1. 1-24 of 243 1 2 3 4 ... 9 10 11 »
    1. Automatic identification of side branch and main vascular measurements in intravascular optical coherence tomography images

      Automatic identification of side branch and main vascular measurements in intravascular optical coherence tomography images

      Automatic identification of side branch and main vascular measurements in IVOCT images take critical roles in pre-interventional decision making for coronary artery disease treatment. Very little works have been presented on these tasks. In this paper, we proposed a novel side branch identification algorithm which utilizes a newly defined global curvature feature to identify the ostium of side branch. Based on identification results, the main vascular can be segmented automatically for measurements. In the measurement of main vascular, the diameter of maximum inscribed circle of main vascular is proposed for the first time, which could be helpful in stent size ...

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    2. High Throughput Photonic Time Stretch Optical Coherence Tomography with Data Compression

      High Throughput Photonic Time Stretch Optical Coherence Tomography with Data Compression

      Photonic time stretch enables real time high throughput optical coherence tomography (OCT), but with massive data volume being a real challenge. In this paper, data compression in high throughput optical time stretch OCT has been explored and experimentally demonstrated. This is made possible by exploiting spectral sparsity of encoded optical pulse spectrum based on compressive sensing (CS) approach. Both randomization and integration have been implemented in the optical domain avoiding electronic bottleneck. Data compression ratio of 66% has been achieved in high throughput OCT measurements with 1.51 MHz axial scan rate using greatly reduced data sampling rate of 50 ...

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    3. Automatic Identification of Pathology-Distorted Retinal Layer Boundaries Using SD-OCT Imaging

      Automatic Identification of Pathology-Distorted Retinal Layer Boundaries Using SD-OCT Imaging

      Objective: We propose an effective automatic method for identification of four retinal layer boundaries from the spectral domain optical coherence tomography images in the presence and absence of pathologies and morphological changes due to disease. Methods: The approach first finds an approximate location of three reference layers and then uses these to bound the search space for the actual layers, which is achieved by modeling the problem as a graph and applying Dijkstra's shortest path algorithm. The edge weight between nodes is determined using pixel distance, slope similarity to a reference, and nonassociativity of the layers, which is designed ...

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    4. Joint Segmentation of Retinal Layers and Focal Lesions in 3-D OCT Data of Topologically Disrupted Retinas

      Joint Segmentation of Retinal Layers and Focal Lesions in 3-D OCT Data of Topologically Disrupted Retinas

      Accurate quantification of retinal structures in 3-D optical coherence tomography data of eyes with pathologies provides clinically relevant information. We present an approach to jointly segment retinal layers and lesions in eyes with topology-disrupting retinal diseases by a loosely coupled level set framework. In the new approach, lesions are modeled as an additional space-variant layer delineated by auxiliary interfaces. Furthermore, the segmentation of interfaces is steered by local differences in the signal between adjacent retinal layers, thereby allowing the approach to handle local intensity variations. The accuracy of the proposed method of both layer and lesion segmentation has been evaluated ...

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    5. Multi-Modality Imaging Enables Detailed Hemodynamic Simulations in Dissecting Aneurysms in Mice

      Multi-Modality Imaging Enables Detailed Hemodynamic Simulations in Dissecting Aneurysms in Mice

      A multi-modality imaging-based modeling approach was used to study complex unsteady hemodynamics and lesion growth in a dissecting abdominal aortic aneurysm model. We combined in vivo ultrasound (geometry and flow) and in vitro optical coherence tomography (OCT) (geometry) to obtain the high resolution needed to construct detailed hemodynamic simulations over large portions of the murine vasculature, which include fine geometric complexities. We illustrate this approach for a spectrum of dissecting abdominal aortic aneurysms induced in male apolipoprotein E-null mice by high-dose angiotensin II infusion. In vivo morphological and hemodynamic data provide information on volumetric lesion growth and changes in blood ...

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    6. Predicting Macular Edema Recurrence from Spatio-Temporal Signatures in Optical Coherence Tomography Image

      Predicting Macular Edema Recurrence from Spatio-Temporal Signatures in Optical Coherence Tomography Image

      Abstract: Prediction of treatment responses from available data is key to optimizing personalized treatment. Retinal diseases are treated over long periods and patients’ response patterns differ substantially, ranging from a complete response to a recurrence of the disease and need for re-treatment at different intervals. Linking observable variables in high-dimensional observations to outcome is challenging. In this paper, we present and evaluate two different data-driven machine learning approaches operating in a high-dimensional feature space: sparse logistic regression and Random Forests based extra trees (ET). Both identify spatio-temporal signatures based on retinal thickness features measured in longitudinal spectral-domain optical coherence tomography ...

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    7. An All-fiber Supercontinuum Source with 30.6 W High Power and Ultra-wide Spectrum Ranging from 385 nm to Beyond 2400 nm

      An All-fiber Supercontinuum Source with 30.6 W High Power and Ultra-wide Spectrum Ranging from 385 nm to Beyond 2400 nm

      An all-fiber high power, blue-enhanced supercontinuum generation in a piece of uniform photonic crystal fiber pumped by a picosecond Yb-doped master oscillator power amplifier (MOPA) is experimentally demonstrated. The MOPA source is seeded by an actively dissipative soliton (DS) mode-locked Yb-doped fiber laser with a fundamental repetition rate of ~15.33 MHz and a large chirp. By introducing giant chirp to the seed pulses and optimizing the pump power in every stage of the MOPA, a SC with 30.6 W output average power and an extremely wide spectrum of 385 nm to beyond 2400 nm is obtained.

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    8. A Feasibility Study of Broadband White Light Emitting Diode (WLED) based Full-Field Optical Coherence Microscopy (FF-OCM) using Derivative-based Algorithm

      A Feasibility Study of Broadband White Light Emitting Diode (WLED) based Full-Field Optical Coherence Microscopy (FF-OCM) using Derivative-based Algorithm

      Developing cost-effective and fast detection methods in full-field optical coherence microscopy (FF-OCM) platform for biological applications is of prime focus today. In this paper, we report a cost-effective Linnik type FF-OCM system with a single broadband white light emitting diode (WLED) (470-850nm, λ0=630nm) light source in conjunction with a derivative-based image reconstruction algorithm. Sequential two-dimensional (2D) multiple phase-shifted interferograms were obtained by moving the sample stage using piezoelectric transducer (PZT) and recorded via a 2D charge complementary oxide semiconductor (CMOS) camera. Subsequently, the en-face sectional images were reconstructed using a derivative-based algorithm. The measured axial and lateral resolutions along ...

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    9. Smoothing Splines on Unit Ball Domains with Application to Corneal Topography

      Smoothing Splines on Unit Ball Domains with Application to Corneal Topography

      Abstract: Optical coherence tomography (OCT) is a non-invasive imaging technique used to study and understand internal structures of biological tissues such as the anterior chamber of the human eye. An interesting problem is the reconstruction of the shape of the biological tissue from OCT images, that is not only a good fit of the data but also respects the smoothness properties observed in the images. A similar problem arises in Magnetic Resonance Imaging (MRI). We cast the problem as a penalized weighted least squares regression with a penalty on the magnitude of the second derivative (Laplacian) of the surface. We ...

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    10. Efficient OCT volume reconstruction from slitlamp microscopes

      Efficient OCT volume reconstruction from slitlamp microscopes

      Since its introduction 25 years ago, Optical Coherence Tomography (OCT) has contributed tremendously to diagnostic and monitoring capabilities of pathologies in the field of ophthalmology. Despite rapid progress in hardware and software technology however, the price of OCT devices has remained high, limiting their use in private practice and in screening examinations. In this paper, we present a slitlamp-integrated OCT device, built with off-the-shelf components, which can generate high-quality volumetric images of the posterior eye segment. To do so, we present a novel strategy for 3D image reconstruction in this challenging domain that allows for state-ofthe- art OCT volumes to ...

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    11. Contrast Enhanced Subsurface Fingerprint Detection using High-speed Optical Coherence Tomography

      Contrast Enhanced Subsurface Fingerprint Detection using High-speed Optical Coherence Tomography

      Spectral-domain optical coherence tomography (SDOCT) has been demonstrated to be a viable tool in forensic science for fingerprint detection, yet it still suffers from certain practical issues, e.g., the limited scanning speed and low image contrast. In this letter, we report a high-speed SD-OCT together with an image contrast enhancement mechanism for reliable subsurface fingerprint detection. The constructed SDOCT system achieves a scanning rate up to 60K A-lines/s, and thus, both 3D volumetric images, reaching up to 20mm × 20mm × 1.2mm, and en face internal fingerprint furrow pattern images could be obtained. Based upon the analyses of the ...

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    12. Optical Coherence Tomography for Brain Imaging and Developmental Biology

      Optical Coherence Tomography for Brain Imaging and Developmental Biology

      Optical coherence tomography (OCT) is a promising research tool for brain imaging and developmental biology. Serving as a three-dimensional optical biopsy technique, OCT provides volumetric reconstruction of brain tissues and embryonic structures with micrometer resolution and video rate imaging speed. Functional OCT enables label-free monitoring of hemodynamic and metabolic changes in the brain in vitro and in vivo in animal models. Due to its noninvasiveness nature, OCT enables longitudinal imaging of developing specimens in vivo without potential damage from surgical operation, tissue fixation and processing, and staining with exogenous contrast agents. In this paper, various OCT applications in brain imaging ...

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    13. Performance analysis of a Hybrid fingerprint extracted from optical coherence tomography fingertip scans

      Performance analysis of a Hybrid fingerprint extracted from optical coherence tomography fingertip scans

      The Hybrid fingerprint is a local-quality-specific blend of the surface and internal fingerprints, extracted from optical coherence tomography scans. Owing to its origin, and the manner in which it is obtained, the Hybrid fingerprint is a high-quality and secure fingerprint acquisition solution. This research entails a detailed description of the Hybrid fingerprint, the techniques involved to produce it, and a performance analysis of it. A dataset of 282 fingertip scans was established. Two recognised minutiae extraction and fingerprint matching algorithms were applied to assess the performance of the Hybrid fingerprint. The best equal error rate measured was 1.25%. NIST ...

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      Mentions: Ann Singh
    14. Miniaturization of plastic lens by injection molding for disposable endoscopie optical coherence tomography system

      Miniaturization of plastic lens by injection molding for disposable endoscopie optical coherence tomography system

      Minimally invasive robotic surgery required disposable endoscopie optical coherence tomography (OCT) for high-resolution deep tissue imaging and cross-contamination prevention. Here, we developed a miniaturized plastic lens by injection molding for developing a disposable endoscopie optical coherence tomography system for the first time. Injection molding provided low-cost and high-production rate to produce a disposable plastic lens and enabled the miniaturization of plastic lens. Transmittance and curvature of the plastic lens was measured. The plastic lens was integrated with an endoscopie OCT system, and the images of human-skin and microspheres embedded in agarose gel were captured. We are currently trying to integrate ...

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      Mentions: Ki Hean Kim
    15. Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography

      Imaging Spinal Structures With Polarization-Sensitive Optical Coherence Tomography

      Impact Statement: We investigate polarization-sensitive optical coherence tomography (PS-OCT) to obtain both intensity and polarization contrast images of in vivo and ex vivo spinal structures like subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, dura, and spinal cord in a piglet model. The PS-OCT can provide enhanced contrast characteristic structures compared to the intensity OCT; therefore it has the potential for guidance in spine interventional procedures. Abstract: We investigate polarization-sensitive optical coherence tomography (PS-OCT) to obtain both intensity and polarization contrast images of in vivo and ex vivo spinal structures like subcutaneous fat, supraspinous ligament, interspinous ligament, ligamentum flavum, dura ...

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    16. Segmentation Based Sparse Reconstruction of Optical Coherence Tomography Images

      Segmentation Based Sparse Reconstruction of Optical Coherence Tomography Images

      We demonstrate the usefulness of utilizing a segmentation step for improving the performance of sparsity based image reconstruction algorithms. In specific, we will focus on retinal optical coherence tomography (OCT) reconstruction and propose a novel segmentation based reconstruction framework with sparse representation, termed segmentation based sparse reconstruction (SSR). The SSR method uses automatically segmented retinal layer information to construct layer-specific structural dictionaries. In addition, the SSR method efficiently exploits patch similarities within each segmented layer to enhance the reconstruction performance. Our experimental results on clinical-grade retinal OCT images demonstrate the effectiveness and efficiency of the proposed SSR method for both ...

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    17. Toward High-Speed Imaging of Cellular Structures in Rat Colon Using Micro-optical Coherence Tomography

      Toward High-Speed Imaging of Cellular Structures in Rat Colon Using Micro-optical Coherence Tomography

      The mucosal microanatomy of the large intestine is characterized by the presence of crypts of Lieberkühn, which is associated predominantly with goblet cells. Such cellular-level intestinal microstructures undergo morphological changes during the progression of bowel diseases, such as colon cancer or ulcerative colitis. As an indicator of gastric cancers, intestinal metaplasia in the large intestine is characterized by the appearance of goblet cells in gastric epithelium, and therefore, visualization of intestinal microstructure changes in cross-sectional view, particularly in vivo, in a highspeed fashion would assist early disease diagnosis and its treatment. In this paper, we investigated the capability of ...

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    18. Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography

      Magnetic and Plasmonic Contrast Agents in Optical Coherence Tomography

      Optical coherence tomography (OCT) has gained widespread application for many biomedical applications, yet the traditional array of contrast agents used in incoherent imaging modalities do not provide contrast in OCT. Owing to the high biocompatibility of iron oxides and noble metals, magnetic and plasmonic nanoparticles, respectively, have been developed as OCT contrast agents to enable a range of biological and pre-clinical studies. Here, we provide a review of these developments within the past decade, including an overview of the physical contrast mechanisms and classes of OCT system hardware add-ons needed for magnetic and plasmonic nanoparticle contrast . A comparison of the ...

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    19. Ghost Reduction in CP-SSOCT Having Multiple References Using Fourier-Domain Shift and Sum

      Ghost Reduction in CP-SSOCT Having Multiple References Using Fourier-Domain Shift and Sum

      We propose, test, and validate a novel Fourier-domain-based method for ghost image artifacts reduction in a common-path SSOCT system having multiple adjacent reference planes. Common-path probes with imaging systems containing high-index sapphire ball or other lenses produce multiple fixed references due to Fresnel reflections from the lens surfaces. The multiple reference planes produce multiple and overlapping optical coherence tomography (OCT) images. Since such ghost artifacts are the result of the superposition of multiple identical images having different amplitudes and spatial shifts, one can correctly shift and sum the images in the Fourier-domain once the relative amplitude and lateral position between ...

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    20. Statistical Modeling of Retinal Optical Coherence Tomography

      Statistical Modeling of Retinal Optical Coherence Tomography

      In this paper, a new model for retinal Optical Coherent Tomography (OCT) images is proposed. This statistical model is based on introducing a nonlinear transform, namely Gaussianization, to convert the probability distribution function (pdf) of each OCT intra-retinal layer to a Gaussian distribution. According to retina anatomy, the retina is a layered structure and in OCT images each of these layers has a specific pdf which is corrupted by speckle noise, therefore a mixture model for statistical modeling of OCT images is proposed. A Normal-Laplace distribution, which is a convolution of a Laplace pdf and Gaussian noise, is proposed as ...

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    21. Acoustic Radiation Force Optical Coherence Elastography of Corneal Tissue

      Acoustic Radiation Force Optical Coherence Elastography of Corneal Tissue

      We report on a real-time acoustic radiation force optical coherence elastography (ARF-OCE) system to map the relative elasticity of corneal tissue. A modulated ARF is used as excitation to vibrate the cornea, while OCE serves as detection of tissue response. To show feasibility of detecting mechanical contrast using this method, we performed tissue-equivalent agarose phantom studies with inclusions of a different stiffness. We obtained 3-D elastograms of a healthy cornea and a highly cross-linked cornea. Finally, we induced a stiffness change on a small portion of a cornea and observed the differences in displacement.

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    22. Speckle Reduction in 3D Optical Coherence Tomography of Retina by A-Scan Reconstruction

      Speckle Reduction in 3D Optical Coherence Tomography of Retina by A-Scan Reconstruction

      Optical coherence tomography (OCT) is a micrometer-scale, cross-sectional imaging modality for biological tissue. It has been widely used for retinal imaging in ophthalmology. Speckle noise is problematic in OCT. A raw OCT image/volume usually has very poor image quality due to speckle noise, which often obscures the retinal structures. Overlapping scan is often used for speckle reduction in a 2D line-scan. However, it leads to an increase of the data acquisition time. Therefore, it is unpractical in 3D scan as it requires a much longer data acquisition time. In this paper, we propose a new method for speckle reduction ...

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    23. 4D imaging of cardiac trabeculae contracting in vitro using gated OCT

      4D imaging of cardiac trabeculae contracting in vitro using gated OCT

      Cardiac trabeculae are widely used as experimental muscle preparations for studying heart muscle. However, their geometry (diameter, length, and shape) can vary not only amongst samples, but also within a sample, leading to inaccuracies in estimating their stress production, volumetric energy output, and/or oxygen consumption. Hence, it is desirable to have a system that can accurately image each trabecula in vitro during an experiment. To this end, we constructed an optical coherence tomography (OCT) system and implemented a gated imaging procedure to image actively contracting trabeculae and reconstruct their time-varying geometry. By imaging a single cross section while monitoring ...

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    24. The Application of Full-Field Optical Coherence Tomography on Evaluating Film Coating of Pharmaceutical Pellets

      The Application of Full-Field Optical Coherence Tomography on Evaluating Film Coating of Pharmaceutical Pellets

      This paper focuses on the application of full-field optical coherence tomography (FF-OCT) imaging on quantifying coating thickness and characterizing coating structures of two layer pharmaceutical pellets. This FF-OCT system used aninexpensive infrared light-emitting diode (LED) as the opticalsource and a commercial high speed complementary metal-oxidesemiconductor (CMOS) camera as the detector. A total volume of700 × 50 × 200 μm3 (x-y-z) were imaged by using the FF-OCTdevice. A high spatial resolution of 4.0 × 5.0 μm2 (axial × lateral)was achieved. In the cross-sectional image the internal structuredetails can be clearly observed and in particular particle-likefeatures can be clearly ...

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    1-24 of 243 1 2 3 4 ... 9 10 11 »
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