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Fleshy fruits come in a diversity of colours. Some of this diversity can be attributed to unique selection pressures exerted by different types of frugivores. For example, mammals tend to consume g...

Appearance preservation aims to estimate reflectance functions to model the way real materials interact with light. These functions are especially useful in digital preservation of heritage and realistic rendering, as they reproduce the appearance of real materials in virtual scenes. This work proposes an image-based process that aims to preserve the appearance of surfaces whose reflectance properties are spatially variant. During image acquisition, this process considers the whole environment as a source of light over the area to be preserved and, assuming the environment is static, it does not require controlled environments. To achieve this goal, the scene geometry and relative camera positions are approximated from a set of HDR images taken inside the real scene, using a combination of structure from motion and multi-view stereo methods. Based on this data, a set of unstructured lumigraphs is traced, on-demand, inside the reconstructed scene. The color information retrieved from these lumigraphs is then used to estimate a linear combination of basis BRDFs for a grid of points in the surface area, defining thus its SVBRDF. This paper details the proposed method and presents the results obtained using real and synthetic settings. It shows that considering the whole environment as a source of light is a viable approach to obtain reliable results and to enable more flexible acquisition setups.

Lighting, both natural and electric, is one of the key points in the indoor environmental quality in buildings and it is directly related to their energy efficiency and indoor comfort conditions. Since final lighting conditions depend on the luminous reflectance properties of interior surfaces, an accurate characterization of this property is essential in evaluating its effect on the aforementioned lighting conditions. However, there is scarce research into the effect of this type of binder as well as roughness and colour on the indoor luminous conditions. The aim of this research is to evaluate the influence of the luminous reflectance and texture of the finishing layers of plasters and renders based on lime and gypsum pastes with three different colours (non-coloured, ochre and red) and two types of finishing (smooth and rough) under the luminous conditions. The results show that lime paste samples showed a higher reflectance than those of gypsum. In both cases, the performance is diffused with an optimal reflectance when light incidences are between 45° and 75°. Furthermore, four different methods for measuring the reflectance were used to find a practical way of assessing the daylighting potential. Laboratory measurements under artificial lighting were compared with controlled laboratory measurements with natural lighting as well as on site evaluations under real clear sky conditions. While with lime samples clear correlations were found, differences up to 13% were found in gypsum pastes, possibly due to their glossy finish.

This paper presents a novel system for freckle retouching and skin tone adjustment based on a set of exemplar image pairs obtained before and after cosmetic laser therapy. Our key observation is that cosmetic laser therapy relies on decomposing and adjusting melanin and hemoglobin to change skin appearance, and the reflectance properties of the two pigments can greatly influence human skin color. We thus retouch freckles and adjust skin tone in a query image by changing the densities of melanin and hemoglobin to match the variation of those in the exemplar image pairs. Based on the proposed system, we can easily and intuitively generate an output image that looks similar to the results of cosmetic laser therapy. Our system also can detect more skin flaws and define their regions more accurately than previous retouching methods.

The spectral variability of reflectance properties of pictorial layers can be caused by chemical parameters, such as the nature of pigments and binders, or by morphological parameters, such as the pigment concentration, the thickness of the layer or the size distribution of pigments. This work proposes a study of the influence of morphological parameters on reflectance spectra using both hyperspectral measurements on physical samples and reflectance spectra calculated using an optical model based on the four-flux model. The spectral variability is evaluated by comparing the spectra to a reference spectrum, thanks to the Kullback–Leibler Pseudo-Divergence.

Material appearance hinges on material reflectance properties but also surface geometry and illumination. The unlimited number of potential combinations between these factors makes understanding and predicting material appearance a very challenging task. In this work, we collect a large-scale dataset of perceptual ratings of appearance attributes with more than 215,680 responses for 42,120 distinct combinations of material, shape, and illumination. The goal of this dataset is twofold. First, we analyze for the first time the effects of illumination and geometry in material perception across such a large collection of varied appearances. We connect our findings to those of the literature, discussing how previous knowledge generalizes across very diverse materials, shapes, and illuminations. Second, we use the collected dataset to train a deep learning architecture for predicting perceptual attributes that correlate with human judgments. We demonstrate the consistent and robust behavior of our predictor in various challenging scenarios, which, for the first time, enables estimating perceived material attributes from general 2D images. Since our predictor relies on the final appearance in an image, it can compare appearance properties across different geometries and illumination conditions. Finally, we demonstrate several applications that use our predictor, including appearance reproduction using 3D printing, BRDF editing by integrating our predictor in a differentiable renderer, illumination design, or material recommendations for scene design.

A spacecraft in near-Earth orbit is exposed to extreme environmental factors, such as high vacuum, zero gravity, collisions with meteors and orbital debris, corpuscular and electromagnetic radiations, etc. These factors result in changing properties of spacecraft surfaces which leads to changes in mechanical, optical, electrical and physical properties of materials and elements of spacecrafts. This paper presents experimental data obtained from ground-based photometric observations of several geostationary satellites (GSS) built on different types of buses, starting from the beginning of their operational lives and during several years after their launches. It has been experimentally proved that spectral reflectance properties of the satellite surface materials undergo gradual degradation with time of the satellite’s stay in space. Noticeable changes in spectral reflectance properties of GSS make it possible to detect damages to the satellite external payload. Comparison of changes in the reflective characteristics of different platforms over time can show the level of technical and scientific progress of spacecraft designers

The acquisition of the geometry of general scenes is related to the interplay of surface geometry, material properties and illumination characteristics. Surface texture and non-Lambertian reflectance properties degrade the reconstruction results by structured light technique. Existing structured light techniques focus on different coding strategy and light sources to improve reconstruction accuracy. The hybrid system consisting of a structured light technique and photometric stereo combines the depth value with normal information to refine the reconstruction results. In this paper, we propose a novel hybrid system consisting of stripe-based structured light and photometric stereo. The effect of surface texture and non-Lambertian reflection on stripe detection is first concluded. Contrary to existing fusion strategy, we propose an improved method for stripe detection to reduce the above factor&rsquo, s effects on accuracy. The reconstruction problem for general scene comes down to using reflectance properties to improve the accuracy of stripe detection. Several objects, including checkerboard, metal-flat plane and free-form objects with complex reflectance properties, were reconstructed to validate our proposed method, which illustrates the effectiveness on improving the reconstruction accuracy of complex objects. The three-step phase-shifting algorithm was implemented and the reconstruction results were given and also compared with ours. In addition, our proposed framework provides a new feasible scheme for solving the ongoing problem of the reconstruction of complex objects with variant reflectance. The problem can be solved by subtracting the non-Lambertian components from the original grey values of stripe to improve the accuracy of stripe detection. In the future, based on stripe structured light technique, more general reflection models can be used to model different types of reflection properties of complex objects.

We report on the extended observing campaign of the surviving Soviet/Russian spacecraft Molniya, carried out in the years 2014–17 at Mexican and Italian telescopes. Spectrophotometry and astrodynamical analysis have been carried out for all the 43 demised payloads still in uncontrolled HEO orbit at late 2017, in order to assess dynamical and reflectance properties of such a wide family of virtually identical orbiting objects, as well as their long-term orbit evolution, according to full historic Two-Line Elements (TLE) datasets in synergy with mathematical modeling to properly size up the prevailing effect of lunisolar perturbation and atmospheric drag.

In visual design, harmony refers to the similarity among objects and the components of these objects that appear as if they belong together. Harmony is related to the body, mind, and emotions as we relate to our living space, which means that the harmony of real objects is an important characteristic. Although the appearance harmony in specific materials has been investigated, harmony among different materials has not received adequate attention. In a previous study, we investigated the appearance harmony among various materials by psychophysical experiments. In this study, we correlated the psychophysical evaluations obtained from the experiments and the physical properties of the materials. By analyzing the relationship between psychophysical evaluations and the physical measurements for each material pairs based on cluster analysis, we found that the property of texture represented by the anisotropy histogram and that of reflectance obtained from the data of the bidirectional reflectance distribution function are important indices that can be used to judge the harmony of materials. In particular, the texture properties were more effective in judging the appearance harmony of material pairs in the fixed condition for illumination and viewing angles, and the reflectance properties were superior for the material pairs in the variable condition for illumination and viewing angles.

Computer graphics is a valuable tool used from industrial applications to entertainment; it enables creation of images from virtual scenes. One of the aims of computer graphics is to generate photorealistic scenes; an important part of realism is relying on the accuracy of material models. Hence, the study of material models and reflectances is crucial.Recently, measured materials gained popularity. This works well for uniform materials but spatially varying materials present multiple challenges in acquisition, storage, rendering and edition. This thesis presents methods for processing and editing measured materials.We propose a technique for fast acquisition of anisotropic spatially varying bidirectional reflectances (SVBRDF) with a limited amount of light directions and a fixed point of view. While not suitable for high fidelity measurements, it gives a starting point to edit a real-world material while other techniques require lengthy measurement time and complex granty setups.Then, we propose a pipeline to fit measured materials (BTF) to analytical materials (BRDF). This technique drastically decreases the memory footprint of a measured material by approximating it with analytical BRDFs parametrized with 2D maps. It allows direct edition of those 2D maps and combination of different materials from various datasets.Finally, we introduce a method to mix the reflectance properties of two materials. We can use the shininess of a material with the anisotropy of another while allowing edition of each contribution separately., L'informatique graphique a prouvé son utilité dans de nombreux domaines. Du prototypage industriel en passant par les loisirs avec le cinéma ou le jeu vidéo ou encore pour l'archivage du patrimoine historique. Elle permet la création d'image à partir de scènes virtuelles. L'un des objectifs de l'informatique graphique est la génération de rendus photo-réalistes. Une part importante est due à la fidélité des modèles de matériaux. Ainsi, leur étude ainsi que celle des réflectances est capitale.Les matériaux mesurés ont pris de l'importance en informatique graphique. Ils sont efficaces pour la représentation de matériaux homogènes. Cependant, pour les matériaux avec une variation structurelle spatiale, leur numérisation, utilisation pour le rendu, stockage et édition révèle de nombreuses difficultés. Cette thèse se propose de présenter des méthodes pour le traitement et l'édition de tels matériaux.Nous proposons une technique pour l'acquisition rapide de matériaux anisotropes avec variation spatiale à partir d'un nombre restreint d'illuminations et avec un point de vue fixe. Cette méthode est adaptée pour des mesures ne requérant pas une fidélité critique. Alors que d'autres techniques nécessitent un système de mesure couteux et une durée d'acquisition importante, notre technique permet d'obtenir un point de départ pour l'édition à partir de paramètres issus de matériaux réels.Ensuite, nous proposons une procédure pour l'approximation de données mesurées par une fonction analytique. Elle permet de réduire significativement l'emprunte mémoire requise par le stockage des données mesurées tout en proposant l'édition aisée du matériau ainsi représenté. Il est aussi possible de modifier la distribution spatiale des matériaux et ainsi remplacer des matériaux d'une surface par ceux d'une autre.Enfin, nous proposons une méthode permettant l'utiliser une partie des propriétés de réflectances de matériaux pour les fusionner avec celles d'un second. Cette méthode permet aussi l'édition des deux caractéristiques indépendamment l'une de l'autre de façon intuitive.

Optically transparent titanium dioxide and Barium titanium dioxide material by sputtering have shown to have high permittivity in the gigahertz regime. This makes it potential good electromagnetic shielding material for the dome of drone which housed the IR/ visible camera needed for navigation and to capture the image of ground terrain. In this work, airline method and arch reflectance technique are used to determine its permittivity and also to obtain the S11 parameter which is indicative of its good anti-reflective properties in the gigahertz regime especially the radar X-Band.

Facial attractiveness is judged through a combination of multiple cues including morphology (facial shape) and skin properties (facial reflectance). While several studies have examined the way in which people in Western cultures judge facial attractiveness, there have been fewer investigations into non-Western attitudes. This is because stimuli that quantitatively vary the attractiveness of non-Western faces are rare. In the present study, we built a model of the attractiveness of East-Asian faces, judged by East-Asian observers. Therefore, 400 computer-generated East-Asian faces were created and attractiveness rating scores were collected from Japanese observers. Data-driven mathematical calculations were used to identify quantitative links between facial attractiveness and shape and reflectance properties, with no prior hypothesis. Results indicate that faces with larger eyes, smaller noses and brighter skin are judged as more attractive, regardless of the sex of the faces, possibly reflecting a general preference for femininity. Shape is shown to be a strong determinant of attractiveness for both male and female faces, while reflectance properties are less important in judging male facial attractiveness. Our model provides a tool to effectively produce East-Asian face stimuli that quantitatively varies attractiveness and can be used to elucidate visual processes related to attractiveness judgements.

Colour variation across climatic gradients is a common ecogeographical pattern; yet there is long-standing contention over underlying causes, particularly selection for thermal benefits. We tested the evolutionary association between climate gradients and reflectance of near-infrared (NIR) wavelengths, which influence heat gain but are not visible to animals. We measured ultraviolet (UVA), visible (Vis) and NIR reflectance from calibrated images of 372 butterfly specimens from 60 populations (49 species, five families) spanning the Australian continent. Consistent with selection for thermal benefits, the association between climate and reflectance was stronger for NIR than UVA–Vis wavelengths. Furthermore, climate predicted reflectance of the thorax and basal wing, which are critical to thermoregulation; but it did not predict reflectance of the entire wing, which has a variable role in thermoregulation depending on basking behaviour. These results provide evidence that selection for thermal benefits has shaped the reflectance properties of butterflies.

The remote-sensing community uses grey-scale Spectralon to evaluate the performance of instruments designed to observe geologic surfaces with a range of reflectance values. This article presents the normalized biconical reflectance factor of a series of grey-scale Spectralon targets taken at viewing angles ranging from 10° to 80°. The darkest Spectralon standard, when illuminated at nadir incidence with s-polarized 1064 nm light, first undergoes a decrease in reflectance factor with increasing viewing angle, then encounters a minimum, after which the reflectance factor increases with increasing viewing angle. When progressively brighter Spectralon samples are measured, the reflectance factor dip at lower emergence angles becomes less pronounced and the slope at higher emergence angles is more gradual until, for the 20% Spectralon sample, the curve dips downward at the highest emergence angles. Measuring the grey-scale Spectralon set of targets using p-polarized incident light, the same trends described above are seen, except for the darkest Spectralon target, which monotonically decreases in reflectance factor. The data show a total decrease of 44%. The reflectance factor curves observed at 852 nm are similar to those seen at 1064 nm in that the same number of inflection points and the same sign of slope is seen at both wavelengths. However, comparing two different incidence angles using 1064 nm s polarized incident light, the slope of the reflectance factor curve does change significantly. For the brightest Spectralon target, the slope is positive for = 60° and negative for = 0° at all viewing angles measured. For the darkest Spectralon target, the slope is larger for = 60° than for = 0° at all viewing angles measured. At = 60°, the data show a total increase of 1360% in reflectance factor.

Iridescence is a visual property of those surfaces that change in colour with viewing angle. Iridescence has been rarely reported in reptiles, but some snakes and lizards show this type of coloration. Here we study the effect of different angles of light incidence and observation on the spectrophotometrically assessed reflectance of dorsal coloration in the lizard Podarcis muralis. The results demonstrate clear angle dependence of several colour parameters. In particular, different angles of light incidence and observation result in changes in hue of more than 30 nm. This suggests that lizard dorsal coloration may be perceived, depending on viewing geometry, as being of different colours by a wide range of potential observers. Functional implications of iridescence in dorsal coloration are discussed.

The use of artificially coloured stimuli, especially to test hypotheses about sexual selection and anti-predator defence, has been common in behavioural ecology since the pioneering work of Tinbergen. To investigate the effects of colour on animal behaviour, many researchers use paints, markers and dyes to modify existing colours or to add colour to synthetic models. Because colour perception varies widely across species, it is critical to account for the signal receiver's vision when performing colour manipulations. To explore this, we applied 26 typical coloration products to different types of avian feathers. Next, we measured the artificially coloured feathers using two complementary techniques—spectrophotometry and digital ultraviolet--visible photography—and modelled their appearance to mammalian dichromats (ferret, dog), trichromats (honeybee, human) and avian tetrachromats (hummingbird, blue tit). Overall, artificial colours can have dramatic and sometimes unexpected effects on the reflectance properties of feathers, often differing based on feather type. The degree to which an artificial colour differs from the original colour greatly depends on an animal's visual system. ‘White’ paint to a human is not ‘white’ to a honeybee or blue tit. Based on our analysis, we offer practical guidelines for reducing the risk of introducing unintended effects when using artificial colours in behavioural experiments.

Methods for 3D reconstruction such as Photometric stereo recover the shape and reflectance properties using multiple images of an object taken with variable lighting conditions from a fixed viewpoint. Photometric stereo assumes that a scene is illuminated only directly by the illumination source. As result, indirect illumination effects due to inter-reflections introduce strong biases in the recovered shape. Our suggested approach is to recover scene properties in the presence of indirect illumination. To this end, we proposed an iterative PS method combined with a reverted Monte-Carlo ray tracing algorithm to overcome the inter-reflection effects aiming to separate the direct and indirect lighting. This approach iteratively reconstructs a surface considering both the environment around the object and its concavities. We demonstrate and evaluate our approach using three datasets and the overall results illustrate improvement over the classic PS approaches., 8 pages, 11 figure, SITIS conference

Optical surface monitoring systems (OSMSs) are designed to assist patient setup and patient motion management during radiotherapy treatments. Systems use projected and reflected patterns of coloured light on the patients surface and therefore depend on the skin’s optical absorbance and reflectance properties, which can vary with surface shape and colour. This study aimed to identify optimal operating parameters for the Catalyst HD OSMS (C-rad, Uppsala, Sweden) when used to monitor the surfaces of 3D-printed objects with various convex and concave surfaces, one of which was painted in six different colours with various levels of red and black saturation (from light pink to dark grey). The degree of surface detection was assessed via the Catalyst HD interface, with different levels of gain (100–600%) and signal integration time (1–7 ms). The OSMS was able to detect horizontal and convex shapes more consistently than vertical or steeply angled surfaces. The OSMS was not able to detect the darkest surface at all, even with the highest gain and the longest integration times. Mid-grey surfaces were detectable only when the integration time was increased to 2 s. All pink surfaces were easily detectable at the shortest integration time, with the OSMS performing best when red saturation was highest. Further work is recommended, as the red undertone of all human skin may lead to improved results for real patients. However, these preliminary results indicate that careful commissioning and optimisation of OSMS systems may be required before they can be used in radiotherapy treatments for a broad patient cohort.

We consider the characteristics of macroalgal (kelp) targets of a LiDAR capable of assessing algal 3D morphology and quantifying algal biomass via fluorescence or differential absorption. Spectral absorption, fluorescence emission, fluorescence efficiency, and temporal fluorescence induction dynamics of Arctic algae can differ by class due to variation in photopigment complement. Surface reflectance characteristics of macroalgae can vary by morphology and structure. In this, work, we present an investigation of fluorescence via excitation-emission spectra of Arctic macroalgal targets. Simulations using these optical characteristics will later guide us in optimizing LiDAR configuration and performance under various operating conditions.

A modeling scheme for active imaging through atmospheric turbulence is presented. The model consists of two parts: In the first part, the illumination laser beam is propagated to a target that is described by its reflectance properties, using the well-known split-step Fourier method for wave propagation. In the second part, the reflected intensity distribution imaged on a camera is computed using an empirical model developed for passive imaging through atmospheric turbulence. The split-step Fourier method requires carefully chosen simulation parameters. These simulation requirements together with the need to produce dynamic scenes with a large number of frames led us to implement the model on GPU. Validation of this implementation is shown for two different metrics. This model is well suited for Gated-Viewing applications. Examples of imaging simulation results are presented here.

We propose a technique to reconstruct a general 3D object using surface reflectance information from multiple viewpoints. Our core optimization framework uses multi-view normal integration, which can recovers water-tight surface of the object iteratively in a coarse to fine manner. The integration requires normal vector field from multiple viewpoints, which we can derive from surface reflectance. We then handle the topological changes if self-intersection occurs from the optimization. We also employ the idea of multi-resolution and weighted data heuristic which helps dealing with noisy data and improves both accuracy and optimization time. Our experiment shows that the framework is able to robustly recover 3D surface well with both synthetic and real data.

This paper presents the reflection bands, photonic band gaps, of the one-dimensional annul photonic crystal (APC) containing double negative (DNG) metamaterials and air. The proposed annular structure consists of the alternate layers of dispersive DNG material and air immersed in free space. The reflectance properties of the APC by employing the transfer matrix method (TMM) in the cylindrical waves for TE polarization is studied theoretically. In addition of this, we have also studied the effect of plasma frequency on the reflection behavior of the considered annular structure.

Road lighting efficiency depends not only on the use of effective lighting devices but also on the illuminated surface — road pavements. This paper focuses on studying the effects of aggregate lightness and aggregate colour on reflectance properties of different pavements types in Ukraine. The aim of paper is prove that the road surface is an important factor in optimizing energy efficiency and road lighting. Reflectance properties of pavements are very important in road lighting design and energy saving and should be considered more carefully in the design process of the road lighting.

Images obtained during the low‐altitude campaign in the final year of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission provide the highest‐spatial‐resolution views of Mercury's polar deposits. Images for distinct areas of permanent shadow within 35 north polar craters were successfully captured during the campaign. All of these regions of permanent shadow were found to have low‐reflectance surfaces with well‐defined boundaries. Additionally, brightness variations across the deposits correlate with variations in the biannual maximum surface temperature across the permanently shadowed regions, supporting the conclusion that multiple volatile organic compounds are contained in Mercury's polar deposits, in addition to water ice. A recent large impact event or ongoing bombardment by micrometeoroids could deliver water as well as many volatile organic compounds to Mercury. Either scenario is consistent with the distinctive reflectance properties and well‐defined boundaries of Mercury's polar deposits and the presence of volatiles in all available cold traps.

We have developed an instrument and a method to perform in vivo hyperspectral imaging of the human iris in order to quantitatively measure its spectral reflectance. Understanding age-related changes in the reflectance properties of the iris is important for multiple aspects of vision research. The images are acquired in the spectral range 450–810nm from three healthy volunteers. The spectral resolution is equal to 30nm, while each image of 1024×768 pixels has a spatial resolution of 22.5μm. The instrument appears suitable for measuring iris pigmentation changes over time. These measurements could offer new diagnostic possibilities in ophthalmology.

PURPOSE. We investigate the reflectance properties of the cone mosaic in adaptive optics (AO) images of healthy subjects and subjects with nonproliferative diabetic retinopathy (NPDR) over time. METHODS. We acquired images of the parafoveal cone mosaic over 5 years in 12 healthy subjects and in six patients with mild NPDR. We analyzed the parameters of the cone intensity histogram distribution (mean, SD, and skewness), two metrics of the cone mosaic texture (sharpness and entropy), and two novel metrics (cone/intercone intensity and slope of the variogram). Each metric was calculated on the same four retinal locations (200 X 200 mu m areas, 2 degrees from the fovea along the four meridians) over dine for each subject. RESULTS. The histogram distributions of cone intensities were similar between the two study groups. However, the cone/intercone intensity, slope of the variograms and entropy showed a significant difference between healthy and NPDR subjects (P = 0.036, P = 0.002, P = 0.014, respectively). All parameters, except for mean cone intensity did not change with time in this study CONCLUSIONS. We observed significant differences in cone mosaic reflectance properties between healthy eyes and eyes with NPDR, in its spatial organization and in its intensity especially between directional and nondirectional backscattering. We introduced a novel method for the study of the spatial distribution of cone reflectance, the variogram, which was able to quantify differences of the spatial dependence of cone intensities over a short range between NPDR and healthy eyes.

International audience; Directional optical coherence tomography (D-OCT) reveals reflec-tance properties of retinal structures by changing the incidence angle of the light beam. As no commercially available OCT device has been designed for such use, image processing is required to homogenize the grey levels between off-axis images before differential analysis. We describe here a method for automated analysis of D-OCT images and propose a color representation to highlight angle-dependent structures. Clinical results show that the proposed approach is robust and helpful for clinical interpretation.

We report the discovery of a new asteroid family among the dark asteroids residing in the Phocaea region the Tamara family. We make use of available physical data to separate asteroids in the region according to their surface reflectance properties, and establish the membership of the family. We determine the slope of the cumulative magnitude distribution of the family, and find it to be significantly steeper than the corresponding slope of all the asteroids in the Phocaea region. This implies that sub-kilometer dark Phocaeas are comparable in number to bright S-type objects, shedding light on an entirely new aspect of the composition of small Phocaea asteroids. We then use the Yarkovsky V-shape based method and estimate the age of the family to be 264$\pm$43 Myr. Finally, we carry out numerical simulations of the dynamical evolution of the Tamara family. The results suggest that up to 50 Tamara members with absolute magnitude H, Accepted for publication in AJ

Images acquired by NASA's MESSENGER spacecraft have revealed the morphology of frozen volatiles in Mercury's permanently shadowed polar craters and provide insight into the mode of emplacement and evolution of the polar deposits. The images show extensive, spatially continuous regions with distinctive reflectance properties. A site within Prokofiev crater identified as containing widespread surface water ice exhibits a cratered texture that resembles the neighboring sunlit surface except for its uniformly higher reflectance, indicating that the surficial ice was emplaced after formation of the underlying craters. In areas where water ice is inferred to be present but covered by a thin layer of dark, organic-rich volatile material, regions with uniformly lower reflectance extend to the edges of the shadowed areas and terminate with sharp boundaries. The sharp boundaries indicate that the volatile deposits at Mercury's poles are geologically young, relative to the time scale for lateral mixing by impacts, and either are restored at the surface through an ongoing process or were delivered to the planet recently.

Glossiness is the visual appearance of an object's surface as defined by its surface reflectance properties. Despite its ecological importance, little is known about the neural substrates underlying its perception. In this study, we performed the first human neuroimaging experiments that directly investigated where the processing of glossiness resides in the visual cortex. First, we investigated the cortical regions that were more activated by observing high glossiness compared with low glossiness, where the effects of simple luminance and luminance contrast were dissociated by controlling the illumination conditions (Experiment 1). As cortical regions that may be related to the processing of glossiness, V2, V3, hV4, VO-1, VO-2, collateral sulcus (CoS), LO-1, and V3A/B were identified, which also showed significant correlation with the perceived level of glossiness. This result is consistent with the recent monkey studies that identified selective neural response to glossiness in the ventral visual pathway, except for V3A/B in the dorsal visual pathway, whose involvement in the processing of glossiness could be specific to the human visual system. Second, we investigated the cortical regions that were modulated by selective attention to glossiness (Experiment 2). The visual areas that showed higher activation to attention to glossiness than that to either form or orientation were identified as right hV4, right VO-2, and right V3A/B, which were commonly identified in Experiment 1. The results indicate that these commonly identified visual areas in the human visual cortex may play important roles in glossiness perception.

The bidirectional reflectance properties of the anisotropic light field above the water surface are important for a range of applications. The bidirectional reflectance distribution function of oceanic waters has been well characterized but there is a lack of information for turbid inland waters. In addition, there is a lack of bidirectional reflectance data measured in turbid inland waters partially due to the difficulty in collecting in situ water-surface multi-angle remote-sensing reflectance data. To facilitate bidirectional reflectance studies of turbid inland waters using in situ multi-angular reflectance data, we have designed and developed a simple hand-held 3D positioning pole to position the spectrometer optical fibre probe and a specific method to collect the multi-angular reflectance data above the water surface with this pole. Using this device, we collected multi-angular reflectance data in Meiliang Bay, Taihu Lake, China, and analysed the uncertainties in this method. We analysed the bidire...

A next-generation technology iteration of Qualcomm's Mirasol displays, called the single mirror interferometric (SMI) display, is demonstrated. SMI features individual pixels whose reflectance properties can tune through a continuum of colors, including high contrast black and white reflectance states. The MEMS optical pixel is described, along with early system demonstrations.

High-resolution images of the Surveyor, Luna, and Apollo landing sites obtained by the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) show regions around the landers where reflectivity of the surface was modified. We interpret the change in reflectance properties of these regions mainly as disturbance of the regolith by rocket exhaust during descent of the spacecraft and we refer to these areas herein as “blast zones” (BZs). The BZs consist of an area of lower reflectance (LR-BZ) compared to the surroundings that extends up to a few meters out from the landers, as well as a broader halo of higher reflectance (HR-BZ) that extends tens to hundreds of meters away from the landers. When approximated as an ellipse, the average Apollo BZ area is ∼29,000 m2 (∼175 ± 60 m by 200 ± 27 m) which is 10× larger than the average Luna BZ, and over 100× larger than the average Surveyor BZ. The LR-BZs are most evident at the Apollo sites, especially where astronaut activity disturbed the soil, leading to a 15–30% (relative to background undisturbed areas) reduction in reflectance at ∼30° phase angle. The LR-BZs at the Surveyor and Luna sites are less evident and are unresolvable with NAC images. The average reflectance in the HR-BZs as determined for 30° phase angle is 3–12% higher than in the undisturbed surrounding areas; this magnitude is the same, within uncertainty, for all sites, indicating a common process or combination of processes causing differences in reflectance properties of the regolith. Phase-ratio images and photometric data collected over a range of illumination geometries show that a greater separation in reflectance occurs between the HR-BZs and undisturbed areas at phase angles between 0° and 70° and indicates that the HR-BZs are less backscattering than undisturbed areas. The LR-BZs are affected by macroscopic disruption of the surface and astronaut activity (at the Apollo sites). For the HR-BZ areas, reflectance has likely been affected by scouring from particles entrained by exhaust gases with low-angle trajectories. Regolith particle interactions with surface soil within HR-BZs may destroy fine-scale surface structure (e.g., “fairy-castle”) and decrease macroscopic roughness, contributing to a decrease in backscattering character within the HR-BZs and an increase in backscattering character within the LR-BZs. Redistribution of fine particles from the LR-BZ to the HR-BZ may have also contributed to the changed reflectance. Photometric modeling is consistent with one or a combination of these processes.

The appearance of a static scene as sensed by a camera changes considerably as a result of changes in the illumination that falls upon it. Scene appearance modeling is thus necessary for understanding which changes in the appearance of a scene are the result of illumination changes. For any camera, the appearance of the scene is a function of the illumination sources in the scene, the three-dimensional configuration of the objects in the scene and the reflectance properties of all the surfaces in the scene. A scene appearance model is described here as a function of the behavior of static illumination sources, within or beyond the scene, and arbitrary three-dimensional configurations of patches and their reflectance distributions. Based on the suggested model, a spatial prediction technique was developed to predict the appearance of the scene, given a few measurements within it. The scene appearance model and the prediction technique were developed analytically and tested empirically. Two potential applications are briefly explored.

Several recent studies have shown that the mass-based concentration of nitrogen in foliage (%N) is positively correlated with canopy near-infrared reflectance (NIRr) and midsummer shortwave albedo across North American forests. Understanding the mechanisms behind this relationship would aid in interpretation of remote sensing imagery and improve our ability to predict changes in reflectance under future environmental conditions. The purpose of this study was to investigate the extent to which foliar nitrogen at leaf and canopy scales covary with leaf- and canopy-scale structural traits that are known to influence NIR scattering and reflectance. To accomplish this, we compared leaf and canopy traits with reflectance spectra at 17 mixed temperate forest stands. We found significant positive associations among %N and NIRr at both the leaf and canopy scale. At the canopy scale, both %N and NIRr were correlated with a number of structural traits as well as with the proportional abundance of deciduous and evergreen foliage. Identifying specific causal factors for observed reflectance patterns was complicated by interrelations among multiple traits across scales. Among simple metrics of canopy structure, we saw no relationship between NIRr and leaf area index, but we observed a strong, inverse relationship with the number of leaves per unit canopy volume.

Most asteroids of the near-Earth population have experienced significant collisional processing since they formed, being disrupted and excavated and consequently producing smaller bodies that are delivered from the Main asteroid Belt to the near-Earth asteroid region, thanks to planetary resonances and non-gravitational forces. By studying meteorites arrived to Earth we can obtain clues on this processing through the study of shock metamorphism and brecciation of their rock constituents, among other features. The massive Chelyabinsk meteorite fall produced about one metric ton of meteorites that can be analyzed to decipher the physical processes affecting the surface of this Potentially Hazardous Asteroid. Here we describe physical properties of Chelyabinsk samples, and how impact processing has affected asteroid albedos, a first step in order to relate this data with the reflectance properties of near-Earth asteroids population. This information will be of major interest for future asteroid deflecting missions.

In this present communication, we study the three dimentionalomni-directional reflection bands in Plasma Photonic Crystals (PPC), having alternate regions of plasma-dielectric. We have calculated the reflectivity of the proposed structure at the various angles of incidence for both polarizations (TE - & TM) in three dimensions.

In this present communication, we have studied the optical properties of Photonics Crystals with super conducting constituent using the TMM method for a stratified medium. We also studied the three dimensional reflectance property of superconductor-dielectric photonic crystal at different temperature and thickness. From above study we show that the superconductor-dielectric photonic crystal may be used as broad band reflector and omnidirectional reflector at low temperature below to the critical temperature. Such property may be applied to make of the reflector which can be used in low temperature region.

Nitrogen Status Determination of Rice by Leaf Chlorophyll Fluorescence and Reflectance Properties Hao Hu1, Kefeng Zheng1 ∗, Xiaoming Zhang2, Yanting Lu2, and Hao Zhang1 1Institute of Digital Agriculture, Zhejiang Academy of Agriculture Sciences, Zhejiang, Hangzhou 310021, P. R. China 2Institute of Crops and Nuclear Technology Utilization, Zhejiang Academy of Agriculture Sciences, Zhejiang, Hangzhou 310021, P. R. China

Ribbon silicon solar cells have been investigated because they can be produced with a lower material cost. However, it is very difficult to get good texturing with a conventional acid solution. To achieve high efficiency should be minimized for the reflectance properties. In this paper, acid vapor texturing and anti-reflection coating of SiNx was applied for EFG Ribbon Si Wafer. P-type ribbon silicon wafer had a thickness of 200 μm and a resistivity of 3 Ω-㎝. Ribbon silicon wafers were exposed in an acid vapor. Acid vapor texturing was made by reaction between the silicon and the mixed solution of HF : HNO3.. After acid vapor texturing process, nanostructure of less than size of 1 μm was formed and surface reflectance of 6.44% was achieved. Reflectance was decreased to 2.37% with anti-reflection coating of SiNx.