1. Articles from Josh Hogan

    1-13 of 13
    1. Development of a first-generation miniature multiple reference optical coherence tomography imaging device

      Development of a first-generation miniature multiple reference optical coherence tomography imaging device

      Multiple reference optical coherence tomography (MR-OCT) is a technology ideally suited to low-cost, compact OCT imaging. This modality is an extension of time-domain OCT with the addition of a partial mirror in front of the reference mirror. This enables extended, simultaneous depth scanning with the relatively short scan range of a miniature voice coil motor on which the scanning mirror is mounted. This work details early stage development of the first iteration of a miniature MR-OCT device. This iteration utilizes a fiber-coupled input from an off-board superluminescent diode. The dimensions of the module are 40×57  mm40×57  mm ...

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    2. Evaluation of a polarization sensitive multiple reference optical coherence tomography system

      Evaluation of a polarization sensitive multiple reference optical coherence tomography system

      Multiple reference optical coherence tomography (MR-OCT) is a new compact optical sensor platform based on a small form factor recirculating reference arm scanning optical delay, which promises a robust, cost-effective semisolid state design for integration with next generation mobile devices. The miniature re-circulating optical delay is based on a voice coil motor (VCM) actuator and a partial mirror. Imaging capability of MR-OCT has been recently demonstrated using a non-polarizing bulk optics design and an unbalanced detection system with a sensitivity of up to 98 dB at an axial rate of 1200 A-scans per second. In this study, we implemented a ...

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    3. Development of a miniature multiple reference optical coherence tomography imaging device

      Development of a miniature multiple reference optical coherence tomography imaging device

      Multiple reference optical coherence tomography (MR-OCT) is a new technology ideally suited to low-cost, compact OCT imaging. This modality is an extension of time-domain OCT with the addition of a partial mirror in front of the reference mirror. This enables extended, simultaneous depth scanning with the relatively short sweep of a miniature voice coil motor on which the scanning mirror is mounted. Applications of this technology include biometric security, ophthalmology, personal health monitoring and non-destructive testing. This work details early-stage development of the first iteration of a miniature MR-OCT device. This device utilizes a fiber-coupled input from an off-board superluminescent ...

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    4. The impact of relative intensity noise on the signal in multiple reference optical coherence tomography

      The impact of relative intensity noise on the signal in multiple reference optical coherence tomography

      Multiple reference optical coherence tomography (MR-OCT) applies a unique low-cost solution to enhance the scanning depth of standard time domain OCT by inserting an partial mirror into the reference arm of the interferometric system. This novel approach achieves multiple reflections for different layers and depths of an sample with minimal effort of engineering and provides an excellent platform for low-cost OCT systems based on well understood production methods for micro-mechanical systems such as CD/DVD pick-up systems. The direct integration of a superluminescent light-emitting diode (SLED) is a preferable solution to reduce the form- factor of an MR-OCT system. Such ...

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    5. Assessment of curing behavior of light-activated dental composites using intensity correlation based multiple reference optical coherence tomography

      Assessment of curing behavior of light-activated dental composites using intensity correlation based multiple reference optical coherence tomography

      Background and Objectives Monitoring the curing kinetics of light-activated resin is a key area of research. These resins are used in restorative applications and particularly in dental applications. They can undergo volumetric shrinkage due to poor control of the depth dependent curing process, modulated by the intensity and duration of the curing light source. This often results in the formation of marginal gaps, causing pain and damage to the restoration site. In this study, we demonstrate the capabilities of a correlation method applied using a multiple references optical coherence tomography (MR-OCT) architecture to monitor the curing of the resin. Study ...

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    6. 3D nondestructive testing system with an affordable multiple reference optical-delay-based optical coherence tomography

      3D nondestructive testing system with an affordable multiple reference optical-delay-based optical coherence tomography

      Optical coherence tomography (OCT) is emerging as a powerful noncontact imaging technique, allowing high-quality cross-sectional imaging of scattering specimens nondestructively. However, the complexity and cost of current embodiments of an OCT system limit its use in various nondestructive testing (NDT) applications at resource-limited settings. In this paper, we demonstrate the feasibility of a novel low-cost OCT system for a range of nondestructive testing (NDT) applications. The proposed imaging system is based on an enhanced time-domain OCT system with a low cost and small form factor reference arm optical delay, called multiple reference OCT (MR-OCT), which uses a miniature voice coil ...

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    7. Characterization of light distribution and optimization of detector position for multiple reference optical coherence tomography

      Characterization of light distribution and optimization of detector position for multiple reference optical coherence tomography

      A time-domain optical coherence tomography system with respect to multiple reflections in the reference arm is simulated with Zemax and the optimal detector position is discussed based on the wavefront error. Multiple reference optical coherence tomography (MR-OCT) is a novel optical imaging platform using a single miniature actuator and partial mirror to recirculate light multiple times within the interferometric system. The recirculation corresponds to multiple path delays extending effectively the axial scan-range. The simulation of MR-OCT with lenses of 5 mm diameter shows that it is suitable to build a compact system using low-cost components. Subsequently MR-OCT enables an affordable ...

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    8. Signal simulation and signal processing for multiple reference optical coherence tomography

      Signal simulation and signal processing for multiple reference optical coherence tomography

      The generation of a synthetic MR-OCT signal is presented and compared to a real acquired signal. Multiple reference optical coherence tomography (MR-OCT) is a novel time-domain interferometric system. The MR-OCT principle is adding a partial mirror to extend the axial scan range, which effectively extends the scan depth for imaging. The actuation of the scan mirror required for time-domain OCT, was demonstrated to operate with a low cost miniature voice coil, such as a speaker extracted from a smartphone or CD/DVD pick-up system. Building a compact and cost-effective optical imaging system will enable affordable medical diagnosis at low-resource setting ...

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    9. MR-OCT: Affordable Tomographic Imaging Applications

      MR-OCT: Affordable Tomographic Imaging Applications

      The application of optical coherence tomography (OCT) in the field of biomedical imaging has increased rapidly in recent years and may continue on this trajectory with growth potential in clinical diagnostics. 1 Integration of OCT for affordable point-of-care (POC) diagnostic applications and personal-care monitoring should lead to miniature, inexpensive, portable, robust optical instrumentation that is accurate and simple to use. However, the current embodiments of OCT systems are highly expensive, utilize large-form-factor optical design, and require accurate alignment of complex optics, making them impractical for the POC environment. In recent years, there has been an increasing interest in the development ...

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    10. Dermascope guided multiple reference optical coherence tomography

      Dermascope guided multiple reference optical coherence tomography

      In this paper, we report the feasibility of integrating a novel low cost optical coherence tomography (OCT) system with a dermascope for point-of-care applications. The proposed OCT system is based on an enhanced time-domain optical coherence tomographic system, called multiple reference OCT (MR-OCT), which uses a single miniature voice coil actuator and a partial mirror for extending the axial scan range. The system can simultaneously register both the superficial dermascope image and the depth-resolved OCT sub-surface information by an interactive beam steering method. A practitioner is able to obtain the depth resolved information of the point of interest by simply ...

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    11. Enhanced OCT Measurement And Imaging Apparatus And Method

      Enhanced OCT Measurement And Imaging Apparatus And Method

      The invention teaches a method, apparatus and system for enhancing measurement and imaging using optical coherence tomography (OCT) by using a pressure wave, such as ultrasound, in conjunction with OCT to make measurements and generate images of a target. The pressure signal modulates the refractive index of the target at high speed, thereby disrupting the generation of a constant speckle noise pattern and thereby reducing speckle noise. The pressure signal can also be switched between at least two states at high speed which enables acquiring a high speed differential signal related weak scattering sites thereby enabling enhanced measurement and imaging ...

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    12. Dermascope assisted interactive patient interface for multiple reference optical coherence tomography

      Dermascope assisted interactive patient interface for multiple reference optical coherence tomography

      There has been a growing interest in the development of a low cost depth-resolved non-invasive dermis imaging tool for both clinical and fundamental investigations of skin diseases. Multiple reference optical coherence tomography (MR-OCT) is a recently developed miniature time-domain low coherence interferometeric imaging platform, which promises to fit into robust, cost-effective designs that are virtually solid state, typical of handheld devices. In this paper we demonstrate the feasibility of MR-OCT for dermis imaging applications by incorporating it in a dermascope, which provides simultaneous imaging of dermis and an interactive tool for beam steering and registration of the OCT imaging beam ...

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    13. Voice coil based robust and miniature optical delay for multiple reference optical coherence tomography

      Voice coil based robust and miniature optical delay for multiple reference optical coherence tomography

      Multiple reference optical coherence tomography (MR-OCT) is a recently developed time-domain interferometeric imaging platform, which promises to fit into robust, cost-effective designs that are virtually solid state. An optical delay is created by the reference mirror which is mounted on a piezo-electric transducer (PZT) and the key element of MR-OCT technology is the presence of a partial mirror in front of the reference mirror. However, the limited axial displacement range at higher scanning-frequencies are a limitation of a PZT-based optical delay. Moreover, PZT-based actuators require a relatively high operational voltage and are expensive. In this paper we present a voice ...

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    1-13 of 13
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    1. (12 articles) National University of Ireland, Galway
    2. (12 articles) Martin J. Leahy
    3. (11 articles) Roshan Dsouza
    4. (8 articles) Hrebesh M. Subhash
    5. (6 articles) Compact Imaging, Inc
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    Voice coil based robust and miniature optical delay for multiple reference optical coherence tomography Dermascope assisted interactive patient interface for multiple reference optical coherence tomography Enhanced OCT Measurement And Imaging Apparatus And Method Dermascope guided multiple reference optical coherence tomography MR-OCT: Affordable Tomographic Imaging Applications Signal simulation and signal processing for multiple reference optical coherence tomography Characterization of light distribution and optimization of detector position for multiple reference optical coherence tomography 3D nondestructive testing system with an affordable multiple reference optical-delay-based optical coherence tomography Assessment of curing behavior of light-activated dental composites using intensity correlation based multiple reference optical coherence tomography Development of a first-generation miniature multiple reference optical coherence tomography imaging device Early microvascular retinal changes in optical coherence tomography angiography in patients with type 1 diabetes mellitus Computational optical coherence tomography