimensional imaging method available, and MATLAB has become the programming language of choice for engineering and physics students. Whereas most books solely address the theory behind these 3D imaging techniques, this monograph concentrates on the exact code needed to perform complex mathematical and physical operations.

Digital Holographic Microscopy

Digital Holographic Microscopy
Title Digital Holographic Microscopy PDF eBook
Author Myung K. Kim
Publisher Springer Science & Business Media
Pages 251
Release 2011-08-09
Genre Technology & Engineering
ISBN 1441977929

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Digital holography is an emerging field of new paradigm in general imaging applications. The book presents an introduction to the theoretical and numerical principles and reviews the research and development activities in digital holography, with emphasis on the microscopy techniques and applications. Topics covered include the general theory of diffraction and holography formations, and practical instrumentation and experimentation of digital holography. Various numerical techniques are described that give rise to the unique and versatile capabilities of digital holography. Representative special techniques and applications of digital holography are discussed. The book is intended for researchers interested in developing new techniques and exploring new applications of digital holography.