Orthogonal Edges Research Articles

Two-edge-resolved three-dimensional non-line-of-sight imaging with an ordinary camera

We introduce an approach for three-dimensional full-colour non-line-of-sight imaging with an ordinary camera that relies on a complementary combination of a new measurement acquisition strategy, scene representation model, and tailored reconstruction method. From an ordinary photograph of a matte line-of-sight surface illuminated by the hidden scene, our approach reconstructs a three-dimensional image of the scene hidden behind an occluding structure by exploiting two orthogonal edges of the structure for transverse resolution along azimuth and elevation angles and an information orthogonal scene representation for accurate range resolution. Prior demonstrations beyond two-dimensional reconstructions used expensive, specialized optical systems to gather information about the hidden scene. Here, we achieve accurate three-dimensional imaging using inexpensive, and ubiquitous hardware, without requiring a calibration image. Thus, our system may find use in indoor situations like reconnaissance and search-and-rescue.

A Compact Tri-Band Penta-Polarization Reconfigurable Planar Antenna for Interference Management in 5G Ultra-Dense Network Environment

Interference and multipath are the most common issues in the wireless domain due to the coexistence of a large number of wireless nodes operating within the constraint spectrum. A compact planar antenna with five reconfigurable polarization states in three distinct operating bands is presented in this article. A square patch is enclosed by a square outer ring in the design, and these antennas are coupled-decoupled successively using switching diodes to excite three distinct operating bands. Coplanar microstrip lines are used to feed the orthogonal edges of the antenna. The diagonal corners of the inner and outer ring patches are truncated to realize dual circular polarization (CP) states with proper biasing. Switching diodes are placed at the etched corners to realize vertical (VP) and horizontal (HP) polarization. Both the orthogonal feed lines are activated simultaneously with identical phase and amplitude to realize 45° linear polarization. A low-profile, single-feed, compact prototype reconfigurable microstrip antenna (MSA) is finally designed, fabricated, and measured at 1.8 GHz, 2.4 GHz, and 5.8 GHz bands, respectively. Each operating band shows five distinct operating states. The simulation results for all fifteen states are found to be consistent with the measurement.

Biomolecules Orchestrating Cardiovascular Calcification.

Vascular calcification, once considered a degenerative, end-stage, and inevitable condition, is now recognized as a complex process regulated in a manner similar to skeletal bone at the molecular and cellular levels. Since the initial discovery of bone morphogenetic protein in calcified human atherosclerotic lesions, decades of research have now led to the recognition that the regulatory mechanisms and the biomolecules that control cardiovascular calcification overlap with those controlling skeletal mineralization. In this review, we focus on key biomolecules driving the ectopic calcification in the circulation and their regulation by metabolic, hormonal, and inflammatory stimuli. Although calcium deposits in the vessel wall introduce rupture stress at their edges facing applied tensile stress, they simultaneously reduce rupture stress at the orthogonal edges, leaving the net risk of plaque rupture and consequent cardiac events depending on local material strength. A clinically important consequence of the shared mechanisms between the vascular and bone tissues is that therapeutic agents designed to inhibit vascular calcification may adversely affect skeletal mineralization and vice versa. Thus, it is essential to consider both systems when developing therapeutic strategies.

Effect of width/height of the gap between piston and wall on the performance of a novel small volume emulsification device

The concept of a small volume emulsification device developed by the authors is further studied in the present work. Following suggestions of previous work, five different piston plates with orthogonal edges are constructed to oscillate inside a small cube-shaped cell. The different pistons yield several combinations of gap width and height between the plates and the walls of the cell. Their performance is assessed by performing emulsification experiments over an extensive range of piston stroke frequency and emulsification time for a specific non-coalescing system (fixed oil fraction and surfactant concentration). The resulting droplet size distributions are estimated by microscopy images analysis and by phase separation observations. The combined information from these techniques is necessary in order to register the broad size range of droplets. A semiquantitative analysis of the flow field in the gap reveals that droplet breakage process starts at the laminar boundary layers developed between the piston and the cell walls and allows characterization of this field. A theoretical analysis for the mechanism of droplet breakup is presented. The analysis of experimental results demonstrates that four of the five tested piston plates are appropriate for emulsification regarding the generated droplet size distribution and the choice among them requires additional criteria, e.g. energy requirements.

In-Depth Study of 3D Color-Resist Coating Process for Optically Uniform Image Sensors

The color filter required for manufacturing a CMOS image sensor was redeveloped to optimize its optical uniformity. An in-depth study of the three-dimensional (3D) coating process and how it gives rise to various radial-shaped striation patterns was conducted. These radial-shaped striation patterns were systematically investigated with reference to two types of patterns: the orthogonal type found only at the orthogonal edges of the wafer and the diagonal type found mostly at the corner of each quadrant. The formation of the orthogonal pattern was based on the wide standing wave created by the incident force of the spreading color photoresist (PR) and the reflective force from the bump pads acting as coating barriers. The diagonal pattern was found to be generated by the turbulent wakes created behind the bump pads by the drag force, which interfered with the coating flow. An in-depth study using Ansys CFX software and an in-line inspection tool revealed that lowering the viscosity of the color PR material is a key factor for improving the phenomenon whereby the 3D striation patterns of the orthogonal and diagonal types are formed. Based on this finding, it was possible to drastically reduce the formation of the 3D striation patterns by decreasing the viscosity of the material comprising each color PR. This study provides not only an empirical and theoretical understanding of the 3D color PR coating mechanism, but also guidelines for future color filter processes.

A Differentiable Mapping of Mesh Cells Based on Finite Elements on Quadrilateral and Hexahedral Meshes

Abstract Finite elements of higher continuity, say conforming in H 2 {H^{2}} instead of H 1 {H^{1}} , require a mapping from reference cells to mesh cells which is continuously differentiable across cell interfaces. In this article, we propose an algorithm to obtain such mappings given a topologically regular mesh in the standard format of vertex coordinates and a description of the boundary. A variant of the algorithm with orthogonal edges in each vertex is proposed. We introduce necessary modifications in the case of adaptive mesh refinement with nonconforming edges. Furthermore, we discuss efficient storage of the necessary data.

An Efficient Rectilinear and Octilinear Steiner Minimal Tree Algorithm for Multidimensional Environments

The rectilinear/octilinear Steiner problem is the problem of connecting a set of terminals $Z$ using orthogonal and diagonal edges with minimum length. This problem has many applications, such as the EDA, VLSI circuit design, fault-tolerant routing in mesh-based broadcast, and Printed Circuit Board (PCB). This paper proposes an obstacle-avoiding 4/8/10/26-directional heuristic algorithm for this problem based on the Areibi’s concept, Higher Geometry Maze Routing, and Sollin’s minimal spanning tree algorithm. The major contributions of this paper are (1) our work is the first report for the octilinear SMTs in the multidimensional environments, (2) we provide an optimal point-to-point routing without any refinement, and (3) the proposed algorithm has higher adaptability to deal with any irregular environment, and can be extended to the $\lambda $ -geometry without any extra work, where $\lambda =2$ , 4, 8 and $\infty $ corresponding to rectilinear, 45°, 22.5° and Euclidean geometries respectively.

Three-Dimensional Right-Angled Polytopes of Finite Volume in the Lobachevsky Space: Combinatorics and Constructions

We study combinatorial properties of polytopes realizable in the Lobachevsky space $$\mathbb{L}^{3}$$ as polytopes of finite volume with right dihedral angles. On the basis of E. M. An-dreev’s theorem we prove that cutting off ideal vertices of right-angled polytopes defines a one-to-one correspondence with strongly cyclically four-edge-connected polytopes different from the cube and the pentagonal prism. We show that any polytope of the latter family can be obtained by cutting off a matching of a polytope from the same family or of the cube with at most two nonadjacent orthogonal edges cut, in such a way that each quadrangle results from cutting off an edge. We refine D. Barnette’s construction of this family of polytopes and present its application to right-angled polytopes. We refine the known construction of ideal right-angled polytopes using edge twists and describe its connection with D. Barnette’s construction via perfect matchings. We make a conjecture on the behavior of the volume under operations and give arguments to support it.

Design of Compact Single-Layer Textile MIMO Antenna for Wearable Applications

A compact single-layer textile MIMO antenna is designed for wearable applications. The theory of characteristic mode is used to guide the antenna design and analyze its performance. The MIMO antenna utilizes a small ground plane as the main radiator, which is capacitively loaded by two strips along two orthogonal edges. The whole system occupies a volume of 38.1 mm $\times38.1$ mm $\times2$ mm, with each antenna having a dipole-like radiation pattern of linear polarization. Good isolation of above 12 dB is achieved due to the quasi-orthogonal radiations generated by the two antennas, providing pattern and polarization diversities. The envelope correlation coefficient between the antennas is below 0.01. The proposed antenna, fabricated on a flexible felt with a permittivity of 1.2, has a wide bandwidth of 20%. Due to its broadband behavior, the antennas remain well matched at the target band when worn on the body and bended. The loss of the human tissue results in the drop of the antenna gains to 1.6 dBi and 1.2 dBi, respectively, for the two antennas. The proposed antenna is competitive for wearable applications, due to its compact size, single-layer structure, easy integration, robustness, and reasonable on-body antenna gain.

A novel planar dual polarized millimetre wave antenna for KU band applications

A dual polarized antenna array to operate in Ku band is analysed and designed. Cross polarization is the major factor considered. The second requirement is the uni-layer fabrication used for any vertical interconnection accesses. Circular microstrip patches are chosen as the radiating elements. The antenna is fed through the two orthogonal linear edges and shown in microstrip line pattern. Reduction of sidelobes is done by using dolphchebychev distribution. scattering parameters procedure is done to get efficient stimulation. The properties of antenna array simulation are fixed over a bandwidth having center frequency 500MHz. Hence proven, showing that a cross polarised antenna is used for ku band frequencies or millimeter wave applications. The design procedure and parameters are explained clearly to utilize the fact that the antenna array could be reduced.

Single‐Layer, Dual‐Port, Dual‐Band, and Orthogonal‐Circularly Polarized Microstrip Antenna Array with Low Frequency Ratio

A single‐layer, dual‐port, dual‐band, and dual circularly polarized (CP) microstrip array is designed for satellite communication in this paper. The operating frequencies are 8.2 and 8.6 GHz with a very low ratio of 1.05. First, a rectangular patch element is fed through microstrip lines at two orthogonal edges to excite two orthogonal dominant modes of TM01 and TM10. The very low frequency ratio can be realized with high polarization isolations. Then, a 2‐by‐2 dual‐band dual‐CP subarray is constructed by two independent sets of sequentially rotated (SR) feed structures. An 8‐by‐8 array is designed on the single‐layer thin substrate. Finally, by utilizing one‐to‐four power dividers and semirigid coaxial cables, a 16‐by‐16 array is developed to achieve higher gain. Measured results show that the 16‐by‐16 array has 15 dB return loss (RL) bandwidths of 4.81% and 6.75% and 3 dB axial ratio (AR) bandwidths of 2.84% and 1.57% in the lower and the upper bands, respectively. Isolations of 18.6 dB and 19.4 dB and peak gains of 25.1 dBic and 25.6 dBic are obtained at 8.2 and 8.6 GHz, respectively.

A Planar Dual-Polarized Microstrip 1-D-Beamforming Antenna Array for the 24-GHz Band

A planar linearly dual-polarized mm-wave antenna array is designed, fabricated, and investigated in detail. The requirements are two orthogonal polarizations with good purity and suitability of the array column for 1-D beamforming applications. Since single-layer fabrication without using vertical interconnection accesses is another important requirement, the chosen radiating elements are square microstrip patches, fed at two orthogonal edges. The array feeding is designed in series microstrip line fashion, providing a highly compact structure. In that way, 1-D beamforming agility is gained, when multiple array columns are arranged side by side and the individual columns are fed with appropriate phases. The sidelobe level of the array columns is decreased by implementing an amplitude taper within the series array, following the Dolph–Chebychev distribution. A fast scattering parameter calculation procedure is presented to achieve an efficient simulation and design process. The simulated and measured antenna properties are very stable over a bandwidth of 500 MHz around the center frequency proving that such a challenging dual-polarized design can be successfully implemented at millimeter-wave (mm-wave) frequencies with just one metallization layer on a grounded substrate. The design parameters and the design procedure are demonstrated in a step by step manner to give sufficient insight into the process together with the possibility of reusing the antenna array itself, as well as the underlying concepts.

Testing the role of luminance edges in White's illusion with contour adaptation.

White's illusion is the perceptual effect that two equiluminant gray patches superimposed on a black-and-white square-wave grating appear different in lightness: A test patch placed on a dark stripe of the grating looks lighter than one placed on a light stripe. Although the effect does not depend on the aspect ratio of the test patches, and thus on the amount of border that is shared with either the dark or the light stripe, the context of each patch must, in a yet to be specified way, influence their lightness. We employed a contour adaptation paradigm (Anstis, 2013) to test the contribution of each of the test patches' edges to the perceived lightness of the test patches. We found that adapting to the edges that are oriented parallel to the grating slightly increased the lightness illusion, whereas adapting to the orthogonal edges abolished, or for some observers even reversed, the lightness illusion. We implemented a temporal adaptation mechanism in three spatial filtering models of lightness perception, and show that the models cannot account for the observed adaptation effects. We conclude that White's illusion is largely determined by edge contrast across the edge orthogonal to the grating, whereas the parallel edge has little or no influence. We suggest mechanisms that could explain this asymmetry.

The responses of V1 cortical neurons to flashed presentations of orthogonal single lines and edges.

How cortical neurons process multiple inputs is a fundamental issue in modern neuroscience. Neurons in visual cortical area V1 have been shown to exhibit cross-orientation suppression, where the response to an optimally oriented visual stimulus is reduced by the simultaneous presence of an orthogonally oriented stimulus. This is consistent with the view that cortical neurons respond to multiple inputs with a weighted average (or normalization) of the responses to the inputs presented separately. However, most of these studies have used drifting or counterphase-modulated grating stimuli, potentially confounding orientation effects with non-orientation-specific gain control mechanisms. Additionally, primate vision depends to a great extent on transient stimulus presentations during fixations between saccades. Therefore this study examined the responses of primate V1 neurons to orthogonal flashed-onset single edges and lines, and to their combinations. Single edges or lines do not typically cause strong suppression of the responses to an orthogonal stimulus, even though a grating does. This appears to hold true regardless of the relative contrasts of the orthogonal single lines or edges. This is consistent with response suppression from an orthogonal grating being due to non-orientation-specific contrast gain control (Koeling M, Shapley R, Shelley M. J Comp Neurosci 25: 390-400, 2008; Priebe NJ, Ferster D. Nat Neurosci 9: 552-561, 2006; Walker GA, Ohzawa I, Freeman RD. J.Neurophysiol 79: 227-239, 1998). While normalization mechanisms are clearly important for the cerebral cortex, under many conditions the responses of V1 cortical neurons to an optimally oriented stimulus can be unaffected by the presence of orthogonal stimuli, which may be important to avoid confounding the interpretation of a neural response.

A second life: Recycling production waste during the Middle Palaeolithic in layer L at Grotta del Cavallo (Lecce, Southeast Italy)

This paper presents the modalities of recycling in lithic assemblage in layer L at Grotta del Cavallo (Middle Palaeolithic, Southeast Italy). The layer exhibits a high diversity of exogenous (>50 km) and local (<5 Km) raw material, including marine shells for producing retouched tools. Recycling is attested in local raw material and in shell valves. I identified four recycling modalities, related to four object categories, and analysed each one separately: lithic retouched tools, macro tools, short products with sharp edges, and marine-shell tools with two orthogonal edges. I interpreted this behaviour in relation to a time-cost model. The aim was to evaluate the role of recycling in changing technological costs and to investigate if recycling was a planned strategy and how it was incorporated into the techno-economic organisation of the human group. The lithic assemblage displays a high spatio-temporal segmentation of productive sequences based on discoidal methods, the production of small flakes, the majority less than 3 cm in length, and a high technical investment in retouch. The results of the recycling cost-benefit analysis suggest that this behaviour was integrated into an economic setting regulated by time constrictions during tasks performed at the site within a logistic mobility. In this layer, recycling was an occasional behaviour, which allowed humans to respond to unplanned needs, and was facilitated by the low degree of volumetric constraints in the productive methods applied and by the short dimensions of the tools used. Recycling was an element that contributed to define the cultural entity, appearing as a specific trait in a given human group.

Evaluating the Cutting Mechanics of Woodworking Hand-Saw Teeth

The research detailed in this paper investigates the chip formation modes for woodworking handsaw teeth. Two tooth geometries (beveled and un-beveled) were evaluated using a single tooth rig. A high speed video camera was used to observe the chip formation in real time. For both tooth geometries the video footage provides evidence of a shearing mechanism cutting along the wood grain, and a bending mechanism cutting across the wood grain. Un-beveled teeth (with orthogonal edges) generally yield high cutting forces yet are very effective at removing material along the wood grain in a chisel like cutting action. Beveled teeth with sharp lateral edges generally yield low cutting forces and are well suited to severing the wood fibers perpendicular to the grain in a knife like cutting action.

A mixed-integer model for two-dimensional polyominoes strip packing and tiling problems

Two-dimensional irregular strip packing problem is one of the common cutting and packing problems, where it is required to assign (cut or pack) a set of 2D irregular-shaped items to a rectangular sheet. The sheet width is fixed, while its length is extendable and has to be minimised. In this paper, a new mixed-integer programming (MIP) model is introduced to optimally solve a special case of the problem, where item shapes are polygons with orthogonal edges, named polyominoes. Polyominoes strip packing may be classified as polyominoes tiling; a problem that can also be handled by the proposed model. Reasonable problem sizes (e.g. 45 polyominoes inside a 10 × 25 sheet) are solvable using an ordinary PC. Larger problem sizes are expected to be solvable when using state-of-the-art computational facilities. The model is also verified via a set of benchmark problems that are collected from the literature and provided optimal solution for all cases.

Historical photography-based computer-aided architectural design: Demolished buildings information modeling with reverse engineering functionality

This paper is about single three-point perspective historical photography-based CAAD modeling (amateur camera calibration, pose and 3-d reconstruction) of man-made environments, buildings and monuments, rich in geometrical regularity. The proposed method, gains profit from the presence in the image (historical photography) of three vanishing directions and two orthogonal object edges with known length ration, and then focuses on the graphical estimation of the skew intrinsic parameter of the uncalibrated camera (i.e. the angle of dot' s x and y optical axes, in photography plane), dealing in this way even with the skew presence case (non-rectangle dot). The presence of skew is not a negligible factor in historical photography of early 20th century years, due to dot optical axes failure (carelessness manufacturing) or collapse, as well as the twist effect (distortion) from the undocumented film development process in 1920s. The graphical recovery of the skew factor is the main contribution of the paper to the pose and CAAD literature. It is shown that a single three-point perspective amateur photography, even with the presence of skew, is adequate for calibration, pose and planar structure (building façades) recovery, if the usual in building's architecture geometric clues are present (i.e. planarity, orthogonality and parallelism) and some metric data (e.g. length and width of demolished building's dimensions) are available. The proposed method was validated on a simulated cuboid and demonstrated on a number of demolished historical buildings for which only one uncalibrated (and skewed) photography was available. The accuracy evaluation shows that the method is suitable for CAAD modeling applications regarding demolished buildings and monuments of the early 20th century years (2% relative accuracy, i.e. 40 cm for a 20 m façade, included the metric data inaccuracy). The method is of interest for architecture, archaeology, reverse engineering and virtual reality.

A Rich Discrete Labeling Scheme for Line Drawings of Curved Objects

We present a discrete labeling scheme for line drawings of curved objects which can be seen as an information-rich extension of the classic line-labeling scheme in which lines are classified as convex, concave, occluding or extremal. New labels are introduced to distinguish between curved and planar surface-patches, to identify orthogonal edges and to indicate gradient directions of planar surface-patches.

TEXTURE SEGREGATION AND TEXTURE TRANSPARENCY

This paper reviews the literature on texture segregation and texture transparency, and proposes a new account of texture transparency based on the theory of texture segregation. To date, it has been suggested that the perception of transparency might stem from perceptual grouping or spacing effects between texture elements. Based on recent data, this paper argues that texture transparency should be explained by a Filter-Rectify-Filter mechanism, which underlies texture segregation; the integration of collinear texture edges and the separation of orthogonal texture edges at texture-defined junctions are a critical factor in causing texture transparency. Moreover, outstanding problems with the theory of texture transparency were discussed in terms of the nature of second-order junctions, the time-course of overlaid texture surfaces, and synergetic effects by combining several visual attributes such as orientation and spatial frequency.