95,706 research outputs found

    Overcomplete steerable pyramid filters and rotation invariance

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    A given (overcomplete) discrete oriented pyramid may be converted into a steerable pyramid by interpolation. We present a technique for deriving the optimal interpolation functions (otherwise called 'steering coefficients'). The proposed scheme is demonstrated on a computationally efficient oriented pyramid, which is a variation on the Burt and Adelson (1983) pyramid. We apply the generated steerable pyramid to orientation-invariant texture analysis in order to demonstrate its excellent rotational isotropy. High classification rates and precise rotation identification are demonstrated

    Improving Bag-of-Words model with spatial information

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    Bag-of-Words (BOW) models have recently become popular for the task of object recognition, owing to their good performance and simplicity. Much work has been proposed over the years to improve the BOW model, where the Spatial Pyramid Matching technique is the most notable. In this work, we propose three novel techniques to capture more re_ned spatial information between image features than that provided by the Spatial Pyramids. Our techniques demonstrate a performance gain over the Spatial Pyramid representation of the BOW model

    Laser cooling with a single laser beam and a planar diffractor

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    A planar triplet of diffraction gratings is used to transform a single laser beam into a four-beam tetrahedral magneto-optical trap. This `flat' pyramid diffractor geometry is ideal for future microfabrication. We demonstrate the technique by trapping and subsequently sub-Doppler cooling 87Rb atoms to 30microKelvin.Comment: 3 pages, 4 figure

    Enhanced spatial pyramid matching using log-polar-based image subdivision and representation

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    This paper presents a new model for capturing spatial information for object categorization with bag-of-words (BOW). BOW models have recently become popular for the task of object recognition, owing to their good performance and simplicity. Much work has been proposed over the years to improve the BOW model, where the Spatial Pyramid Matching (SPM) technique is the most notable. We propose a new method to exploit spatial relationships between image features, based on binned log-polar grids. Our model works by partitioning the image into grids of different scales and orientations and computing histogram of local features within each grid. Experimental results show that our approach improves the results on three diverse datasets over the SPM technique

    Fabrication of pyramidal probes with various periodic patterns and a single nanopore

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    The nanometer-scale patterned pyramidal probe with an electron beam-induced nanopore on the pyramid apex is an excellent candidate for an optical biosensor. The nanoapertures surrounded with various periodic groove patterns on the pyramid sides were fabricated using a focused ion beam technique, where the optical characteristics of the fabricated apertures with rectangular, circular, and elliptical groove patterns were investigated. The elliptical groove patterns on the pyramid were designed to maintain an identical distance between the grooves and the apex for the surface waves and, among the three patterns, the authors observed the highest optical transmission from the elliptically patterned pyramidal probe. A 103-fold increase of the transmitted optical intensity was observed after patterning with elliptical grooves, even without an aperture on the pyramid apex. The nanopore on the apex of the pyramid was fabricated using electron beam irradiation and was optically characterized

    High-Dimensional Spatio-Temporal Indexing

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    There exist numerous indexing methods which handle either spatio-temporal or high-dimensional data well. However, those indexing methods which handle spatio-temporal data well have certain drawbacks when confronted with high-dimensional data. As the most efficient spatio-temporal indexing methods are based on the R-tree and its variants, they face the well known problems in high-dimensional space. Furthermore, most high-dimensional indexing methods try to reduce the number of dimensions in the data being indexed and compress the information given by all dimensions into few dimensions but are not able to store now - relative data. One of the most efficient high-dimensional indexing methods, the Pyramid Technique, is able to handle high-dimensional point-data only. Nonetheless, we take this technique and extend it such that it is able to handle spatio-temporal data as well. We introduce a technique for querying in this structure with spatio-temporal queries. We compare our technique, the Spatio-Temporal Pyramid Adapter (STPA), to the RST-tree for in-memory and on-disk applications. We show that for high dimensions, the extra query-cost for reducing the dimensionality in the Pyramid Technique is clearly exceeded by the rising query-cost in the RST-tree. Concluding, we address the main drawbacks and advantages of our technique

    IMPROVING STUDENTSā€™ WRITING SKILL USING PYRAMID STRATEGY (A CLASSROOM ACTION RESEARCH AT THE FIRST YEAR OF MTS MUHAMMADIYAH BLIMBING SUKOHARJO)

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    This study is aimed to describe the process of improving studentā€™s writing skill using pyramid strategy in MTs Muhammadiyah Blimbing Sukoharjo and find whether teaching writing using pyramid strategy can improve the studentsā€™ writing ability. The result of the study is expected to contribute to the teaching learning of writing. The study was implemented in MTs Muhammadiyah Blimbing Sukoharjo, especially class VIA using action research. The researcher took 25 students as the subject of research. The object of the research was implementation of pyramid strategy in MTs Muhammadiyah Blimbing Sukoharjo. The researcher gets the data of this research from teaching, event, informant, and document. The techniques of collecting data are observation, test, document and interview. The result of the study shows that pyramid strategy technique is appropiate and quite effective for teaching writing. The studentsā€™ motivation improves and maintains in teaching learning process of writing. By using this technique, the students are capable of writing a composition easily. They are enthusiasthic, interested, and motivated in the classroom, because the teacher used kinds of interesting material such as story to encourage the students to involve in teaching learning process
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