Horizontal Contours Research Articles

Modified Roll Envelope Technique Combined With Apically Repositioned Flap (MRARF) for Peri-Implant Soft Tissue Augmentation-A Case Series.

In the present case series, we performed implant surgery using a modified roll envelope technique and an apically repositioned flap (MRARF). To improve patients' peri-implant soft tissue phenotypes, they underwent dental implantation following the buccal contour concavities, inadequate keratinized tissue width, and soft tissue thickness simultaneously. This case series includes 4 patients treated between July 2021 and February 2022 who received dental implants and guided bone regeneration treatment 6 months earlier and were to be taken up for second-stage surgery. They were eligible for the MRARF technique if each implant site showed a labial and buccal deficiency and a reduced keratinized mucosa width than the adjacent teeth. Sutures were removed 2 weeks after surgery, and a provisional restoration was delivered. A final impression was taken at 6 weeks to produce the definitive implant-supported restoration. All surgery sites healed uneventfully, and no postoperative pain or excessive swelling was reported. The modified flap design allowed for increasing the width and thickness of keratinized mucosa with a minimally invasive technique. A harmonious color, texture, and mucogingival junction position that matched the surrounding tissue and adjacent teeth was achieved, and all patients were satisfied with the final results. MRARF at second-stage implant surgery could obtain satisfactory results regarding vertical and horizontal aesthetic gingival contours and an adequate width and thickness of keratinized mucosa around the implants.

Machine Vision for Knot Detection and Location in Chinese Fir Lumber

Abstract In order to be utilized in the design of a wood building, the lumber must pass grade. Machine-vision inspection grading offers higher efficiency and accuracy than traditional manual visual grading. In this paper, a fast and accurate method for identifying defects in large-size structural lumber based on machine vision of Fujian Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) constructional lumber (FCF CL) is proposed. Specifically, the grey matrix of the captured images on the surface of the sawn timber is initially scanned and the pixel weights on the edges of the image greyness variables are calculated. A matrix-valued torus was formed by fitting the knot edge profile and analyzing changes in the gradient values at the knot's edge, as well as calculating the directional derivative's rate of change. The knot three-dimensional mapping curves were projected onto the plane to form horizontal rise contours. Observe from the contour map of the whole large-size sawn timber, and extract the positional information of the knot where there is a trough (groove). The test results show that the rRMSE (Relative Root Mean Square Error) measured at the x axis position of knots is within 0.49 percent; the rRMSE measured at the y axis is 0.35 percent, which has high detection accuracy and meets the production requirements. We also investigated the effect of knots in different positions on the modulus of elasticity and the bending strength of FCF CL, with a view to establishing a link between machine-vision knot detection and mechanical properties of sawn timber in our next work.

Investigation of Parameters of Fused Deposition Modelling 3D Prints with Compression Properties

Three-dimensional (3D) printing has been attracting a great deal of attention in recent years in many application fields, for example, in the aerospace, construction, industry, art, education, protection, security, and medical fields. Printing methods, materials, and parameters influence the performance quality and determine the application sector of 3D prints. In this study, the print parameters are used as independent variables to investigate the compression strength of 3D printed cubes/cubes. The prints were produced by considering infill type, infill percentages, vertical wall, horizontal contours, and dimensions of items as the product parameters. The different printed samples were subjected to atmospheric conditions for 24 hours at (20 ± 1)°C temperature and (65 ± 2)% relative humidity. The samples were then subjected to a cyclic compression test with an indentation depth of 5 mm. The compression force to the planned displacement was measured. As seen from the results, the print parameters investigated in this research significantly influence the compression force and determine the performance of 3D prints according to the application sector. Although all parameters significantly influence the compression force of 3D prints, the magnitude and level of performance are different. Vertical walls relatively withstand high compression force while filling type gives soft and weak products with a relatively low mass. However, the choice of different pressure parameters can influence the compressive strength. With this knowledge, it will be possible in the future to print human soft tissues with a specific compressive strength using the FDM printing process.

Boundary-spanning in public value co-creation through the lens of multilevel governance

ABSTRACT The prospects and challenges of boundary-spanning public value co-creation are one of the quintessential features of public management in the current age of complexity. This paper argues that boundary-spanning takes on a heightened salience in multilevel jurisdictions where actors must not only navigate the horizontal contours of inter-organizational relations but also vertical tiers of jurisdiction in pursuit of joint action. Drawing insights from the multilevel governance literature, and using Canada's recent Innovation Superclusters Initiative as case study, the paper sheds some light on how public managers and policy entrepreneurs navigate strategically across boundaries in federal and other multitiered systems.

Spatial clustering of orientation preference in primary visual cortex of the large rodent agouti.

SummaryAll rodents investigated so far possess orientation-selective neurons in the primary visual cortex (V1) but – in contrast to carnivores and primates – no evidence of periodic maps with pinwheel-like structures. Theoretical studies debating whether phylogeny or universal principles determine development of pinwheels point to V1 size as a critical constraint. Thus, we set out to study maps of agouti, a big diurnal rodent with a V1 size comparable to cats'. In electrophysiology, we detected interspersed orientation and direction-selective neurons with a bias for horizontal contours, corroborated by homogeneous activation in optical imaging. Compatible with spatial clustering at short distance, nearby neurons tended to exhibit similar orientation preference. Our results argue against V1 size as a key parameter in determining the presence of periodic orientation maps. They are consistent with a phylogenetic influence on the map layout and development, potentially reflecting distinct retinal traits or interspecies differences in cortical circuitry.

A Fast High Precision Skew Angle Estimation of Digitized Documents

In this paper, we treated the problem of automatic skew angle estimation of scanned documents. The skew of document occurs very often, due to incorrect positioning of the documents or a manipulation error during scanning. This has negative consequences on the steps of automatic analysis and recognition of text. It is therefore essential to verify, before proceeding to these steps, the presence of skew on the document to be processed and to correct it. The difficulty of this verification is associated to the presence of graphic zones, sometimes dominant, that have a considerable impact on the accuracy of the text skew angle estimation. We also noted the importance of preprocessing to improve the accuracy and the calculation cost of skew estimation approaches. These two elements have been taken into consideration in our design and development of a new approach of skew angle estimation and correction. Our approach is based on local binarization followed by horizontal smoothing by the Run Length Smoothing Algorithm (RLSA) method, detection of horizontal contours and the Hierarchical Hough Transform (HHT). The algorithms involved in our approach have been chosen to guarantee a skew estimation: accurate, fast and robust, especially to graphic dominance and real time application. The experimental tests show the effectiveness of our approach on a representative database of the Document Image Skew Estimation Contest (DISEC) contest International Conference on Document Analysis and Recognition (ICDAR)

Villa Gamberaia compositional features

The object of the study is Villa Gamberaia in Settignano. This Italian Renaissance villa was created during the 16th century, but its spatial structure differs from its contemporary compositions. In this work, the method of the compositional analysis is used. A complex of compositional techniques characteristic of the early Renaissance gardens has been revealed. These gardens were a vivid illustration of the worldview of humanism, which proclaimed nature as a beautiful, and man as a part of it and a supernatural being. In the garden space, this was achieved by such techniques as terraces organization along the horizontal contours of the relief, which provided a panoramic opening of the garden space to the surrounding landscape; parterre composition of terraces, within which people dominated; contrast of near and far plans. These features are revealed in the construction of the Villa Gamberaia space, which allows us to attribute its composition to the best examples of the early Renaissance.

Algorithm for alerting the unmanned aerial vehicle operator based on the image potential obstacle borders detection on the flight trajectory using the OPEN CV library

The article describes several modifications of the obstacle detection algorithm on the flight trajectory of an unmanned aerial vehicle (UAV). First, we give an illustration of the problems on the example of the relief image on topographic maps and the essence of the relief image by horizontal contours. Then the conclusion is made about necessity of development of algorithm and software, which can help the operator of the UAV in deciding on necessary trajectory changes of UAV, since, for example, guided solely by the method image of the terrain or another similar method in the planning of the UAV trajectory as preliminary preparation for the flight, however, such methods are fairly static and are not suitable in such situations as, for example, detection of unexpected obstacles. Further, the article describes the process of developing several modifications of the algorithm that solves the above problem and generates a notification of the UAV operator. It is also described depending on the flight speed of the UAV and natural conditions; it is possible to choose the most appropriate modification of the algorithm, which has different sensitivity to potential obstacles. The conclusion shows the settings screen and results of the software work and the principle of visual notification of the UAV operator with the proposal direction of the flight around detected obstacles.

Soft tissue augmentation at immediate implants using a novel xenogeneic collagen matrix in conjunction with immediate provisional restorations: A prospective case series.

Collagen matrices used around immediate implants may reduce morbidity although there is limited evidence on their performance. To evaluate soft and hard tissue changes when combining immediate implants, hard and soft tissue grafting, and an immediate provisional restoration. In 12 patients, immediate implants were placed in the anterior maxillary and first premolar area together with a xenogeneic bone substitute. Then a xenogeneic collagen matrix was placed under the buccal mucosal margin with an immediate provisional restoration. Study casts and clinical measurements were taken before extraction (Baseline/BS) at 6 months (6M) and 12 months (1Y) after implant placement. Files from the scanned casts were matched to calculate the linear and volumetric changes at the buccal tissues. Cone Bean Computed Tomographies (CBCTs) were taken prior to extraction and at 6M. The superimposed DICOM files allowed for assessing hard tissue changes and the superimposition of DICOM and STL files allowed for evaluating of soft tissue thickness at BS and 6M. After 6 months, the horizontal tissue contours decreased 0.66 ± 0.57 mm, concomitant with a horizontal bone loss of 1.31 ± 1.32 mm, measured 1 mm below the most coronal aspect of the ridge. In contrast, the soft tissue thickness, 1 mm below the gingival margin, increased 0.75 ± 1.12 mm. At 1-year, tissue contours had decreased 1.01 ± 0.67 mm compared to BS reaching statistical significance. The mean volume loss after 1Y was 20.43 ± 11.70 mm3 while the mean mucosal margin recession was 0.86 ± 0.67 mm. These changes had a limited clinical impact as the PES Scores remained stable. The tested protocol resulted in a significant reduction of the tissue contours and osseous ridge dimensions that was partially compensated by a non-significant increase in soft tissue thickness.

Contour changes after guided bone regeneration of large non-contained mandibular buccal bone defects using deproteinized bovine bone mineral and a porcine-derived collagen membrane: an experimental in vivo investigation.

The objective of this study was to evaluate soft tissue contour changes after three different regenerative therapies in chronic ridge defects. Buccal bone defects were created in the mandible of nine beagle dogs. Augmentation procedures were performed 3months later using a bone replacement graft (BRG), resorbable collagen membrane (MBG), or a combination of both procedures (CBG). Silicone impressions were taken before tooth extraction (T1), before the augmentation procedure (T2), and 3months after the regenerative surgeries (T3). Casts were optically scanned and stereolithography files were superimposed to analyze the horizontal changes in ridge contours. After defect creation, most part of the horizontal changes occurred 4 and 6mm below the gingival margin. In the mesial defect (D1) at T3, the mean horizontal gain in MBG amounted to 0.47±0.34mm, 0.79±0.67mm in the BRG, and 0.87±0.69mm for the CBG. In the middle defect (D2), the mean changes for the MBG were 0.11±0.31, 1.01±0.91 for the BRG, and 0.98±0.49 for the CBG. The mean changes in the distal defect (D3) amounted to 0.24±0.72 for the MBG, 1.04±0.92 for the BRG, and 0.86±0.56 for the CBG. The differences reached significance in all defects for the comparison MBG-BRG and MBG-CBG, while similar parameters were observed for the comparison BRG-CBG. BRG and CBG were equally effective and superior to MBG in increasing the horizontal tissue contours. The augmentation seldom reached the values before extraction. Scaffolding materials are needed for contour augmentation when using resorbable collagen membranes.

Significance of Natural Scene Statistics in Understanding the Anisotropies of Perceptual Filling-in at the Blind Spot

Psychophysical experiments reveal our horizontal preference in perceptual filling-in at the blind spot. On the other hand, tolerance in filling-in exhibit vertical preference. What causes this anisotropy in our perception? Building upon the general notion that the functional properties of the early visual system are shaped by the innate specification as well as the statistics of the environment, we reasoned that the anisotropy in filling-in could be understood in terms of anisotropy in orientation distribution inherent in natural scene statistics. We examined this proposition by investigating filling-in of bar stimuli in a Hierarchical Predictive Coding model network. The model network, trained with natural images, exhibited anisotropic filling-in performance at the blind spot, which is similar to the findings of psychophysical experiments. We suggest that the over-representation of horizontal contours in the natural scene contributes to the observed horizontal superiority in filling-in and the broader distribution of vertical contours contributes to the observed vertical superiority of tolerance in filling-in. These results indicate that natural scene statistics plays a significant role in determining the filling-in performance at the blind spot and shaping the associated anisotropies.

Selective interhemispheric circuits account for a cardinal bias in spontaneous activity within early visual areas

Ongoing brain activity exhibits patterns resembling neural ensembles co-activated by stimulation or task performance. Such patterns have been attributed to the brain's functional architecture, e.g. selective long-range connections. Here, we directly investigate the contribution of selective connections between hemispheres to spontaneous and evoked maps in cat area 18 close to the 17/18 border. We recorded voltage-sensitive dye imaging maps and spiking activity while manipulating interhemispheric input by reversibly deactivating corresponding contralateral areas. During deactivation, spontaneous maps continued to be generated with similar frequency and quality as in the intact network but a baseline cardinal bias disappeared. Consistently, neurons preferring either horizontal (HN) or vertical (VN), as opposed to oblique contours, decreased their resting state activity. HN decreased their rates also when stimulated visually.We conclude that structured spontaneous maps are primarily generated by thalamo- and/or intracortical connectivity. However, selective long-range connections through the corpus callosum – in perpetuation of the long-range intracortical network – contribute to a cardinal bias, possibly, because they are stronger or more frequent between neurons preferring horizontal and/or cardinal contours. As those contours are easier perceived and appear more frequently in natural environment, long-range connections might provide visual cortex with a grid for probabilistic grouping operations in a larger visual scene.

Within-site variation of growth rates and terminal sizes in Mytilus californianus along wave exposure and tidal gradients.

Mytilus californianus is a foundation species of rocky shores of western North America. Its dominance depends on rapid growth to large sizes, which confers an advantage in size-dependent species interactions. Initial rates of growth and final (terminal) sizes of the mussels depend on environmental factors. Prior comparisons of growth made over large spatial scales (tens of meters to hundreds of kilometers) indicate that temperature, submergence time, and wave exposure affect growth. However, there are few studies quantifying variation in temperature, wave force, and mussel growth parameters at small scales within local populations-that is, meter-level increments. Such measures are necessary to better understand the consequences of the complex spatial mosaic of physical factors in the intertidal zone. We measured variation in temperature, wave force, size-specific shell growth, and terminal size at 3-4-m intervals along horizontal contours within two mussel beds separated by 15 ds of latitude. Both mussel beds showed the same general trends: growth rates attenuated along gradual clines from low and wave-exposed to high shore and sheltered. For example, young adults from low and wave-exposed microhabitats grew 9- and 6-fold higher than those from high-shore-wave-sheltered points. While higher flow may promote growth by enhancing feeding, it also appears to exert a positive effect by moderating energetically costly temperature stress. Consistent with the growth rate findings, cumulative degree-hours explained 83% and 69% of the variation of terminal sizes in regressions for the two locations.

Coverage Path Planning with Real-time Replanning and Surface Reconstruction for Inspection of Three-dimensional Underwater Structures using Autonomous Underwater Vehicles

We present a novel method for planning coverage paths for inspecting complex structures on the ocean floor using an autonomous underwater vehicle AUV. Our method initially uses a 2.5-dimensional 2.5D prior bathymetric map to plan a nominal coverage path that allows the AUV to pass its sensors over all points on the target area. The nominal path uses a standard mowing-the-lawn pattern in effectively planar regions, while in regions with substantial 3D relief it follows horizontal contours of the terrain at a given offset distance. We then go beyond previous approaches in the literature by considering the vehicle's state uncertainty rather than relying on the unrealistic assumption of an idealized path execution. Toward that end, we present a replanning algorithm based on a stochastic trajectory optimization that reshapes the nominal path to cope with the actual target structure perceived in situ. The replanning algorithm runs onboard the AUV in real time during the inspection mission, adapting the path according to the measurements provided by the vehicle's range-sensing sonars. Furthermore, we propose a pipeline of state-of-the-art surface reconstruction techniques we apply to the data acquired by the AUV to obtain 3D models of the inspected structures that show the benefits of our planning method for 3D mapping. We demonstrate the efficacy of our method in experiments at sea using the GIRONA 500 AUV, where we cover part of a breakwater structure in a harbor and an underwater boulder rising from 40i¾?m up to 27i¾?m depth.

Computing Retinal Contour from Optical Biometry

To describe a new methodology that derives horizontal posterior retinal contours from partial coherence interferometry (PCI) and ray tracing using the corneal topography. Corneal topography and PCI for seven horizontal visual field eccentricities correspondent to the central 60 degrees of the posterior pole were obtained in 55 myopic eyes. A semicustomized eye model based on the subject's corneal topography and the Navarro eye model was generated using Zemax-EE software. The model was used to compute the optical path length in the seven directions where PCI measurements were obtained. Vitreous chamber depth was computed using the PCI values obtained at each of those directions. Matlab software was developed to fit the best conic curve to the set of points previously obtained. We tested the limit in the accuracy of the methodology when the actual cornea of the subject is not used and for two different lens geometries. A standard eye model can induce an error in the retina sagitta estimation of the order of hundreds of micrometers in comparison with the semicustomized eye model. However, the use of a different lens model leads to an error of the order of tens of micrometers. The apical radius and conic constant of the average fit were -11.91 mm and -0.15, respectively. In general, a nasal-temporal asymmetry in the retina contour was found, showing mean larger values of vitreous chamber depth in the nasal side of the eye. The use of a semicustomized eye model, together with optical path length measured by PCI for different angles, can be used to predict the retinal contour within tenths of micrometers. This methodology can be useful in studies trying to understand the effect of peripheral retinal location on myopia progression as well as modeling the optics of the human eye for a wide field.

Sensitivity to Information Conveyed by Horizontal Contours is Correlated with Face Identification Accuracy

We measured thresholds in a 1-of-10 face identification task in which stimuli were embedded in orientation-filtered Gaussian noise. For upright faces, the threshold elevation produced by the masking noise varied as a function of noise orientation: significantly greater masking was obtained with horizontal noise than with vertical noise. However, the orientation selectivity of masking was significantly less with inverted faces. The performance of an ideal observer was qualitatively similar to human observers viewing upright faces: the masking function exhibited a peak for horizontally oriented noise although the selectivity of masking was greater than what was observed in human observers. These results imply that significantly more information about facial identity was conveyed by horizontal contours than by vertical contours, and that human observers use this information more efficiently to identify upright faces than inverted faces. We also found a significant positive correlation between selectivity for horizontal information and face identification accuracy for upright, but not inverted faces. Finally, there was a significant positive correlation between horizontal tuning and the size of the face inversion effect. These results demonstrate that the use of information conveyed by horizontal contours is associated with face identification accuracy and the magnitude of the face inversion effect.

Research on Characters Segmentation in One-Row and Two-Row of Vietnam License Plates

Characters Segmentation is one important step in the Automatic License Plate Recognition (ALPR) system. This paper proposed an improved method for one-row & two-row of Vietnam license plates (LP) characters segmentation. The proposed method consists of two main modules: the first task is pre-processing (image quantization, normalized image, adjust horizontal contours, morphology opening to remove noises), the second task is characters segmentation based on the method named peak-to-valley in order to segment the pictures in digit images getting the two bounds of the each digit segment according to the statistical parameter. We tested for 600 Vietnam LP (300 one-row LP, 300 two-row LP), the average rate of accuracy of our method is 98.03%.

Contrast independence of cardinal preference: stable oblique effect in orientation maps of ferret visual cortex

The oblique effect was first described as enhanced detection and discrimination of cardinal orientations compared with oblique orientations. Such biases in visual processing are believed to originate from a functional adaptation to environmental statistics dominated by cardinal contours. At the neuronal level, the oblique orientation effect corresponds to the numerical overrepresentation and narrower tuning bandwidths of cortical neurons representing the cardinal axes. The anisotropic distribution of orientation preferences over large cortical regions was revealed with optical imaging, providing further evidence for the cortical oblique effect in several mammalian species. Our present study explores whether the dominant representation of cardinal contours persists at different stimulus contrasts. Performing intrinsic optical imaging in the ferret visual cortex and presenting drifting gratings at various orientations and contrasts (100%, 30% and 10%), we found that the overrepresentation of vertical and horizontal contours was invariant across stimulus contrasts. In addition, the responses to cardinal orientations were also more robust and evoked larger modulation depths than responses to oblique orientations. We conclude that orientation maps remain constant across the full range of contrast levels down to detection thresholds. Thus, a stable layout of the functional architecture dedicated to processing oriented edges seems to reflect a fundamental coding strategy of the early visual cortex.

A simple model for solar isorotational contours

The solar convective zone, or SCZ, is nearly adiabatic and marginally convectively unstable. But the SCZ is also in a state of differential rotation, and its dynamical stability properties are those of a weakly magnetized gas. This renders it far more prone to rapidly growing rotational baroclinic instabilities than a hydrodynamical system would be. These instabilities should be treated on the same footing as convective instabilites. If isentropic and isorotational surfaces coincide in the SCZ, the gas is marginally (un)stable to {\em both} convective and rotational disturbances. This is a plausible resolution for the instabilities associated with these more general rotating convective systems. This motivates an analysis of the thermal wind equation in which isentropes and isorotational surfaces are identical. The characteristics of this partial differential equation correspond to isorotation contours, and their form may be deduced even without precise knowledge of how the entropy and rotation are functionally related. Although the exact solution of the global SCZ problem in principle requires this knowledge, even the simplest models produce striking results in broad agreement with helioseismology data. This includes horizontal (i.e. quasi-spherical) isorotational contours at the poles, axial contours at the equator, and approximately radial contours at midlatitudes. The theory does not apply directly to the tachocline, where a simple thermal wind balance is not expected to be valid. The work presented here is subject to tests of self-consistency, among them the prediction that there should be good agreement between isentropes and isorotational contours in sufficiently well-resolved large scale numerical MHD simulations.

Weakened feedback abolishes neural oblique effect evoked by pseudo-natural visual stimuli in area 17 of the cat

The psychological oblique effect, a well-known phenomenon that humans and some mammals are more visually sensitive to cardinal (vertical and horizontal) contours than to oblique ones, has commonly been associated with the overrepresentation of cardinal orientations in the visual cortex. In contrast to the oblique effect, however, Essock et al. [E.A. Essock, J.K. DeFord, B.C. Hansen, M.J. Sinai, Oblique stimuli are seen best (not worst!) broad-band stimuli: a horizontal effect, Vision Res. 43 (2003) 1329-1335] reported a psychological 'horizontal effect', in which visual stimuli dominated by oblique orientations were best perceived by human subjects when tested with unique natural broad-band stimuli. In this study, using optical imaging and the similar visual stimuli, we found an overrepresentation of cardinal orientations, i.e. the neural oblique effect, but not 'horizontal effect', in area 17 of the cat. In addition, the oblique effect was abolished by GABA administration in area 21a due to the preferred orientation shifting (6.0%) and decrease of orientation selectivity strength of neurons (26.9%) in area 17. These results indicate a neuronal basis of the oblique effect when animals watch a more natural scene, whereas no evidence was found for the 'horizontal effect'.