Download or read book Characterization of an AO OCT System written by and published by . This book was released on 2007 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-volumetric-resolution, images of the retina. The AO-OCT system at UC Davis has been under development for 2 years and has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging [1]. The current system uses an AOptix bimorph deformable mirror (DM) for low-order, high-stroke correction [2] and a 140-actuator Boston Micromachines DM for high-order correction [3]. We are beginning to investigate the potential for increasing the image contrast in this system using higher-order wavefront correction. The first step in this analysis is to quantify the residual wavefront error (WFE) in the current system. Developing an error budget is a common tool for improved performance and system design in astronomical AO systems [4, 5]. The process for vision science systems is also discussed in several texts e.g. [6], but results from this type of analysis have rarely been included in journal articles on AO for vision science. Careful characterization of the AO system will lead to improved performance and inform the design of a future high-contrast system. In general, an AO system error budget must include an analysis of three categories of residual WFE: errors in measuring the phase, errors caused by limitations of the DM(s), and errors introduced by temporal variation. Understanding the mechanisms and relative size of these errors is critical to improving system performance. In this paper we discuss the techniques for characterizing these error sources in the AO-OCT system. It is useful to first calculate an error budget for the simpler case using a model eye, and then add the additional errors introduced for the case of a human subject. Measurement error includes calibration error, wavefront sensor (WFS) CCD noise, and sampling errors. Calibration errors must be measured by an external system. Typically this error is inferred from measurements of the point spread function (PSF). It can also be estimated by measuring known wavefront errors and comparing to the WFS measurement. Both methods will be used in the AO-OCT system. In this particular system measurement error introduced by the WFS can be caused by low light levels, poor camera sensitivity at the operating wavelength and noise introduced by heat in the uncooled CCD. Also, the gaussian beam profile of the system causes centroids near the edges of the pupil to be dimmer, and thus noisier. The easiest way to estimate measurement error is to compare successive wavefront measurements when the system is stable. This techniques will include vibrations and other systematic errors. Alternatively the measurement error can be estimated from measured signal to noise. This is more complicated but will decouple measurement errors from stability measurements. Ultimately, even if the phase is measured perfectly, performance will still be limited by the fitting error [7]. This error is inversely proportional to the number of actuators of the DM. Basically wavefront errors with spatial frequencies greater than half the number of actuators across the aperture cannot be corrected. For DMs with modal influence functions (like the AOptix Bimorph in the AO-OCT system), this translates to the number of modes which can be corrected. The AO-OCT system over-samples the wavefront, so to some extent, we can measure these out-of-band errors directly. In addition to fitting error, the DM will introduce errors based on the ability of each individual actuator to go to the position demanded by the control system. Generally this voltage step size is limited by the resolution of the drive electronics and can be calculated analytically.
Download or read book Performance of a MEMS based AO OCT System Using Fourier Reconstruction written by and published by . This book was released on 2009 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-resolution (3.5 [mu]m isotropic), 3-D images of the retina. The AO-OCT system at UC Davis has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging. The current system uses an AOptix bimorph deformable mirror (DM) for low-order, high-stroke correction and a 140-actuator Boston Micromachines DM for high-order correction. Developments to improve performance or functionality of the instrument are on-going. Based on previous work in system characterization we have focused on improved AO control. We present preliminary results and remaining challenges for a newly implemented Fourier transform reconstructor (FTR). The previously reported error budget analysis is also reviewed and updated, with consideration of how to improve both the amount of residual error and the robustness of the system. Careful characterization of the AO system will lead to improved performance and inform the design of future systems.
Download or read book Retinal Optical Coherence Tomography Image Analysis written by Xinjian Chen and published by Springer. This book was released on 2019-07-05 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the latest optical coherence tomography (OCT) imaging and computerized automatic image analysis techniques, and their applications in the diagnosis and treatment of retinal diseases. Discussing the basic principles and the clinical applications of OCT imaging, OCT image preprocessing, as well as the automatic detection and quantitative analysis of retinal anatomy and pathology, it includes a wealth of clinical OCT images, and state-of-the-art research that applies novel image processing, pattern recognition and machine learning methods to real clinical data. It is a valuable resource for researchers in both medical image processing and ophthalmic imaging.
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 Adaptive Optics for Industry and Medicine written by Christopher Dainty and published by World Scientific. This book was released on 2008 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume presents the very latest developments in non-astronomical adaptive optics. This international workshop, the sixth in a biennial series, was the largest ever held and boasted significant involvement by industry. Adaptive optics is on the verge of being used in many products; indeed, at this meeting, the use of adaptive optics in DVD players was disclosed for the first time.
Download or read book Characterization of an Adaptive Optics System for Vision Studies written by Yu Bai and published by . This book was released on 2016 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics (AO) is a technology used to sharpen images through real time compensation of optical aberrations. The adaptive optics was firstly used in astronomical telescopes. Now this technique is widely adopted in fields encompassing physics, chemistry, electronics, and computer science. Particularly in vision science, adaptive optics can compensate the aberrations in the eye such that the information of a diseased eye can be read easily. Though the adaptive optics technology is relatively young, it has been demonstrated for advanced ophthalmoscopy as well as for vision test. In this thesis, a commercially available adaptive optics system was assembled up and tested firstly. Then the adaptive optics system was modified to test an eye model. The eye model consists of a lens and a movable mirror, which can simulate different types of diseased eyes by changing the distance between the mirror and the lens. The diseased eye model introduced aberrations to the system, and the deformable mirror in the adaptive optics system was activated and changed the shape to compensate the aberrations. But the correction range by the deformable mirror is limited. By testing the simple eye model, the working range of the deformable mirror and the wavefront sensor were characterized and determined.
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 Adaptive Optics for Vision Science written by Jason Porter and published by John Wiley & Sons. This book was released on 2006-06-12 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading experts present the latest technology and applications in adaptive optics for vision science Featuring contributions from the foremost researchers in the field, Adaptive Optics for Vision Science is the first book devoted entirely to providing the fundamentals of adaptive optics along with its practical applications in vision science. The material for this book stems from collaborations fostered by the Center for Adaptive Optics, a consortium of more than thirty universities, government laboratories, and corporations. Although the book is written primarily for researchers in vision science and ophthalmology, the field of adaptive optics has strong roots in astronomy. Researchers in both fields share this technology and, for this reason, the book includes chapters by both astronomers and vision scientists. Following the introduction, chapters are divided into the following sections: * Wavefront Measurement and Correction * Retinal Imaging Applications * Vision Correction Applications * Design Examples Readers will discover the remarkable proliferation of new applications of wavefront-related technologies developed for the human eye. For example, the book explores how wavefront sensors offer the promise of a new generation of vision correction methods that can deal with higher order aberrations beyond defocus and astigmatism, and how adaptive optics can produce images of the living retina with unprecedented resolution. An appendix includes the Optical Society of America's Standards for Reporting Optical Aberrations. A glossary of terms and a symbol table are also included. Adaptive Optics for Vision Science arms engineers, scientists, clinicians, and students with the basic concepts, engineering tools, and techniques needed to master adaptive optics applications in vision science and ophthalmology. Moreover, readers will discover the latest thinking and findings from the leading innovators in the field.
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 Optical Coherence Tomography Angiography of the Eye written by David Huang and published by Kugler Publications. This book was released on 2024-01-08 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography angiography (OCTA) has undergone tremendous growth since its first commercial introduction in 2014. Because it provides injection-free, capillary-resolution, 3-dimensional angiography of the retina and choroid, OCTA is likely to overtake fluorescein as the most important angiographic imaging technique in the eye. Nearly all manufacturers of ophthalmic OCT now offer OCTA products. A PubMed search now yields over 5700 articles on OCTA and related terms. Clinical investigators have already found a use for OCTA in almost every category of retinal and optic nerve diseases. This book is meant to bring together all this information so clinicians can have one authoritative text to turn to as we begin to use this new imaging modality that was never taught when we were in formal training. Table of contents Introduction Dedication About the Editors Contributors 1. Optical coherence tomography systems for angiography 2. Optical coherence tomographic angiography algorithms 3. Vascular anatomy of the normal retina and choroid 4. OCTA of the normal anterior eye circulations 5. Artifacts 6. Quantification 7. Artificial intelligence in optical coherence tomographic angiography 8. Terminology: a new standard 9. AngioVue SSADA OCTA on the Optovue SOLIX Spectral-Domain OCT 10. Optical microangiography with AngioPlex® and PLEX® Elite systems 11. Optical coherence tomography angiography imaging on the Topcon Triton and Maestro2 systems 12. NIDEK Mirante OCT angiography 13. OCTA on the Heidelberg spectralis spectral-domain OCT 14. OCTA on the Optopol REVO NX spectral-domain OCT 15. OCTA on the Canon OCT-HS100 and Xephilio OCT-A1 Spectral-Domain OCT 16. Exudative neovascular age-related macular degeneration—Type 1, 2 and 3 neovascularization 17. Retinal angiomatous proliferation—type 3 choroidal neovascularization 18. Short- and long-term follow-up of macular neovascularization response to antiangiogenic treatment 19. Nonexudative neovascular age-related macular degeneration 20. Non-neovascular age-related macular degeneration 21. Polypoidal choroidal vasculopathy 22. Macular telangiectasia 23. Central serous chorioretinopathy 25. Nonproliferative diabetic retinopathy 26. Subclinical neovascular diabetic retinopathy 27. Proliferative diabetic retinopathy 28. Retinal venous occlusion 29. Retinal arterial occlusion 30. Plexus-specific occlusions in retinal vascular diseases 31. Paracentral acute middle maculopathy 32. Inherited retinal degenerations 33. Pathologic myopia 34. Multimodal imaging and the role of optical coherence tomography angiography in retinal vasculitis 35. White spot syndromes 36. Choroidal tumors 37. Radiation retinopathy 38. Open-angle glaucoma 39. Primary angle-closure glaucoma 40. Optic neuritis and multiple sclerosis 41. Alzheimer’s disease 42. Corneal neovascularization 43. Ocular surface and iris tumors
Download or read book Optimization of Multi functional 1310 Nm Spectral domain Optical Coherence Tomography SD OCT System and Three dimensional Volumetric OCT Image Registration written by Junze Liu and published by . This book was released on 2018 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is a novel and promising imaging technique that has been widely applied in clinical practice and research. Currently advanced spectral-domain OCT is capable for fast generating three dimensional (3D) volumetric image and extracting multi-biological information that has potential uses in disease study. Based on a laboratory-built multi-functional spectral-domain OCT system with center wavelength of 1310 nm, the research goal in this thesis is to solve problems about proper optical characterization method of volumes of in vivo biological sample taken at different time points which requires appropriate 3D volume registration and alignment. In this thesis, system optimization is introduced in order to improve OCT signal-to-noise ratio (SNR) and image quality for better image registration performance. Details of a computational-efficient 3D volume alignment based on cross-correlation image registration is discussed. Optical characterization of post-traumatic epilepsy (PTE) is described as an example to demonstrate the feasibility of the OCT system and to evaluate the image post-processing method in actual neural disease research.
Download or read book Adaptive Optics for Industry and Medicine written by Christopher Dainty and published by Imperial College Press. This book was released on 2008 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume presents the very latest developments in non-astronomical adaptive optics. This international workshop, the sixth in a biennial series, was the largest ever held and boasted significant involvement by industry. Adaptive optics is on the verge of being used in many products; indeed, at this meeting, the use of adaptive optics in DVD players was disclosed for the first time. Sample Chapter(s). Liquid Crystal Lenses For Correction Of Presbyopia (586 KB). Contents: Wavefront Correctors and Control: Liquid Crystal Lenses for Correction of Presbyopia (G Li & N Peyghambarian); Woofer-Tweeter Adaptive Optics (T Farrell & C Dainty); Wavefront Sensors: A Fundamental Limit for Wavefront Sensing (C Paterson); Direct Diffractive Image Simulation (A P Maryasov et al.); Adaptive Optics in Vision Science: A Study of Field Aberrations in the Human Eye (A V Goncharov et al.); Characterization of an AO-OCT System (J W Evans et al.); Adaptive Optics in Optical Storage and Microscopy: Commercialization of the Adaptive Scanning Optical Microscope (ASOM) (B Potsaid et al.); Towards Four Dimensional Particle Tracking for Biological Applications (H I Campbell et al.); Adaptive Optics in Lasers: New Results in High Power Lasers Beam Correction (A Kudryashov et al.); Adaptive Optics Control of Solid-State Lasers (W Lubeigt et al.); Adaptive Optics in Communication and Atmospheric Compensation: Fourier Image Sharpness Sensor for Laser Communications (K N Walker & R K Tyson); Adaptive Optics System for a Small Telescope (G Vdovin et al.); and other papers. Readership: Industry- and university-level researchers in optics and laser physics.
Download or read book Guide to Interpreting Spectral Domain Optical Coherence Tomography written by Lumbroso Bruno and published by JP Medical Ltd. This book was released on 2011-09 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book guides ophthalmologists through the interpretation of Optical Coherence Tomography (OCT) images. The first phase of analysis subdivides each image into its smallest components. The second phase combines these fine details to allow diagnosis and identification of appropriate treatment. Written by leading European experts, this manual features detailed schematic illustrations as well as actual scans, and offers information on the technical and clinical uses in the study of glaucoma and on three dimensional images.
Download or read book A Practical Guide to Clinical Application of OCT in Ophthalmology written by Michele Lanza and published by BoD – Books on Demand. This book was released on 2019-10-02 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: I am very proud and excited to introduce to you this book, which provides many interesting indications on how to better understand and handle the world of opticalcoherence tomography (OCT). Reading the chapters, you will be aware that this device is extremely important not just in the clinical practice of retinal diseases, but is also very useful as a surgical tool. Moreover, application of OCT has crossed the borders of the retina and is currently being applied to corneal diseases and glaucoma. I amconfident you will find enough useful information to improve your practice using OCT and to provide a better quality of care for your patients.
Download or read book Selected Topics in Optical Coherence Tomography written by Gangjun Liu and published by BoD – Books on Demand. This book was released on 2012-02-08 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes different exciting topics in the OCT fields, written by experts from all over the world. Technological developments, as well as clinical and industrial applications are covered. Some interesting topics like the ultrahigh resolution OCT, the functional extension of OCT and the full field OCT are reviewed, and the applications of OCT in ophthalmology, cardiology and dentistry are also addressed. I believe that a broad range of readers, such as students, researchers and physicians will benefit from this book.
Download or read book Optical Coherence Tomography in Current Glaucoma Practice written by Digvijay Singh and published by JP Medical Ltd. This book was released on 2014-05-30 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glaucoma is a condition of the eye in which the optic nerve is damaged due to increased fluid pressure in the eye. Left untreated, the condition may lead to permanent blindness. Optical coherence tomography (OCT) is a non-invasive imaging test that uses light waves to take cross-section pictures of the retina, the light-sensitive tissue lining the back of the eye (geteyesmart.org). OCT is commonly used in the evaluation of patients with glaucoma. This manual is a concise guide to the use of OCT for the diagnosis of glaucoma. Beginning with an introduction to OCT, the book then provides in depth discussion on its use in glaucoma. Each of the following chapters describes the use of OCT for analysing associated parts of the eye, including the optic nerve, retinal nerve and ganglion cell, as well as macular and anterior segment OCT. The advantages and common pitfalls in OCT imaging and its interpretation are discussed at length. Key points Concise guide to OCT for diagnosis and evaluation of glaucoma Explains use of OCT for analysis of associated parts of the eye In depth discussion of advantages and common pitfalls in OCT imaging Includes more than 115 images and illustrations
