Sharp Contours Research Articles

Object Shape Approximation and Contour Adaptive Depth Image Coding for Virtual View Synthesis

A depth image provides partial geometric information of a 3D scene, namely the shapes of physical objects as observed from a particular viewpoint. This information is important when synthesizing images of different virtual camera viewpoints via depth-image-based rendering (DIBR). It has been shown that depth images can be efficiently coded using contour-adaptive codecs that preserve edge sharpness, resulting in visually pleasing DIBR-synthesized images. However, contours are typically losslessly coded as side information, which is expensive if the object shapes are complex. In this paper, we pursue a new paradigm in depth image coding for color-plus-depth representation of a 3D scene: in a pre-processing step, we pro-actively simplify object shapes in a depth and color image pair to reduce depth coding cost, at a penalty of a slight increase in synthesized view distortion. Specifically, we first mathematically derive a distortion upper-bound proxy for 3DSwIM—a quality metric tailored for DIBR-synthesized images. This proxy reduces inter-dependency among pixel rows in a block to ease optimization. We then approximate object contours via a dynamic programming algorithm to optimally tradeoff coding the cost of contours using arithmetic edge coding with our proposed view synthesis distortion proxy. We modify the depth and color images according to the approximated object contours in an inter-view consistent manner. These are then coded, respectively, using a contour-adaptive image codec based on graph Fourier transform for edge preservation and High Efficiency Video Coding (HEVC) intra. Experimental results show that by maintaining sharp but simplified object contours during contour-adaptive coding, for the same visual quality of DIBR-synthesized virtual views, our proposal can reduce depth image coding rate by up to 22% in 3DSwIM and 42% in peak signal-to-noise ratio compared with alternative coding strategies, such as HEVC intra.

Effect of molecular weight of starch on the properties of cassava starch microspheres prepared in aqueous two-phase system

Starch microspheres (SMs) were fabricated in an aqueous two-phase system (ATPS). A series of starch samples with different molecular weight were prepared by acid hydrolysis, and the effect of molecular weight of starch on the fabrication of SMs were investigated. Scanning electron microscopy (SEM) showed that the morphologies of SMs varied with starch molecular weight, and spherical SMs with sharp contours were obtained while using starch samples with weight-average molecular weight (M¯w)≤1.057×105g/mol. X-ray diffraction (XRD) results revealed that crystalline structure of SMs were different from that of native cassava starch, and the relative crystallinity of SMs increased with the molecular weight of starch decreasing. Differential scanning calorimetry (DSC) results showed peak gelatinization temperature (Tp) and enthalpy of gelatinization (ΔH) of SMs increased with decreased M¯wof starch. Stability tests indicated that the SMs were stable under acid environment, but not stable under α-amylase hydrolysis.

Endometrial Tubercular Abscess

A 57-year-old menopausal woman, gravida 5 para 5, with no history of any hormonal therapy presented with irregular heavy bleeding per vaginum after 5 years of amenorrhea. A vaginal ultrasound scan was unremarkable, showing an endometrial thickness of 2.5 mm. This patient was posted for hysteroscopic evaluation. The anterior uterine cavity wall seen in panoramic view revealed multiple whitish abscess like circumscribed lesions that appeared distinctly pale in comparison with the surrounding endometrium (Fig. 1). A closer visualization (Fig. 2) revealed lesions that were oval in shape and had sharp regular margins, and the endometrium surrounding the lesions appeared dirty, pale, and irregular with no visible endometrial gland openings. The endometrium did not bleed on touch. Targeted biopsies were taken from the rounded lesions. Histopathology revealed endometrium with atrophic changes along with caseating epitheloid granulomata; there was no evidence of malignancy. BACTEC culture (Becton, Dickinson and Company, Sparks, MD) was also suggestive of endometrial tuberculosis. The patient was administered antitubercular therapy, to which she subsequently responded. Fig. 2Closer visualization reveals the regular sharp contours of the endometrial tubercular abscesses. View Large Image Figure Viewer Download Hi-res image

What flowers do we like? The influence of shape and color on the rating of flower beauty

There is no doubt that people find flowers beautiful. Surprisingly, we know very little about the actual properties which make flowers so appealing to humans. Although the evolutionary aesthetics provides some theories concerning generally preferred flower traits, empirical evidence is largely missing. In this study, we used an online survey in which residents of the Czech Republic (n = 2006) rated the perceived beauty of 52 flower stimuli of diverse shapes and colors. Colored flowers were preferred over their uncolored versions. When controlling for flower shape, we found an unequal preference for different flower colors, blue being the most and yellow the least preferred. In the overall assessment of beauty, shape was more important than color. Prototypical flowers, i.e., radially symmetrical flowers with low complexity, were rated as the most beautiful. We also found a positive effect of sharp flower contours and blue color on the overall rating of flower beauty. The results may serve as a basis for further studies in some areas of the people-plant interaction research.

Can Hospital Form Trigger Fear Response?

To examine whether exposure to curve versus sharp contours in the built healthcare setting produces systematic and identifiable patterns of amygdala activation and behavioral response in healthy adults. Recent studies in cognitive neuroscience suggest that humans prefer objects with a curved contour compared with objects that have pointed features and a sharp-angled contour. An implicit perception of threat represented by sharp objects, in humans, was hypothesized to explain this bias. The study adopted a within-subject experimental design, where 36 subjects (representing three age-groups and both sexes) were exposed to a randomized order of 312 real-life images (objects, interiors, exteriors, landscape, and a set of control images). Amygdala activation was simultaneously captured using functional magnetic resonance imaging technology. Subjects' preference (like/dislike) data were also collected while in the scanner. Data were collected in 2013. In case of images depicting landscape and healthcare objects, brain scans show significant higher amygdala activation associated with sharp contours. However, in relation to images depicting hospital interiors and exterior envelops, brain scans show significant higher amygdala activation associated with curve contours. These activations pertain to exposure during the precognitive stages of the subjects' perception. Hospital forms do have systematic impact on fear response during precognitive stages of human perception. Whether this first impression colors the subsequent experience of an actual patient with real illness or injury is unknown.

SU‐E‐T‐05: 4D Measurement‐Guided Dose Reconstruction (4D‐MGDR) in End‐End Quality Assurance (E2E QA) for Assessing Safety Margin in Radiosurgery (SRS) From Clinical Perspectives

Purpose:To assess the plan robustness and safety margin in SRS from 4DMGDR in E2E QA based on clinical objectives.Methods:OCTAVIUS SRS 1000 detector array and 4D phantom (PTW, Freiburg, Germany) were used to measure 5 coplanar SRS plans with 1 and 2 mm planning target volume (PTV). 3 targets were clinical, and 2 were virtual simulated to be 1mm from the brainstem (BS), and between chiasm (CS) and optic nerve (ON). Planning was done on Monaco v5.0 (Elekta, Maryland Heights, MO) to achieve 95–99% PTV and 100% gross tumor volume (GTV) prescription dose coverage. CBCT setup of the 4D phantom by 6D robotic couch was performed as for real patient. 4D‐MGDR in patient CT and dosimetric analysis were performed in PTW Verisoft v6.1. The safety margin that achieved 100% GTV coverage was determined, and doses to 2% (D2%) of BS, ON and CS were assessed from E2E QA.Results:100% GTV coverage was achieved with 1mm margin for 2 plans and 2mm margin for all plans. 98.3% and 99.4% GTV coverage were found in E2E QA for 1mm PTVs that either had sharp changing contour, or was nearby CS and ON or BS, and had either low planned minimum GTV dose (∼101% of the prescribed dose vs.∼106%) or compromised PTV coverage (95% vs. 99%). D2% to CS obtained with 4D‐MGDR for one virtual target were 18.8Gy for 1mm PTV and 19.2Gy for 2mm PTV, exceeding the planned tolerance of 18Gy/3 fractions for prescription dose of 24Gy.Conclusion:1mm margin is generally sufficient for dose planning and machine delivery errors. Irregular GTV with just enough dose coverage to spare critical organs may need 2mm margin at the costs of possible higher organ doses. 4D MGDR in an E2E QA approach can put the treatment plan evaluation in clinical perspectives.

Investigation of Vision-Based Underwater Object Detection with Multiple Datasets

In this paper, we investigate the potential of vision-based object detection algorithms in underwater environments using several datasets to highlight the issues arising in different scenarios. Underwater computer vision has to cope with distortion and attenuation due to light propagation in water, and with challenging operating conditions. Scene segmentation and shape recognition in a single image must be carefully designed to achieve robust object detection and to facilitate object pose estimation. We describe a novel multi-feature object detection algorithm conceived to find human-made artefacts lying on the seabed. The proposed method searches for a target object according to a few general criteria that are robust to the underwater context, such as salient colour uniformity and sharp contours. We assess the performance of the proposed algorithm across different underwater datasets. The datasets have been obtained using stereo cameras of different quality, and diverge for the target object type and colour, acquisition depth and conditions. The effectiveness of the proposed approach has been experimentally demonstrated. Finally, object detection is discussed in connection with the simple colour-based segmentation and with the difficulty of tri-dimensional processing on noisy data.

Possibility of thermal imaging use in studies of natural convection heat transfer on the example of an isothermal vertical plate

A new method of infrared (IR) camera use in convective heat transfer studies has been presented. Until now, IR cameras were utilized for temperature field visualizations of flat heated surfaces of solid objects only. Because liquids and gasses do not emit radiation in the infrared range of wave lengths, detection of temperature field in the air was conducted with the use of plastic mesh, which, after heating by hot air, emits infrared radiation visible by IR camera. As the mesh is made from a low conductivity material, it therefore maintains the sharp contours of isotherms without blurring. The radiation from lateral surface of the grid (perpendicular positioned to the heated surface and parallel to gravity) can be recorded by IR camera set perpendicularly to the mesh. From the obtained temperature field and the temperature of heated surface, also measured by the IR camera, temperature gradients on the wall ∂T/∂y|y=0 and their distribution on surface can be found. From these measured gradients and its distribution, the local heat transfer coefficients αx and local Nusselt numbers Nux on the heated surface can be calculated. By integrating the local values of Nux the average value of the Nusselt number Nu, representative for the entire surface, can be obtained. Verification of accuracy of the presented new method has been conducted through three dimensional temperature field visualization studies of free convective heat transfer from an isothermal heat plate. This configuration was deliberately chosen because the vertical plate was the earliest and most thoroughly studied case and its rich scientific documentation is best known and therefore the most reliable. The results, obtained by the use of IR camera, presented in the form of Nusselt–Rayleigh relation Nug = 0.571 Ra0.25 have a good correlation with the literature data, which testifies the positive verification and utility presented in this new method of convection heat transfer investigation.

The choice of the necessary: class, tastes and lifestyles

Purpose– Our attitudes, values and tastes are shaped by our position in social space. At least, that was the argument Pierre Bourdieu set out in his seminal work,La Distinction. The purpose of this paper is to consider Bourdieu's theory of cultural reproduction and his argument that working-class families exhibit cultural attitudes and tastes for social necessity.Design/methodology/approach– Attitudinal data relating to social necessity are taken from a national social survey of the British population. The results provide a rich source of data for exploring classed attitudes towards necessity in contemporary Britain.Findings– Bourdieu's original claims for working-class “choice of the necessary” and working-class “taste for necessity” are based on his observations grounded in social survey evidence drawn from 1960s French society. Analysis of contemporary British social survey and attitudinal data also reveals sharp contours and differences in attitudes and tastes according to class fractions. These are evident in classed tastes and preferences for food, clothes, the home and social life.Social implications– Within the Bourdieusian theoretical framework, we understand that the tastes of necessity are preferences that arise as adaptations to deprivation of necessary goods and services.La Distinctionand Bourdieu's approach to unmasking inequalities and structures in social space continue to be relevant in contemporary Britain. More generally, study findings add to the growing evidence that casts some doubt on current arguments concerning “individualisation”, claiming that social class has ceased to be significant in modern societies.Originality/value– This paper sheds fresh light on the empirical validity and continuing theoretical relevance of Bourdieu's work examining the role of social necessity in shaping working-class culture. Bourdieu argues that the real principle of our preferences is taste and for working-class families, this is a virtue made of necessity.

The framing of unconventional natural gas resources in the foreign energy policy discourse of the Russian Federation

The advent of unconventional resources of natural gas has altered the order on global as well as continental gas markets. With rising liquidity, the position of established dominant suppliers is eroding. We focus on the initial response of Russia, the leading supplier of natural gas to Europe, to the new situation, building the research on unit-level constructivism and discourse analysis. We use frame analysis to reveal what image of unconventional resources was constructed in Russian foreign energy policy discourse (FEPD) in the period between 2009 and 2011, when the “unconventional revolution” did not yet have any sharp contours. We conclude that in Russian FEPD the unconventionals are considered as a distinctive and inferior source of energy compared to conventional natural gas. Emphasis is put on their economic irrationality and environmental hazards. The bottom line of the discourse is the idea that there is a choice between conventional and unconventional sources, with this choice being framed as one between good and bad, or right and wrong.

Accuracy of computed tomography arthrography to detect cartilage defects in the ovine knee

Accuracy of computed tomography arthrography to detect cartilage defects in the ovine knee

Depth spreading through empty space induced by sparse disparity cues

A key goal of visual processing is to develop an understanding of the three-dimensional layout of the objects in our immediate vicinity from the variety of incomplete and noisy depth cues available to the eyes. Binocular disparity is one of the dominant depth cues, but it is often sparse, being definable only at the edges of uniform surface regions, and visually resolvable only where the edges have a horizontal disparity component. To understand the full 3D structure of visual objects, our visual system has to perform substantial surface interpolation across unstructured visual space. This interpolation process was studied in an eight-spoke depth spreading configuration corresponding to that used in the neon color spreading effect, which generates a strong percept of a sharp contour extending through empty space from the disparity edges within the spokes. Four hypotheses were developed for the form of the depth surface induced by disparity in the spokes defining an incomplete disk in depth: low-level local (isotropic) depth propagation, mid-level linear (anisotropic) depth-contour interpolation or extrapolation, and high-level (anisotropic) figural depth propagation of a disk figure in depth. Data for both perceived depth and position of the perceived contour clearly rejected the first three hypotheses and were consistent with the high-level figural hypothesis in both uniform disparity and slanted disk configurations. We conclude that depth spreading through empty visual space is an accurately quantifiable perceptual process that propagates depth contours anisotropically along their length and is governed by high-level figural properties of 3D object structure.

Five patients with melanosis of the nipple and areola clinically mimicking melanoma

Pigmented lesions on the nipple and areola concern patients and physicians as melanoma and pigmented mammary Paget's disease must be considered in the differential diagnoses. There have been only six case reports of melanosis of the nipple and areola in the medical literature yet five cases presented to our department in a 26-month period. Five women aged between 26 and 34years presented with pigmentation of the areola and/or nipple. Two patients were pregnant and one also had vitiligo. All lesions were solitary, eccentrically located with a sharp but irregular contour, and homogeneous pigmentation. Dermoscopy was performed and reassuring features included light to dark brown cobblestone pigmentation with ring-like structures and reticulation. Blue-white veil and irregular centred black dots were not seen. Histology confirmed melanosis of the nipple and areola. Melanosis of the nipple and areola is probably significantly underreported in the medical literature and, based on our experience, is likely to be the most common cause of pigmentation at this site. Considering this, benign condition on clinical and dermoscopic features should lead to biopsy rather than excision to confirm the diagnosis. Further reports of the dermoscopic features will help to define this condition further.

Ring-Oven Based Preconcentration Technique for Microanalysis: Simultaneous Determination of Na, Fe, and Cu in Fuel Ethanol by Laser Induced Breakdown Spectroscopy

The ring-oven technique, originally applied for classical qualitative analysis in the years 1950s to 1970s, is revisited to be used in a simple though highly efficient and green procedure for analyte preconcentration prior to its determination by the microanalytical techniques presently available. The proposed preconcentration technique is based on the dropwise delivery of a small volume of sample to a filter paper substrate, assisted by a flow-injection-like system. The filter paper is maintained in a small circular heated oven (the ring oven). Drops of the sample solution diffuse by capillarity from the center to a circular area of the paper substrate. After the total sample volume has been delivered, a ring with a sharp (c.a. 350 μm) circular contour, of about 2.0 cm diameter, is formed on the paper to contain most of the analytes originally present in the sample volume. Preconcentration coefficients of the analyte can reach 250-fold (on a m/m basis) for a sample volume as small as 600 μL. The proposed system and procedure have been evaluated to concentrate Na, Fe, and Cu in fuel ethanol, followed by simultaneous direct determination of these species in the ring contour, employing the microanalytical technique of laser induced breakdown spectroscopy (LIBS). Detection limits of 0.7, 0.4, and 0.3 μg mL(-1) and mean recoveries of (109 ± 13)%, (92 ± 18)%, and (98 ± 12)%, for Na, Fe, and Cu, respectively, were obtained in fuel ethanol. It is possible to anticipate the application of the technique, coupled to modern microanalytical and multianalyte techniques, to several analytical problems requiring analyte preconcentration and/or sample stabilization.

Self-organizing capacity of nanocelluloses via droplet evaporation

The relation between the fibril shapes and the self-organizing capacity was investigated by comparing the results of evaporation-induced self-assembly (EISA) in 2D (“coffee rings”) and 3D (spray-dried microparticles (MPs)) for rod-like and semi-flexible nanocelluloses. The rod-like tunicin nanowhiskers formed nematic alignment along the perimeter of coffee rings, and also formed curved discotic microparticles having nematic rings of width ∼300 nm by spray drying. On the other hand, the semi-flexible tunicin nanofibers failed to undergo a phase transition by EISA, and formed spray-dried MPs with multiple sharp kinks and rough contours. The rod-like nanocelluloses exhibited the self-organizing capacity of the phase transition and left-handed chirality. The expression of the self-organizing capacity of rod-like particles was found to be independent of initial droplet shapes and sizes via surface tension measurements.

Severe Hypothermia in Parkinson's Disease

Hypothermia has been reported in many clinical states and sometimes it is life threatening. However, there are rare cases reported about hypothermia related with Parkinson's disease (PD) 1, 2, 3. We now present a patient with PD, who developed an episode of severe hypothermia. The unique changes both in electrocardiogram (ECG) and in electroencephalogram (EEG) during hypothermia were presented and discussed.

Four-dimensional ultrasound imaging in neuro-ophthalmology

Summary Purpose To demonstrate diagnostic abilities of space–time (4D) ultrasound imaging in patients with eye pathology and some neuro-ophthalmic syndromes. Methods Fifteen healthy controls and 15 patients with eye pathology (papilledema, retinal detachment, macular degeneration and intraocular metastasis) were studied by multimodal (color duplex, B-flow and 3D/4D imaging) sonography. Results Normal optic disc resulted in a smooth and sharp contour without swelling. Papilledema was presented as a hyperechoic prominence into the vitreous. On its side the optic sheath diameter was increased in association with the degree of optic disc swelling. The retinal detachment was imaged as a hyperechoic undulating membrane, the neovascular macular degeneration – as a hyperechoic membrane behind the retina, and the intraocular metastasis – as irregular unifocal formation into the vitreous. Conclusions The 4D neuro-ophthalmo-sonology helps for the quick and non-invasive volume imaging of the type, size, location and severity of optic disc and optic nerve edema and its differentiation from other types of eye lesions.

So who am I really? Personal identity in the age of the Internet

The Internet has become a field of dragon teeth for a person’s identity. It has made it possible for your identity to be mistaken by a credit agency, spied on by the government, foolishly exposed by yourself, pilloried by an enemy, pounded by a bully, or stolen by a criminal. These harms to one’s integrity could be inflicted in the past, but information technology has multiplied and aggravated such injuries. They have not gone unnoticed and are widely bemoaned and discussed. The government and private watchdogs are working to protect the identity of citizens though at least in the United States both the government and individuals all too often side with prosperity when it conflicts with privacy. Still, these information-technological threats to identity have been recognized and can be reasonably met through legislation, regulation, and discretion. There is another kind of danger to our identity that is more difficult to define and to meet, for it has no familiar predecessors, has no criminal aspects, and exhibits no sharp moral or cultural contours. Still that threat to our identity haunts us constantly and surfaces occasionally in conversations and the media. It makes us feel displaced, distracted, and fragmented at the very times when to all appearances we seem to be connected, busy, and energetic. At the same time, the culture of technology, and of information technology particularly, has opened up fields of diversity and contingency that invite us to comprehend our identities in newly responsible, intricate, and open-minded ways.

Virtual worlds as sites for social and cultural innovation

There is a growing recognition of the importance of virtual worlds as environments and media that carry the potential for social and cultural innovation by making possible new forms of social relationships based on communication among avatars. The articles in this special issue exemplify some aspects of this potential but also point out some of the many questions and unsolved problems that follow with innovation and the continuous development of virtual worlds. The two key concepts of virtual worlds and innovation are both widely used concepts that refer to emergent and rapidly changing phenomena without sharp contours or clearly defined boundaries. In the context of this special issue, we treat both virtual worlds and innovation as emergent phenomena in flux. Some of the features of virtual worlds, however, may also be seen as stable. According to Bell (2008) and Schroeder (2008, 2011), virtual worlds depend on stable, persistent digital infrastructures. Moreover, the online presence of gamers and residents is referred to by digital symbols and signs – be they avatars, space ships or green dots – and the technological platforms are accessible 24/7 over longer periods of time. They appear to be stable technologies and platforms, almost permanent. How is it, then, that we see them as emergent phenomena in flux? Our focus in this special issue of Convergence is on social and cultural innovation in and with virtual worlds which means that the technological innovation of the digital platforms and of the technology in itself are not our primary interest of reflection and analysis. Social and cultural innovation are phenomena of a fluid nature, subject to continuous change: the way we see and understand ourselves and each other, the way we experience exciting and extraordinary events or seek inspiration by thought-provoking art installations, the way we build virtual communities of high ideals or take the opportunity to live out behaviours otherwise not acceptable in our everyday life, these are all examples of human relationships with distinctive features that hold the potential for creative and innovative responses to new environments.

Russkaja rukopis' "Postniceskih slov Vasilija Velikogo" rubeza XIV-XV vekov, RNB, F.p.I.40, i ej miniatjura

The author deals with the miniature from a manuscript containing St. Basil the Great?s ?Asketikon?, written at the end of the fourteenth century (St. Petersburg, National Library of Russia, F.n.I.40). The miniature depicts St. Basil in monk?s attire, writing his text. The compact composition, sharp and tense contours, the dark colouring and the saint?s concentration, create a striking image of monastic virtue and dignity. The manuscript, which originates from one of the monasteries in northeastern Russia, confirms the importance of monastic figures in art in the countries of the Byzantine cultural circle, from the end of the fourteenth century.