1. Articles from Patrice Tankam

    1-13 of 13
    1. Ph.D. positions in Optical Imaging and Vision Science at Indiana University Bloomington

      Ph.D. positions in Optical Imaging and Vision Science at Indiana University Bloomington

      Two Ph.D. positions are available in Dr. Tankam’s laboratory in the Frontiers of Optical Imaging and Biology at Indiana University School of Optometry. The group focuses on developing cutting-edge optical imaging systems, including high-resolution optical coherence tomography and fluorescence microscopy, to enable new investigations in the biomedical research field. The group uses a translational approach to study disease mechanisms; from the fundamental understanding of biological processes involved in normal and pathological conditions in animal models to the early diagnostic and monitoring of disease progression in human subjects. The laboratory is looking for highly motivated students from various background ...

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    2. Quantitative assessment of human donor corneal endothelium with Gabor domain optical coherence microscopy

      Quantitative assessment of human donor corneal endothelium with Gabor domain optical coherence microscopy

      We report on a pathway for Gabor domain optical coherence microscopy (GD-OCM)-based metrology to assess the donor’s corneal endothelial layers ex vivo . Six corneas from the Lions Eye Bank at Albany and Rochester were imaged with GD-OCM. The raw 3-D images of the curved corneas were flattened using custom software to enhance the 2-D visualization of endothelial cells (ECs); then the ECs within a circle of 500-μm-diameter were analyzed using a custom corner method and a cell counting plugin in ImageJ. The EC number, EC area, endothelial cell density (ECD), and polymegethism (CV) were quantified in five ...

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    3. Capabilities of Gabor-domain optical coherence microscopy for the assessment of corneal disease

      Capabilities of Gabor-domain optical coherence microscopy for the assessment of corneal disease

      To identify the microstructural modification of the corneal layers during the course of the disease, optical technologies have been pushing the boundary of innovation to achieve cellular resolution of deep layers of the cornea. Gabor-domain optical coherence microscopy (GD-OCM), an optical coherence tomography-based technique that can achieve an isotropic of ∼2-μm resolution over a volume of 1  mm  ×  1  mm  ×  1.2  mm, was developed to investigate the microstructural modifications of corneal layers in four common corneal diseases. Since individual layer visualization without cutting through several layers is challenging due to corneal curvature, a flattening algorithm was developed to ...

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    4. 3D wide field-of-view Gabor-domain optical coherence microscopy advancing real-time in-vivo imaging and metrology

      3D wide field-of-view Gabor-domain optical coherence microscopy advancing real-time in-vivo imaging and metrology

      Real-time volumetric high-definition wide-field-of-view in-vivo cellular imaging requires micron-scale resolution in 3D. Compactness of the handheld device and distortion-free images with cellular resolution are also critically required for onsite use in clinical applications. By integrating a custom liquid lens-based microscope and a dual-axis MEMS scanner in a compact handheld probe, Gabor-domain optical coherence microscopy (GD-OCM) breaks the lateral resolution limit of optical coherence tomography through depth, overcoming the tradeoff between numerical aperture and depth of focus, enabling advances in biotechnology. Furthermore, distortion-free imaging with no post-processing is achieved with a compact, lightweight handheld MEMS scanner that obtained a 12-fold reduction ...

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    5. Optical Assessment of Soft Contact Lens Edge-Thickness

      Optical Assessment of Soft Contact Lens Edge-Thickness

      Purpose: To assess the edge shape of soft contact lenses using Gabor-Domain Optical Coherence Microscopy (GD-OCM) with a 2-μm imaging resolution in three dimensions and to generate edge-thickness profiles at different distances from the edge tip of soft contact lenses. Methods: A high-speed custom-designed GD-OCM system was used to produce 3D images of the edge of an experimental soft contact lens (Bausch + Lomb, Rochester, NY) in four different configurations: in air, submerged into water, submerged into saline with contrast agent, and placed onto the cornea of a porcine eyeball. An algorithm to compute the edge-thickness was developed and applied ...

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    6. MEMS-based handheld scanning probe with pre-shaped input signals for distortion-free images in Gabor-domain optical coherence microscopy

      MEMS-based handheld scanning probe with pre-shaped input signals for distortion-free images in Gabor-domain optical coherence microscopy

      High-speed scanning in optical coherence tomography (OCT) often comes with either compromises in image quality, the requirement for post-processing of the acquired images, or both. We report on distortion-free OCT volumetric imaging with a dual-axis micro-electro-mechanical system (MEMS)-based handheld imaging probe. In the context of an imaging probe with optics located between the 2D MEMS and the sample, we report in this paper on how pre-shaped open-loop input signals with tailored non-linear parts were implemented in a custom control board and, unlike the sinusoidal signals typically used for MEMS, achieved real-time distortion-free imaging without post-processing. The MEMS mirror was ...

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    7. Gabor-domain optical coherence microscopy with integrated dual-axis MEMS scanner for fast 3D imaging and metrology

      Gabor-domain optical coherence microscopy with integrated dual-axis MEMS scanner for fast 3D imaging and metrology

      Fast, robust, nondestructive 3D imaging is needed for characterization of microscopic structures in industrial and clinical applications. A custom micro-electromechanical system (MEMS)-based 2D scanner system was developed to achieve 55 kHz A-scan acquisition in a Gabor-domain optical coherence microscopy (GD-OCM) instrument with a novel multilevel GPU architecture for high-speed imaging. GD-OCM yields high-definition volumetric imaging with dynamic depth of focusing through a bio-inspired liquid lens-based microscope design, which has no moving parts and is suitable for use in a manufacturing setting or in a medical environment. A dual-axis MEMS mirror was chosen to replace two single-axis galvanometer mirrors; as ...

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    8. Optimization of galvanometer scanning for optical coherence tomography

      Optimization of galvanometer scanning for optical coherence tomography

      We study experimentally the effective duty cycle of galvanometer-based scanners (GSs) with regard to three main parameters of the scanning process: theoretical/imposed duty cycle (of the input signal), scan frequency, and scan amplitude. Sawtooth and triangular input signals for the device are considered. The effects of the mechanical inertia of the oscillatory element of the GS are analyzed and their consequences are discussed in the context of optical coherence tomography (OCT) imaging. When the theoretical duty cycle and the scan amplitude are increased to the limit, the saturation of the device is demonstrated for a useful range of scan ...

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    9. Assessing microstructures of the cornea with Gabor-domain optical coherence microscopy: pathway for corneal physiology and diseases

      Assessing microstructures of the cornea with Gabor-domain optical coherence microscopy: pathway for corneal physiology and diseases

      Gabor-domain optical coherence microscopy (GD-OCM) was applied ex vivo in the investigation of corneal cells and their surrounding microstructures with particular attention to the corneal endothelium. Experiments using fresh pig eyeballs, excised human corneal buttons from patients with Fuchs’ endothelial dystrophy (FED), and healthy donor corneas were conducted. Results show in a large field of view ( 1     mm × 1     mm ) high definition images of the different cell types and their surrounding microstructures through the full corneal thickness at both the central and peripheral locations of porcine corneas. Particularly, an image of the endothelial cells lining the bottom of the cornea ...

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    10. Development of cellular resolution Gabor-domain optical coherence microscopy for biomedical applications

      Development of cellular resolution Gabor-domain optical coherence microscopy for biomedical applications

      We have developed a cellular resolution imaging modality, Gabor-Domain Optical Coherence Microscopy, which combines the high lateral resolution of confocal microscopy with the high sectioning capability of optical coherence tomography to image deep layers in tissues with high-contrast and volumetric resolution of 2 μm. A novelty of the custom microscope is the biomimetics that incorporates a liquid lens, as in whales’s eyes, for robust and rapid acquisition of volumetric imaging of deep layers in tissue down to 2 mm, thus overcoming the tradeoff between lateral resolution and depth of focus. The system incorporates a handheld scanning optical imaging head ...

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    11. Measurement of a multi-layered tear film phantom using optical coherence tomography and statistical decision theory

      Measurement of a multi-layered tear film phantom using optical coherence tomography and statistical decision theory

      To extend our understanding of tear film dynamics for the management of dry eye disease, we propose a method to optically sense the tear film and estimate simultaneously the thicknesses of the lipid and aqueous layers. The proposed method, SDT-OCT, combines ultra-high axial resolution optical coherence tomography (OCT) and a robust estimator based on statistical decision theory (SDT) to achieve thickness measurements at the nanometer scale. Unlike conventional Fourier-domain OCT where peak detection of layers occurs in Fourier space, in SDT-OCT thickness is estimated using statistical decision theory directly on the raw spectra acquired with the OCT system. In this ...

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    12. Parallelized multi–graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy

      Parallelized multi–graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy

      Gabor-domain optical coherence microscopy (GD-OCM) is a volumetric high-resolution technique capable of acquiring three-dimensional (3-D) skin images with histological resolution. Real-time image processing is needed to enable GD-OCM imaging in a clinical setting. We present a parallelized and scalable multi-graphics processing unit (GPU) computing framework for real-time GD-OCM image processing. A parallelized control mechanism was developed to individually assign computation tasks to each of the GPUs. For each GPU, the optimal number of amplitude-scans (A-scans) to be processed in parallel was selected to maximize GPU memory usage and core throughput. We investigated five computing architectures for computational speed-up in processing ...

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    1-13 of 13
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    1. (12 articles) University of Rochester
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    3. (4 articles) UCLA
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    Parallelized multi–graphics processing unit framework for high-speed Gabor-domain optical coherence microscopy Measurement of a multi-layered tear film phantom using optical coherence tomography and statistical decision theory Development of cellular resolution Gabor-domain optical coherence microscopy for biomedical applications Assessing microstructures of the cornea with Gabor-domain optical coherence microscopy: pathway for corneal physiology and diseases Optimization of galvanometer scanning for optical coherence tomography Gabor-domain optical coherence microscopy with integrated dual-axis MEMS scanner for fast 3D imaging and metrology Optical Assessment of Soft Contact Lens Edge-Thickness 3D wide field-of-view Gabor-domain optical coherence microscopy advancing real-time in-vivo imaging and metrology Capabilities of Gabor-domain optical coherence microscopy for the assessment of corneal disease Ph.D. positions in Optical Imaging and Vision Science at Indiana University Bloomington KU Leuven leads €6 million research project on heart disease and dementia Gabor optical coherence tomographic angiography (GOCTA) (Part II): theoretical basis of sensitivity improvement and optimization for processing speed