Rectangular Features Research Articles

Rectangular Patterns Using Block Copolymer Directed Assembly for High Bit Aspect Ratio Patterned Media

We report a nanofabrication method that combines block copolymer directed assembly with e-beam lithography to achieve highly uniform rectangular patterns with a critical dimension of 16 nm, a full pitch of 27 nm, and arbitrary aspect ratio. This fabrication method enables geometries that are not natural to block copolymer assembly, preserves both the feature uniformity and the center-to-center spacing of the original block copolymer, sustains long-range translational order, and facilitates high-resolution, high-density patterns through feature density multiplication. These highly uniform arrays of dense rectangular features are particularly attractive for fabricating magnetic bit patterned media with high bit aspect ratio.

Pose measurement of large non-cooperative satellite based on collaborative cameras

In recent years some communications satellites lost their ability due to the failure of mechanisms to deploy, which resulted in large cost. A space robotic system is expected to perform the on-orbit repairing mission. This is a tremendous challenge since the targets are generally non-cooperative, i.e. no facilities used for relative state measurement are mounted on the targets. Moreover these targets are very large. Limited by the FOV (field of view), a monocular camera cannot supply enough information of the targets in close range. In this paper, a method based on two collaborative cameras is proposed to determine the pose (position and orientation) of a large non-cooperative target. Firstly, we designed a sensing system used for the non-cooperative measurement, according to the investigation of the characteristics of communications satellites. A rectangular feature, which is common in the configuration of a satellite, is chosen as the recognized object. Secondly, we proposed that two cameras share the recognition task in a collaborative behavior, i.e. each provides partial image of the rectangle, and the full feature is then obtained by fusing their information. Lastly, the corresponding algorithm of image processing and pose measurement is addressed. Simulation results of typical cases verify the proposed approach.

Ingested pebbles causing abdominal radio-opaque shadows

Sir, We present a plain abdominal radiograph of 3 years and 7 months old boy with history of pica showing multiple small rounded radio-opaque shadows in sigmoid colon and descending colon. Similar shadows were seen in part of transverse and ascending colon. This boy had ingested small pebbles over a period of few days and presented with history of pain abdomen, abdominal distension and passing small pebbles in stools. He was referred to the department of surgery, Government medical college, Jammu where gradual per rectal manual evacuation of pebbles was done over a period of few days. When the plain abdominal radiograph shows multiple radio-opaque shadows, the possible differential diagnosis include multiple gall stones, urinary stones or multiple calcified lymphnodes, teratoma of mesentery, mesenteric fat necrosis and enteroliths. 1 In a child with such a radiograph, possibility of ingested foreign bodies must be kept in mind. Foreign body ingestion is seen in children of all age groups and there is a tendency in small children to ingest foreign material in curiosity. Thus, the incidence of foreign body is greatest in children aged 6 months to 4 years. 2-3 A similar abdominal radiograph may be seen in an adult and rarely in older child having enteroliths. Enteroliths are seen as multiple radio-opaque shadows of various shapes i.e, oval, round or rectangular with chronic abdominal symptoms. These shadows have dense rim with pale core of oval, round or rectangular features, coinend-on appearance and wide mobility. 1 Enteroliths are intestinal calculi formed due to stasis and are known to occur with tuberculosis but has uncommonly been reported from India. 4 Widespread abdominal lymph node calcification or diffuse peritoneal calcification due to abdominal tuberculosis also produce multiple radio-opaque shadows on plain abdominal radiograph. 5,6 Abdominal lymph node calcification is occasionally caused by histoplasmosis or rarely by paracoccidioidomycosis and other chronic granulomatous infections. Fat nodule calcification, hydatid infestation, phlebolith formation in hemangiomatosis or remainants of radio-opaque dye may also produce similar picture on plain abdominal radiograph. 7

Skew detection in document images based on rectangular active contour

The digitalization processes of documents produce frequently images with small rotation angles. The skew angles in document images degrade the performance of optical character recognition (OCR) tools. Therefore, skew detection of document images plays an important role in automatic document analysis systems. In this paper, we propose a Rectangular Active Contour Model (RAC Model) for content region detection and skew angle calculation by imposing a rectangular shape constraint on the zero-level set in Chan–Vese Model (C-V Model) according to the rectangular feature of content regions in document images. Our algorithm differs from other skew detection methods in that it does not rely on local image features. Instead, it uses global image features and shape constraint to obtain a strong robustness in detecting skew angles of document images. We experimented on different types of document images. Comparing the results with other skew detection algorithms, our algorithm is more accurate in detecting the skews of the complex document images with different fonts, tables, illustrations, and layouts. We do not need to pre-process the original image, even if it is noisy, and at the same time the rectangular content region of a document image is also detected.

Hydrostatic Optimization of Inkjet-Printed Films

In this work, we study the optimization of the geometry of inkjet-printed polymer films and develop a simple analytic framework to understand our results and establish limitations on inkjet-printed patterns. We show how drop spacing and ink concentration affect the thickness of a printed film and how hydrostatic conditions with contact angle hysteresis have to be considered to print optimized rectangular features. If advancing and receding contact angle are not taken into account, printed features will either bulge or break up into smaller beads. Thus, we provide a comprehensive analysis of the limits of film formation using regular assemblies of droplets.

사각형 특징 기반 분류기와 클래스 매칭을 이용한 실시간 얼굴 검출 및 인식

본 논문은 사각형 특징 기반 분류기를 제안하여 실시간으로 얼굴 영역을 검출하며, 계산의 효율성과 검출 성능을 동시에 만족시키는 강인한 검출 알고리즘을 구현하고자 한다. 제안한 알고리즘은 특징 생성, 분류기 학습, 실시간 얼굴 영역 검출의 세 단계로 구성된다. 특징 생성은 제안된 5개의 사각형 특징으로 특징 집합을 구성하며, SAT(Summed-Area Tables)를 이용하여 특징 값을 효율적으로 계산한다. 분류기 학습은 AdaBoost 알고리즘을 이용하여, 분류기를 계층적으로 생성한다. 또한 중요한 얼굴 패턴은 다음 레벨에 반복적으로 적용함으로써 우수한 검출 성능을 가진다. 실시간 얼굴 영역 검출은 생성된 사각형 특징 기반 분류기를 통해, 빠르고 효율적으로 얼굴 영역을 찾아낸다. 또한 얼굴 영역을 검출한 영역을 인식의 입력 영상으로 사용하여 PCA와 KNN 알고리즘을 이용하여 기존의 매칭 방법인 Point to point 방법이 아닌 Class to Class 방식을 이용하여 인식률을 향상시켰다. This paper proposes a classifier based on rectangular feature to detect face in real time. The goal is to realize a strong detection algorithm which satisfies both efficiency in calculation and detection performance. The proposed algorithm consists of the following three stages: Feature creation, classifier study and real time facial domain detection. Feature creation organizes a feature set with the proposed five rectangular features and calculates the feature values efficiently by using SAT (Summed-Area Tables). Classifier learning creates classifiers hierarchically by using the AdaBoost algorithm. In addition, it gets excellent detection performance by applying important face patterns repeatedly at the next level. Real time facial domain detection finds facial domains rapidly and efficiently through the classifier based on the rectangular feature that was created. Also, the recognition rate was improved by using the domain which detected a face domain as the input image and by using PCA and KNN algorithms and a Class to Class rather than the existing Point to Point technique.

Control of the microparticle position in the channel based on dielectrophoresis

We report here the control of the microparticles position within fluid flow based on its size by using dielectrophoresis (DEP) with a microelectrode array consisted of rectangular features with the different size of width and gap. 3 μm- and 10 μm-diameter particles were introduced into the channel with 300 μm height at 30 μl/min. An AC electric field (20 V peak–peak and 2 MHz) was then applied to microelectrode arrays to form dielectrophoretic fluid cage, resulting in a formation of flow paths with low electric fields on the arrays. The microparticles separately flow in line streams along the paths formed between the rectangular features of the arrays, the 3 μm-diameter particles mainly flow through the narrow path and 10 μm-diameter particles through the wide path. These results indicated that positions of two types of microparticles in the fluidic channel were easily separated and controlled using the n-DEP.

A Sparsity-Enforcing Method for Learning Face Features

In this paper, we propose a new trainable system for selecting face features from over-complete dictionaries of image measurements. The starting point is an iterative thresholding algorithm which provides sparse solutions to linear systems of equations. Although the proposed methodology is quite general and could be applied to various image classification tasks, we focus here on the case study of face and eyes detection. For our initial representation, we adopt rectangular features in order to allow straightforward comparisons with existing techniques. For computational efficiency and memory saving requirements, instead of implementing the full optimization scheme on tenths of thousands of features, we propose a three-stage architecture which consists of finding first intermediate solutions to smaller size optimization problems, then merging the obtained results, and next applying further selection procedures. The devised system requires the solution of a number of independent problems, and, hence, the necessary computations could be implemented in parallel. Experimental results obtained on both benchmark and newly acquired face and eyes images indicate that our method is a serious competitor to other feature selection schemes recently popularized in computer vision for dealing with problems of real-time object detection. A major advantage of the proposed system is that it performs well even with relatively small training sets.

View independent face detection based on horizontal rectangular features and accuracy improvement using combination kernel of various sizes

This paper proposes a view independent face detection method based on horizontal rectangular features, and accuracy improvement by combining kernels of various sizes. Since the view changes of faces induce large variation in appearance in the horizontal direction, local kernels are applied to horizontal rectangular regions to model such appearance changes. Local kernels are integrated by summation, and then used as a summation kernel for support vector machine (SVM). View independence is shown to be realized by the integration of local horizontal rectangular kernels. However, in general, local kernels (features) of various sizes have different similarity measures, such as detailed and rough similarity, and thus their error patterns are different. If the local and global kernels are combined well, the generalization ability is improved. This research demonstrates the comparative effectiveness of combining the global kernel and local kernels of various sizes as a summation kernel for SVM against use of only the global kernel, only the combination of local kernels and Adaboost with SVMs with a kind of local kernel.

Particle Assembly on Patterned Surfaces Bearing Circular (Dots) and Rectangular (Stripes) Surface Features

Irreversible and localized adsorption of spherical particles on surface features of various shapes (collectors) was studied using the random sequential adsorption (RSA) model. Collectors in the form of dots and rectangles were considered, including the two limiting cases of squares and stripes. Numerical simulation of the Monte Carlo type enabled one to determine particle configurations, average coverage of particles, and the distribution for various collector length to particle size ratios L = L/d and collector width to particle size ratios B = b/d. It was predicted that particle coverage under the jamming state was highly nonuniform, exhibiting a maximum at the center and at the periphery of the collectors. The averaged number of particles Np adsorbed at the jamming state was also determined as a function of the L and B parameters, as well as the averaged number of particles per unit length in the case of stripes. It was revealed that Np was the highest for the circular and square collectors (for a fixed value of L). On the other hand, for L > 5, our numerical results could be well approximated by the analytical expressions Np = thetainfinityL2 for circles, Np = 4thetainfinityL2/pi for squares, Np = 4thetainfinityBL/pi for rectangles, and Np = 4thetainfinityB/pi for stripes (per unit length). It was demonstrated that the theoretical results are in agreement with experimental data obtained for latex particles adsorbing on patterned surfaces obtained by a polymer-on-polymer stamping technique of gold covered silicon and on photolitographically patterned silane layers on silica.

Periodic Structures for Improved Light Management in Thin-film Silicon Solar Cells

AbstractAdvanced light management in thin-film solar cells is important in order to improve the photo-current and, thus, to raise up the conversion efficiencies of the solar cells. In this article two types of periodic structures ¡V one-dimensional diffraction gratings and photonic crystals,are analyzed in the direction of showing their potential for improved light trapping in thin-film silicon solar cells. The anti-reflective effects and enhanced scattering at the gratings with the triangular and rectangular features are studied by means of two-dimensional optical simulations. Simulations of the complete microcrystalline solar cell incorporating the gratings at all interfaces are presented. Critical optical issues to be overcome for achieving the performances of the cells with the optimized randomly textured interfaces are pointed out. Reflectance measurements for the designed 12 layer photonic crystal stack consisting of amorphous silicon nitride and amorphous silicon layers are presented and compared with the simulations. High reflectance (up to 99 %) of the stack is measured for a broad wavelength spectrum. By means of optical simulations the potential for using a simple photonic crystal structure as a back reflector in an amorphous silicon solar cell is demonstrated.

The structure of cobalt nanoparticles on Ge(001)

In this contribution we present scanning tunnelling microscopy (STM) and spectroscopy (STS) investigations on isolated cobalt clusters in contact with Ge(001). Mass-filtered nanoparticles with diameters ranging from 3 to 11 nm are generated using an arc cluster ion source (ACIS) and deposited under soft landing conditions (Ekin/atom < 0.5 eV). Since the tip radius is of the same order as the nanoparticle diameters the recorded STM images are significantly affected by tip folding. By means of the “blind reconstruction method" it is possible to approximate the tip shape. After a respective deconvolution of the image structural features of the particle facets become observable. According to the equilibrium shape of the clusters being a truncated octahedron in the size range under investigation, hexagonal and rectangular features appear in the images. STS is sensitive to occupied and unoccupied states near the Fermi level and reveals the existence of distinct states in the tunnelling conductivity of the substrate as well as on the clusters. The richly structured density of states of the germanium surface serves here as tip condition test. First measurements of the tunnelling conductivity of the CoN/Ge(001) are presented and discussed.

Ultrathin Poly(ethylene glycol) Monolayers Formed by Chemical Vapor Deposition on Silicon Substrates

Poly(ethylene glycol) (PEG) monolayer was formed through the chemisorption of a vapor phase organosilane. Photochemically cleaned silicon substrate covered with native oxide (SiO2/Si) was exposed to a vapor of an organosilane, that is, 2-(methoxy[polyethyleneoxy]propyl) trimethoxysilane (MPEOPS) for 1-7 h at 150 degrees C. The resulting sample surfaces became relatively hydrophobic showing a static water-contact angle of ca. 67 +/- 2 degrees and their thickness was ellipsometrically measured to be ca. 0.8 +/- 0.1 nm. Atomic force microscopy confirmed that the sample surface was extremely smooth and homogeneous. Isoelectric point of the MPEOPS-monolayer-covered SiO2/Si substrate was measured to be at around pH 4.9, which was close to that of the methoxytri(ethylene glycol)-terminated alkanethiol SAM on gold (pH 4.3). Furthermore, we demonstrated micropatterning of the MPEOPS monolayer based on a direct photolithography using 172 nm VUV light through a photomask. A well-defined microstructure composed of 5 microm x 25 microm rectangular features was successfully fabricated on a MPEOPS monolayer surface. Subsequently treated it by spatially defined CVD treatment using aminosilane molecule, binary microstructures composed of PEG and amino-terminated surfaces were successfully fabricated.

로봇과 인간의 상호작용을 위한 얼굴 표정 인식 및 얼굴 표정 생성 기법

In the last decade, face analysis, e.g. face detection, face recognition, facial expression recognition, is a very lively and expanding research field. As computer animated agents and robots bring a social dimension to human computer interaction, interest in this research field is increasing rapidly. In this paper, we introduce an artificial emotion mimic system which can recognize human facial expressions and also generate the recognized facial expression. In order to recognize human facial expression in real-time, we propose a facial expression classification method that is performed by weak classifiers obtained by using new rectangular feature types. In addition, we make the artificial facial expression using the developed robotic system based on biological observation. Finally, experimental results of facial expression recognition and generation are shown for the validity of our robotic system.

Scanning tunnelling microscopy with atomic resolution on the twofold surface of the icosahedral AlPdMn quasicrystal

We have investigated the 2-fold surface of an icosahedral Al70Pd21Mn9 quasicrystal by means of low-temperature scanning tunnelling microscopy (77 K). The sequence of the terrace step edge heights revealed a Fibonacci sequence with S = 2.40 Å and L = τS = 3.88 Å as fundamental terrace step heights. S and L can be related to the pentagon edge length of the below terrace Bergman polytope and the surface dissected Bergman polytope of the 5-fold surface. The atomic resolution STM images of the 2-fold surface have been compared to the M-model structure of the i-AlPdMn and the experimental STM surface structure of the 5-fold surface by analysis of the FFT spots. We could show that the positions of the FFT spots in the 2-fold surface are related to the FFT spots of the 5-fold surface by projections onto the fivefold axis and are in good correspondence to the model structure. We identified characteristic rectangular features on the 2-fold surface with edge length of 4.8, 7.7 and 12.6 Å corresponding to D2, τD2 and τ 2D2 with D2 being the pentagon edge length of the surface dissected Bergman polytope. We interpret our results as being a strong indication for the bulk termination of the 2-fold surface of the i-AlPdMn quasicrystal.

Dynamics of low capillary number interfaces moving through sharp features

The success of any nanoimprint process depends upon its ability to exactly reproduce the template pattern. Thus, complete filling of recessed features in the template is an important issue that is controlled by the dynamics of the flow through these sharp structures. At these small scales, capillary forces are large and must be included in the fluid flow model. The mechanism of interface advancement at low capillary number through sharp rectangular features is useful for understanding how and why features fill or trap air. In this study we present a two-dimensional simulation of this feature filling to capture the details of the process, including the viscous and capillary effects. Fluid is injected into the channel between the template and substrate, where the fluid–air interface soon encounters a rectangular feature with some height greater than the channel gap. As the fluid advances through the channel, the shape of the interface is a circular arc due to the strong capillary forces. The interface maintains this circular arc as it negotiates the first sharp corner of the feature; the upper contact line effectively pins to the initial corner of the feature as it moves around this corner, during which time the lower contact line continues to advance forward along the substrate surface, causing the interface to stretch. For sufficiently wide or shallow features, once the upper contact line has negotiated the first corner and has moved vertically up the inner wall of the feature, it must move through the top corner of the feature. At this point the interface undergoes a rapid reconfiguration from a high surface area circular arc to a lower surface area circular arc inside the feature. Alternatively, for narrow or high features, the stretched interface can catch on the far, final corner of the feature, trapping air inside the feature and preventing filling. The conditions for filling are studied parametrically for a variety of wetting contact angles and feature dimensions with both the simulation and a simpler, successful geometric model. The dynamics of the feature filling suggest an effective boundary condition for a macroscopic lubrication model of the imprint lithography process in which a critical pressure is required to move fluid through a feature.

Ultrahigh density microarrays of solid samples

We present a sectioning and bonding technology to make ultrahigh density microarrays of solid samples, cutting edge matrix assembly (CEMA). Maximized array density is achieved by a scaffold-free, self-supporting construction with rectangular array features that are incrementally scalable. This platform technology facilitates arrays of >10,000 tissue features on a standard glass slide, inclusion of unique sample identifiers for improved manual or automated tracking, and oriented arraying of stratified or polarized samples.

Robot navigation using panoramic tracking

A vision-based navigation system is presented for determining a mobile robot's position and orientation using panoramic imagery. Omni-directional sensors are useful in obtaining a 360° field of view, permitting various objects in the vicinity of a robot to be imaged simultaneously. Recognizing landmarks in a panoramic image from an a priori model of distinct features in an environment allows a robot's location information to be updated. A system is shown for tracking vertex and line features for omni-directional cameras constructed with catadioptric (containing both mirrors and lenses) optics. With the aid of the panoramic Hough transform, line features can be tracked without restricting the mirror geometry so that it satisfies the single viewpoint criteria. This allows the use of rectangular scene features to be used as landmarks. Two paradigms for localization are explored, with experiments conducted with synthetic and real images. A working implementation on a mobile robot is also shown.

Using geometric complexity to enhance the interfacial strength of heterogeneous structures fabricated in a multi-stage, multi-piece molding process

Interfaces in heterogeneous structures are typically engineered for optimal strength through the control of surface roughness and the choice of adhesives. Advances in manufacturing technologies are now making it possible to also tailor the geometries of interfaces from the nanoscale to the macroscale to create geometrically complex interfaces that exhibit enhanced performance characteristics. However, the impact of geometric complexity on the mechanical behavior of interfaces has not yet been ascertained. In this investigation, the first step is taken towards understanding the effects of geometric complexity on interfacial strength. A new multi-stage, multi-piece molding process is used to create heterogeneous polymer structures with geometrically complex interfaces consisting of rectangular and circular interlocking features. The structural integrity of these heterogeneous structures is characterized through interfacial tension testing. The full-field deformation measurement technique known as digital image correlation is also used during the testing to visualize the deformation fields around the geometrically complex features. Through this characterization, it is determined that the complex geometries increase the interfacial strength by approximately 20–25%, while reducing the statistical variation by 50%. These effects are attributed to a transition in the failure mechanism from interfacial fracture to homogeneous ligament failure. Results also indicate that geometrically complexity can be used on completely debonded interfaces to increase the strength to at least 25–35% of the bonded interface. Based on these results, some simple design rules have been proposed that enable geometrically complex interfaces to be engineered with enhanced strengths approaching the weaker of the two base materials. These design rules can also be used in the engineering of interfaces to facilitate the development of heterogeneous structures using new design paradigms, such as design for recyclability and the design of products based on bio-inspired concepts.

The use of nitrogen to disorder GaInP

Significant changes in microstructure, surface structure, and alloy composition have been observed in GaInP with the addition of nitrogen. These effects occur due to surface changes induced by small concentrations of nitrogen. Transmission electron microscopy and photoluminescence experiments indicate that the use of the surfactant N nearly eliminates the CuPtB ordered structure typically seen in organometallic vapor phase epitaxially grown Ga0.5In0.5P lattice matched to GaAs. In situ surface photoabsorption measurements show a large change in the surface structure indicating that N reduces the concentration of P dimers on the surface, decreasing the driving force for ordering. Nitrogen also has a significant effect on the Ga/In ratio in the bulk. The indium content in the solid is decreased by 71% with a DMHy/III ratio of 60 (DMHy—1,1 dimethyl hydrazine). Nitrogen roughens the surface causing the formation of hillocks and small rectangular features that can be up to 50 nm tall.