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Non-invasive thermal imaging of cardiac remodeling in mice

BIOMEDICAL OPTICS EXPRESS 2019年第12期10卷 6189-6203页

作者： Brzezinski, Rafael Y. Ovadia-Blechman, Zehava Lewis, Nir Rabin, Neta Zimmer, Yair Levin-Kotler, Lapaz Tepper-Shaihov, Olga Naftali-Shani, Nili Tsoref, Olga Grossman, Ehud Leor, Jonathan Hoffer, Oshrit Tel Aviv Univ Sackler Fac Med IL-6997801 Tel Aviv Israel Tel Aviv Univ Sackler Fac Med Neufeld Cardiac Res Inst Tel Aviv Israel Sheba Med Ctr Leviev Heart Ctr Tamman Cardiovasc Res Inst IL-52621 Tel Hashomer Israel Afeka Tel Aviv Acad Coll Engn Sch Med Engn IL-6910717 Tel Aviv Israel Tel Aviv Univ Dept Ind Engn IL-6997801 Tel Aviv Israel Sheba Med Ctr Internal Med Wing & Hypertens Unit IL-52621 Tel Hashomer Israel Afeka Tel Aviv Acad Coll Engn Sch Elect Engn IL-6910717 Tel Aviv Israel

Thermal infrared imaging has been suggested as a non-invasive alternative to monitor physiological processes and disease. However, the use of this technique to image internal organs, such as the heart, has not yet been investigated. We sought to determine the ability of our novel thermal image-processing algorithm to detect structural and functional changes in a mouse model of hypertension and cardiac remodeling. Twelve mice were randomly assigned to receive either the pro-inflammatory, hypertensive hormone angiotensin-II (2 mg/kg/day, n = 6) or saline (n = 6) infusion for 28 days. We performed weekly blood pressure measurements, together with serial trans-thoracic echocardiography studies and histopathological evaluation of the hearts. Thermal images were captured with a commercially available thermal camera, and images were processed by our novel algorithm which analyzes relative spatial temperature variation across the animal's thorax. We assessed cardiac inflammation by measuring inflammatory cell infiltration through flow cytometry. Angiotensin infusion increased blood pressure together with cardiac hypertrophy and fibrosis. Thermal imaging at day 28 of the experiment detected an increase in the fraction of the skin heated by the heart in angiotensin-treated mice. Thermal image findings were significantly correlated to left ventricular volume and mass parameters seen on echocardiography (r = 0.8, p < 0.01 and r = 0.6, p = 0.07). We also identified distinct changes in the spatial heat profiles of all angiotensin-treated hearts, possibly reflecting remodeling processes in the hypertensive heart. Finally, a machine learning based model using thermal imaging parameters predicted intervention status in 10 out of 11 mice similar to a model using echocardiographic measurements. Our findings suggest, for the first time, that a new thermal image-processing algorithm successfully correlates surface thermography with cardiac structural changes in mice with hypertensive he

关键词： Feature extraction image processing image processing algorithms Magnetic resonance imaging Thermal imaging Thermal infrared imaging

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Three-dimensional imaging of stationary and moving targets in turbid underwater environments using a single-photon detector array

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OPTICS EXPRESS 2019年第20期27卷 28437-28456页

作者： Maccarone, Aurora Della Rocca, Francesco Mattioli McCarthy, Aongus Henderson, Robert Buller, Gerald S. Heriot Watt Univ Sch Engn & Phys Sci Inst Photon & Quantum Sci Edinburgh EH14 4AS Midlothian Scotland Univ Edinburgh Sch Engn Inst Integrated Micro & Nano Syst Edinburgh EH9 3FF Midlothian Scotland

Three-dimensional imaging in underwater environments was investigated using a picosecond resolution silicon single-photon avalanche diode (SPAD) detector array fabricated in complementary metal-oxide semiconductor (CMOS) technology. Each detector in the 192 x 128 SPAD array had an individual time-to-digital converter allowing rapid, simultaneous acquisition of data for the entire array using the time-correlated single-photon counting approach. A picosecond pulsed laser diode source operating at a wavelength of 670 nm was used to illuminate the underwater scenes, emitting an average optical power up to 8 mW. Both stationary and moving targets were imaged under a variety of underwater scattering conditions. The acquisition of depth and intensity videos of moving targets was demonstrated in dark laboratory conditions through scattering water, equivalent to having up to 6.7 attenuation lengths between the transceiver and target. Data were analyzed using a pixel-wise approach, as well as an image processing algorithm based on a median filter and polynomial approximation. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.

关键词： Charge coupled devices Detector arrays Forward scattering image processing algorithms Low light levels Spatial frequency

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Modeling and optimization of a geometrical calibration procedure for stereoscopic video endoscopes

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS image SCIENCE AND VISION 2019年第11期36卷 1871-1882页

作者： Gorevoy, Alexey, V Machikhin, Alexander S. Khokhlov, Demid D. Batshev, Vladislav, I Natl Res Univ Moscow Power Engn Univ Inst Automat & Comp Engn Dept Elect Engn & Introscopy 14 Krasnokazarmennaya St Moscow 111250 Russia Russian Acad Sci Lab Acoustoopt Spect Sci & Technol Ctr Unique Instrumentat 15 Butlerova St Moscow 117342 Russia Bauman Moscow State Tech Univ Dept Lasers & Optoelect Syst 5 2 Ya Baumanskaya St Moscow 105005 Russia

Stereoscopic video endoscopes are widely used for remote visual inspection and precise three-dimensional (3D) measurements in industrial and biomedical applications. The reconstruction of 3D points from the corresponding image points requires a geometrical calibration procedure, the accuracy of which affects the measurement uncertainty. We propose to perform an optimal choice of the calibration technique and the calibration target parameters using a computer simulation at the design stage. The effectiveness of this approach is demonstrated via the design of a self-developed miniature prism-based stereoscopic system. We simulated acquisition of calibration and measurement data using optical design software. The conventional calibration technique, requiring many positions of the flat target with arbitrary displacements and rotations, was compared with another one that uses the translation stage to provide pure translation of the target. We analyzed the impact of the translation uncertainty, the number of positions, the number of targets, and the uncertainty of image point coordinates on the uncertainty of calibration parameters and 3D measurements. We have shown that the second technique could provide acceptable measurement accuracy using only two images. The results of the computer simulation were confirmed experimentally using the prototype of the stereoscopic endoscope. The proposed approach may be used to optimize calibration techniques and reduce the cost of calibration equipment for various stereoscopic measurement systems. (C) 2019 Optical Society of America

关键词： Camera calibration Digital image processing image processing algorithms image quality Optical design software Three dimensional image processing

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Laser light source limited uncertainty of speckle-based roughness measurements

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APPLIED OPTICS 2019年第23期58卷 6436-6445页

作者： Patzelt, Stefan Stoebener, Dirk Fischer, Andreas Univ Bremen Bremen Inst Metrol Automat & Qual Sci Linzer Str 13 D-28359 Bremen Germany Univ Bremen Inst Technol & Educ Hochschulring 20 D-28359 Bremen Germany Univ Bremen MAPEX Ctr Mat & Proc Bremen Germany

Surface microtopography measurement (e.g., form, waviness, roughness) is a precondition to assess the surface quality of technical components with regard to their applications. Laser speckle-based roughness measurement is an optical scattered light measuring technique that provides field of view dimensions of some square millimeters and measuring frequencies in the kilohertz domain enabling in-process roughness characterization of even moving part surfaces. However, camera exposure times of microseconds or less and a high detector pixel density mean less light energy per pixel. This affects the minimal achievable measurement uncertainty, which has not been clarified yet for almost plain sample shapes. For this reason, the measurement uncertainty limit of the surface roughness parameter Sa due to fundamental, inevitable noise sources such as laser shot noise and detector noise is analytically estimated and compared to experimental data. The results show a mainly shot-noise-limited measurement uncertainty contribution of less than 0.033 nm. In addition, a significant influence of laser beam profile variations on the achievable roughness measurement uncertainty is identified for the current experimental setup, which is generally below 0.3 nm and can be improved in future setups. The already achieved low measurement uncertainty offers ideal preconditions for in-process roughness measurements on samples with a similar surface structure in industrial environments. (C) 2019 Optical Society of America

关键词： Atomic force microscopy CCD cameras High power diode lasers image processing algorithms Laser sources Speckle patterns

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Back propagation neutral network based signal acquisition for Brillouin distributed optical fiber sensors

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OPTICS EXPRESS 2019年第4期27卷 4549-4561页

作者： Cao, Zhiyuan Guo, Nan Li, Meihong Yu, Kuanglu Gao, Kaiqiang Beijing Jiaotong Univ Sch Comp & Informat Technol Beijing 100044 Peoples R China Hong Kong Polytech Univ Dept Elect & Informat Engn Kowloon Hong Kong Peoples R China China Elect Power Res Inst Dept Informat & Commun Beijing 100085 Peoples R China

This manuscript proposes a method based on back propagation (BP) neural network and the spectral subtraction method to quickly obtain sensing information in Brillouin fiber optics sensors. BP neural network's characteristics which can realize any complex nonlinear mapping help to determine the frequency shift section(s) information. The training function, transfer function and number of hidden layer nodes of BP neural network are determined with experimental data. The experimental results show that comparing with traditional Lorentz fitting algorithm and edge detection with Sobel operator, the BP neural network is about 1/12 in terms of time complexity with the Lorentz algorithm, about 1/9 with the edge detection based on Sobel operator;while the respective accuracy on determine the frequency shifted section(s) has improved by 79.4% and 27.9%. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Digital image processing Edge detection image processing image processing algorithms Neural networks Pattern recognition

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Brain segmentation, spatial censoring, and averaging techniques for optical functional connectivity imaging in mice

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BIOMEDICAL OPTICS EXPRESS 2019年第11期10卷 5952-5973页

作者： White, Brian R. Padawer-Curry, Jonah A. Cohen, Akiva S. Licht, Daniel J. Yodh, Arjun G. Childrens Hosp Philadelphia Div Pediat Cardiol Dept Pediat 3401 Civ Ctr BlvdPediat Cardiol-8NW Philadelphia PA 19104 USA Childrens Hosp Philadelphia Div Neurol Dept Pediat 3501 Civ Ctr Blvd Philadelphia PA 19104 USA Childrens Hosp Philadelphia Dept Anesthesiol & Crit Care Med Abramson Res Ctr 3615 Civ Ctr BlvdRoom 816-H Philadelphia PA 19104 USA Univ Penn Dept Phys & Astron 3231 Walnut St Philadelphia PA 19104 USA

Resting-state functional connectivity analysis using optical neuroimaging holds the potential to be a powerful bridge between mouse models of disease and clinical neurologic monitoring. However, analysis techniques specific to optical methods are rudimentary, and algorithms from magnetic resonance imaging are not always applicable to optics. We have developed visual processing tools to increase data quality, improve brain segmentation, and average across sessions with better field-of-view. We demonstrate improved performance using resting-state optical intrinsic signal from normal mice. The proposed methods increase the amount of usable data from neuroimaging studies, improve image fidelity, and should be translatable to human optical neuroimaging systems. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Diffuse optical tomography Functional imaging image processing algorithms image quality Imaging techniques Optical imaging

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Synchronized, concurrent optical coherence tomography and videostroboscopy for monitoring vocal fold morphology and kinematics

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BIOMEDICAL OPTICS EXPRESS 2019年第9期10卷 4450-4461页

作者： Maguluri, Gopi Mehta, Daryush Kobler, James Park, Jesung Iftimia, Nicusor Phys Sci Inc 20 New England Business Ctr Andover MA 01810 USA Massachusetts Gen Hosp Ctr Laryngeal Surg & Voice Rehabil Boston MA 02114 USA

Voice disorders affect a large number of adults in the United States, and their clinical evaluation heavily relies on laryngeal videostroboscopy, which captures the medial-lateral and anterior-posterior motion of the vocal folds using stroboscopic sampling. However, videostroboscopy does not provide direct visualization of the superior-inferior movement of the vocal folds, which yields important clinical insight. In this paper, we present a novel technology that complements videostroboscopic findings by adding the ability to image the coronal plane and visualize the superior-inferior movement of the vocal folds. The technology is based on optical coherence tomography, which is combined with videostroboscopy within the same endoscopic probe to provide spatially and temporally co-registered images of the mucosal wave motion, as well as vocal folds subsurface morphology. We demonstrate the capability of the rigid endoscopic probe, in a benchtop setting, to characterize the complex movement and subsurface structure of the aerodynamically driven excised larynx models within the 50 to 200 Hz phonation range. Our preliminary results encourage future development of this technology with the goal of its use for in vivo laryngeal imaging. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： image processing image processing algorithms Imaging systems In vivo imaging Optical coherence tomography Optical imaging

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Sea surface clutter suppression method based on time-domain polarization characteristics of sun glint

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OPTICS EXPRESS 2019年第3期27卷 2142-2158页

作者： Liang, Jian-An Wang, Xia He, Si Jin, Wei-Qi Beijing Inst Technol Sch Optoelect Beijing 100081 Peoples R China

A method for suppressing sea surface clutter, based on the characteristics of sun glint, is proposed. The proposed method is built on an infrared polarization radiation model of the dynamic sea surface. Based on the time-domain polarization characteristics of sun glint in a dynamic sea scene, a method for taking linearly polarized images at different analyzer angles over fixed intervals is used to suppress sea clutter by using the minimum operation. Experimental results show that the proposed method can effectively improve the contrast between a target and its background. Following simplification, this method can also provide a streamlined sea clutter suppression method with obvious results. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： image processing image processing algorithms image quality Polarimetric imaging Polarized light Three dimensional imaging

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Improvement of an optical image by the measurement reduction technique at parametric multiplexing

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS 2019年第4期36卷 901-909页

作者： Balakin, D. A. Chirkin, A. S. Moscow MV Lomonosov State Univ Fac Phys Leninskie Gory 1Bld 2 Moscow 119991 Russia Moscow MV Lomonosov State Univ Int Laser Ctr Leninskie Gory 1Bld 62 Moscow 119991 Russia

In the process of parametric optical image amplification, images are formed at new frequencies in addition to the amplified original image. We show that parametric multiplexing of optical images can be used to produce an image with improved quality. As an example, we study the parametric amplification of an optical image at low-frequency pumping in which multiplexed optical images turn out to be quantum-correlated. Additional improvement is made possible by using the information about the object that is available to the researcher, in particular, about sparsity of its image. To take the available information into account, we apply the measurement reduction technique. (C) 2019 Optical Society of America

关键词： Fourier transforms image processing image processing algorithms image quality Point spread function Wavelet transforms

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Active photonic sensing for super-resolved reading performance in simulated prosthetic vision

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BIOMEDICAL OPTICS EXPRESS 2019年第3期10卷 1081-1096页

作者： Abraham, Chen Farah, Nairouz Gerbi-Zarfati, Liron Harpaz, Yuval Zalvesky, Zeev Mandel, Yossi Bar Ilan Univ Fac Engn Ramat Gan Israel Bar Ilan Univ Nanotechnol Ctr Ramat Gan Israel Bar Ilan Univ Fac Life Sci Sch Optometry & Vis Sci Ramat Gan Israel Bar Ilan Univ Bar Ilan Inst Nanotechnol & Adv Mat BINA Ramat Gan Israel Bar Ilan Univ Gonda Brain Res Ctr Ramat Gan Israel

In this work, we study the enhancement of simulated prosthetic reading performance through "active photonic sensing" in normally sighted subjects. Three sensing paradigms were implemented: active sensing, in which the subject actively scanned the presented words using the computer mouse, with an option to control text size;passive scanning produced by software-initiated horizontal movements of words;and no scanning. Our findings reveal a 30% increase in word recognition rate with active scanning as compared to no or passive scanning and up to 14-fold increase with zooming. These results highlight the importance of a patient interactive interface and shed light on techniques that can greatly enhance prosthetic vision quality. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

关键词： Eye movements Field size image processing algorithms Retinal ganglion cells Visual acuity Visual system

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