1. Articles from P. Scott Carney

    1-26 of 26
    1. Wavefront measurement using computational adaptive optics

      Wavefront measurement using computational adaptive optics

      In many optical imaging applications, it is necessary to correct for aberrations to obtain high quality images. Optical coherence tomography (OCT) provides access to the amplitude and phase of the backscattered optical field for three-dimensional (3D) imaging samples. Computational adaptive optics (CAO) modifies the phase of the OCT data in the spatial frequency domain to correct optical aberrations without using a deformable mirror, as is commonly done in hardware-based adaptive optics (AO). This provides improvement of image quality throughout the 3D volume, enabling imaging across greater depth ranges and in highly aberrated samples. However, the CAO aberration correction has a ...

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    2. Computational optical coherence tomography [Invited]

      Computational optical coherence tomography [Invited]

      Optical coherence tomography (OCT) has become an important imaging modality with numerous biomedical applications. Challenges in high-speed, high-resolution, volumetric OCT imaging include managing dispersion, the trade-off between transverse resolution and depth-of-field, and correcting optical aberrations that are present in both the system and sample. Physics-based computational imaging techniques have proven to provide solutions to these limitations. This review aims to outline these computational imaging techniques within a general mathematical framework, summarize the historical progress, highlight the state-of-the-art achievements, and discuss the present challenges.

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    3. Inverse scattering for frequency-scanned full-field optical coherence tomography

      Inverse scattering for frequency-scanned full-field optical coherence tomography

      Full-field optical coherence tomography (OCT) is able to image an entire en face plane of scatterers simultaneously, but typically the focus is scanned through the volume to acquire three-dimensional structure. By solving the inverse scattering problem for full-field OCT, we show it is possible to computationally reconstruct a three-dimensional volume while the focus is fixed at one plane inside the sample. While a low-numerical-aperture (NA) OCT system can tolerate defocus because the depth of field is large, for high NA it is critical to correct for defocus. By deriving a solution to the inverse scattering problem for full-field OCT, we ...

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    4. Filtering for unwrapping noisy Doppler optical coherence tomography images for extended microscopic fluid velocity measurement range

      Filtering for unwrapping noisy Doppler optical coherence tomography images for extended microscopic fluid velocity measurement range

      In this Letter, we report the first application of two phase denoising algorithms to Doppler optical coherence tomography (DOCT) velocity maps. When combined with unwrapping algorithms, significantly extended fluid velocity dynamic range is achieved. Instead of the physical upper bound, the fluid velocity dynamic range is now limited by noise level. We show comparisons between physical simulated ideal velocity maps and the experimental results of both algorithms. We demonstrate unwrapped DOCT velocity maps having a peak velocity nearly 10 times the theoretical measurement range.

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    5. Computational adaptive optics of the human retina

      Computational adaptive optics of the human retina

      It is well known that patient-specific ocular aberrations limit imaging resolution in the human retina. Previously, hardware adaptive optics (HAO) has been employed to measure and correct these aberrations to acquire high-resolution images of various retinal structures. While the resulting aberration-corrected images are of great clinical importance, clinical use of HAO has not been widespread due to the cost and complexity of these systems. We present a technique termed computational adaptive optics (CAO) for aberration correction in the living human retina without the use of hardware adaptive optics components. In CAO, complex interferometric data acquired using optical coherence tomography (OCT ...

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    6. Automated interferometric synthetic aperture microscopy and computational adaptive optics for improved optical coherence tomography

      Automated interferometric synthetic aperture microscopy and computational adaptive optics for improved optical coherence tomography

      In this paper, we introduce an algorithm framework for the automation of interferometric synthetic aperture microscopy (ISAM). Under this framework, common processing steps such as dispersion correction, Fourier domain resampling, and computational adaptive optics aberration correction are carried out as metrics-assisted parameter search problems. We further present the results of this algorithm applied to phantom and biological tissue samples and compare with manually adjusted results. With the automated algorithm, near-optimal ISAM reconstruction can be achieved without manual adjustment. At the same time, the technical barrier for the nonexpert using ISAM imaging is also significantly lowered.

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    7. Polarization-sensitive interferometric synthetic aperture microscopy

      Polarization-sensitive interferometric synthetic aperture microscopy

      Three-dimensional optical microscopy suffers from the well-known compromise between transverse resolution and depth-of-field. This is true for both structural imaging methods and their functional extensions. Interferometric synthetic aperture microscopy (ISAM) is a solution to the 3D coherent microscopy inverse problem that provides depth-independent transverse resolution. We demonstrate the extension of ISAM to polarization sensitive imaging, termed polarization-sensitive interferometric synthetic aperture microscopy (PS-ISAM). This technique is the first functionalization of the ISAM method and provides improved depth-of-field for polarization-sensitive imaging. The basic assumptions of polarization-sensitive imaging are explored, and refocusing of birefringent structures is experimentally demonstrated. PS-ISAM enables high-resolution volumetric imaging ...

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    8. Intraoperative Assessment of Final Margins with a Handheld Optical Imaging Probe During Breast-Conserving Surgery May Reduce the Reoperation Rate: Results of a Multicenter Stud

      Intraoperative Assessment of Final Margins with a Handheld Optical Imaging Probe During Breast-Conserving Surgery May Reduce the Reoperation Rate: Results of a Multicenter Stud

      Background A multicenter, prospective, blinded study was performed to test the feasibility of using a handheld optical imaging probe for the intraoperative assessment of final surgical margins during breast-conserving surgery (BCS) and to determine the potential impact on patient outcomes. Methods Forty-six patients with early-stage breast cancer (one with bilateral disease) undergoing BCS at two study sites, the Johns Hopkins Hospital and Anne Arundel Medical Center, were enrolled in this study. During BCS, cavity-shaved margins were obtained and the final margins were examined ex vivo in the operating room with a probe incorporating optical coherence tomography (OCT) hardware and interferometric ...

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    9. Computational high-resolution optical imaging of the living human retina

      Computational high-resolution optical imaging of the living human retina

      High-resolution in vivo imaging is of great importance for the fields of biology and medicine. The introduction of hardware-based adaptive optics (HAO) has pushed the limits of optical imaging, enabling high-resolution near diffraction-limited imaging of previously unresolvable structures 1 , 2 . In ophthalmology, when combined with optical coherence tomography, HAO has enabled a detailed three-dimensional visualization of photoreceptor distributions 3 , 4 and individual nerve fibre bundles 5 in the living human retina. However, the introduction of HAO hardware and supporting software adds considerable complexity and cost to an imaging system, limiting the number of researchers and medical professionals who could benefit ...

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    10. Three-dimensional motion correction using speckle and phase for in vivo computed optical interferometric tomography

      Three-dimensional motion correction using  speckle and phase for in vivo computed optical  interferometric tomography

      Over the years, many computed optical interferometric techniques have been developed to perform high-resolution volumetric tomography. By utilizing the phase and amplitude information provided with interferometric detection, post-acquisition corrections for defocus and optical aberrations can be performed. The introduction of the phase, though, can dramatically increase the sensitivity to motion (most prominently along the optical axis). In this paper, we present two algorithms which, together, can correct for motion in all three dimensions with enough accuracy for defocus and aberration correction in computed optical interferometric tomography. The first algorithm utilizes phase differences within the acquired data to correct for motion ...

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    11. Computed optical interferometric tomography for high-speed volumetric cellular imaging

      Computed optical interferometric tomography for high-speed volumetric cellular imaging

      hree-dimensional high-resolution imaging methods are important for cellular-level research. Optical coherence microscopy (OCM) is a low-coherence-based interferometry technology for cellular imaging with both high axial and lateral resolution. Using a high-numerical-aperture objective, OCM normally has a shallow depth of field and requires scanning the focus through the entire region of interest to perform volumetric imaging. With a higher-numerical-aperture objective, the image quality of OCM is affected by and more sensitive to aberrations. Interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO) are computed imaging techniques that overcome the depth-of-field limitation and the effect of optical aberrations in optical coherence ...

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    12. Stability in computed optical interferometric tomography (Part II): in vivo stability assessment

      Stability in computed optical interferometric tomography (Part II): in vivo stability assessment

      Stability is of utmost importance to a wide range of phase-sensitive processing techniques. In Doppler optical coherence tomography and optical coherence elastography, in addition to defocus and aberration correction techniques such as interferometric synthetic aperture microscopy and computational/digital adaptive optics, a precise understanding of the system and sample stability helps to guide the system design and choice of imaging parameters. This article focuses on methods to accurately and quantitatively measure the stability of an imaging configuration in vivo . These methods are capable of partially decoupling axial from transverse motion and are compared against the stability requirements for computed optical ...

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    13. Stability in computed optical interferometric tomography (Part I): Stability requirements

      Stability in computed optical interferometric tomography (Part I): Stability requirements

      As imaging systems become more advanced and acquire data at faster rates, increasingly dynamic samples can be imaged without concern of motion artifacts. For optical interferometric techniques such as optical coherence tomography, it often follows that initially, only amplitude-based data are utilized due to unstable or unreliable phase measurements. As systems progress, stable phase maps can also be acquired, enabling more advanced, phase-dependent post-processing techniques. Here we report an investigation of the stability requirements for a class of phase-dependent post-processing techniques – numerical defocus and aberration correction with further extensions to techniques such as Doppler, phase-variance, and optical coherence elastography. Mathematical ...

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    14. Multifocal interferometric synthetic aperture microscopy

      Multifocal interferometric synthetic aperture microscopy

      There is an inherent trade-off between transverse resolution and depth of field (DOF) in optical coherence tomography (OCT) which becomes a limiting factor for certain applications. Multifocal OCT and interferometric synthetic aperture microscopy (ISAM) each provide a distinct solution to the trade-off through modification to the experiment or via post-processing, respectively. In this paper, we have solved the inverse problem of multifocal OCT and present a general algorithm for combining multiple ISAM datasets. Multifocal ISAM (MISAM) uses a regularized combination of the resampled datasets to bring advantages of both multifocal OCT and ISAM to achieve optimal transverse resolution, extended effective ...

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    15. Feature Of The Week 5/12/13: University of Illinois at Urbana-Champaign Reports on Real-Time In Vivo Computed Optical Interferometric Tomography

      Feature Of The Week 5/12/13: University of Illinois at Urbana-Champaign Reports on Real-Time In Vivo Computed Optical Interferometric Tomography

      Real-time, high-resolution tomography over an extended field-of-view in scattering tissues remains an elusive goal for biomedical imaging. The apparent trade-off between the depth-of-field and lateral resolution in optical imaging degrades the image resolution outside the confocal region in OCT. Although a number of approaches have been utilized to overcome these limitations, many of these techniques are plagued by either high computational complexity or complicated optical setups. ISAM is a computational technique that can yield spatially invariant transverse resolution by resampling the Fourier space of the data. However, a full 3D ISAM reconstruction requires extensive manipulation of volumetric datasets, imposing significant ...

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    16. Real-time in vivo computed optical interferometric tomography

      Real-time in vivo computed optical interferometric tomography

      High-resolution real-time tomography of scattering tissues is important for many areas of medicine and biology 1 , 2 , 3 , 4 , 5 , 6 . However, the compromise between transverse resolution and depth-of-field, in addition to low sensitivity deep in tissue, continues to impede progress towards cellular-level volumetric tomography. Computed imaging has the potential to solve these long-standing limitations. Interferometric synthetic aperture microscopy 7 , 8 , 9 is a computed imaging technique enabling high-resolution volumetric tomography with spatially invariant resolution. However, its potential for clinical diagnostics remains largely untapped because full volume reconstructions required lengthy post-processing, and the phase-stability requirements have been difficult to satisfy ...

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    17. Feature Of The Week 12/9/12: University of Illinois at Urbana Champaign Researchers Extend Astronomical Guide-Star Techniques to Computational OCT Imaging

      Feature Of The Week 12/9/12: University of Illinois at Urbana Champaign Researchers Extend Astronomical Guide-Star Techniques to Computational OCT Imaging

      Researchers at the University of Illinois at Urbana-Champaign have a long history of novel work in the field of OCT and related fields.  This includes the very promising area of computational adaptive optics and related methods that offer the promise of dramatically improved images in a wide variety of settings by performing post-acquisition processing of magnitude and phase data.  Below is a summary of some of their recent work.  Aberrations degrade resolution, contrast, and signal-to-noise ratio in optical microscopy. In optical coherence tomography (OCT), aberrations limit the resolution of diagnostic features, notably in retinal OCT. With optical coherence microscopy, which ...

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    18. Guide-star-based computational adaptive optics for broadband interferometric tomography

      Guide-star-based computational adaptive optics for broadband interferometric tomography

      We present a method for the numerical correction of optical aberrations based on indirect sensing of the scattered wavefront from point-like scatterers (“guide stars”) within a three-dimensional broadband interferometric tomogram. This method enables the correction of high-order monochromatic and chromatic aberrations utilizing guide stars that are revealed after numerical compensation of defocus and low-order aberrations of the optical system. Guide-star-based aberration correction in a silicone phantom with sparse sub-resolution-sized scatterers demonstrates improvement of resolution and signal-to-noise ratio over a large isotome. Results in highly scattering muscle tissue showed improved resolution of fine structure over an extended volume. Guide-star-based computational adaptive ...

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    19. Feature Of The Week 6/10/12: Computational Adaptive Optics: A New Digital Post-Processing Technique to Optimize Resolution in OCT and other Interferometric Optical Imaging Applications

      Feature Of The Week 6/10/12: Computational Adaptive Optics: A New Digital Post-Processing Technique to Optimize Resolution in OCT and other Interferometric Optical Imaging Applications

      OCT and other interferometric optical 2D and 3D imaging techniques have long been plagued by the fundamental optical limitations such as that which occurs between depth-of-field (Rayleigh range) and lateral resolution or limitations in image resolution due to optical aberrations (spatial and spectral) that occur within delivery or collection optics or within tissue themselves.  Over the past few years there have been a variety of new powerful post optical detection signal processing techniques that promise to shatter these traditional limitations and take OCT and other interferometric optical imaging techniques to a new level.  These techniques are all related on some ...

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    20. Computational adaptive optics for broadband optical interferometric tomography of biological tissue

      Computational adaptive optics for broadband optical interferometric tomography of biological tissue

      Aberrations in optical microscopy reduce image resolution and contrast, and can limit imaging depth when focusing into biological samples. Static correction of aberrations may be achieved through appropriate lens design, but this approach does not offer the flexibility of simultaneously correcting aberrations for all imaging depths, nor the adaptability to correct for sample-specific aberrations for high-quality tomographic optical imaging. Incorporation of adaptive optics (AO) methods have demonstrated considerable improvement in optical image contrast and resolution in noninterferometric microscopy techniques, as well as in optical coherence tomography. Here we present a method to correct aberrations in a tomogram rather than the ...

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    21. The impact of aberrations on object reconstruction with interferometric synthetic aperture microscopy

      The impact of aberrations on object reconstruction with interferometric synthetic aperture microscopy

      Interferometric synthetic aperture microscopy (ISAM) reconstructs the scattering potential of a sample with spatially invariant resolution, based on the incident beam profile, the beam scan pattern, the physical model of light sample interaction, and subsequent light collection by the system. In practice, aberrations may influence the beam profile, particularly at higher NA, when ISAM is expected to provide maximum benefit over optical coherence microscopy. Thus it is of interest to determine the effects of aberrations on ISAM reconstructions. In this paper we present the forward model incorporating the effects of aberrations, which forms the basis for aberration correction in ISAM ...

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    22. Interferometric Synthetic Aperture Microscopy: Microscopic Laser Radar

      Interferometric Synthetic Aperture Microscopy: Microscopic Laser Radar
      Combining optical coherence tomography instrumentation and the principles of synthetic aperture radar, researchers have developed a new method for reconstructing 3-D optical images—even in regions that are out of focus in the raw data. Doctors may soon be able to use this approach as a noninvasive diagnostic tool in clinical settings. Microscopic 3-D optical imaging provides guidance to tomorrow’s doctors during surgical interventions. In many clinical scenarios, doctors require high-resolution visualization of tissues and their underlying cellular structures. Perhaps the most common example is for the identification, diagnosis and treatment of cancer. In such cases, clinicians typically take ...
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    23. Cross-validation of interferometric synthetic aperture microscopy and optical coherence tomography

      Cross-validation of interferometric synthetic aperture microscopy and optical coherence tomography
      Computationally reconstructed interferometric synthetic aperture microscopy is coregistered with optical coherence tomography (OCT) focal plane data to provide quantitative cross validation with OCT. This is accomplished through a qualitative comparison of images and a quantitative analysis of the width of the point-spread function in simulation and experiment. The width of the ISAM point-spread function is seen to be independent of depth, in contrast to OCT.
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    24. Partially coherent illumination in full-field interferometric synthetic aperture microscopy

      A model is developed for optical coherence tomography and interferometric synthetic aperture microscopy (ISAM) systems employing full-field frequency-scanned illumination with partial spatial coherence. This model is used to derive efficient ISAM inverse scattering algorithms that give ... [J. Opt. Soc. Am. A 26, 376-386 (2009)]
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    25. Interferometric synthetic aperture microscopy: tissue structure inferred by computed imaging techniques

      Interferometric synthetic aperture microscopy: tissue structure inferred by computed imaging techniques
      Daniel L. Marks, Tyler S. Ralston, Brynmor J. Davis et al. Interferometric Synthetic Aperture Microscopy (ISAM) is an optical microscopy computed-imaging technique for measuring the optical properties of three-dimensional structures and biological tissues. In this work, the principle of ISAM is reviewed, and its application to imaging tissue properties in v ... [Proc. SPIE Int. Soc. Opt. Eng. 6864, 686407 (2008)] published Fri Feb 15, 2008.
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    26. Interferometric synthetic aperture microscopy

      Interferometric synthetic aperture microscopy
      State-of-the-art methods in high-resolution three-dimensional optical microscopy require that the focus be scanned through the entire region of interest. However, an analysis of the physics of the light–sample interaction reveals that the Fourier-space coverage is independent of depth. Here we show that, by solving the inverse scattering problem for interference microscopy, computed reconstruction yields volumes with a resolution in all planes that is equivalent to the resolution achieved only at the focal plane for conventional high-resolution microscopy. In short, the entire illuminated volume has spatially invariant resolution, thus eliminating the compromise between resolution and depth of field. We describe ...
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    1-26 of 26
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    Interferometric synthetic aperture microscopy: tissue structure inferred by computed imaging techniques Interferometric synthetic aperture microscopy Cross-validation of interferometric synthetic aperture microscopy and optical coherence tomography Interferometric Synthetic Aperture Microscopy: Microscopic Laser Radar Computational adaptive optics for broadband optical interferometric tomography of biological tissue Feature Of The Week 6/10/12: Computational Adaptive Optics: A New Digital Post-Processing Technique to Optimize Resolution in OCT and other Interferometric Optical Imaging Applications Guide-star-based computational adaptive optics for broadband interferometric tomography Feature Of The Week 12/9/12: University of Illinois at Urbana Champaign Researchers Extend Astronomical Guide-Star Techniques to Computational OCT Imaging Feature Of The Week 5/12/13: University of Illinois at Urbana-Champaign Reports on Real-Time In Vivo Computed Optical Interferometric Tomography Notal Vision Engages Wasatch Photonics Bringing AI-Enabled Home-Based Optical Coherence Tomography Closer to Market Semiconductor Lasers and Diode-based Light Sources for Biophotonics (Textbook) Inside the “Razor Effect”: Lessons From Optical Coherence Tomography—What Does Angiography Hide?