Spatial Vision Research Articles

Three-dimensional physical models of sedimentary basins as a resource for teaching-learning of geology

Three-dimensional modeling connects several fields of knowledge, both basic and applied. 3D models are relevant in educa-tional research because the manipulation of 3D objects favors students' acquisition of spatial vision, but in the Geosciences, there are few didactic publications in Portuguese on the subject. The authors develop an educational research project to produce three-dimensional models of didactic examples of sedimentary basins: the Paraná Basin (Silurian-Upper Cretaceous), the Tau-baté and the São Paulo basins (Neogene). 3D-compatible files will be produced to compose didactic and display material, from maps and geological-structural profiles of certain regional stratigraphic levels of each basin. The research challenges are: (a) to obtain an overview of the available resources for 3D modeling; (b) to evaluate their potential, characteristics, advantages and limitations for applications in Geology and Geosciences; (c) to create computational models of the basins; (d) to produce at least one physical model based on one of the computational models of each basin. The resources will subsidize training work-shops for in-service teachers, technical-scientific articles and Internet pages.

Functional architecture of the foveola revealed in the living primate.

The primate foveola, with its high cone density and magnified cortical representation, is exquisitely specialized for high-resolution spatial vision. However, uncovering the wiring of retinal circuitry responsible for this performance has been challenging due to the difficulty in recording receptive fields of foveal retinal ganglion cells (RGCs) in vivo. In this study, we use adaptive optics scanning laser ophthalmoscopy (AOSLO) to image the calcium responses of RGCs in the living primate, with a stable, high precision visual stimulus that allowed us to localize the receptive fields of hundreds of foveal ganglion cells. This approach revealed a precisely radial organization of foveal RGCs, despite the many distortions possible during the extended developmental migration of foveal cells. By back projecting the line connecting RGC somas to their receptive fields, we have been able to define the ‘physiological center’ of the foveola, locating the vertical meridian separating left and right hemifields in vivo.

Using Systematic Conservation Planning to support Marine Spatial Planning and achieve marine protection targets in the transboundary Benguela Ecosystem

The Benguela Current Large Marine Ecosystem (BCLME) is subject to moderate to high levels of fishing, mining and numerous other human pressures, all of which are set to intensify through current socio-economic development initiatives in Angola, Namibia and South Africa. There is, however, minimal spatial protection of marine and coastal ecosystems in the region, potentially reducing the sustainability of the planned development and the likelihood of achieving Sustainable Development Goals. As a precursor to Marine Spatial Planning (MSP) processes in the three countries, and to guide establishment of Marine Protected Areas (MPAs), this study aimed to: assess two headline indicators of ecosystem status, namely their potential threat status and current spatial protection levels; and to use Systematic Conservation Planning (SCP) to prioritise specific areas for protection to achieve networks of MPAs that are representative of national and regional biodiversity. Two hundred and forty eight ecosystem types in the coastal (n = 134), offshore benthic (n = 86) and pelagic (n = 28) zones of the BCLME were classified, mapped and assessed. Overall, 35% of all ecosystem types in the study domain were threatened, with more threatened coastal (37%) and offshore benthic (37%) ecosystem types compared to pelagic ecosystem types (14%), although the same pattern was not necessarily evident within each country. Nearly two thirds (59%) of the BCLME ecosystem types were not protected in MPAs, and most of those that were well (19%) or moderately protected (14%) were coastal types that are within a single extensive MPA in Namibia. Notwithstanding, there was still a sufficient area of most ecosystem types that was assessed to be in good ecological condition in all three countries and that could be prioritised for representative protection of the region's biodiversity. A portfolio of priority conservation areas was identified from Marxan selection-frequency outputs, providing a spatial vision for protected areas in the BCLME that includes coastal, inshore and offshore areas in all three countries. This first assessment of marine ecosystem threat and protection status for an entire LME demonstrates a rapid science-based approach that can inform integrated ocean management and multiple development goals. The study provides a basis for identifying Ecologically or Biologically Significant Marine Areas, potential sites for MPAs or other spatial management in the region, and demonstrates the contribution of SCP and spatial management to MSP.

Visual impairments in tobacco use disorder

Prior studies found small effects of chronic smoking on spatial and color vision, but they were inconclusive. This study tries to: (1) replicate and extend these previous findings, and (2) rule in that this relationship is pronounced by tobacco addiction. Data were recorded in 71 healthy controls (M = 33.5 years; SD = 5.4 years) and 63 individuals with tobacco addiction (M = 34.7 years; SD = 4.8 years). Visual processing was assessed in the forms of contrast sensitivity for linear sine-wave gratings (spatial frequencies ranging between 0.2 and 16 cycles per degree) and color discrimination (using the Ellipse and Trivector subtests). The groups were matched for age, gender and level of education. The group with heavy smokers had reduced sensitivity for all spatial frequencies (p < .001), and impairments in color discrimination for both Trivector (all p-values < .001 for Protan, Deutan and Tritan) and Ellipse (all p-values < .001). This study consistently replicates and extended previous findings, and showed that visual processing can be strongly associated with tobacco addiction. These results indicate that excessive use of cigarettes, or chronic exposure to their compounds, affects visual discrimination, supporting the existence of overall deficits in visual processing in tobacco addiction.

3D reconstruction of GMAW pool surface using composite sensor technology

Weld pool is the most direct signal to reflect welding quality, that means measurement and reconstruction of the pool surface is one of the most urgent task in industrial robotic welding. A lot of researches have been done in this area, but the strong welding arc and the violent oscillation of weld pool affect their effectiveness. To better resolve this problem, a composite vision sensing system was proposed in our previous study, which consists of an active vision part and a passive vision part. The geometric parameters of the weld cross section and the weld pool have been successfully extracted by using this system. Based on the obtained information, the dynamic relationship between the weld speed and the bead geometric parameters is established by multistep predictive model based on neural network. By using the established model and iterative algorithm, the pool tail height is estimated in this paper. A spatial vision calibration is also proposed to calculate the real geometric parameters of the weld pool. Then the 3D surface of the weld pool is also reconstructed by the means of space curved surface fitting. Finally, the verification experiment is also conducted to verify the feasibility of this method.

Urban Risk Generalization in China: Space and Governance*

As an issue in Chinese urban development, handling urban risk generalization invites reflection on the structural features and internal development of the immediate or potential risks entailed in rapid urbanization across the globe. As part of research on national governance modernization, China has reached a consensus on managing urban risks. A study of spatial theory indicates that urban risk generalization in China is essentially a structural issue arising from an immature system of generalized benefits in urban space rights and interests along with an unbalanced spatial structure, functional disarray and ecological disruption arising from inequitable and unbalanced urban spatial development, readjustment and renovation. As an innovative form of modern urban public management with its target shifting from the pursuit of material things to people-centered development, spatial management enlists actors including government, business, society and citizens to seek a “community of shared spatial interests” with a rational structure, effective functions and an optimized environment at the level of spatial production and interest distribution. We need innovation in the spatial structures, drivers and mechanisms of urban public management and cultural ecology to realize their institutionalization, synthesis and reordering, strategically forestalling and resolving urbanization risks and realizing a spatial governance vision of the scientific, fair and sustainable allocation, growth and renovation of urban space in the risk era.

Protective effect of crocin against the declining of high spatial frequency-based visual performance in mice

The high spatial frequency-based vision was primary on cone rich macular vision. Crocin is a major bioactive constituent of saffron (Crocus sativus L. flowers) and gardenia fruit (Gardenia spp.), which has powerful antioxidant capacities in retina. The study aim to evaluate the influence of crocin on visual performance in light-damaged mouse retinas in vivo. The visual acuity (VA), and visual contrast sensitivity function (VCSF) were measured by the behavioral optomotor reflex method. The histological changes of retinas were monitored. Both VA and VCSF declines, and that accompanied by Müller cell hypertrophic gliosis and cone cellular damage were detected in the vehicle groups. Prophylactic crocin treated groups improved VA and VCSF on sensitive to high spatial frequency, protected retinal integrity and Müller cells, and modulated the cellular function of cone. This study provides the potential use of crocin to ameliorate the visual performance due to its anti-photodamage and cytoprotective effects.

Interhemispheric asymmetry of reactions to spatial modulations of local visual indications

Visual perception starts with a parallel spatial-frequency filtering. A visual scene is presented by a number of local indications in outputs of first-order filters. Their spatial association is the next important operation. It is the grouping of local indicators that underlies the transition to spatial vision. Recent research indicates that second-ordervisual filters perform this grouping. It is believed that the right hemisphere plays the leading role in spatial vision.The present study puts forward a hypothesis that this dominance can be formed even at the stage of the transition from a local to a global description of visual scenes. For this purpose the authors investigated interhemispheric asymmetry of potentials caused by functioning of second-order visual filters. These elements integrate the outputsof first-order filters and respond to spatial modulations of local visual indications. To solve this problem the authors recorded visual evoked potentials to a non-modulated texture and textures sinusoidally modulated in orientation, spatial frequency, and contrast. Next, they subtracted the response to the non-modulated texture from theresponse to the modulated texture. In result, each derivation received three different waves (d-waves): to the modulation of contrast, orientation, or spatial frequency. The comparison of d-waves in symmetric derivations revealed that its amplitude for all theused modulations is higher in the right hemisphere. Interhemispheric asymmetry to the modulation of orientation was most pronounced; it manifested itself better in occipital regions. The findings of the study showed the leading role of the right hemisphere in the processes of spatial association of local visual indications.

Orientation tuning for spatial vision and stereopsis: Factor analysis of individual differences in contrast and disparity thresholds

Orientation tuning for spatial vision and stereopsis: Factor analysis of individual differences in contrast and disparity thresholds

The gaze stability of 4- to 10-week-old human infants.

The relationship between gaze stability, retinal image quality, and visual perception is complex. Gaze instability related to pathology in adults can cause a reduction in visual acuity (e.g., Chung, LaFrance, & Bedell, 2011). Conversely, poor retinal image quality and spatial vision may be a contributing factor to gaze instability (e.g., Ukwade & Bedell, 1993). Though much is known about the immaturities in spatial vision of human infants, little is currently understood about their gaze stability. To characterize the gaze stability of young infants, adult participants and 4- to 10-week-old infants were shown a dynamic random-noise stimulus for 30-s intervals while their eye positions were recorded binocularly. After removing adultlike saccades, we used 5-s epochs of stable intersaccade gaze to estimate bivariate contour ellipse area and standard deviations of vergence. The geometric means (with standard deviations) for infants' bivariate contour ellipse area were left eye = −0.697 ± 0.534 log(°2), right eye = −0.471 ± 0.367 log(°2). For binocular vergence stability, the infant geometric means (with standard deviations) were horizontal = −1.057 ± 0.743 log(°), vertical = −1.257 ± 0.573 log(°). These values were all not significantly different from those of the adult comparison sample, suggesting that gaze instability is not a significant limiting factor in retinal image quality and spatial vision during early postnatal development.

Spatial summation in the human fovea: Do normal optical aberrations and fixational eye movements have an effect?

Psychophysical inferences about the neural mechanisms supporting spatial vision can be undermined by uncertainties introduced by optical aberrations and fixational eye movements, particularly in fovea where the neuronal grain of the visual system is fine. We examined the effect of these preneural factors on photopic spatial summation in the human fovea using a custom adaptive optics scanning light ophthalmoscope that provided control over optical aberrations and retinal stimulus motion. Consistent with previous results, Ricco's area of complete summation encompassed multiple photoreceptors when measured with ordinary amounts of ocular aberrations and retinal stimulus motion. When both factors were minimized experimentally, summation areas were essentially unchanged, suggesting that foveal spatial summation is limited by postreceptoral neural pooling. We compared our behavioral data to predictions generated with a physiologically-inspired front-end model of the visual system, and were able to capture the shape of the summation curves obtained with and without pre-retinal factors using a single postreceptoral summing filter of fixed spatial extent. Given our data and modeling, neurons in the magnocellular visual pathway, such as parasol ganglion cells, provide a candidate neural correlate of Ricco's area in the central fovea.

Word recognition: re-thinking prosthetic vision evaluation

Objective. Evaluations of vision prostheses and sensory substitution devices have frequently relied on repeated training and then testing with the same small set of items. These multiple forced-choice tasks produced above chance performance in blind users, but it is unclear if the observed performance represents restoration of vision that transfers to novel, untrained items. Approach. Here, we tested the generalizability of the forced-choice paradigm on discrimination of low-resolution word images. Extensive visual training was conducted with the same 10 words used in previous BrainPort tongue stimulation studies. The performance on these 10 words and an additional 50 words was measured before and after the training sessions. Main results. The results revealed minimal performance improvement with the untrained words, demonstrating instead pattern discrimination limited mostly to the trained words. Significance. These findings highlight the need to reconsider current evaluation practices, in particular, the use of forced-choice paradigms with a few highly trained items. While appropriate for measuring the performance thresholds in acuity or contrast sensitivity of a functioning visual system, performance on such tasks cannot be taken to indicate restored spatial pattern vision.

Correlation of disorders of the spatial vision system (strabismus) and amblyopia by changes in neural-reflex excitability and metabolic disorders at the stages of restoration of pre-, perinatal encephalopathy

Correlation of disorders of the spatial vision system (strabismus) and amblyopia by changes in neural-reflex excitability and metabolic disorders at the stages of restoration of pre-, perinatal encephalopathy

Intensity–duration–frequency (IDF) rainfall curves in Senegal

Abstract. Urbanization resulting from sharply increasing demographic pressure and infrastructure development has made the populations of many tropical areas more vulnerable to extreme rainfall hazards. Characterizing extreme rainfall distribution in a coherent way in space and time is thus becoming an overarching need that requires using appropriate models of intensity–duration–frequency (IDF) curves. Using a 14 series of 5 min rainfall records collected in Senegal, a comparison of two generalized extreme value (GEV) and scaling models is carried out, resulting in the selection of the more parsimonious one (four parameters), as the recommended model for use. A bootstrap approach is proposed to compute the uncertainty associated with the estimation of these four parameters and of the related rainfall return levels for durations ranging from 1 to 24 h. This study confirms previous works showing that simple scaling holds for characterizing the temporal scaling of extreme rainfall in tropical regions such as sub-Saharan Africa. It further provides confidence intervals for the parameter estimates and shows that the uncertainty linked to the estimation of the GEV parameters is 3 to 4 times larger than the uncertainty linked to the inference of the scaling parameter. From this model, maps of IDF parameters over Senegal are produced, providing a spatial vision of their organization over the country, with a north to south gradient for the location and scale parameters of the GEV. An influence of the distance from the ocean was found for the scaling parameter. It is acknowledged in conclusion that climate change renders the inference of IDF curves sensitive to increasing non-stationarity effects, which requires warning end-users that such tools should be used with care and discernment.

Is the straddle effect in contrast perception limited to second-order spatial vision?

Previous work on the straddle effect in contrast perception (Foley, 2011; Graham & Wolfson, 2007; Wolfson & Graham, 2007, 2009) has used visual patterns and observer tasks of the type known as spatially second-order. After adaptation of about 1 s to a grid of Gabor patches all at one contrast, a second-order test pattern composed of two different test contrasts can be easy or difficult to perceive correctly. When the two test contrasts are both a bit less (or both a bit greater) than the adapt contrast, observers perform very well. However, when the two test contrasts straddle the adapt contrast (i.e., one of the test contrasts is greater than the adapt contrast and the other is less), performance drops dramatically. To explain this drop in performance—the straddle effect—we have suggested a contrast-comparison process. We began to wonder: Are second-order patterns necessary for the straddle effect? Here we show that the answer is “no”. We demonstrate the straddle effect using spatially first-order visual patterns and several different observer tasks. We also see the effect of contrast normalization using first-order visual patterns here, analogous to our prior findings with second-order visual patterns. We did find one difference between first- and second-order tasks: Performance in the first-order tasks was slightly lower. This slightly lower performance may be due to slightly greater memory load. For many visual scenes, the important quantity in human contrast processing may not be monotonic with physical contrast but may be something more like the unsigned difference between current contrast and recent average contrast.

ЯРУСНОЕ ПОСТРОЕНИЕ КОМПОЗИЦИИ КАК ПРИЕМ СТРУКТУРИРОВАНИЯ ТЕАТРАЛЬНОГО И ИЗОБРАЗИТЕЛЬНОГО ПРОСТРАНСТВА В ИСКУССТВЕ АЛЕКСАНДРА ТЫШЛЕРА

The article analyzes the origin, variations, artistic potential of tier composition in the context of Alexander Tyshler’s theatrical-decorative and easel art. The approaching of theatrical and easel arts in A. Tyshler’s methodology occurs on the basis of integrity of spatial vision and form-generative techniques in relation to pictorial plane and scenic dimension. Tyshler’s multi-tier areas fitted into scenic space and his easel paintings compositionally similar to this model are interpreted as an implementation of modernistic intention to uncover the artistic device, which allows the artist to discover conditional and entertaining nature of theatrical performance and pictorial art.

Videogame: mais que um entretenimento, um agente estimulador da criatividade

Este artigo objetiva evidenciar que o videogame é mais que um entretenimento, e atua como um agente estimulador da criatividade. Para embasar o raciocínio, são apresentadas conceituações teóricas sobre criatividade, jogos e videogames; na sequência, realiza-se a análise dos estudos ligados às áreas da Psicologia e Neurociência, de Stošić e Stošić (2014), Sabrina Schenk, Robert K. Lech, Boris Suchan (2015) e Gregory D. Clemenson and Craig E.L. Stark (2015), Daphne Bavelier (2015-2016) e C. Shawn Green (2015-2016), publicados de 2014 a 2016, onde, através de pesquisas, visavam identificar e analisar os benefícios dos videogames relacionados à criatividade, através das habilidades motoras e cognitivas. Observou-se que os videogames estimulam os processos cognitivos, incluindo a visão espacial, emocional e motivacional, além do pensamento crítico, rapidez na tomada de decisão, e também a resolução de problemas e o aumento da memória .

Spatial vision in older adults: perceptual changes and neural bases.

The number of older adults is rapidly increasing internationally, leading to a significant increase in research on how healthy ageing impacts vision. Most clinical assessments of spatial vision involve simple detection (letter acuity, grating contrast sensitivity, perimetry). However, most natural visual environments are more spatially complicated, requiring contrast discrimination, and the delineation of object boundaries and contours, which are typically present on non-uniform backgrounds. In this review we discuss recent research that reports on the effects of normal ageing on these more complex visual functions, specifically in the context of recent neurophysiological studies. Recent research has concentrated on understanding the effects of healthy ageing on neural responses within the visual pathway in animal models. Such neurophysiological research has led to numerous, subsequently tested, hypotheses regarding the likely impact of healthy human ageing on specific aspects of spatial vision. Healthy normal ageing impacts significantly on spatial visual information processing from the retina through to visual cortex. Some human data validates that obtained from studies of animal physiology, however some findings indicate that rethinking of presumed neural substrates is required. Notably, not all spatial visual processes are altered by age. Healthy normal ageing impacts significantly on some spatial visual processes (in particular centre-surround tasks), but leaves contrast discrimination, contrast adaptation, and orientation discrimination relatively intact. The study of older adult vision contributes to knowledge of the brain mechanisms altered by the ageing process, can provide practical information regarding visual environments that older adults may find challenging, and may lead to new methods of assessing visual performance in clinical environments.

Differential effects of high-frequency transcranial random noise stimulation (hf-tRNS) on contrast sensitivity and visual acuity when combined with a short perceptual training in adults with amblyopia

Amblyopia is a neuro-developmental disorder characterised by several functional impairments in spatial vision even with the best optical correction. There is evidence that extensive perceptual training can improve visual acuity (VA) and contrast sensitivity (CS) in adults with amblyopia. In the present study, we assessed the efficacy of a recently developed neuro-modulatory technique (i.e., high-frequency transcranial random noise stimulation; hf-tRNS) combined with a short perceptual training in adults with amblyopia. One group of ten participants underwent a short (8 sessions) monocular training in a contrast detection task with concurrent hf-tRNS, whereas another group of ten participants underwent the same training protocol but with Sham stimulation (control group). The training consisted of a two-interval forced choice (2IFC) contrast detection task in which participants had to detect the presence of a central Gabor patch flanked by two high-contrast collinear Gabors (lateral masking). The results showed a significant and similar improvement of CS for both groups, suggesting that hf-tRNS is not crucial for the improvement of CS. However, for VA, a significant improvement was only observed in the hf-tRNS group with a mean VA improvement of 0.19 LogMAR in the amblyopic eye. Most notably, this improvement was achieved after eight training sessions. The results are discussed in terms of the influence of hf-tRNS on short-term neural plasticity.

The Government Land Sales programme and developers’ willingness to pay for accessibility in Singapore, 1990–2015

Singapore has been internationally referred to as a successful model of state-led spatial development alongside world-class infrastructure investment, but there is a paucity of evidence on the effectiveness of the city-state’s Government Land Sales (GLS) programme as an instrument of strategic spatial integration used to increase land productivity/profitability via accessibility enhancements at various locations in dynamic sequences. This study examines whether developers’ willingness to pay for accessible land around major transport and green infrastructure facilities was consistent with the city-state’s strategic spatial vision by analysing GLS transaction cases for the period 1990–2015. The spatiotemporal regressions of the GLS programme’s transaction unit prices, attributable to tendering conditions, permitted development parameters, and locational characteristics, including the availability of major infrastructure facilities within certain distances, reveal that accessibility premiums appeared to be most significant within 500 m of mass rapid transit (MRT) stations, where Singapore’s statutory agencies were likely to distribute state-owned sites reactively after the new MRT stations came into operation. Singapore’s experience over a quarter of a century implies that government land ownership and development guidance could bring about competitive and sustainable market outcomes if a range of site sales implemented by local agencies are collectively programmed for strategic spatial planning in fast-growing regions of the world.