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Purpose: To evaluate the effect of the intracameral adrenaline and trypan blue used during cataract surgery on corneal endothelial parameters in pseudoexfoliation syndrome (PEX) patients. Methods: The patients were divided into four groups according to intraoperative use of agents during cataract surgery: intracameral adrenaline (1/10,000, 0.1 ml) (group 1), trypan blue (0.6 mg/ml, 0.1 ml) (group 2), combination of adrenaline and trypan blue (group 3) and none (group 4). Results: Preoperative ECD, CV, HEX and CCT parameters were similar between the groups. A mean loss of 12.7% in ECD was observed at the postoperative third months compared to the preoperative. In group 3, ECD was found to be lower in the postoperative third months compared to the preoperative (p = 0.014). In the other groups, no statistically significant difference was found in preoperative and postoperative comparisons. Conclusion: In conclusion, the utilization of intracameral adrenaline or trypan blue did not cause a significant difference in corneal endothelium in PEX patients. However, their combined use may have a negative effect on endothelial cell density. In a cataract surgery performed in the presence of PEX, the increased likelihood of endothelial damage should be taken into consideration, and appropriate precautions should be taken preoperatively and intraoperatively. [ABSTRACT FROM AUTHOR]

Estimating depth from images is a common technique in 3D perception. However, dealing with non-Lambertian materials, e.g., transparent or specular, is still nowadays an open challenge. However, to overcome this challenge with deep stereo matching networks or monocular depth estimation, data sets with non-Lambertian objects are mandatory. Currently, only few real-world data sets are available. This is due to the high effort and time-consuming process of generating these data sets with ground truth. Currently, transparent objects must be prepared, e.g., painted or powdered, or an opaque twin of the non-Lambertian object is needed. This makes data acquisition very time consuming and elaborate. We present a new measurement principle for how to generate a real data set of transparent and specular surfaces without object preparation techniques, which greatly reduces the effort and time required for data collection. For this purpose, we use a thermal 3D sensor as a reference system, which allows the 3D detection of transparent and reflective surfaces without object preparation. In addition, we publish the first-ever real stereo data set, called TranSpec3D, where ground truth disparities without object preparation were generated using this measurement principle. The data set contains 110 objects and consists of 148 scenes, each taken in different lighting environments, which increases the size of the data set and creates different reflections on the surface. We also show the advantages and disadvantages of our measurement principle and data set compared to the Booster data set (generated with object preparation), as well as the current limitations of our novel method. [ABSTRACT FROM AUTHOR]

Christine Montalbetti has published twenty-odd texts at the Éditions P.O.L over the years, beginning with Sa fable achevée, Simon sort dans la bruine, which appeared in 2001. While she has practiced short forms and theater (with several plays produced at the Comédie-Française), her central literary concern has been the novel. Her novels are innovative, engaging, and exceptionally canny constructions. Each of them testifies to a smart, sustained reflection on narrative art, upon its possibilities and its limits, upon its articulative power. Those novels are moreover "critical" in character. That is, they display a broad recognition of the tradition out of which they arise. They invite their reader to share that recognition, and to exercise his or her critical faculties in a very conscious manner. These are generous texts, granted the way in which Christine Montalbetti welcomes her reader into the fictional world, and encourages her or him to participate in a shared meditation on literature and its uses. Her books constitute one of the key sites where contemporary French literature takes full account of its potential and seeks new expressive avenues. [ABSTRACT FROM AUTHOR]

The goal of Mixed Reality (MR) is to achieve a seamless and realistic blending between real and virtual worlds. This requires the estimation of reflectance properties and lighting characteristics of the real scene. One of the main challenges within this task consists in recovering such properties using a single RGB-D camera. In this article, we introduce a novel framework to recover both the position and color of multiple light sources as well as the specular reflectance of real scene surfaces. This is achieved by detecting and incorporating information from both specular reflections and cast shadows. Our approach is capable of handling any textured surface and considers both static and dynamic light sources. Its effectiveness is demonstrated through a range of applications including visually-consistent mixed reality scenarios (e.g., correct real specularity removal, coherent shadows in terms of shape and intensity) and retexturing where the texture of the scene is altered whereas the incident lighting is preserved. [ABSTRACT FROM AUTHOR]

This article considers the relationships between brothers and sisters from the angle of a more primitive problematic which encompasses them. The archaic bond to the mother, with its moments of subject/object confusion and envious aggressiveness, pervades the ordinary rivalry proper to the fraternal bond - which is a corollary of the specular structure of the self, between narcissistic triumph and annihilation. An adult clinical case shows the traumatic depressant impact, in the transferential aftermath, of the birth of a younger brother - and how analysis was able to unravel this neurotic complex. [ABSTRACT FROM AUTHOR]

Abstract With the recent increase in numbers of small and versatile low-power meteor radars, the opportunity exists to benefit from simultaneous application of multiple systems spaced by only a few hundred km and less. Transmissions from one site can be recorded at adjacent receiving sites using various degrees of forward scatter, potentially allowing atmospheric conditions in the mesopause regions between stations to be diagnosed. This can allow a better spatial overview of the atmospheric conditions at any time. Such studies have been carried out using a small version of such so-called multistatic meteor radars, e.g. Chau et al. (Radio Sci 52:811–828, 2017, https://doi.org/10.1002/2016rs006225). These authors were able to also make measurements of vorticity and divergence. However, measurement uncertainties arise which need to be considered in any application of such techniques. Some errors are so severe that they prohibit useful application of the technique in certain locations, particularly for zones at the midpoints of the radars sites. In this paper, software is developed to allow these errors to be determined, and examples of typical errors involved are discussed. The software should be of value to others who wish to optimize their own MMR systems.

In scenes lit with sharp point-like light sources, light can bounce several times on specular materials before getting into our eyes, forming purely specular light paths. However, to our knowledge, rendering such multi-bounce pure specular paths has not been handled in previous work: while many light transport methods have been devised to sample various kinds of light paths, none of them are able to find multi-bounce pure specular light paths from a point light to a pinhole camera. In this paper, we present path cuts to efficiently render such light paths. We use a path space hierarchy combined with interval arithmetic bounds to prune non-contributing regions of path space, and to slice the path space into regions small enough to empirically contain at most one solution. Next, we use an automatic differentiation tool and a Newton-based solver to find an admissible specular path within a given path space region. We demonstrate results on several complex specular configurations, including RR, TT, TRT and TTTT paths. [ABSTRACT FROM AUTHOR]

In this work, we propose an overcomplete representation of multiview imagery for the purpose of compression. We present a rate-distortion (R-D) driven approach to decompose multiview datasets into two additive parts which can be interpreted as diffuse and specular content. We choose distinct and different sparsifying transforms for the diffuse and specular components and employ an R-D inspired measure as our optimization cost function to drive the decomposition based solely on compressibility. We first describe a framework which performs data separation in a registered domain to avoid the complexity of warping between views. Then a more comprehensive approach is proposed to separate specular data progressively from coordinates of multiple reference views. Experimental results show a coding gain of up to 0.6 dB for synthetic datasets and up to 0.9 dB for real datasets. [ABSTRACT FROM AUTHOR]

Fuchs endothelial corneal dystrophy (FECD) is characterized by the progressive degeneration of the corneal endothelium (CE). The purpose of this article is to review the diagnostic tools available to image and assess the CE in FECD. Slit-lamp biomicroscopy with specular reflection and retroillumination are important techniques to assess the CE. Objective diagnostic tests, such as retroillumination photographic analysis, specular microscopy, in vivo confocal microscopy (IVCM), and anterior segment optical coherence tomography, are valuable tools to evaluate the CE in FECD. Specular microscopy can be performed rapidly without touching the eye but requires a clear cornea with a smooth CE. In contrast, IVCM can image all layers of the cornea, even in advanced FECD. However, IVCM is contact-based and more technically challenging. It is important to select the appropriate objective diagnostic test to image and assess the CE in managing patients with FECD. [ABSTRACT FROM AUTHOR]

Summary: In this "hundreds" written in honor of Kathleen Stewart, I offer a dialectical image of subjects transfixed in the window of a New York City butcher shop, set against the backdrop of pandemic. [ABSTRACT FROM AUTHOR]

The objective of the work is to model the shape of the sinusoidal shape of regular water waves generated in a laboratory flume. The waves are traveling in time and render a smooth surface, with no white caps or foam. Two methods are proposed, treating the water as a diffuse and specular surface, respectively. In either case, the water is presumed to take the shape of a traveling sine wave, reducing the task of the 3D reconstruction to resolve the wave parameters. The first conceived method performs the modeling part purely in 3D space. Having triangulated the points in a separate phase via bundle adjustment, a sine wave is fitted into the data in a least squares manner. The second method presents a more complete approach for the entire calculation workflow beginning in the image space. The water is perceived as a specular surface, and the traveling specularities are the only observations visible to the cameras, observations that are notably single image. The depth ambiguity is removed given additional constraints encoded within the law of reflection and the modeled parametric surface. The observation and constraint equations compose a single system of equations that is solved with the method of least squares adjustment. The devised approaches are validated against the data coming from a capacitive level sensor and on physical targets floating on the surface. The outcomes agree to a high degree.

SCoBi-Veg stands for Signals of opportunity Coherent Bistatic scattering model for Vegetated terrains. It simulates polarimetric reflectometry of vegetation canopy over a flat ground using a Monte Carlo scheme. The model is aimed at assessing the value of navigation and communication satellite Signals of Opportunity in a range of frequencies from P- to S-bands for remote sensing of a number of geophysical land parameters such as soil moisture and biomass. A fully polarimetric expression for bistatic scattering from a vegetation canopy is first formulated for a general case and is then specialized to the practical case of ground-based/low-altitude platforms with passive receivers overlooking vegetation using the signals transmitted from large distances. Using analytical wave theory in conjunction with distorted Born approximation, the transmit and receive antenna effects (i.e., polarization crosstalk/mismatch, orientation, and altitude) are explicitly accounted for. The forward model developed here enables the understanding of the effect of different geophysical parameters and system configurations on the coherent and incoherent components of the reflected signatures. It can thus help developing robust inverse algorithm for extraction of soil moisture and biomass. The model is applied to P-band signals of geostationary communication satellites to describe polarimetric reflections from tree canopies as observed from down-looking platforms at various altitudes. The relative contributions of diffuse and specular scattering on total reflected power and reflectivity are quantified for various observing scenarios. [ABSTRACT FROM AUTHOR]

We consider in this paper the mathematical and numerical modeling of reflective boundary conditions (BC) associated to Boltzmann–Poisson systems, including diffusive reflection in addition to specularity, in the context of electron transport in semiconductor device modeling at nano scales, and their implementation in Discontinuous Galerkin (DG) schemes. We study these BC on the physical boundaries of the device and develop a numerical approximation to model an insulating boundary condition, or equivalently, a pointwise zero flux mathematical condition for the electron transport equation. Such condition balances the incident and reflective momentum flux at the microscopic level, pointwise at the boundary, in the case of a more general mixed reflection with momentum dependant specularity probability p ( k → ) . We compare the computational prediction of physical observables given by the numerical implementation of these different reflection conditions in our DG scheme for BP models, and observe that the diffusive condition influences the kinetic moments over the whole domain in position space. [ABSTRACT FROM AUTHOR]

UVA radiation (320–400 nm) exposure is linked to detrimental health effects, including DNA damage, eye damage and impacts on immune suppression. Occupational exposure to UVA radiation could increase the risk of developing such health effects, through increased exposure from reflective surfaces. A range of surfaces have been investigated for broadband (from spectral) UVA and visible reflectance, from horizontal, inclined and vertical orientations. A selection of this data has been presented graphically. Non-metallic and coated metallic surfaces were shown to have low UVA broadband reflectance (<0.20) compared to some metallic surfaces UVA broadband reflectance (0.1–0.5). Uncoated metallic surfaces can use UVA reflectance as a function of visible reflectance, however non-coated metallic surfaces have no similar function. The metallic surface type data were used to correlate UVA broadband reflectance to visible broadband reflectance and a model developed to express UVA broadband as a function of visible reflectance. The model for zinc aluminium coated steel is a linear regression, with UVA reflectance ranging from 0.09 to 0.46 and visible reflectance ranging from 0.05 to 0.57, with an R 2 of 0.95. The reflective coefficients used to create the model were produced on a solar zenith angle (SZA) range of 18°–70.5°. The model was tested on a different dataset with a SZA range of 5.7°–62.9° on clear days and was shown to have reasonable results with an RMSE of 0.049 for prediction of UVA reflectance from visible reflectance allowing prediction of the UVA reflectance from the visible reflectance for this surface type. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a solution to the problem of specular meteor radar interferometry cast on the complex plane. This technique is applicable to all meteor radars at the output of the receiver's pulsed Doppler signal processing chain. Specular meteor trail radar echoes are modeled as exponentially decaying sinusoids impinging on a sparse interferometric antenna array. A set of 10 underdense meteor trail radar parameters are estimated using nonlinear least squares optimization of the physical model parameters. Meteor trail spatial locations are determined by estimating all parameters through global optimization of the complex‐valued interferometric angle‐of‐arrival equations. Statistical precision of the estimated meteor radar parameters of Doppler, diffusion coefficient, angle‐of‐arrival, and height are subsequently characterized by calculation of the full covariance matrix. The determination of statistical uncertainties in the measured parameters is a key innovation in the field, as it lays the groundwork for calculating the statistical precision of the subsequently derived wind field. [ABSTRACT FROM AUTHOR]

Crosstalk effects in multilayer graphene nanoribbon (GNR) interconnects for the future nanoscale integrated circuits are investigated with the help of ABCD parameter matrix approach for intermediate- and global-level interconnects at 11nm and 8nm technology nodes. The worst-case crosstalk-induced delay and peak crosstalk noise voltages are derived for both neutral and doped zigzag GNR interconnects and compared to those of conventional copper interconnects. The worst-case crosstalk delays for perfectly specular, doped multilayer GNR interconnects are less than 4% of that of copper interconnects for 1mm long intermediate interconnects and less than 7% of that of copper interconnects for 5mm long global interconnects at 8nm node. As far as the worst-case peak crosstalk noise voltage is concerned, neutral GNR interconnects are slightly better performing than their doped counterparts. But from the perspective of overall noise contribution, doped GNR interconnects outperform neutral ones for all the cases. Finally, our analysis shows that from the signal integrity perspective, perfectly specular, doped multilayer zigzag GNR interconnects are a suitable alternative to copper interconnects for the future-generation integrated circuit technology. [ABSTRACT FROM AUTHOR]

Current work presents the design and applications of the grazing-incidence small-angle neutron scattering (GISANS) based on SANS- Suanni spectrometer at the 20 MW China Mianyang research reactor (CMRR)-based neutron center. A multi-dimensional sample stage with both front and back slits were designed and set up on SANS- Suanni for achieving the geometry. Experimentally, thin films samples with mono-dispersed silica on sapphire substrates were prepared for collecting two-dimensional (2D) GISANS patterns at beam size setting of 4 mm width and 5 mm height. Typical signals such as the specular reflection peak, Yoneda peak, as well as the sample scattering, etc. were obtained. Moreover, integrated 1D GISANS profiles in different directions, namely vertical and horizontal directions of the incident beam (0V, 0H), and horizontal direction of the Yoneda peak (YH) were obtained via rectangular integration. Accordingly, incident angle (α i) as about 0.76° and the contrast of the sample systems as around 4.07 × 1010 cm−2 were determined. Moreover, the overlapping of 0H curves and the SANS profiles indicates that GISANS can cover some of the structural information as SANS provided, along with the capability of measuring the thin film samples. [ABSTRACT FROM AUTHOR]

We present a novel approach to real-time dense visual simultaneous localisation and mapping. Our system is capable of capturing comprehensive dense globally consistent surfel-based maps of room scale environments and beyond explored using an RGB-D camera in an incremental online fashion, without pose graph optimization or any post-processing steps. This is accomplished by using dense frame-to-model camera tracking and windowed surfel-based fusion coupled with frequent model refinement through non-rigid surface deformations. Our approach applies local model-to-model surface loop closure optimizations as often as possible to stay close to the mode of the map distribution, while utilizing global loop closure to recover from arbitrary drift and maintain global consistency. In the spirit of improving map quality as well as tracking accuracy and robustness, we furthermore explore a novel approach to real-time discrete light source detection. This technique is capable of detecting numerous light sources in indoor environments in real-time as a user handheld camera explores the scene. Absolutely no prior information about the scene or number of light sources is required. By making a small set of simple assumptions about the appearance properties of the scene our method can incrementally estimate both the quantity and location of multiple light sources in the environment in an online fashion. Our results demonstrate that our technique functions well in many different environments and lighting configurations. We show that this enables (a) more realistic augmented reality rendering; (b) a richer understanding of the scene beyond pure geometry and; (c) more accurate and robust photometric tracking. [ABSTRACT FROM AUTHOR]

Crosstalk induced overshoot/undershoot effects in multilayer graphene nano ribbon interconnects (MLGNRs) are investigated with the help of ABCD parameter matrix approach for intermediate level interconnects at both 11 nm and 8 nm technology node. The worst case crosstalk induced peak overshoot voltage for perfectly specular, doped multilayer zigzag GNR interconnects is comparable to that of copper interconnects. The performance of neutral GNR interconnects is better than that of its doped counterpart with respect to peak crosstalk overshoot. But from the perspective of overall overshoot width and overshoot area contribution, perfectly specular, doped MLGNR interconnects outperform all other alternatives. As far as the effective electric field across the gate oxide is concerned, the doped MLGNR interconnects outperform neutral ones and copper interconnects for all the cases. It is estimated that the doped perfectly specular multilayer GNR interconnects have gate oxide failure rates ( AFR ) of ~ 240 × and ~ 790 × lesser than copper interconnects for 11 nm and 8 nm technology node respectively. So, from the gate oxide reliability perspective, perfectly specular, doped multilayer zigzag GNR interconnects are great advantageous to copper interconnects for the future integrated circuit technology generations. [ABSTRACT FROM AUTHOR]

Reality is the most realistic representation. We introduce a material display called ZoeMatrope that can reproduce a variety of materials with high resolution, dynamic range and light field reproducibility by using compositing and animation principles used in a zoetrope and a thaumatrope. With ZoeMatrope, the quality of the material is equivalent to that of real objects and the range of expressible materials is diversified by overlaying a set of base materials in a linear combination. ZoeMatrope is also able to express spatially-varying materials, and even augmented materials such as materials with an alpha channel. In this paper, we propose a method for selecting the optimal material set and determining the weights of the linear combination to reproduce a wide range of target materials properly. We also demonstrate the effectiveness of this approach with the developed system and show the results for various materials. [ABSTRACT FROM AUTHOR]

We considered whether optic flow generated by 3D relief of a foreground surface might influence visually-mediated self-motion perception (vection). We generated background motion consistent with self-rotation, and a foreground object with bumpy relief was either rotated with the observer (ego-centric) or fixed in world coordinates (world-centric).We found that vection strength ratings were greater in conditions with world-centric retinal motion of the foreground object, despite generating flow that was opposite to background motion. This effect was explained by observer judgments of the axis self-rotation in depth; whereas ego-centric flow generated experiences of more on-axis self-rotation, world-centric flow generated experiences of centrifugal rotation around the foreground object. These data suggest that foreground object motion can increase the perception of self-motion generated by optic flow, even when they reduce net retinal motion coherence and promote conditions for multisensory conflict. This finding supports the view that self-motion perception depends on mid-level representations of whole-scene motion. [ABSTRACT FROM AUTHOR]

The narrow-angle spectral specular reflectance and angular scattering of conventional and novel reflective materials for solar concentrators are measured over the wavelength range 300–2500 nm at incidence angles ranging from 15° to 60° using a spectroscopic goniometry system. The solar-weighted specular reflectance at near normal incidence and an acceptance half-angle of 17.5 mrad is 0.941 for back-silvered glass, 0.908–0.926 for silvered polymer films, 0.895 for aluminized polyester film, 0.939–0.954 for silvered aluminum sheets, and 0.860 for aluminized aluminum sheet. The angular scattering, quantified in terms of the standard deviation of a Gaussian distribution, is found to be negligible for aluminized polyester (<0.05 mrad) and back-silvered glass (<0.07 mrad), and noticeable for silvered polymer films (0.27–1.12 mrad) and silvered aluminum sheets (0.12–1.66 mrad). In addition, the spectral transmittance of semi-transparent materials suitable for protective covers is measured, yielding solar-weighted normal transmittance values of 0.913 and 0.946 for 100 μm thin films of ETFE (ethylene-tetrafluoroethylene) and FEP (fluorinated ethylene propylene), respectively. The measured optical properties are incorporated in a Monte Carlo ray-tracing program and applied to analyze the optical performance of solar concentrators. [ABSTRACT FROM AUTHOR]

In this paper, we present analytical and numerical investigations in order to determine the incident radiation and radiative flux in a semi-transparent medium at radiative equilibrium and enclosed in a cylindrical annulus with two specularly reflecting surfaces. As for the case of a purely diffuse reflexion, we show that the incident radiation and radiative flux can be completely defined by some weighting coefficients whose closed-form analytical expressions are detailed. The specular part of the weighting coefficients is computed with a Gauss quadrature, and a numerical validation is performed by comparing the numerical results to optically thin approximation analytical solutions. Finally some examples show that the results for temperature and radiative flux fields may strongly be different from the ones obtained in the case of a purely diffuse reflexion. [ABSTRACT FROM AUTHOR]

The objective of the work is to model the shape of the sinusoidal shape of regular water waves generated in a laboratory flume. The waves are traveling in time and render a smooth surface, with no white caps or foam. Two methods are proposed, treating the water as a diffuse and specular surface, respectively. In either case, the water is presumed to take the shape of a traveling sine wave, reducing the task of the 3D reconstruction to resolve the wave parameters. The first conceived method performs the modeling part purely in 3D space. Having triangulated the points in a separate phase via bundle adjustment, a sine wave is fitted into the data in a least squares manner. The second method presents a more complete approach for the entire calculation workflow beginning in the image space. The water is perceived as a specular surface, and the traveling specularities are the only observations visible to the cameras, observations that are notably single image. The depth ambiguity is removed given additional constraints encoded within the law of reflection and the modeled parametric surface. The observation and constraint equations compose a single system of equations that is solved with the method of least squares adjustment. The devised approaches are validated against the data coming from a capacitive level sensor and on physical targets floating on the surface. The outcomes agree to a high degree. [ABSTRACT FROM AUTHOR]

Avaliou-se a espessura corneana central de 13 gatos normais com microscópio especular de não-contato Topcon SP-2000P e paquímetro ultra-sônico. Foi observado aumento da espessura corneana mensurada pelo paquímetro ultra-sônico comparado ao microscópio especular.The central corneal thickness of 13 normal cats was evaluated by a Topcon SP-2000P noncontact specular microscope and by an ultrasonic pachymetry was evaluated. An increase on the corneal thickness measured by ultrasonic pachymetry as compared to the specular microscope was observed.

Identification of illumination, the main step in colour constancy processing, is an important problem in imaging for digital images or video, forming a prerequisite for many computer vision applications. In this paper we present a new and effective physics-based colour constancy algorithm which makes use of a novel Log-Relative-Chromaticity planar constraint. We call the new feature the Zeta-image. We show that this new feature makes use of a novel application of the Kullback–Leibler Divergence, here applied to chromaticity values instead of probabilities. The new method requires no training data or tunable parameters. Moreover it is simple to implement and very fast. Our experimental results across datasets of real images show that the proposed method significantly outperforms other unsupervised methods while its estimation accuracy is comparable with more complex, supervised, methods. As well, we show that the new planar constraint can be used as a post-processing stage for any candidate colour constancy method in order to improve its accuracy. Its application in this paper demonstrates its utility, delivering state of the art performance. The Zeta-image is a wholly new representation for understanding highlights in images, and we show as well that it can be used to identify and remove specularities. More generally, since the Zeta-image is intimately bound up with specularities, we show how specular content in the image can be manipulated, either decreasing or increasing highlights. [ABSTRACT FROM AUTHOR]

Nowadays, GNSS-Reflectometry (GNSS-R) can be a new promising remote sensing tool in the ocean, snow/ice and land surfaces, e.g., vegetation biomass monitoring. Although GNSS-R provides a potentially special L-band multi-angular and multi-polarization measurement, the theoretical vegetation scattering properties and mechanisms for GNSS-R are not understood clearly. In this paper, the GNSS-R vegetation polarization scattering properties are studied and modeled at different incidence angles (specular direction). The bistatic scattering model Bi-mimics is employed, which is the first-order radiative transfer equation. As a kind of forest stand, the Aspen's crown layer is composed of entire leaves, and its parameters in Mimics handbook are used as model input. The specular circular polarizations (co-polarization RR and cross-polarization LR) are simulated. For cross-polarization, the received polarization is assumed as a linear (horizontal and vertical) polarizations and ±45° linear polarizations. Therefore, the HR VR, +45R and −45R polarizations are simulated here. Contributions from different scattering components at RR, LR and VR polarization are also presented. For co-polarization, it is large in the whole specular angles (10-80°). The scattering trends of the other cross polarization (HR, LR, +45R and −45R) are a little similar when compared to the RR and RV. Therefore, the RHCP and V polarizations are more favorable to collect the reflected signals. The trunk heights and crown depths do not affect the scattering trends of RR, RV and RL, while the trunk height has some effect on the scattering amplitude of different polarizations. The azimuth angle has more effects on RR, RL and RV scattering, especially in lower than 50°. The observation angles and polarization combinations are extremely important for GNSS-R remote sensing. [ABSTRACT FROM AUTHOR]

The multifrequency biplanar interferometric imaging technique (MBI) is applied to data from vertical, split-beam echosounders to produce sub-beam estimates of seabed surface-backscattering strength (Ss), incidence angle (θ), and roughness (${\rm {\cal R}}$). A simple model is used to quantify the variation of Ss versus θ = {2–20°} and acoustic frequency, f = {18, 38, 70, 120 and 200 kHz}. The coefficients of the angle- and frequency-dependent terms of the model indicate seabed material properties, principally small- and large-scale roughness and hardness. These indices are combined with the estimates of θ and ${\rm {\cal R}}$ to classify the seabed using unsupervised cluster analysis. This technique is applied to data from the Forty-Three-Fathom Bank, a seamount in the Southern California Bight. The resulting seabed classifications are consistent with the surficial lithology and the spatial distribution of known rockfish (Sebastes spp.) habitat. The method should be generally applicable to seabed classification. [ABSTRACT FROM PUBLISHER]

In many industrial applications, it is important to identify defects on specular surfaces. On machined surfaces, defect identification may be further complicated by the presence of marks from a machining process. These marks may dramatically and unpredictably change the appearance of the surface, while not altering its ability to function. To differentiate between surface characteristics that constitute a defect and those that do not, we propose a system that directly illuminates specular machined surfaces with a programmable array of high-power light-emitting diodes that allows the angle of the incident light to be varied over a series of images. A reflection model is used to predict the reflected intensity as a function of incident lighting angle for each point on the imaged surface. A surface defect causes the observed reflected intensity as a function of incident lighting angle to differ from that predicted by the reflection model. Such differences between the observations and the reflection model are shown to identify surface defects such as porosities, dents and scratches in the presence of marks from the machining process. [ABSTRACT FROM AUTHOR]

Certain characteristics of a material such as the surface reflectivities can be determined even without knowledge of its internal properties. In this letter, a direct relationship (Azzam relationship) and an analytical approximation (Azzam–Sohn–Hong (ASH) approximation) between the vertically and horizontally polarized reflectivities of specular surfaces are derived and validated using the refractive indices of water and metal in a variety of spectral regions. For the purpose of practical remote applications, land, sea water, sea ice, and oil surfaces are considered and compared using the Hong and ASH approximations. Consequently, ASH approximation has an advantage in a variety of spectral bands for materials with a small imaginary part of refractive index, while the Hong approximation does well in the microwave spectral region, or when the imaginary part of the reflective index is not neglected. Thus, a combination of the Hong and ASH approximations is suggested to improve upon previous studies that used only the Hong approximation in a variety of applications. [ABSTRACT FROM PUBLISHER]

It is well known that ambient light reduces the contrast ratio. However binocular human perception is often better than expected by monocular measurements. We evaluated this by subjects and adapted the measurement set-up to binocular vision. Typical mobile displays were examined and we verified the binocular visual perception of small specular light sources. [ABSTRACT FROM AUTHOR]

Abstract: This study focuses on the directionality of wheat leaf reflectance as a function of leaf surface characteristics. Wheat leaf BRF measurements were completed under 45° zenith illumination angle in three visible broad spectral bands with a conoscope that provides very high angular resolution data over a large portion of the whole hemisphere, including around the illumination direction. The measurements show a clear anisotropy with a specular lobe in the forward scattering direction and a small but significant hotspot feature in the backward scattering direction. The BRF directional features further depend on the illumination orientation because of the leaf roughness created by longitudinal veins: the specular lobe was more pronounced when the illumination was perpendicular to the veins, while specular reflection was more spread over azimuths for longitudinal illumination. Moreover, a sharp hotspot feature was observed for transversal illumination where the apparent roughness is the largest. The scattering was tentatively decomposed into specular, hotspot and isotropic components. Results showed that the hotspot contribution to the directional hemispherical reflectance factor (DHRF) was marginal conversely to that of the specular component that ranges between 0.036 and 0.050 (absolute DHRF value). The specular component was almost the same in the three visible bands considered. The isotropic component originating from volume scattering was contributing the most to the DHRF and was depending on wavelength, ranging between 0.055 and 0.097 in absolute DHRF value. A simple model was proposed to estimate the volume scattering from the isotropic and the surface components. Consequences of these findings were drawn on the ability to estimate leaf biochemical composition independently from leaf surface scattering, as well as on the interpretation of remote sensing at the canopy level. [Copyright &y& Elsevier]

Theories of images are bound to the diversity of their manifestations and to the plurality of the perspectives adopted on them. Unlike Gilbert Durand, who makes use of an archetypological perspective, we approach the problem of the image from a different perspective: the ontological perspective (the specular image) and the metaphysical perspective (imago Christi). These angles enable us to retrace the connection between the Eastern European intellectual space, especially the one of the Romanian élite, among which we note figures such as Nae Ionescu, Mircea Eliade, Alexandru Dragomir, Mircea Vulcănescu, Andrei Pleşu, and the Occidental space, as represented by Henry Corbin, Roger Caillois, Gaston Bachelard, Gilbert Durand, Michel Maffesoli, Jean-Jacques Wunenburger. [ABSTRACT FROM AUTHOR]

Abstract: The Polynomial Texture Map framework (PTM) extends the simple model of image formation from the Lambertian variant of Photometric Stereo (PST) to more general reflectances and to more complex-shaped surfaces. It forms an alternative method for apprehending object color, albedo, and surface normals. Here we consider solving such a model in a robust version, not to date attempted for PTM, with the upshot that both shadows and specularities are identified automatically without the need for any thresholds. Instead of the linear model used in few-source PST for Lambertian surfaces, PTM adopts a higher degree polynomial model. PTM has two aims: interpolation of images for new lighting directions, and recovery of surface properties. Here we show that a robust approach is a good deal more accurate in recovering surface properties. For new-lighting interpolation, we demonstrate that a simple radial basis function interpolation can accurately interpolate specularities as well as attached and cast shadows even with a medium-sized image set, with no need for reflectance sharing across pixels or extremely large numbers of interpolation coefficients. [Copyright &y& Elsevier]

This state of the art report covers reconstruction methods for transparent and specular objects or phenomena. While the 3D acquisition of opaque surfaces with Lambertian reflectance is a well-studied problem, transparent, refractive, specular and potentially dynamic scenes pose challenging problems for acquisition systems. This report reviews and categorizes the literature in this field. Despite tremendous interest in object digitization, the acquisition of digital models of transparent or specular objects is far from being a solved problem. On the other hand, real-world data is in high demand for applications such as object modelling, preservation of historic artefacts and as input to data-driven modelling techniques. With this report we aim at providing a reference for and an introduction to the field of transparent and specular object reconstruction. We describe acquisition approaches for different classes of objects. Transparent objects/phenomena that do not change the straight ray geometry can be found foremost in natural phenomena. Refraction effects are usually small and can be considered negligible for these objects. Phenomena as diverse as fire, smoke, and interstellar nebulae can be modelled using a straight ray model of image formation. Refractive and specular surfaces on the other hand change the straight rays into usually piecewise linear ray paths, adding additional complexity to the reconstruction problem. Translucent objects exhibit significant sub-surface scattering effects rendering traditional acquisition approaches unstable. Different classes of techniques have been developed to deal with these problems and good reconstruction results can be achieved with current state-of-the-art techniques. However, the approaches are still specialized and targeted at very specific object classes. We classify the existing literature and hope to provide an entry point to this exiting field. [ABSTRACT FROM AUTHOR]