Scale Shift Research Articles

Treatment and Outcome in Stroke Patients With Acute M2 Occlusion and Minor Neurological Deficits.

Treatment in stroke patients with M2 segment occlusion of the middle cerebral artery presenting with mild neurological deficits is a matter of debate. The main purpose was to compare the outcome in patients with a minor stroke and a M2 occlusion. Consecutive intravenous thrombolysis (IVT) eligible patients admitted to the Bernese stroke center between January 2005 and January 2020 with acute occlusion of the M2 segment and National Institutes of Health Stroke Scale score ≤5 were included. Outcome was compared between IVT only versus endovascular therapy (EVT) including intra-arterial thrombolysis and mechanical thrombectomy (MT; ±IVT) and between IVT only versus MT only. Among 169 patients (38.5% women, median age 70.2 years), 84 (49.7%) received IVT only and 85 (50.3%) EVT (±IVT), the latter including 39 (45.9%) treated with MT only. Groups were similar in sex, age, vascular risk factors, event cause, or preevent independency. Compared with IVT only, there was no difference in favorable outcome (modified Rankin Scale score, 0-2) for EVT (adjusted odds ratio, 0.96; adjusted P=0.935) or for MT only (adjusted odds ratio, 1.12; adjusted P=0.547) groups. Considering only patients treated after 2015, there was a significantly better 3-month modified Rankin Scale shift (adjusted P=0.032) in the EVT compared with the IVT only group. Our study demonstrates similar effectiveness of IVT only versus EVT (±IVT), and of IVT only versus MT only in patients with peripheral middle cerebral artery occlusions and minor neurological deficits and indicates a possible benefit of EVT considering only patients treated after 2015. There is an unmet need for randomized controlled trials in this stroke field, including imaging parameters, and more sophisticated evaluation of National Institutes of Health Stroke Scale score subitems, neurocognition, and quality of life neglected by the standard outcome scales such as modified Rankin Scale and National Institutes of Health Stroke Scale score.

Stroke Imaging Selection Modality and Endovascular Therapy Outcomes in the Early and Extended Time Windows.

Advanced imaging has been increasingly used for patient selection in endovascular stroke therapy. The impact of imaging selection modality on endovascular stroke therapy clinical outcomes in extended time window remains to be defined. We aimed to study this relationship and compare it to that noted in early-treated patients. Patients from a prospective multicentric registry (n=2008) with occlusions involving the intracranial internal carotid or the M1- or M2-segments of the middle cerebral arteries, premorbid modified Rankin Scale score 0 to 2 and time to treatment 0 to 24 hours were categorized according to treatment times within the early (0-6 hour) or extended (6-24 hour) window as well as imaging modality with noncontrast computed tomography (NCCT)±CT angiography (CTA) or NCCT±CTA and CT perfusion (CTP). The association between imaging modality and 90-day modified Rankin Scale, analyzed in ordinal (modified Rankin Scale shift) and dichotomized (functional independence, modified Rankin Scale score 0-2) manner, was evaluated and compared within and across the extended and early windows. In the early window, 332 patients were selected with NCCT±CTA alone while 373 also underwent CTP. After adjusting for identifiable confounders, there were no significant differences in terms of 90-day functional disability (ordinal shift: adjusted odd ratio [aOR], 0.936 [95% CI, 0.709-1.238], P=0.644) or independence (aOR, 1.178 [95% CI, 0.833-1.666], P=0.355) across the CTP and NCCT±CTA groups. In the extended window, 67 patients were selected with NCCT±CTA alone while 180 also underwent CTP. No significant differences in 90-day functional disability (aOR, 0.983 [95% CI, 0.81-1.662], P=0.949) or independence (aOR, 0.640 [95% CI, 0.318-1.289], P=0.212) were seen across the CTP and NCCT±CTA groups. There was no interaction between the treatment time window (0-6 versus 6-24 hours) and CT selection modality (CTP versus NCCT±CTA) in terms of functional disability at 90 days (P=0.45). CTP acquisition was not associated with better outcomes in patients treated in the early or extended time windows. While confirmatory data is needed, our data suggests that extended window endovascular stroke therapy may remain beneficial even in the absence of advanced imaging.

Medrie Macphee: Works on Paper

Medrie Macphee: Works on Paper Karen Wilkin (bio) Over the many years I have been following Medrie MacPhee’s work, I have watched her imagery become steadily more abstract and metaphorical, yet, at the same time, it appears to be more about being human and more about distilled lived experience—not literally, but by implication. Her recent works on paper, many of them made in response to the enforced limitations of life during COVID-19 and the political upheavals of 2020, are solemn, tense conversations among non-specific elements that are at once autonomous, mutable, and vaguely anthropomorphic. Her large, dramatically confrontational paintings, made during the same fraught period, could be described very much the same way, although at first acquaintance they can be read as non-allusive, uncompromising abstractions constructed with generous shapes. We soon become engaged by nuances of surface and texture—gritty passages of paint thickened with pumice, delicate edges, subtle pleating—and, if we pay attention, realize that the entire richly inflected expanse has been constructed by collaging. Paint challenges, contradicts, and sometimes even destroys the character of the applied material. We begin to focus on linear elements and rhythmic repetitions—a row of narrow, regularly spaced, short rectangles or what seems to be the memory of stitching—and then recognize a piece of waistband or a flattened collar. MacPhee, we discover, builds her works with deconstructed clothing from 99-cent stores, collaging with fabric and sometimes incorporating buttons, zippers, and other fragments of actuality, transubstantiating them by their new context. It’s a testimony to the power of her paintings that we never fixate on the previous lives of these allusions to [End Page 267] the quotidian, but continue to read them as drawing and punctuation that enliven the canvas. The origins of these snippets of the real world and their intimate connection to the human body are subsumed by the new invented worlds of the paintings they inhabit, yet, on some perhaps subliminal level, we remain faintly aware of the former identity of shirts and trousers, before the artist dissected and reassembled their parts. It’s as if a benign ghost haunted MacPhee’s recent work. Her works on paper share this collaging aspect, with more isolated, personable shapes engaged in inchoate dramas. Like her paintings, her paperworks deploy a vocabulary of suave curves and expressive drawing, played against the edges of the support, and elicit maximum expression from different textures, varied paint applications, unpredictable patterns, and encounters between line and expanse. The zones of texture are even more aggressive in her works on paper, contrasting strongly with the neutral expanse that surrounds them and helping to turn floating, often soft-edged shapes into self-sufficient personages, so dense that they can seem physically distinct from the surface. These robust individuals dominate MacPhee’s recent paperworks, discrete presences that enter into dialogues with fragile, insistent lines and smooth forms that are sometimes punctuated with small, scattered incidents. The shift in scales between the dense, blunt, heavily textured shapes and the delicate lines and spatterings of little rectangles animates the frontal, resonant images. The swelling, agile characters that populate MacPhee’s recent works on paper can seem both comic and intensely serious, more or less at the same time, which intensifies our sense of their having been provoked by the events of our difficult, sometimes improbable present. MacPhee’s brooding, antic abstract works on paper become potent, intimate metaphors for the stresses of the past year. [End Page 268] Click for larger view View full resolution Hello Darkness (2020), mixed media on paper, 30 x 22 inches. © Medrie MacPhee. [End Page 269] Click for larger view View full resolution That’s Your Lookout (2020), mixed media on paper, 30 x 22 inches. © Medrie MacPhee. [End Page 270] Click for larger view View full resolution Up the Hill (2020), mixed media on paper, 30 x 22 inches. © Medrie MacPhee. [End Page 271] Click for larger view View full resolution A Change in Identities (2019), mixed media on paper, 30 x 22 inches. © Medrie MacPhee. [End Page 272] Click for larger view View full resolution Green as Grass (2018), mixed media on paper, 30 x 22...

Time scale of the growth progress in bacterial cultures: a self-consistent choice

An empirical model describes the behavior of an ideal microbial culture that mimics the real one. The predicted growth curve, log[N(t)], includes the onset tail of the observed sigmoid trend, while the latency phase that precedes the cell duplication is a time gap, which does not coincide with the so-called lag phase of other models. Unsolved remains the issue of the time scale: does the origin of the time scale of the experimenter coincide with that of the microbial culture? The correlation between duration of latency phase and maximum slope of the growth trend allows determination of a “true” starting point of the growth progress as the origin of the time scale of the microbial culture. Rigid shifts in the time scale of the experimenter allow alignment of the growth trends of real microbial cultures (in excess substrate, in the same medium and at the same temperature), no matter the starting population density. The time scale of the bacterial culture allows a consistent evaluation of the extent of the latency phase that can include a “negative” time span, which is supposed to deal with some basal cell metabolism not aimed at duplication. Some examples, dealing with real psychrotrophic bacterial cultures, support the model and perfect the prediction of the extent of the latency phase at various temperatures.

Shape-preserving prediction for stationary functional time series

This article presents a novel method for prediction of stationary functional time series, in particular for trajectories that share a similar pattern but display variable phases. The limitation of most of the existing prediction methodologies for functional time series is that they only consider vertical variation (amplitude, scale, or vertical shift). To overcome this limitation, we develop a shape-preserving (SP) prediction method that incorporates both vertical and horizontal variation. One major advantage of our proposed method is the ability to preserve the shape of functions. Moreover, our proposed SP method does not involve unnatural transformations and can be easily implemented using existing software packages. The utility of the SP method is demonstrated in the analysis of non-metanic hydrocarbons (NMHC) concentration. The analysis demonstrates that the prediction by the SP method captures the common pattern better than the existing prediction methods and also provides competitive prediction accuracy.

Larval drift dynamics, thermal conditions and the shift in juvenile capelin distribution and recruitment success around Iceland and East Greenland

Global warming is not uniformly distributed, the climate is expected to change most rapidly in the arctic regions. Large scale changes in the arctic biosphere is therefore of particular concern. Capelin (Mallotus villosus) is a keystone species in the many arctic marine ecosystem including the seas around Iceland in Greenland. Its summer/autumn distribution has shifted over thousands of kilometres and production has decreased substantially. Multiple drivers may be involved in this change. Here, we explore the roles of changes in larval drift and thermal conditions around spawning and the larvae. Using model based simulations of the period 1993–2015, we find that vertical behaviour of the larvae, geographical distribution of the spawning and to some extent also timing of the spawning affect the drift trajectories. Our results from the simulations indicate large interannual variation in westwards drift, but without a long-term trend. The shift in distribution of the capelin did consequently not appear to result from a large scale shift in currents. Unlike the current, ambient temperature had a long term trend, and the temperature level changed abruptly and significantly between 2002 and 2003. The long-term shift in distribution might have been driven by the warming through a combination of earlier and more northern spawning and mortality dynamics. However, the timing of the shift in temperature (from 2003) was not in agreement with the timing of the events during the shift (starting in 2002). The first year may, on the other hand, be explained by the strong westwards currents particularly in 2002. Also, we point out a striking match between the abrupt increase in ambient temperature and the observed decrease in recruitment from 2003.

Label-Free in-Situ Detection for DNA Hybridization Employing Grapefruit-Microstructured-Optical-Fiber-Based Microfluidic Whispering Gallery Mode Resonator

A whispering gallery mode (WGM) microresonator based on grapefruit microstructured optical fibers (MOFs) is proposed for in-situ DNA biosensing. The MOF microresonator has a porous structure that offers natural microfluidic channels to load microfluidic samples of volume down to 100 μL. Moreover, the WGM mechanism greatly enhances the interaction between WGM light and liquid sample kept inside the microcavity. The inner surface of the microcavity is functionalized with poly-L-lysine monolayer to achieve label-free binding of the single-strand probe DNA (ssDNA) through electrostatic force, and the probe immobilization as well as DNA hybridization processes are monitored in real time. The linear fitting of resonance wavelength shift versus DNA concentration in logarithmic scale indicates that DNA detection is available from 0.01 fmol/μL to 100 fmol/μL. The proposed WGM microresonator biosensor possesses such desirable merits as ease of operation, fast response, label free method, and high specificity, making it a promising candidate for in-situ DNA detection and related biosensing applications.

Health movements in the age of austerity: rescaling resistance in Spain and the United Kingdom

ABSTRACT Since the outbreak of the global financial crisis that started in 2007/8, austerity measures have been promoted in many European countries. Frequently justified as a form of crisis-management, these measures have been used to further privatise and deregulate welfare systems, as well as to reinforce the isolation of certain decision-making arenas from democratic processes. At the same time, they have also generated new strategic opportunities for resistance to different forms of anti-austerity disruptive agency. The paper analyses the rescaling strategies implemented in public health services in Spain and the UK during the current economic crisis, and contributes to the understanding of the scalar dynamics and strategies of two social struggles against the privatisation of hospitals and health centres in these two contexts: Marea Blanca (White Tide) in Madrid and Keep Our NHS Public in Greater Manchester. It argues that social movements are more successful when they exploit scale shifts to transform institutions into centres of resistance.

Embodied Aporia: exploring the potentials for posing questions through architecture

Through shifts in scale, as illustrated in creative spatial practices, affinities can be drawn out between persons and architectures that lead to encounters with forms and materials as both familiar and strange. Such encounters hold potential for developing sensitivity to the forces at play between body and surroundings, and the identification of separate bodies can be shifted to identification with, and as part of, an ecology of bodies. Using examples from artist-architects Shusaku Arakawa and Madeline Gins alongside art historical examples of Minimalist sculpture, lines of connection are drawn between disparate practices in order to illustrate a continuity of questioning the body directly through the construction of environments. These spatial practices evidence that certain questions are best posed by architecture, as questions which cannot be posed through language can be posed through other methods. Strategies for increasing this sensitivity are parsed out towards the identification of a particular form of embodied doubt, a lived puzzlement felt body wide.

Evaluating the potential environmental impacts of a large scale shift to off-hour deliveries

This paper assesses the potential environmental impacts of a large-scale deployment of off-hour deliveries (OHD), focusing on CO2 and pollutant emissions. We use a methodological framework involving four steps: transport demand estimation, traffic simulation, emissions calculation and emissions environmental social cost calculation. Based on five scenarios, depending on the scale of the shift to OHD, and applied to the case of the Lyon urban area, we find that OHDs lead to a reduction in CO2 and pollutant emissions. However, their impact is rather small. The maximum reduction in CO2 emissions is 3.4% for 100% OHD for the whole urban area of Lyon (1.9 million inhabitants and 3325 km2). Some factors (population size, density, traffic conditions, research methodology, vehicle fleet composition, etc.) limit the comparability of the results obtained from other case studies. One of the reasons for this low environmental impact of OHDs is that the LUA is a small and not very congested metropolitan area. This impact is 5% when we focus on the densest area (core of area with 0.7 million inhabitants on 2.2% of surface area) which is more important than in the least dense area (outskirts of area with 0.6 million inhabitants on 83.6% of surface area) with 2.6%. These results confirm the limited impacts of OHDs in smaller, less congested urban areas. It also reaffirms the need for OHDs to be implemented in the densest parts of metropolitan areas. The maximum decrease in the environmental social cost is 4.25 million euros per year. Furthermore, the analysis reveals that the adoption of OHD makes it possible to achieve gains of 2.5 million hours per year in travel time that augur a productivity gain for all the actors involved in urban goods movement.

Facet-Dependent Cobalt Ion Distribution on the Co3O4 Nanocatalyst Surface.

Co3O4 is an important catalyst widely used for CO oxidation or electrochemical water oxidation near room temperature and was also recently used as support for single-atom catalysts (SACs). Co3O4 with a spinel structure hosts dual oxidation states of Co2+ and Co3+ in the lattice, leading to the complexity of its surface structure as the exposure of Co2+ and Co3+ has a significant impact on the performance of the catalysts. Although it is acknowledged that different facets exhibit varied catalytic activities and different abilities in hosting single atoms to provide active centers in SACs, the Co3O4 surface structure remains under-investigated. In this study, major facets of {111}, {110}, and {100} were studied down to subangstrom scale using advanced electron microscopy. We noticed that each facet has its own most stable surface configuration. The distribution of Co2+ and Co3+ on each facet was quantified, revealing a facet-dependent distribution of Co2+ and Co3+. Co3+ was found to be preferentially exposed on {100} and {110} as well as surface steps. Surface reconstruction was revealed, where a subangstrom scale shift of Co2+ was confirmed on facets of {111} and {100} due to polarity compensation and oxygen deficiency on the surface. This work not only improves our fundamental understanding of the Co3O4 surface structure but also may promote the design of Co3O4-based catalysts with tunable activity and stability.

Scale Shifts from Polk Street to a Broken Earth; or, Literary Naturalism’s Geontological Affordances

Scale Shifts from Polk Street to a Broken Earth; or, Literary Naturalism’s Geontological Affordances

Modeling Process‐Based Biogeochemical Dynamics in Surface Fresh Waters of Large Watersheds With the IMAGE‐DGNM Framework

AbstractOver the last centuries, human activities have exerted increasing pressures on the environment, leading to drastic alterations in the functioning of freshwater bodies (e.g., eutrophication). Global biogeochemical models have proven crucial to investigate interactions between humans, hydrology, and water quality of surface fresh waters. However, most do not account for high‐resolution spatial and temporal variability within watersheds, and they typically lack any representation of benthic dynamics that can drive pollution legacy effects. We present here the Integrated Model to Assess the Global Environment‐Dynamic Global Nutrient Model (IMAGE‐DGNM), which couples global, spatially explicit hydrology and integrated assessment models with process‐based biogeochemistry in surface fresh waters. The new Dynamic In‐Stream Chemistry (DISC) module calculates advective transport from headwaters to estuaries, processes in the water column and in bed sediments, as well as the exchanges between these two compartments. As application examples of IMAGE‐DGNM, we simulate sediment dynamics and nitrogen cycling in two large river basins. We assess in‐stream concentration time series at specific locations, and identify governing processes in transfers along the aquatic continuum. Results highlight the importance of benthic dynamics in watersheds highly perturbed by damming. The implementation of such dynamics within IMAGE‐DGNM allows for including the temporal effect of pollution legacies in large scale water quality studies and shifts in pollutant speciation along river continua. This new framework therefore incorporates new features for large basin to global scale studies that are crucial to better predict the effects on receiving ecosystems and evaluate future environmental management pathways.

The line asymmetry in the spectra of the Sun and solar-type stars

We have analysed the asymmetry of lines Fe I and Fe II in spectra of a solar flux using three FTS atlases and the HARPS atlas and also in spectra of 13 stars using observation data on the HARPS spectrograph. To reduce observation noise individual line bisectors of each star have been averaged. The obtained average bisectors in the stellar spectra are more or less similar to the shape C well known to the Sun. In stars with rotation velocities greater than 5 km/s the shape of the bisectors is more like /. The curvature and span of the bisectors increase with the temperature of the star. Our results confirm the known facts about strong influence of rotation velocity on the span and shape of bisectors. The average convective velocity was determined based on the span of the average bisector, which shows the largest difference between the velocity of cold falling and hot rising convective flows of the matter. It’s equal to -420 m/s for the Sun as a star. In stars, it grows from -150 to -700 m/s with an effective temperature of 4800 to 6200 K, respectively. For stars with greater surface gravity and greater metallicity, the average convective velocity decreases. It also decreases with star age and correlates with the velocity of micro and macroturbulent movements. The results of solar flux analysis showed that absolute wavelength scales in the atlases used coincide with an accuracy of about -10 m/s, except for the FTS-atlas of Hinkle et al., whose scale is shifted and depends on the wavelength. In the range from 450 to 650 nm, the scale shift of this atlas varies from -100 to -330 m/s, respectively, and it equals on average of 240 m/s. The resulting average star bisectors contain information about the fields of convective velocities and may be useful for hydrodynamic modeling of stellar atmospheres in order to study the characteristic features of surface convection.

Asymmetry of Lines in the Spectra of the Sun and Solar-Type Stars

We have analysed the asymmetry of lines Fe I and Fe II in spectra of a solar flux using three FTS atlases and the HARPS atlas and also in spectra of 13 stars using observation data on the HARPS spectrograph. To reduce observation noise individual line bisectors of each star have been averaged. The obtained average bisectors in the stellar spectra are more or less similar to the shape C well known to the Sun. In stars with rotation speeds greater than 5 km/s the shape of the bisectors is more like /. The curvature and span of the bisectors increase with the temperature of the star. Our results confirm the known facts about strong influence of rotation velocity on the span and shape of bisectors. The average convective speed was determined based on the span of the average bisector, which shows the largest difference between the velocity of cold falling and hot rising convective flows of the matter. It's equal to -420 m/s for the Sun as a star. In solar-type stars, it grows from -150 to -700 m/s with an effective temperature of 4800 to 6200 K, respectively. For stars with greater surface gravity and greater metallicity, the average convective velocity decreases. It also decreases with star age and correlates with the speed of micro and macroturbulent movements. The results of solar flux analysis showed that absolute wavelength scales in the FTS atlases used coincide with an accuracy of about -10 m/s, except for the atlas of Hinkle, etc., whose scale is shifted and depends on the wavelength. In the range from 450 to 650 nm, the scale shift of this atlas varies from -100 to -330 m/s, respectively, and it equals on average of -240 m/s. The resulting average star bisectors contain information about the fields of convective velocities and may be useful for hydrodynamic modeling of stellar atmospheres in order to study the characteristic features of surface convection.

Distilling Culture into Commodity? The Emergent Homemade Alcohol Trade and Gendered Livelihoods in Upland Northern Vietnam

Ethnic minorities in the uplands of northern Vietnam are experiencing rapid state- and market-induced economic and agrarian transformations. These communities are having to make important livelihood adaptations to adjust, while living at Vietnam’s economic and political margins. We analyse one such market-induced transformation that some upland communities are deciding to engage with, connected to an increasing demand for locally distilled alcohol. Against the backdrop of traditional production for domestic consumption, distilled alcoholic beverages are now (re)emerging as a cash-earning opportunity. Drawing on interviews and observations with ethnic minority Hmong and Yao women and men in Lào Cai Province, we analyse the degree to which household members have engaged with this market opportunity and the often complex reasons behind their choices. We reveal how an apparently simple shift in scale of a customary activity generates nuanced cultural, gendered and generational debates that, at times, are at odds with mere profitability.

The Imagined Globe: Remapping the World Through Public Diplomacy at the Asia Society

Debates about public diplomacy have recently turned to the role of non-governmental organizations (NGOs) in what had been primarily a conversation about state-to-state affairs. We contribute to this conversation through an in-depth analysis of the Asia Society. Founded by John D. Rockefeller III in 1956, the Asia Society was established to educate Americans about Asia at a time when there was much less contact between the USA and Asia. Since then, the institution has undergone several reinventions, each contributing to and reflecting changing understandings of Asia and its relationship to the USA. We track the kinds of artwork the Asia Society collects and puts on display, the range of countries it categorizes as Asian, and the goals and content of its programming to reveal these shifts in scale and focus and demonstrate how they mirror and drive forward shifts in US-Asian relations. We argue that understanding how cultural institutions contribute to changing geographic imaginaries and geopolitics is an important, often overlooked aspect of public diplomacy. They are both a catalyst and reflection of changing political economic dynamics that, in turn, shape how citizens imagine their world and their nation’s place within it.

The visible effects of ‘invisible politics’: ‘everyday forms of resistance’ and possible outcomes

ABSTRACT We evaluate existing case studies of ‘everyday forms of resistance’ and explore the possibilities for a systematic research on its political impacts. Due to its elusive nature, the impact of this less visible resistance has rarely been studied. We only find single case studies that make references to varied outcomes in a particular context. Main theorists within the field do suggest a loose hypothesis of ‘cumulative’ effects in which (thousands of) individual acts can have a significant impact over time, with triggered mobilization of ‘scale shifts’ into public mass actions. Our exploration points to a potential for establishing knowledge of immediate outcomes, particularly through comparative case studies.

Local food policies – their constraints and drivers: Insights from Portuguese Urban Agriculture initiatives

Abstract Two interconnected questions are addressed in this paper: (i) why urban agriculture (UA) and food-related initiatives take usually years to materialise in Portugal; and (ii) why resilient initiatives do not scale up and shift from practices to local food policies. We argue that existing initiatives are viewed as single events and therefore garner quite limited long-term political commitment and support. Based on interviews with food champions and a literature review, four Portuguese UA initiatives are analysed and these highlight the constraints that hinder their scaling-up. We conclude that drivers to lead to scaling-up are a combination of factors, with an enabling environment the most relevant one. On the other hand, constraints are related to limited democratic governance and poor policies, insufficient funding and weak participatory processes. Such findings are quite in line with existing literature. The limited integration of Portugal within the international UA and food debates might partially explain why UA is still struggling to find its proper place in Portuguese cities and their peripheries. Raising awareness among decision makers is critical to scaling-up UA initiatives and turning them an integral component of local food systems. A national observatory able to gather relevant data and produce knowledge, assess and monitor on-going initiatives may be the key step to gather different stakeholders together, that can then better advocate and then lead to higher political support, not only in Portugal but in any country where UA and food issues are emerging.

Intra Coding With Geometric Information for Urban Building Scenes

Regarding the interior non-local correlations of image content, the intra predictions in image/video coding standards have still not exploited them efficiently. In this article, we propose an intra coding method that leverages the geometric information extracted from the image content to strengthen the coding performance. During the process of image capturing, if the imaging plane of the camera is not fronto-parallel to the surface of an object in reality, the repetitive patterns on the object's surface in real world will appear with a scale shift in the image domain. Thus, the corresponding potential non-local redundancy cannot be removed through the direct utilization of intra block copy and its variants. To address this problem, we begin with a theoretic analysis into the perspective transformation matrix and derive the underlying geometric information that causes the scale shift in the image domain; afterwards, we propose an intra coding framework based on the geometric information to alleviate the scale shift. It is essential for the coding framework to realize block matching in the rectified domain. Our framework mainly consists of two components, i.e., the intra block copy in the rectified domain through planar perspective transformation to obtain a more accurate prediction for the current coding block and the non-local post-processing filtering in the rectified domain after decompression to achieve a better quality of the reconstructed image. The experimental results show that our proposed method can achieve as high as 18% and an average of 5.0% bit-rate saving on the common dataset Urban100 compared to the HEVC reference software HM-SCC-extension with intra block copy and non-local post-processing filtering.