Light Patches Research Articles

Edge enhancement improves disruptive camouflage by emphasising false edges and creating pictorial relief.

Disruptive colouration is a visual camouflage composed of false edges and boundaries. Many disruptively camouflaged animals feature enhanced edges; light patches are surrounded by a lighter outline and/or a dark patches are surrounded by a darker outline. This camouflage is particularly common in amphibians, reptiles and lepidopterans. We explored the role that this pattern has in creating effective camouflage. In a visual search task utilising an ultra-large display area mimicking search tasks that might be found in nature, edge enhanced disruptive camouflage increases crypsis, even on substrates that do not provide an obvious visual match. Specifically, edge enhanced camouflage is effective on backgrounds both with and without shadows; i.e. this is not solely due to background matching of the dark edge enhancement element with the shadows. Furthermore, when the dark component of the edge enhancement is omitted the camouflage still provided better crypsis than control patterns without edge enhancement. This kind of edge enhancement improved camouflage on all background types. Lastly, we show that edge enhancement can create a perception of multiple surfaces. We conclude that edge enhancement increases the effectiveness of disruptive camouflage through mechanisms that may include the improved disruption of the object outline by implying pictorial relief.

Prehistoric animals, in living color

Paleontologists are looking beyond bones to reveal the hues of prehistoric animals that vanished millions of years ago. But the young field has its share of disagreements. Michael Benton used to tell his paleontology students that they would never know the true color of a dinosaur. After all, even fossils that sport light or dark patches may not indicate the creature’s original hue. But in recent years, the vertebrate paleontologist at the University of Bristol in the United Kingdom has had to revise those lectures. Researchers reconstructed the plumage color of a Jurassic birdlike dinosaur called A. huxleyi using color-imparting melanosomes, the morphology of which had been preserved in fossil feathers. Image courtesy of Michael DiGiorgio (artist). In 2010, Benton and colleagues found evidence that the feathered dinosaur Sinosauropteryx prima had reddish-brown stripes on its tail (1). The same year, another group claimed that birdlike Anchiornis huxleyi bore a red crest on its head (2). Since then, others have discovered that a marine ichthyosaur was dark-colored, and that the early bird Confuciusornis sanctus possessed dark feathers with light wing tips (3, 4) (Table 1). Suddenly, the color of prehistoric animals has become an active topic for research rather than speculation, turning Benton into an optimist: “If you’re a scientist, never say anything is impossible,” he now tells students. Most of these colorful revelations have emerged from fossils that contain evidence of melanin pigments—responsible for earth tones, such as red, black, brown, and buff—or the tiny cellular bags, called melanosomes, which produce and store melanins. But some scientists are already identifying the brighter hues of ancient snakes and insects. “Probably all of the colors can eventually be identified,” predicts Benton. The work is not only helping to repaint the colorful pictures of dinosaurs that charm schoolchildren and museum-goers. Color can …

Defects localization research in photovoltaic cells: Methods and devices

The article presents a method to determine local defects in solar photovoltaic cells (PVC). It is based on the non-contact measurement of PVC area temperature distribution by a special thermovision system when applying forward and reverse voltage to the cell. Distribution of PVC surface temperature is determined by nonuniformity of current density (because of local defects) and reveals itself in the intensity of thermal radiation in the infrared spectrum (IR). The difference between the light detector signals when applying a forward or reverse voltage to PV cells and in the absence of applied voltage to the PVC is used to eliminate the effect of IR light patch, surface irregularities emissivity of solar cells, heterogeneity sensitivity light detector array. The hardware and software implementation techniques using the focal plane array of infrared 3–5 micron spectral range and 320 × 256 elements size are presented.

Effects of Spatial Patch Arrangement and Scale of Covarying Resources on Growth and Intraspecific Competition of a Clonal Plant.

Spatial heterogeneity in two co-variable resources such as light and water availability is common and can affect the growth of clonal plants. Several studies have tested effects of spatial heterogeneity in the supply of a single resource on competitive interactions of plants, but none has examined those of heterogeneous distribution of two co-variable resources. In a greenhouse experiment, we grew one (without intraspecific competition) or nine isolated ramets (with competition) of a rhizomatous herb Iris japonica under a homogeneous environment and four heterogeneous environments differing in patch arrangement (reciprocal and parallel patchiness of light and soil water) and patch scale (large and small patches of light and water). Intraspecific competition significantly decreased the growth of I. japonica, but at the whole container level there were no significant interaction effects of competition by spatial heterogeneity or significant effect of heterogeneity on competitive intensity. Irrespective of competition, the growth of I. japonica in the high and the low water patches did not differ significantly in the homogeneous treatments, but it was significantly larger in the high than in the low water patches in the heterogeneous treatments with large patches. For the heterogeneous treatments with small patches, the growth of I. japonica was significantly larger in the high than in the low water patches in the presence of competition, but such an effect was not significant in the absence of competition. Furthermore, patch arrangement and patch scale significantly affected competitive intensity at the patch level. Therefore, spatial heterogeneity in light and water supply can alter intraspecific competition at the patch level and such effects depend on patch arrangement and patch scale.

Etiology and pathogenesis of melasma

Melasma is a pigmentary skin disorder characterized by light or dark brownish black patches on the face. Recent studies have shown that multiple factors are involved in the pathogenesis of melasma, including structural damage to basilar membrane, increased vascularity, oxidative stress, etc. Moreover, expressions of lipid metabolism-associated genes and the noncoding RNA H19 gene have been found to be down-regulated in melasma lesions. Molecular biology researches have revealed that multiple signal transduction pathways such as Wnt signaling pathway, inducible nitric oxide synthase (iNOS) and AKT/nuclear factor-κB signaling pathway play critical roles in the occurrence of melasma. In addition, neuroregulation is implicated in the pathophysiology of melasma. Key words: Chloasma; Gonadal steroid hormones; Ultraviolet rays; Heredity; Basilar membrane; Signal transduction

Strong pollinator-mediated selection for increased flower brightness and contrast in a deceptive orchid.

Contrasting flower color patterns that putatively attract or direct pollinators toward a reward are common among angiosperms. In the deceptive orchid Anacamptis morio, the lower petal, which makes up most of the floral display, has a light central patch with dark markings. Within populations, there is pronounced variation in petal brightness, patch size, amount of dark markings, and contrast between patch and petal margin. We tested whether pollinators mediate selection on these color traits and on morphology (plant height, number of flowers, corolla size, spur length), and whether selection is consistent with facilitated or negative frequency-dependent pollination. Pollinators mediated strong selection for increased petal brightness (Δβpoll = 0.42) and contrast (Δβpoll = 0.51). Pollinators also tended to mediate stabilizing selection on brightness (Δγpoll = -0.27, n.s.) favoring the most common phenotype in the population. Selection for reduced petal brightness among hand-pollinated plants indicated a fitness cost associated with brightness. The results demonstrate that flower color traits influence pollination success and seed production in A. morio, indicating that they affect attractiveness to pollinators, efficiency of pollen transfer, or both. The documented selection is consistent with facilitated pollination and selection for color convergence toward cooccurring rewarding species.

The influence of lightness, and the crispening effect on the perceived contrast of textured images

We investigate the role of lightness perception in determining the perceived contrast of images. In particular, it is known that the background luminance of a display affects the relationship between onscreen luminance and perceived lightness. Stevens & Stevens (1963) modeled this effect using a simple power law. However, Whittle (1992) observed a more local effect, whereby subjects are more sensitive to lightness variations around the background luminance (the crispening effect). We probe lightness perception by asking subjects to manipulate the contrast of small patches on a uniform background until they appear to vary, from black to white, in a perceptually linear manner. In a second experiment, we estimate the contrast required to match the contrast of a light patch to that of a dark patch. Both experiments are conducted using five background luminance conditions, from 0 to 100% luminance. We find that subjects contrast judgments can only be modeled by first estimating the perceived lightness in a scene, using the empirically estimated lightness functions, before computing contrast. We conclude that models of contrast perception must include sophisticated models of lightness perception.

Aristolochia weixiensis, a new species of Aristolochiaceae from Yunnan, China

Aristolochia weixiensis, a new species from northwest Yunnan, China, is described. A. weixiensis is affinis to A. moupinensis with similar leaf shape, but differs from the latter in the limb with dark purple colour and dense papillae, ca. 3.5 cm in diam., throat with light brown colour and dense brownish red patches, 13–16 mm in diam. Meanwhile, A. weixiensis is similar to A. wuana with similar leaves in shape, but differs in fruit and the size of leaf.

4차원 Light Field 영상에서 Dictionary Learning 기반 초해상도 알고리즘

A 4D light field image is represented in traditional 2D spatial domain and additional 2D angular domain. The 4D light field has a resolution limitation both in spatial and angular domains since 4D signals are captured by 2D CMOS sensor with limited resolution. In this paper, we propose a dictionary learning-based superresolution algorithm in 4D light field domain to overcome the resolution limitation. The proposed algorithm performs dictionary learning using a large number of extracted 4D light field patches. Then, a high resolution light field image is reconstructed from a low resolution input using the learned dictionary. In this paper, we reconstruct a 4D light field image to have double resolution both in spatial and angular domains. Experimental result shows that the proposed method outperforms the traditional method for the test images captured by a commercial light field camera, i.e. Lytro.

Apple detection in nighttime tree images using the geometry of light patches around highlights

Detection of fruit in tree images has been the focus of numerous studies. Although most studies considered approaches based primarily on color analysis, the major drawback of such approaches is that the fruit apparent color depends not only on variety or physiological stage but also on illumination, which is inherently non-uniform within the canopy, even if artificial lighting is used. In the present work we developed a novel approach to detect apples in nighttime images by analyzing the spatial distribution of the light around highlights (“bright spots”). The approach is based on the observation that, under the artificial illumination used, apples exhibit strong specular reflection so that a small, but very bright, spot is visible on almost all apples. Each of these highlights serves as the center of a region of interest and is the seed of the investigated light patch. This patch is initially very small but its size is increased iteratively by annexing pixels with predefined decreasing gray level intensities. The evolution of the patch geometry is used to determine whether it corresponds to an apple. The approach was tested with two datasets containing over 360 images (close to 13,000 apples) acquired in the same ‘Golden Delicious’ orchard in July 2012 and August 2013. Twenty images from the 2012 dataset were randomly selected to develop and calibrate the procedure. The results of these 20 images were used to establish a linear relationship between the number of detected objects and the actual number of apples visible in the images (R2∼0.75). Applying the calibrated procedure to the remaining images of this dataset led to an estimate of 6739 apples compared to a visual count of 6195 apples (∼9% overestimate). Analysis of the 2013 dataset, in which the apparent size of the apples was smaller, required only adjustment of the two parameters related to apple size. Following this adjustment, 12 images were randomly selected to determine the relationship between the number of detected objects and the actual number of apples (R2∼0.74). Using this relationship, the estimated number of apples was 6687, compared to the visual count of 6713 fruits.

Characteristic dermoscopic features of melasma.

To discribe the characteristic dermoscopic features of melasma. Totally 20 patients with typical clinical presentations of melasma were included in this study. The melasma lesion and its surrounding normal skin were evaluated using dermatoscope. Melasma lesions manifested light yellow brown uniform patches in all patients, among whom dark brown patches were found in 19 patients, capillary network in 14 patients,and coarse hair in 6 patients. In contrast, no light yellow brown uniform patch was found in the normal skin in all patients (P<0.001), among whom dark brown patches were found in 10 patients (P<0.001), capillary network in 12 patients (P>0.05), and coarse hair in 2 patients (P>0.05). Light yellow brown uniform patches and dark brown patches are two major dermoscopic features of melasma.

Gingival Depigmentation: Esthetic Enhancement Made Simple and Efficient

Background: Dental esthetic problems in adolescence have significant impact on the psychologic health and well being during this important period of development. These dental problems not only hinder the normal oral functioning of these children, but also have a considerable psychological impact. Dental problems in anterior region may be related to abnormality in shape, size, color and structure of the tooth, pigmentation of the gingiva, traumatic injuries, orthodontic problems. One of the frequently encountered dental problems is gingival pigmentation, which is seen as a purplish staining or as brown or light brown patches. Case: The aim of the report is to describe the management of gingival pigmentation by means of electrocautery as a feasible esthetic alternative in an adolescent girl.

Three new species of the subfamily Microgastrinae (Hymenoptera: Braconidae) from Vietnam

Three new species of the subfamily Microgastrinae (Hymenoptera: Braconidae) from Vietnam

Lighting performance and electrical energy consumption of a virtual window prototype

This article discusses the design and evaluation of a virtual window prototype, built using arrays of LED tiles to simulate the light as well as the view of a window. Arrays of white light LED fixtures with adjustable colour temperatures were incorporated to provide direct light into the test room. Lighting performance was evaluated by measuring horizontal illuminance on the workplane, vertical illuminance on the observer’s eye plane, and luminance perceived by the observer at four vertical points. For estimating the electrical energy consumption, real-time power consumption of the entire system was measured, and three daily usage profile scenarios and two annual modes were considered. In addition, five locations were chosen to represent various climate types. The results show that under the maximum setting, the average workplane illuminance was 239lx for the test room used, whereas discomfort glare at the observer’s positions was classified as imperceptible. Patches of direct light on the side walls could be created as an intended effect from installing the direct light source arrays. Variation of average annual space availability within a given location as a function of usage profile is found to be very small; the values are however sensitive to the chosen criterion of workplane illuminance. Based on the designated daily usage profiles and annual modes, the normalised, total annual electrical energy consumption in all climate types is on average within the range of 0.63–0.79, relative to the total electrical energy consumed by the prototype when it constantly displays the maximum intensity setting.

The achromatic locus: Effect of navigation direction in color space

An achromatic stimulus is defined as a patch of light that is devoid of any hue. This is usually achieved by asking observers to adjust the stimulus such that it looks neither red nor green and at the same time neither yellow nor blue. Despite the theoretical and practical importance of the achromatic locus, little is known about the variability in these settings. The main purpose of the current study was to evaluate whether achromatic settings were dependent on the task of the observers, namely the navigation direction in color space. Observers could either adjust the test patch along the two chromatic axes in the CIE u*v* diagram or, alternatively, navigate along the unique-hue lines. Our main result is that the navigation method affects the reliability of these achromatic settings. Observers are able to make more reliable achromatic settings when adjusting the test patch along the directions defined by the four unique hues as opposed to navigating along the main axes in the commonly used CIE u*v* chromaticity plane. This result holds across different ambient viewing conditions (Dark, Daylight, Cool White Fluorescent) and different test luminance levels (5, 20, and 50 cd/m(2)). The reduced variability in the achromatic settings is consistent with the idea that internal color representations are more aligned with the unique-hue lines than the u* and v* axes.

Influence of Altitude on the Petrological Features of a Soil Climosequence in the Humid Tropical Zone of Cameroon

Although lateritic soils are well documented in the humid tropical zone, work on adiabatic effect, which imposes local climatic variations with increasing altitude, has received very little attention in this zone. The aim of this work was to study and specify a soil climosequence in the humid tropical zone of Cameroon and to show the influence of altitude on the geochemical functioning of tropical soils. The work was done in the field and completed by a battery of laboratory analyses. The results enabled the definition of a soil climosequence for the humid tropical zone in Cameroon. This climosequence is marked by soils whose evolution is conditioned by the geochemistry of iron, silicon and aluminium. In the plateau ecosystems (500-800 m altitude), iron is expressed either as hardened materials (e.g. ferruginous nodules or duricrust) or light patches on the soils, while silicon and aluminium are combined as kaolinite. In the high plateaus (800-2000 m altitude), soil evolution is dominated by aluminium geochemistry, where aluminium forms gibbsite (either indurated or loose) often associated with small amounts of goethite and hematite. Finally, in the mountainous massifs (> 2000 m altitude), soil evolution is controlled by silica geochemistry, where silica is combined with amorphous aluminium to form allophane. In this soil, the presence of a dark and thick humiferous andosolic horizon in the upper part of the profile is very remarkable. Overall, this soil climosequence reflects geochemical functioning processes which grade with altitude in the humid tropical zone of Cameroon, similar to that commonly observed under the temperate climate. This general scheme could be extrapolated to other humid tropical regions with similar climatic and relief conditions as those observed in Cameroon. However, this general tendency often includes site-specific modifications caused by human activity and local variations of environmental conditions.

Response inhibition during avoidance of virtual obstacles while walking

While walking, one often has to suppress and adjust a planned step in order to avoid a fall. Given that steps are preprogrammed this requires some form of motor inhibition. Motor inhibition is commonly tested in hand function and only recently attempts have been made to evaluate inhibition in the lower limbs, during step initiation. As adequate motor inhibition might play a role in avoiding falls a test to assess response inhibition during walking would be valuable. We developed a task in which subjects walked on a treadmill by stepping on projected patches of light, which could suddenly change color forcing the subjects to avoid it by shortening or lengthening their steps. The difficulty level was manipulated in 4 conditions by changing the distance available to respond. We hypothesized that larger demands on motor inhibition during walking would produce more failures and tested the performance of young adults (n=12) in order to establish the protocol for use in older adults. The failure rate on the walking test was analyzed. Reducing the available response distance by 150 mm from the easiest condition resulted in a significant increase in failure rates from 15.6% to 65.1%. Therefore, results indicate this novel test can be used to assess the level of motor inhibition during walking. Additionally, in comparison to previous literature on obstacle avoidance, our experiment shows that changing a precise aiming movement is considerably more challenging than changing the same movement executed automatically.

Design of a LED Module with Special Constraint

LED gradually replaces light source in many fields, it becomes more and more important. For the purpose of letting LED more effective, people usually use secondary optical lens to improve the optical quality. In this research, reflector and lens are used to compose a LED light module. In this study, a LED module is designed to meet the specific requirement of the illumination. It was found that changing lens thickness and lens position can improve the uniformity and the size of light patch. As a result, we found parameters about lens for best results. In the design process, we realized that uniformity can be increased by decreasing D10 value of the light. The best result of simulation was found (which are in the form of point data). We used polynomials to fit the contour of LED module of point data and used it to extend the reflector contour of calculated results. The size of light patch of LED contour with reflector-masked and point data is much smaller than with polynomials.

Achievements of Polish doctors in gastrodiaphanoscopy at the turn of the 19(th) and 20(th) centuries.

Diaphanoscopy/transillumination, the method of shining a bright light through tissues, was devised in the mid-19th century and developed after the invention of the light bulb by T.A. Edison. Benjamin Milliot was the first to examine the stomach by means of an incandescent platinum wire. The experiments conducted by Max Einhorn using a device consisting of a Nelaton catheter with an inserted light bulb, were valuable. In Poland the method of gastrodiaphanoscopy was popularized by Teodor Heryng, Mikołaj Rejchman and by Warsaw doctors. They used a diaphanoscope consisting of a gutta-percha probe distally equipped with a metal attachment with a light bulb hidden in it and with a so-called cooling device. The examination would usually be conducted in the standing position after the stomach had been filled with water. Light patches corresponding to the stomach’s lower and side boundaries would be obtained. Rejchman’s observation, that such a contractile and flexible organ as the stomach, changing its volume and position, is bound to change its light image, was correct. Heryng’s and Rejchman’s research inspired the foreign researchers Renvier, Leopold Kuttner and John Jacobson. Extensive research was subsequently conducted by C.A. Meltzing and Wilhelm Schwartz. Diaphanoscopy would also be performed by Walery Jaworski, the pioneer of gastrology. He was particularly interested in transillumination of the stomach, peritoneum and omentum tumours. Eugeniusz Kozierowski, a practicing physician from Gorlice, diagnosed neoplastic pylorostenosisusing this method. Gastrodiaphanoscopy is a historical method, now of no value against gastroendoscopy and the state-of-the-art methods of image diagnostics.

Cockarde (Target-Like Lesion) Seborrheic Keratosis: An Unusual Clinical Pattern

Dear Editor: Seborrheic keratosis (SK) is the most common type of benign epidermal neoplasm, and has variable clinical presentation. Typically, SK first presents as yellowish, circumscribed papules, which later become more exophytic, brown and/or hyperpigmented. Greasy, adherent squamous material subsequently develops1. These lesions commonly present as round or oval keratotic papules or plaques with a classically papillomatous surface that is sprinkled with comedon-like openings. To the best of our knowledge, SK with a target-like morphology has not been previously reported. Herein, we report a case of SK with an uncommon target-like appearance, which we denominate 'cockarde (target-like lesion) SK'. A 57-year-old woman presented to our clinic with a several-year history of an asymptomatic lesion on her left thigh, which she reported to have gradually increased in size over the past several months. The patient denied any other relevant clinical past history, and all initial laboratory tests were within normal limits. Dermatologic examination revealed a sharply demarcated, slightly elevated, well-defined, darkly pigmented, target-shaped lesion on the left thigh. Additionally, the lesion contained a round black inner plaque measuring 0.5 cm in diameter, which was surrounded by a light brown arcuate patch, so that the diameter of the overall lesion was 1.5 cm (Fig. 1). Fig. 1 Targetoid seborrheic keratosis. Central black plaque surrounded by a brownish patch. A subsequent elliptical biopsy was performed containing the inner round plaque and a part of the surrounding patch (Asterisk: round black inner plaque. Black and white ... An elliptical biopsy including the inner round plaque and part of the surrounding patch was then performed, with the subsequent histopathological examination revealing generalized hyperkeratosis and acanthosis and a proliferation of sharply demarcated intraepithelial nests of large pale cells in the epidermis of the central lesion. The adjacent epidermis in the specimen was also noted to lie on a straight line. Given these histological features, a diagnosis of SK (clonal type) was reached (Fig. 2). Fig. 2 Histopathologic characteristics of seborrheic keratosis (clonal type). (A, B) Histopathological examination revealed generalized hyperkeratosis, acanthosis, and a proliferation of sharply demarcated intraepithelial nests of large pale cells in the epidermis ... In the dermatology literature, target-like lesions are most commonly associated with erythema multiforme, Stevens-Johnson's syndrome, toxic epidermal necrolysis2, cockarde nevus3, drug eruption, vasculitis, acute hemorrhagic edema of infancy, and various connective tissue and blistering diseases4. Therefore, when a patient complains of a target-like lesion, the above-mentioned diseases should be considered in the first instance. In many cases, SK can be readily diagnosed based on clinical presentation. However, Bryant5 reported that only 44.1% of cases of SK are correctly diagnosed by dermatologists. The report also suggests that SK in which lesions present with an unusual appearance is likely to be even more difficult to diagnose. Although SK is divided into many subtypes, its clinical variants are rare: these have been reported to be stucco keratosis, dermatosis papulosa nigra, and Leser-Trelat syndrome1. To the best of our knowledge, target-like SK or cockarde SK has not previously been reported in the literature. As such, we contend that this case is unique secondary to the presenting clinical features, and thus propose that 'cockarde SK' be recognized as an additional clinical variant of SK. Knowledge of this unusual variant of SK would be helpful in differentiating several target-shaped diseases, as well as in making a proper diagnosis of this rare condition.