Angular Feature Research Articles

Registration for 3-D point cloud using angular-invariant feature

This paper proposes an angular-invariant feature for 3-D registration procedure to perform reliable selection of point correspondence. The feature is a k -dimensional vector, and each element within the vector is an angle between the normal vector and one of its k nearest neighbors. The angular feature is invariant to scale and rotation transformation, and is applicable for the surface with small curvature. The feature improves the convergence and error without any assumptions about the initial transformation. Besides, no strict sampling strategy is required. Experiments illustrate that the proposed angular-based algorithm is more effective than iterative closest point (ICP) and the curvature-based algorithm.

Textural and local spatial statistics for the object‐oriented classification of urban areas using high resolution imagery

Textural and local spatial statistical information is important in the classification of urban areas using very high resolution imagery. This paper describes the utility of textural and local spatial statistics for the improvement of object‐oriented classification for QuickBird imagery. All textural/spatial bands were used as additional bands in the supervised object‐oriented classification. The texture analysis is based on two levels: segmented image objects and moving windows across the whole image. In the texture analysis over image objects, the angular second moment textural feature at a 45° angle showed an improved classification performance with regard to buildings, depicting the patterns of buildings better than any other directions. The texture analysis based on moving windows across the whole image was conducted with various window sizes (from 3×3 to 13×13), and four grey‐level co‐occurrence matrix (GLCM) textural features (homogeneity, contrast, angular second moment, and entropy) were calculated. The contrast feature with the 7×7 window size improved classification up to 6%. One type of local spatial statistics, Moran's I feature with the vertical neighbourhood rule, improved the classification accuracy even further, up to 7%. Comparison of results between spectral and spectral+textural/spatial information indicated that textural and spatial information can be used to improve the object‐oriented classification of urban areas using very high resolution imagery.

Structures and Luminescent Properties of Seven Coordination Polymers of Zinc(II) and Cadmium(II) with 3,3′,4,4′-Benzophenone Tetracarboxylate Anion and Bis(imidazole)

Seven coordination polymers, namely [Zn(BPTC)0.5(L1)0.5(H2O)] (1), [Zn2(BPTC)(L2)]·H2O (2), [Zn2(BPTC)(L3)2]·3H2O (3), [Zn2.5(BPTC)(L4)(OH)(H2O)] (4), [Zn2(BPTC)(L5)(H2O)2]·3H2O (5), [Cd2(BPTC)(L5)(H2O)]·H2O (6), and [Cd(BPTC)0.5(L6)]·H2O (7), where L1 = 4,4′-bis(imidazol-1-ylmethyl)bibenzene, L2 = 4,4′-bis(imidazol-1-ylmethyl)benzene, L3 = 1,4-bis(imidazol-1-yl)butane, L4 = 1,4-bis(2-ethyl-imidazol-1-yl)butane, L5 = 1,3-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, L6 = 1,2-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, and BPTC = 3,3′,4,4′-benzophenone tetracarboxylate ligand, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. The structure of 1 exhibits a (4,6)-connected network with a (44·62)(44·610·8) topology formed by L1 ligands connecting BPTC−Zn sheets. The structure of 2 is a chiral 3D network in which there exists a Zn−O helical chain which may transmit the chirality to the whole framework. In compound 3, multicarboxylate ligands link L3−metal helical chains to generate a layer which is further connected by intermolecular H bonds to form a 3D supramolecular structure. In compound 4, the L4−Zn sheets are connected by BPTC pillars to generate a 3D framework with a distorted α-Po topology. Compound 5 shows infinite chains. Compound 6 shows two kinds of novel infinite chains which are linked by π−π stacking interactions to form 2D supramolecular sheets. Compound 7 is a (3,4)-connected framework with a (62·8)2(62·84) topology. The structural differences among 1–4 indicate the importance of the flexibility of the ligands (L1−L4) for the framework formation of the coordination polymers. By varying the angular feature of the ligands (L5 and L6), compounds 5–7 have been separated completely. In additon, the luminescent properties of these compounds are discussed.

805 円弧切欠き弾性ヒンジの変形特性に関する数値的検討(OS11-1,オーガナイズドセッション:11 機械要素の高度化と精密機構の性能向上)

805 円弧切欠き弾性ヒンジの変形特性に関する数値的検討(OS11-1,オーガナイズドセッション:11 機械要素の高度化と精密機構の性能向上)

Estratigrafia de seqüências da plataforma mista neogênica na Bacia Potiguar, Margem Equatorial Brasileira

The aim of this paper is the tertiary mixed siliciclastic-carbonate platform in the Potiguar Basin. The main goal is to address answers to some questions about mixed siliciclastic-carbonate settings, such as depositional shelf dynamics, lateral and vertical facies and their response to sea level variations, questions that have seldom been dealt with or published. The study area covers over 2500 km 2 , it is located in the basin’s submersed portion, it has as its offshore limit the 200 m bathymetry and it concentrates only on the coastal, shelf and upper slope facies. The section of this study comprises part of the Neogenic sedimentary rocks, which is composed of three lithostratigraphic units known as the Tibau Formation (sandstones and conglomerates), the Guamare Formation (limestones), and the Ubarana Formation (marine shales). These units make up a large regressive cycle, starting at the Late Campanian through to Holocene. They form a seaward thickening coastal-shelf-slope-basin system. The present paper focuses on a section deposited on the shelf after an Early Miocene erosional unconformity whose angular feature is easily recognized in the submersed portion of the Potiguar Basin, as well as in other basins on the Brazilian coast. The method used in the present study was the integrated stratigraphic analysis, based on sequence stratigraphy concepts through seismic stratigraphy, well logs and biostratigraphy. The integrated approach of the data allowed a subdivision of the section under study in 3 rd order depositional sequences, which were detailed in system tracts and higher frequency sequences. The stratigraphic framework obtained allowed for the proposal of a more refined depositional model for the Neogenic mixed platforms in the area under this study.

Iterative Angular Feature Extraction (IAFE) Method for Reverse Engineering

Extracting exact features from noisy point data is an important problem, in practice, for the application of reverse engineering. Several feature extraction methods have been used to handle noisy point data, such as the "angular" method and the "chordal" method. They work well for most cases, but the generation of extra features cannot be avoided for some cases. A new feature extraction method that deals with noisy scanned point data is proposed in this paper. We call it the iterative angular feature extraction (IAFE) method, since it extends the concept of the angular method. The IAFE method first distinguishes the feature regions from point clouds, then the iterative algorithm is applied to refine each feature region into ultimate feature points. A "noise dilution" concept is used to reduce the noise effect. A "multiple point" algorithm, an "angle variation" algorithm and an "iterations for convergence" algorithm are developed to implement the noise dilution concept. The IAFE(I) method for planar models and the IAFE(II) method for curved models are designed. The IAFE method demonstrated its usefulness in dealing with noisy point data.

Process Tolerance Control in a 2D Angular Tolerance Chart

The main tasks of tolerance charting include the identification of dimensional chains, the calculation of mean working dimensions, and the allocation of proper tolerances to the working dimensions for all machining cuts. When an angular featured component is involved, tolerance charting becomes very difficult because the axial dimensions are interrelated with the radial dimensions due to the angular feature. The purpose of this paper is to accomplish the above three tasks in a 2D tolerance chart, constructed for a component with an angular feature. With the algebraic method, the reverse chain matrix, which contains the reverse tolerance chains, is obtained first and the mean working dimensions are determined from the reverse chain matrix. The forward chain matrix for the forward tolerance chains is then obtained by inversing the reverse chain matrix. Thereafter, by using the forward chain matrix in a linear programming model, the tolerances are optimally allocated to the working dimensions. A numerical example is given in the paper.

Optical angular mapping for pattern recognition using self-pumped phase conjugation

An optical angular feature mapping of an object for pattern recognition is presented that uses self-pumped phase conjugation followed by a vertical projection. In this method the vertical contour features of an object are most enhanced and vertically projected at each angle as the object is rotated. The vertical enhancement of the contour and the projection are performed optically with self-pumped phase conjugation and a cylindrical lens, respectively. The peaks in the resulting projection at the angle are located and integrated to produce an angular signature function. The signature function is then energy normalized for scale invariance, and pattern recognition is performed by calculation of a cross correlation between two signature functions. The method exhibits invariance to shift, rotation, and variations in scale. Effects of a spatial filter and incident-beam conditions used for phase conjugation are also discussed along with experimental results.

Angular feature mapping: an optical method

An optical method is demonstrated where the angles at which line segments in a pattern intersect are estimated and mapped.

Seismic Stratigraphy in Low-Energy Carbonate Depositional Environment: ABSTRACT

Seismic stratigraphic mapping in carbonate rocks has been historically concentrated on the shelf margin environment where unit geometry and abrupt facies-velocity changes are often easily discernible with the seismic tool. In contrast, low-energy, more subtle shelf interior stratigraphic features have attracted less geophysical attention. This report describes the study of seismic data from five United States oil fields which produce from reservoirs formed from shelf interior deposits. Three Smackover fields, a Permian basin producer, and a Williston basin example are compared. Review of the depositional model indicates the difficulty of seismic mapping in non-reef carbonates. If sedimentary accretion is nearly vertical, porosity traps are predicted to exhibit only lateral change in unit velocity. In regressive or transgressive sequences, the geologic model indicates that angular discordance due to sediment buildup in combination with a velocity contrast generates an angular feature that has a different velocity pattern. These five fields provide examples of both trap types. Jay field (Florida) and Walker Creek field (Arkansas) both produce from the Smackover Formation and are (seismic-defined) stratigraphic traps which illustrate angular discordance and velocity contrast owing to regressive buildup. The trapping mechanism at Big Escambia Creek (Alabama), also productive from the Smackover, is from a transgressive pulse devoid of vertical buildup. Hence, the porosity trap is indicated only by a lateral velocity change without angular discordance. Subsurface geologic sections of San Andres production End_Page 798------------------------------ at Cato San Andres field (New Mexico) and Mission Canyon pay at Haas field (North Dakota) reveal no diachronous buildup. As expected these fields demonstrate only a lateral change in velocity within the formation. Application of stratigraphic-seismic techniques to low-energy carbonate facies can fall into two depositionally controlled divisions. When sediment accretes vertically, traps are mapped solely by lateral changes in velocity. Sedimentary buildup in transgressive or regressive sequences provides angularity, which combined with velocity contrast facilitates seismic detection of the trap. End_of_Article - Last_Page 799------------

Transform Faulting in the Thai Peninsula

RECENT mapping by a joint UK/Thai team of geologists1, operating under the Colombo Plan, has shown that the angular elbow-like feature in the Phuket area of peninsular Thailand projecting into the Andaman Sea is the physiographic expression of two major transcurrent faults with a total sinistral displacement of at least 200 km.