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https://www.readbyqxmd.com/read/28613174/mulog-or-how-to-apply-gaussian-denoisers-to-multi-channel-sar-speckle-reduction
#1
Charles-Alban Deledalle, Loic Denis, Sonia Tabti, Florence Tupin
Speckle reduction is a longstanding topic in synthetic aperture radar (SAR) imaging. Since most current and planned SAR imaging satellites operate in polarimetric, interferometric or tomographic modes, SAR images are multi-channel and speckle reduction techniques must jointly process all channels to recover polarimetric and interferometric information. The distinctive nature of SAR signal (complex-valued, corrupted by multiplicative fluctuations) calls for the development of specialized methods for speckle reduction...
June 8, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28600515/evaluation-of-intraretinal-migration-of-retinal-pigment-epithelial-cells-in-age-related-macular-degeneration-using-polarimetric-imaging
#2
Masahiro Miura, Shuichi Makita, Satoshi Sugiyama, Young-Joo Hong, Yoshiaki Yasuno, Ann E Elsner, Shigeo Tamiya, Rintaro Tsukahara, Takuya Iwasaki, Hiroshi Goto
The purpose of the present study was to evaluate the intraretinal migration of the retinal pigment epithelium (RPE) cells in age-related macular degeneration (AMD) using polarimetry. We evaluated 155 eyes at various AMD stages. Depolarized light images were computed using a polarization-sensitive scanning laser ophthalmoscope (PS-SLO), and the degree of polarization uniformity was calculated using polarization-sensitive optical coherence tomography (OCT). Each polarimetry image was compared with the corresponding autofluorescence (AF) images at 488 nm (SW-AF) and at 787 nm (NIR-AF)...
June 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28572602/in-vivo-imaging-of-uterine-cervix-with-a-mueller-polarimetric-colposcope
#3
Jérémy Vizet, Jean Rehbinder, Stanislas Deby, Stéphane Roussel, André Nazac, Ranya Soufan, Catherine Genestie, Christine Haie-Meder, Hervé Fernandez, François Moreau, Angelo Pierangelo
Mueller polarimetric imaging enables the detection and quantification of modifications of the collagen fibers in the uterine cervix due to the development of a precancerous lesion. This information is not accessible through the use of the classic colposcope, a low magnification microscope used in current practice for cervical cancer screening. However, the in vivo application of Mueller polarimetric imaging poses an instrumental challenge: the device should be sufficiently compact, while still being able to perform fast and accurate acquisition of Mueller matrices in real-world conditions...
June 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28570631/interference-figures-of-polarimetric-interferometry-analysis-of-the-human-corneal-stroma
#4
Rodolfo Mastropasqua, Mario Nubile, Niccolò Salgari, Manuela Lanzini, Roberta Calienno, Peter A Mattei, Alessandra Sborgia, Luca Agnifili
A rotating polarimetric 90°-cross linear-filter interferometry system was used to detect the morphological characteristics and features of interference patterns produced in in-vivo corneal stroma in healthy human corneas of 23 subjects. The characteristic corneal isogyres presenting with an evident cross-shaped pattern, grossly aligned with the fixation axis, were observed in all patients with centers within the pupillary dark area, impeding the exact determination of the center point. During the rotational scan in 78...
2017: PloS One
https://www.readbyqxmd.com/read/28490097/influence-of-l-pyroglutamic-acid-on-the-color-formation-process-of-non-enzymatic-browning-reactions
#5
Steffen Wegener, Martin Kaufmann, Lothar W Kroh
Heating aqueous d-glucose model reactions with l-glutamine and l-alanine yielded similar colored solutions. However, size-exclusion chromatography (SEC) revealed that both non-enzymatic browning reactions proceeded differently. Due to a fast occurring cyclization of l-glutamine to pyroglutamic acid, the typical amino-carbonyl reaction was slowed down. However, l-glutamine and l-alanine model reactions showed the same browning index. Closer investigations could prove that l-pyroglutamic acid was able to influence non-enzymatic browning reactions...
October 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28468337/spectralon-spatial-depolarization-towards-an-intrinsic-characterization-using-a-novel-phase-shift-distribution-analysis
#6
Jan Dupont, Xavier Orlik, Romain Ceolato, Thibault Dartigalongue
Spectralons are reference radiometric samples which exhibit a calibrated reflectance. However, in case of low reflectance samples, the degree of polarization (DOP) of scattered light is hard to characterize. Here, an accurate determination of spectralon spatial depolarization is proposed. Based on a spatially resolved polarimetric imaging system, the polarization state of the scattered light is characterized for every pixel. A statistic distribution analysis is carried out over the entire image. The relative phase shift distribution between two orthogonal components of the scattered electric field clearly exhibits a high sensitivity to the reflectance, the phase statistics following a circular Voigt profile...
May 1, 2017: Optics Express
https://www.readbyqxmd.com/read/28464464/mueller-polarimetric-imaging-for-surgical-and-diagnostic-applications-a-review
#7
REVIEW
Ji Qi, Daniel S Elson
Polarization is a fundamental property of light and a powerful sensing tool that has been applied to many areas. A Mueller matrix is a complete mathematical description of the polarization characteristics of objects that interact with light, and is known as a transfer function of Stokes vectors which characterise the state of polarization of light. Mueller polarimetric imaging measures Mueller matrices over a field of view and thus allows for visualising the polarization characteristics of the objects. It has emerged as a promising technique in recent years for tissue imaging, improving image contrast and providing a unique perspective to reveal additional information that cannot be resolved by other optical imaging modalities...
May 2, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28456257/synchronizing-single-shot-high-energy-iodine-photodissociation-laser-pals-and-high-repetition-rate-femtosecond-ti-sapphire-laser-system
#8
J Dostal, R Dudzak, T Pisarczyk, M Pfeifer, J Huynh, T Chodukowski, Z Kalinowska, E Krousky, J Skala, J Hrebicek, T Medrik, J Golasowski, L Juha, J Ullschmied
A system of precise pulse synchronization between a single-shot large-scale laser exploiting an acousto-optical modulator and a femtosecond high repetition rate laser is reported in this article. This opto-electronical system has been developed for synchronization of the sub-nanosecond kJ-class iodine photodissociation laser system (Prague Asterix Laser System-PALS) with the femtosecond 25-TW Ti:sapphire (Ti:Sa) laser operating at a repetition rate 1 kHz or 10 Hz depending on the required energy level of output pulses...
April 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28386426/celestial-polarization-patterns-sufficient-for-viking-navigation-with-the-naked-eye-detectability-of-haidinger-s-brushes-on-the-sky-versus-meteorological-conditions
#9
Gábor Horváth, Péter Takács, Balázs Kretzer, Szilvia Szilasi, Dénes Száz, Alexandra Farkas, András Barta
If a human looks at the clear blue sky from which light with high enough degree of polarization d originates, an 8-shaped bowtie-like figure, the yellow Haidinger's brush can be perceived, the long axis of which points towards the sun. A band of high d arcs across the sky at 90° from the sun. A person can pick two points on that band, observe the yellow brushes and triangulate the position of the sun based on the orientation of the two observed brushes. This method has been suggested to have been used on the open sea by Viking navigators to determine the position of the invisible sun occluded by cloud or fog...
February 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28380917/blazed-wire-grid-polarizer-for-plasmon-enhanced-polarization-extinction-design-and-analysis
#10
Changhun Lee, Eunji Sim, Donghyun Kim
We explore plasmon-enhanced wire-gird polarizers (WGPs) to achieve improved polarimetric performance with more relaxed fabrication parameters compared to conventional WGP. A WGP designed with a blazed wire-grid profile was considered for plasmonic enhancement. The results show that a blazed WGP can achieve extremely high polarimetric extinction at a longer wire-grid period (Λ) compared to conventional WGP structure. Under the optimum geometrical parameters, a blazed WGP may attain an extinction ratio of over 40 dB at Λ = 800 nm, which may allow photolithography for fabrication...
April 3, 2017: Optics Express
https://www.readbyqxmd.com/read/28380813/simplex-coded-polarization-optical-time-domain-reflectometry-system
#11
Chaodong Wang, Ruolin Liao, Wenbo Chen, Ming Tang, Songnian Fu, Jianguan Tang, Ciming Zhou, Deming Liu
In polarization optical time domain reflectometry (POTDR) system, the performance of polarimetric measurement is constrained by the low signal to noise ratio (SNR) due to the weak Rayleigh backscattering and the degradation of the degree of polarization (DOP) of signal light. Therefore, it is indispensable to improve the SNR without sacrificing the DOP of backscattered signal for a sufficient dynamic range. In this paper, a Simplex coded POTDR (sc-POTDR) system is proposed and demonstrated. The relationships between the signal's DOP and coding length/bit width are studied...
March 6, 2017: Optics Express
https://www.readbyqxmd.com/read/28375320/fundamental-limits-of-target-detection-performance-in-passive-polarization-imaging
#12
François Goudail, Matthieu Boffety
We quantitatively determine the target detection performance of different passive polarization imaging architectures perturbed by signal-independent detection noise or signal-dependent Poisson shot noise. We compare the fully adaptive polarimetric imager and the best channel of a static polarimetric imager, and in each case, we compare the use of a polarizer and a polarizing beam splitter as the polarization analyzing device. For all these configurations, we derive a closed-form expression of the target/background separability and quantify the performance gain brought by polarization imaging compared to standard intensity imaging...
April 1, 2017: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
https://www.readbyqxmd.com/read/28375255/high-magnetic-field-measurement-utilizing-faraday-rotation-in-sf11-glass-in-simplified-diagnostics
#13
Premananda Dey, Rohit Shukla, D Venkateswarlu
With the commercialization of powerful solid-state lasers as pointer lasers, it is becoming simpler nowadays for the launch and free-space reception of polarized light for polarimetric applications. Additionally, because of the high power of such laser diodes, the alignment of the received light on the small sensor area of a photo-diode with a high bandwidth response is also greatly simplified. A plastic sheet polarizer taken from spectacles of 3D television (commercially available) is simply implemented as an analyzer before the photo-receiver...
April 1, 2017: Applied Optics
https://www.readbyqxmd.com/read/28368297/automotive-system-for-remote-surface-classification
#14
Aleksandr Bystrov, Edward Hoare, Thuy-Yung Tran, Nigel Clarke, Marina Gashinova, Mikhail Cherniakov
In this paper we shall discuss a novel approach to road surface recognition, based on the analysis of backscattered microwave and ultrasonic signals. The novelty of our method is sonar and polarimetric radar data fusion, extraction of features for separate swathes of illuminated surface (segmentation), and using of multi-stage artificial neural network for surface classification. The developed system consists of 24 GHz radar and 40 kHz ultrasonic sensor. The features are extracted from backscattered signals and then the procedures of principal component analysis and supervised classification are applied to feature data...
April 1, 2017: Sensors
https://www.readbyqxmd.com/read/28352074/optimized-mass-spectrometry-analysis-workflow-with-polarimetric-guidance-for-ex-vivo-and-in-situ-sampling-of-biological-tissues
#15
Michael Woolman, Adam Gribble, Emma Bluemke, Jing Zou, Manuela Ventura, Nicholas Bernards, Megan Wu, Howard J Ginsberg, Sunit Das, Alex Vitkin, Arash Zarrine-Afsar
Spatially Targeted Mass Spectrometry (MS) analysis using survey scans with an imaging modality often requires consecutive tissue slices, because of the tissue damage during survey scan or due to incompatible sample preparation requirements between the survey modality and MS. We report two spatially targeted MS analysis workflows based on polarized light imaging guidance that use the same tissue sample for survey and targeted analysis. The first workflow is applicable for thin-slice analysis, and uses transmission-polarimetry-guided Desorption ElectroSpray Ionization Mass Spectrometry (DESI-MS), and confirmatory H&E histopathology analysis on the same slice; this is validated using quantitative digital pathology methods...
March 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28241667/photopolarimetric-properties-of-a-manmade-target-over-a-wide-range-of-measurement-directions
#16
Zhongqiu Sun, Di Wu, Yunfeng Lv
The optical scattering property of a target is the essential signal for passive remote sensing. In this study, we performed the photopolarimetric measurements of a manmade target in the wavelength range of 400-1000 nm over the hemispherical directions using the Northeast Normal University Laboratory Goniospectrometer System (NENULGS). We discussed the influence of the absorption of a polarizer on the measured Stokes parameters, and used the BRF (bidirectional reflectance factor) and BPRF (bidirectional polarized reflectance factor) to characterize the scattering property of our sample at selected wavelengths...
February 20, 2017: Optics Express
https://www.readbyqxmd.com/read/28241588/colorimetric-discrimination-for-stokes-polarimetric-imaging
#17
Mingxuan Yu, Hesong Huang, Haofeng Hu, Lan Wu, Hongchen Zhai, Tiegen Liu
Traditional methods of discrimination for Stokes polarimetric imaging use grayscale images, in which the difference of the polarimetric properties is only reflected by the difference of grayscale. In this paper, we propose a method of colorimetric discrimination and classification for Stokes polarimetric imaging by the composed color polarimetric image, in which the objects with different polarization properties can appear in different colors. We show with real-world experiment that compared with the traditional method for the grayscale Stokes scalar image, the method proposed in this paper has a better performance for distinguishing objects with different polarization properties...
February 20, 2017: Optics Express
https://www.readbyqxmd.com/read/28198849/free-space-active-polarimetric-imager-operating-at-1-55%C3%A2-%C3%A2-%C3%AE-m-by-orthogonality-breaking-sensing
#18
Francois Parnet, Julien Fade, Noé Ortega-Quijano, Goulc'hen Loas, Ludovic Frein, Mehdi Alouini
We report the design and optimization of an active polarimetric imaging demonstrator operating at 1.55 μm that is based on the orthogonality breaking technique. It relies on the use of a fibered dual-frequency dual-polarization source raster scanned over the scene. A dedicated opto-electronic detection chain is developed to demodulate the optical signal backscattered at each location of the scene in real time, providing multivariate polarimetric image data in one single scan with limited acquisition time. We experimentally show on a homemade scene that contrast maps can be built to reveal hidden dichroic objects over a depolarizing background, as well as their orientation...
February 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28178178/detectability-analysis-of-road-vehicles-in-radarsat-2-fully-polarimetric-sar-images-for-traffic-monitoring
#19
Bo Zhang, Chao Wang, Hong Zhang, Fan Wu, Yi-Xian Tang
By acquiring information over a wide area regardless of weather conditions and solar illumination, space-borne Synthetic Aperture Radar (SAR) has the potential to be a promising application for traffic monitoring. However, the backscatter character of a vehicle in a SAR image is unstable and varies with image parameters, such as aspect and incidence angle. To investigate vehicle detectability in SAR images for traffic monitoring applications, images of four common types of vehicles in China were acquired using the fully polarimetric (FP) SAR of Radarsat-2 in our experiments...
February 6, 2017: Sensors
https://www.readbyqxmd.com/read/28158096/real-time-image-haze-removal-using-an-aperture-division-polarimetric-camera
#20
Wenfei Zhang, Jian Liang, Liyong Ren, Haijuan Ju, Enshi Qu, Zhaofeng Bai, Yao Tang, Zhaoxin Wu
Polarimetric dehazing methods have been proven to be effective in enhancing the quality of images acquired in turbid media. We report a new full-Stokes polarimetric camera, which is based on the division of aperture structure. We design a kind of automatic polarimetric dehazing algorithm and load it into the field programmable gate array (FPGA) modules of our designed polarimetric camera, achieving a real-time image haze removal with an output rate of 25 fps. We demonstrate that the image quality can be significantly improved together with a good color restoration...
February 1, 2017: Applied Optics
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