Download or read book Dynamic Range Enhancement in Swept Source Optical Coherence Tomography written by Jun Zhang and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The imaging penetration depth of an optical coherence tomography (OCT) system is limited by the dynamic range of the system. In a common case that signals exceed the dynamic range of a Fourier domain OCT (FDOCT) system, saturation artifacts degrade the image quality. In this chapter, we demonstrate some new cost-effective techniques to improve the dynamic range of a swept-source OCT (SSOCT) system. For example, one method is based on a dual-channel detection technique to enhance the dynamic range by reconstructing the saturated signals due to strong reflection of the sample surface. Another method utilizes a tunable high-pass filter to compensate the attenuation of light signal in deep tissue. It was demonstrated that these techniques can improve the dynamic range of an SSOCT system by more than 10 dB with a low bit-depth analog-to-digital converter.
Download or read book Optical Coherence Tomography and Its Non medical Applications written by Michael Wang and published by BoD – Books on Demand. This book was released on 2020-05-27 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is a promising non-invasive non-contact 3D imaging technique that can be used to evaluate and inspect material surfaces, multilayer polymer films, fiber coils, and coatings. OCT can be used for the examination of cultural heritage objects and 3D imaging of microstructures. With subsurface 3D fingerprint imaging capability, OCT could be a valuable tool for enhancing security in biometric applications. OCT can also be used for the evaluation of fastener flushness for improving aerodynamic performance of high-speed aircraft. More and more OCT non-medical applications are emerging. In this book, we present some recent advancements in OCT technology and non-medical applications.
Download or read book High Resolution Imaging in Microscopy and Ophthalmology written by Josef F. Bille and published by Springer. This book was released on 2019-08-13 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book provides a comprehensive overview of the application of the newest laser and microscope/ophthalmoscope technology in the field of high resolution imaging in microscopy and ophthalmology. Starting by describing High-Resolution 3D Light Microscopy with STED and RESOLFT, the book goes on to cover retinal and anterior segment imaging and image-guided treatment and also discusses the development of adaptive optics in vision science and ophthalmology. Using an interdisciplinary approach, the reader will learn about the latest developments and most up to date technology in the field and how these translate to a medical setting. High Resolution Imaging in Microscopy and Ophthalmology – New Frontiers in Biomedical Optics has been written by leading experts in the field and offers insights on engineering, biology, and medicine, thus being a valuable addition for scientists, engineers, and clinicians with technical and medical interest who would like to understand the equipment, the applications and the medical/biological background. Lastly, this book is dedicated to the memory of Dr. Gerhard Zinser, co-founder of Heidelberg Engineering GmbH, a scientist, a husband, a brother, a colleague, and a friend.
Download or read book Optical Coherence Tomography written by Wolfgang Drexler and published by Springer Science & Business Media. This book was released on 2008-12-10 with total page 1346 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is the optical analog of ultrasound imaging and is emerging as a powerful imaging technique that enables non-invasive, in vivo, high resolution, cross-sectional imaging in biological tissue. This book introduces OCT technology and applications not only from an optical and technological viewpoint, but also from biomedical and clinical perspectives. The chapters are written by leading research groups, in a style comprehensible to a broad audience.
Download or read book Transversal Resolution Enhancement in Optical Coherence Tomography by Dynamic Coherent Focus written by Franz Lexer and published by . This book was released on 1998 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Coherence Tomography written by Mark E. Brezinski and published by Elsevier. This book was released on 2006-08-25 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Coherence Tomography gives a broad treatment of the subject which will include 1)the optics, science, and physics needed to understand the technology 2) a description of applications with a critical look at how the technology will successfully address actual clinical need, and 3) a discussion of delivery of OCT to the patient, FDA approval and comparisons with available competing technologies. The required mathematical rigor will be present where needed but be presented in such a way that it will not prevent non-scientists and non-engineers from gaining a basic understanding of OCT and the applications as well as the issues of bringing the technology to the market. - Optical Coherence Tomography is a new medical high-resolution imaging technology which offers distinct advantages over current medical imaging technologies and is attracting a large number of researchers. - Provides non-scientists and non-engineers basic understanding of Optical Coherence Tomography applications and issues.
Download or read book Optical Coherence Tomography written by Jianbing Xu and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Optical Coherence Tomography: From System Design to Spectroscopic Applications" by Jianbing, Xu, 徐鉴冰, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Optical coherence tomography (OCT), as a newly developed imaging modality, has attracted significant attention due to its capability to obtain the cross-sectional information of biological tissues in a non-invasive way, with resolution in the range of several micrometers. The third-generation swept source OCT (SS-OCT), is superior in the speed, imaging range and signal-to-noise ratio (SNR) compared with the previous time-domain OCT (TD-OCT) and spectral domain OCT (SD-OCT), and therefore forms our research focus. In this thesis, for the first time, I investigate the deployment of Fourier domain mode-locked (FDML) swept laser by utilizing the bismuth-based erbium doper fiber (Bi-EDF) with a sweeping bandwidth of 81nm achieved. Following, fiber Raman amplifier (FRA) is also investigated by employing multiple Raman pumps. The tuning range is 111.8nm, which is much larger than the previous reported Raman pumped FDML in the 1550nm region. Imaging was performed to validate the feasibility of the proposed schemes for the SS-OCT applications, respectively. In addition to the FDML swept laser cavity design, speckle noise reduction is also of great importance in OCT, which can significantly improve the visibility of the obtained OCT images. I demonstrate two different speckle reduction methods for OCT applications, which are superior in suppressing speckle noise and reserving the one-dimensional (1D) and two-dimensional (2D) signal information, respectively. Applying the proposed wavelet domain compounding (WDC) and contourlet shrinkage method to despeckle the OCT images, the visibility of the OCT images was significantly improved, with negligible edge preservation compromise. Spectroscopic information is also of interest to many researchers as it provides additional spectroscopic contrast, which on one hand, will improve the visualization of the images, and on the other hand, will enable the classification of different tissue types and help the process of discrimination between invasive and noninvasive tumors. Compared with our previous reported work about dual-band spectroscopic OCT based on optical parametric amplifier (OPA) to generate another idler band, which will be used as the second band for dual-band spectroscopic analysis, I further extend the dual-band spectroscopic OCT to the endoscopic applications, and investigate the dual-band FDML swept laser configuration based on a custom-designed dual-channel driver to synchronize the two different wavelength bands, centered at 1310 and 1550 nm, respectively. OCT Images for different bands are captured and post-processed by coding the spectral difference in different colors. In short, in this thesis, the investigations of OCT range from system design, speckle reduction to the spectroscopic applications. All these research efforts will extend the current FDML techniques for a wide range of SS-OCT applications. These schemes may be useful in OCT swept laser source build up, speckle noise reduction, and the extension of spectroscopic analysis. DOI: 10.5353/th_b5317037 Subjects: Optical coherence tomography
Download or read book System Design for Frequency Quadrupling of Reference Clock for a Swept Source Spectral Domain Optical Coherence Tomography written by Karthick Santhanam and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A real time system design to quadruple the frequency of the optical clock that is linear in the optical k-space domain is presented for a swept source spectral domain based polarization sensitive optical coherence tomography system. Advanced OCT imaging techniques have been developed in recent times to obtain high resolution images of retina that may help in early detection of glaucoma. Spatial resolution (sharper details) and depth of such images is of paramount importance. Use of a non-linear clocking system (that is linear in k-space domain) to acquire the sample is shown to be essential in avoiding loss of image resolution. The clock system described in this thesis represents an improvement over current clocking system in terms of faster and better acquisition of samples. The principle of operation and circuit implementation are described in this thesis. A fully functional hardware system has been developed and experimental results are recorded, presented and verified. By using the quadrupled frequency clock (linear in optical k-space domain) in the swept source spectral domain PS-OCT system, significant enhancement has been demonstrated in the axial resolution and depth range of acquired images.
Download or read book High Dynamic Range Imaging with Local Specular Region Contrast Enhancement written by Wei Ting Hsiao and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enhancement of Contrast in Optical Coherence Tomography written by Steven G. Adie and published by . This book was released on 2007 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with exploiting the native optical coherence tomography (OCT) contrast mechanism in new ways and with a new contrast mechanism, in both cases to enhance the information content of the tomographic image. Through experiments in microsphere solutions, we show that static speckle contains information about local particle density when the effective number of scatterers in the OCT resolution volume is less than about five. This potentially provides contrast enhancement in OCT images based on local scatterer density, and we discuss the experimental conditions suited to utilising this in biological tissue. We also describe the corrupting effects of multiple scattering, a ubiquitous phenomenon in OCT, on the information content of the static speckle. Consequently, we detail the development of polarisation-based metrics for characterising multiple scattering in OCT images of solid biological tissues. We exploit a detection scheme used for polarisation-sensitive contrast for a new purpose. We present experiments demonstrating the behaviour of these metrics in liquid phantoms, and in biological tissues, ranging from homogeneous non-birefringent to highly heterogeneous and birefringent samples. We discuss the conditions under which these metrics could be used to characterise the relative contribution of single and multiple scattering and, thus, aid in the study of penetration depth limits in OCT. We present a study of a new contrast mechanism - dynamic elastography which seeks to determine the dynamic mechanical properties of tissues. We present a framework for describing the OCT signal in samples undergoing vibrations, and perform experiments at vibration frequencies in the order of tens to hundreds of Hertz, to confirm the theory, and demonstrate the modes of measurement possible with this technique. These modes of measurement, including acoustic amplitude-sweep and frequency-sweep, could provide new information about the local mechanical properties of a sample. We describe a technological advancement enabling, in principle, measurements of local tissue refractive index contrast much deeper within a sample, than is possible with conventional OCT imaging. The design is based on measurement of the optical path length through tissue filling a fixed-width channel situated at the tip of a needle. The needle design and calibration is presented, as well as measurements of scattering phantoms and various biological tissues. This design potentially enables the use of refractive index-based contrast enhancement in the guidance of breast biopsy procedures.
Download or read book Fundus Autofluorescence written by Noemi Lois and published by Lippincott Williams & Wilkins. This book was released on 2012-02-13 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Featuring over 250 illustrations, this detailed full-color textbook provides up-to-date information on the use of fundus autofluorescence imaging in evaluation of retinal disease. Chapters describe the techniques available to image and quantify fundus autofluorescence and the autofluorescence patterns observed in the healthy eye and in various retinal diseases. Emphasis is on the value of fundus autofluorescence as a diagnostic and prognostic tool and its clinical utility in the context of other imaging techniques, such as fluorescein and indocyanine green angiography and optical coherence tomography. Each chapter also discusses the value of fundus autofluorescence in understanding the pathogenesis of the condition, and provides a comprehensive update on all aspects of the condition. A companion Website will offer the fully searchable text and an image bank.
Download or read book Advanced High Dynamic Range Imaging written by Francesco Banterle and published by CRC Press. This book was released on 2017-07-28 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the methods needed for creating and manipulating HDR content. HDR is a step change from traditional imaging; more closely matching what we see with our eyes. In the years since the first edition of this book appeared, HDR has become much more widespread, moving from a research concept to a standard imaging method. This new edition incorporates all the many developments in HDR since the first edition and once again emphasizes practical tips, including the authors' popular HDR Toolbox (available on the authors' website) for MATLAB and gives readers the tools they need to develop and experiment with new techniques for creating compelling HDR content. Key Features: Contains the HDR Toolbox for readers' experimentation on authors' website Offers an up-to-date, detailed guide to the theory and practice of high dynamic range imaging Covers all aspects of the field, from capture to display Provides benchmarks for evaluating HDR imagery
Download or read book Swept Source Optical Coherence Tomography System Development for Bioimaging Applications written by Luoqin Yu and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantitative Biomedical Optics written by Irving J. Bigio and published by Cambridge University Press. This book was released on 2016-01-07 with total page 703 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on physical science principles, Quantitative Biomedical Optics covers theory, instrumentation, methods and applications, with practical exercises and problem sets.
Download or read book The high dynamic range imaging pipeline written by Gabriel Eilertsen and published by Linköping University Electronic Press. This book was released on 2018-05-15 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: Techniques for high dynamic range (HDR) imaging make it possible to capture and store an increased range of luminances and colors as compared to what can be achieved with a conventional camera. This high amount of image information can be used in a wide range of applications, such as HDR displays, image-based lighting, tone-mapping, computer vision, and post-processing operations. HDR imaging has been an important concept in research and development for many years. Within the last couple of years it has also reached the consumer market, e.g. with TV displays that are capable of reproducing an increased dynamic range and peak luminance. This thesis presents a set of technical contributions within the field of HDR imaging. First, the area of HDR video tone-mapping is thoroughly reviewed, evaluated and developed upon. A subjective comparison experiment of existing methods is performed, followed by the development of novel techniques that overcome many of the problems evidenced by the evaluation. Second, a largescale objective comparison is presented, which evaluates existing techniques that are involved in HDR video distribution. From the results, a first open-source HDR video codec solution, Luma HDRv, is built using the best performing techniques. Third, a machine learning method is proposed for the purpose of reconstructing an HDR image from one single-exposure low dynamic range (LDR) image. The method is trained on a large set of HDR images, using recent advances in deep learning, and the results increase the quality and performance significantly as compared to existing algorithms. The areas for which contributions are presented can be closely inter-linked in the HDR imaging pipeline. Here, the thesis work helps in promoting efficient and high-quality HDR video distribution and display, as well as robust HDR image reconstruction from a single conventional LDR image.
Download or read book OCT Atlas written by Nagahisa Yoshimura and published by Springer. This book was released on 2014-06-24 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: OCT provided a great advantage over other diagnostic modalities, as it could noninvasively provide tomographic images of the retina of a living eye. As a result, a number of new findings in retinal diseases were made using the time-domain OCT. OCT has now become an essential medical equipment OCT has now become an essential medical equipment in ophthalmic care and quality textbooks describing the functionality of OCT are very important in the education of young ophthalmologists and eye care personnel. In this book are chosen high quality OCT images of rather common diseases as well as images of several rare diseases.
Download or read book Development of Phase Stabilized Swept Source Optical Coherence Tomography for Biomedical Imaging and Sensing written by Ravi Kiran Manapuram and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
